Imported Upstream version 1.66.0upstream/1.66.0

14 files changed, 8072 insertions, 0 deletions

diff --git a/boost/beast/http/impl/basic_parser.ipp b/boost/beast/http/impl/basic_parser.ipp
new file mode 100644
index 0000000000..355a76fb16
--- /dev/null
+++ b/boost/beast/http/impl/basic_parser.ipp
@@ -0,0 +1,928 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_BASIC_PARSER_IPP
+#define BOOST_BEAST_HTTP_IMPL_BASIC_PARSER_IPP
+
+#include <boost/beast/core/static_string.hpp>
+#include <boost/beast/core/type_traits.hpp>
+#include <boost/beast/core/detail/clamp.hpp>
+#include <boost/beast/core/detail/config.hpp>
+#include <boost/beast/http/error.hpp>
+#include <boost/beast/http/rfc7230.hpp>
+#include <boost/asio/buffer.hpp>
+#include <boost/make_unique.hpp>
+#include <algorithm>
+#include <utility>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+template<bool isRequest, class Derived>
+template<class OtherDerived>
+basic_parser<isRequest, Derived>::
+basic_parser(basic_parser<
+        isRequest, OtherDerived>&& other)
+    : body_limit_(other.body_limit_)
+    , len_(other.len_)
+    , buf_(std::move(other.buf_))
+    , buf_len_(other.buf_len_)
+    , skip_(other.skip_)
+    , header_limit_(other.header_limit_)
+    , status_(other.status_)
+    , state_(other.state_)
+    , f_(other.f_)
+{
+}
+
+template<bool isRequest, class Derived>
+bool
+basic_parser<isRequest, Derived>::
+keep_alive() const
+{
+    BOOST_ASSERT(is_header_done());
+    if(f_ & flagHTTP11)
+    {
+        if(f_ & flagConnectionClose)
+            return false;
+    }
+    else
+    {
+        if(! (f_ & flagConnectionKeepAlive))
+            return false;
+    }
+    return (f_ & flagNeedEOF) == 0;
+}
+
+template<bool isRequest, class Derived>
+boost::optional<std::uint64_t>
+basic_parser<isRequest, Derived>::
+content_length() const
+{
+    BOOST_ASSERT(is_header_done());
+    if(! (f_ & flagContentLength))
+        return boost::none;
+    return len_;
+}
+
+template<bool isRequest, class Derived>
+void
+basic_parser<isRequest, Derived>::
+skip(bool v)
+{
+    BOOST_ASSERT(! got_some());
+    if(v)
+        f_ |= flagSkipBody;
+    else
+        f_ &= ~flagSkipBody;
+}
+
+template<bool isRequest, class Derived>
+template<class ConstBufferSequence>
+std::size_t
+basic_parser<isRequest, Derived>::
+put(ConstBufferSequence const& buffers,
+    error_code& ec)
+{
+    static_assert(boost::asio::is_const_buffer_sequence<
+        ConstBufferSequence>::value,
+            "ConstBufferSequence requirements not met");
+    using boost::asio::buffer_copy;
+    using boost::asio::buffer_size;
+    auto const p = boost::asio::buffer_sequence_begin(buffers);
+    auto const last = boost::asio::buffer_sequence_end(buffers);
+    if(p == last)
+    {
+        ec.assign(0, ec.category());
+        return 0;
+    }
+    if(std::next(p) == last)
+    {
+        // single buffer
+        return put(boost::asio::const_buffer(*p), ec);
+    }
+    auto const size = buffer_size(buffers);
+    if(size <= max_stack_buffer)
+        return put_from_stack(size, buffers, ec);
+    if(size > buf_len_)
+    {
+        // reallocate
+        buf_ = boost::make_unique_noinit<char[]>(size);
+        buf_len_ = size;
+    }
+    // flatten
+    buffer_copy(boost::asio::buffer(
+        buf_.get(), buf_len_), buffers);
+    return put(boost::asio::const_buffer{
+        buf_.get(), buf_len_}, ec);
+}
+
+template<bool isRequest, class Derived>
+std::size_t
+basic_parser<isRequest, Derived>::
+put(boost::asio::const_buffer const& buffer,
+    error_code& ec)
+{
+    BOOST_ASSERT(state_ != state::complete);
+    using boost::asio::buffer_size;
+    auto p = reinterpret_cast<
+        char const*>(buffer.data());
+    auto n = buffer.size();
+    auto const p0 = p;
+    auto const p1 = p0 + n;
+    ec.assign(0, ec.category());
+loop:
+    switch(state_)
+    {
+    case state::nothing_yet:
+        if(n == 0)
+        {
+            ec = error::need_more;
+            return 0;
+        }
+        state_ = state::start_line;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case state::start_line:
+    {
+        maybe_need_more(p, n, ec);
+        if(ec)
+            goto done;
+        parse_start_line(p, p + (std::min<std::size_t>)(
+            header_limit_, n), ec, is_request{});
+        if(ec)
+        {
+            if(ec == error::need_more)
+            {
+                if(n >= header_limit_)
+                {
+                    ec = error::header_limit;
+                    goto done;
+                }
+                if(p + 3 <= p1)
+                    skip_ = static_cast<
+                        std::size_t>(p1 - p - 3);
+            }
+            goto done;
+        }
+        BOOST_ASSERT(! is_done());
+        n = static_cast<std::size_t>(p1 - p);
+        if(p >= p1)
+        {
+            ec = error::need_more;
+            goto done;
+        }
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case state::fields:
+        maybe_need_more(p, n, ec);
+        if(ec)
+            goto done;
+        parse_fields(p, p + (std::min<std::size_t>)(
+            header_limit_, n), ec);
+        if(ec)
+        {
+            if(ec == error::need_more)
+            {
+                if(n >= header_limit_)
+                {
+                    ec = error::header_limit;
+                    goto done;
+                }
+                if(p + 3 <= p1)
+                    skip_ = static_cast<
+                        std::size_t>(p1 - p - 3);
+            }
+            goto done;
+        }
+        finish_header(ec, is_request{});
+        break;
+
+    case state::body0:
+        BOOST_ASSERT(! skip_);
+        impl().on_body_init_impl(content_length(), ec);
+        if(ec)
+            goto done;
+        state_ = state::body;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case state::body:
+        BOOST_ASSERT(! skip_);
+        parse_body(p, n, ec);
+        if(ec)
+            goto done;
+        break;
+
+    case state::body_to_eof0:
+        BOOST_ASSERT(! skip_);
+        impl().on_body_init_impl(content_length(), ec);
+        if(ec)
+            goto done;
+        state_ = state::body_to_eof;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case state::body_to_eof:
+        BOOST_ASSERT(! skip_);
+        parse_body_to_eof(p, n, ec);
+        if(ec)
+            goto done;
+        break;
+
+    case state::chunk_header0:
+        impl().on_body_init_impl(content_length(), ec);
+        if(ec)
+            goto done;
+        state_ = state::chunk_header;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case state::chunk_header:
+        parse_chunk_header(p, n, ec);
+        if(ec)
+            goto done;
+        break;
+
+    case state::chunk_body:
+        parse_chunk_body(p, n, ec);
+        if(ec)
+            goto done;
+        break;
+
+    case state::complete:
+        ec.assign(0, ec.category());
+        goto done;
+    }
+    if(p < p1 && ! is_done() && eager())
+    {
+        n = static_cast<std::size_t>(p1 - p);
+        goto loop;
+    }
+done:
+    return static_cast<std::size_t>(p - p0);
+}
+
+template<bool isRequest, class Derived>
+void
+basic_parser<isRequest, Derived>::
+put_eof(error_code& ec)
+{
+    BOOST_ASSERT(got_some());
+    if( state_ == state::start_line ||
+        state_ == state::fields)
+    {
+        ec = error::partial_message;
+        return;
+    }
+    if(f_ & (flagContentLength | flagChunked))
+    {
+        if(state_ != state::complete)
+        {
+            ec = error::partial_message;
+            return;
+        }
+        ec.assign(0, ec.category());
+        return;
+    }
+    impl().on_finish_impl(ec);
+    if(ec)
+        return;
+    state_ = state::complete;
+}
+
+template<bool isRequest, class Derived>
+template<class ConstBufferSequence>
+std::size_t
+basic_parser<isRequest, Derived>::
+put_from_stack(std::size_t size,
+    ConstBufferSequence const& buffers,
+        error_code& ec)
+{
+    char buf[max_stack_buffer];
+    using boost::asio::buffer;
+    using boost::asio::buffer_copy;
+    buffer_copy(buffer(buf, sizeof(buf)), buffers);
+    return put(boost::asio::const_buffer{
+        buf, size}, ec);
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+maybe_need_more(
+    char const* p, std::size_t n,
+        error_code& ec)
+{
+    if(skip_ == 0)
+        return;
+    if( n > header_limit_)
+        n = header_limit_;
+    if(n < skip_ + 4)
+    {
+        ec = error::need_more;
+        return;
+    }
+    auto const term =
+        find_eom(p + skip_, p + n);
+    if(! term)
+    {
+        skip_ = n - 3;
+        if(skip_ + 4 > header_limit_)
+        {
+            ec = error::header_limit;
+            return;
+        }
+        ec = error::need_more;
+        return;
+    }
+    skip_ = 0;
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+parse_start_line(
+    char const*& in, char const* last,
+    error_code& ec, std::true_type)
+{
+/*
+    request-line   = method SP request-target SP HTTP-version CRLF
+    method         = token
+*/
+    auto p = in;
+
+    string_view method;
+    parse_method(p, last, method, ec);
+    if(ec)
+        return;
+
+    string_view target;
+    parse_target(p, last, target, ec);
+    if(ec)
+        return;
+
+    int version = 0;
+    parse_version(p, last, version, ec);
+    if(ec)
+        return;
+    if(version < 10 || version > 11)
+    {
+        ec = error::bad_version;
+        return;
+    }
+
+    if(p + 2 > last)
+    {
+        ec = error::need_more;
+        return;
+    }
+    if(p[0] != '\r' || p[1] != '\n')
+    {
+        ec = error::bad_version;
+        return;
+    }
+    p += 2;
+
+    if(version >= 11)
+        f_ |= flagHTTP11;
+
+    impl().on_request_impl(string_to_verb(method),
+        method, target, version, ec);
+    if(ec)
+        return;
+
+    in = p;
+    state_ = state::fields;
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+parse_start_line(
+    char const*& in, char const* last,
+    error_code& ec, std::false_type)
+{
+/*
+     status-line    = HTTP-version SP status-code SP reason-phrase CRLF
+     status-code    = 3*DIGIT
+     reason-phrase  = *( HTAB / SP / VCHAR / obs-text )
+*/
+    auto p = in;
+
+    int version = 0;
+    parse_version(p, last, version, ec);
+    if(ec)
+        return;
+    if(version < 10 || version > 11)
+    {
+        ec = error::bad_version;
+        return;
+    }
+
+    // SP
+    if(p + 1 > last)
+    {
+        ec = error::need_more;
+        return;
+    }
+    if(*p++ != ' ')
+    {
+        ec = error::bad_version;
+        return;
+    }
+
+    parse_status(p, last, status_, ec);
+    if(ec)
+        return;
+
+    // parse reason CRLF
+    string_view reason;
+    parse_reason(p, last, reason, ec);
+    if(ec)
+        return;
+
+    if(version >= 11)
+        f_ |= flagHTTP11;
+
+    impl().on_response_impl(
+        status_, reason, version, ec);
+    if(ec)
+        return;
+
+    in = p;
+    state_ = state::fields;
+}
+
+template<bool isRequest, class Derived>
+void
+basic_parser<isRequest, Derived>::
+parse_fields(char const*& in,
+    char const* last, error_code& ec)
+{
+    string_view name;
+    string_view value;
+    // https://stackoverflow.com/questions/686217/maximum-on-http-header-values
+    static_string<max_obs_fold> buf;
+    auto p = in;
+    for(;;)
+    {
+        if(p + 2 > last)
+        {
+            ec = error::need_more;
+            return;
+        }
+        if(p[0] == '\r')
+        {
+            if(p[1] != '\n')
+                ec = error::bad_line_ending;
+            in = p + 2;
+            return;
+        }
+        parse_field(p, last, name, value, buf, ec);
+        if(ec)
+            return;
+        auto const f = string_to_field(name);
+        do_field(f, value, ec);
+        if(ec)
+            return;
+        impl().on_field_impl(f, name, value, ec);
+        if(ec)
+            return;
+        in = p;
+    }
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+finish_header(error_code& ec, std::true_type)
+{
+    // RFC 7230 section 3.3
+    // https://tools.ietf.org/html/rfc7230#section-3.3
+
+    if(f_ & flagSkipBody)
+    {
+        state_ = state::complete;
+    }
+    else if(f_ & flagContentLength)
+    {
+        if(len_ > body_limit_)
+        {
+            ec = error::body_limit;
+            return;
+        }
+        if(len_ > 0)
+        {
+            f_ |= flagHasBody;
+            state_ = state::body0;
+        }
+        else
+        {
+            state_ = state::complete;
+        }
+    }
+    else if(f_ & flagChunked)
+    {
+        f_ |= flagHasBody;
+        state_ = state::chunk_header0;
+    }
+    else
+    {
+        len_ = 0;
+        state_ = state::complete;
+    }
+
+    impl().on_header_impl(ec);
+    if(ec)
+        return;
+    if(state_ == state::complete)
+    {
+        impl().on_finish_impl(ec);
+        if(ec)
+            return;
+    }
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+finish_header(error_code& ec, std::false_type)
+{
+    // RFC 7230 section 3.3
+    // https://tools.ietf.org/html/rfc7230#section-3.3
+
+    if( (f_ & flagSkipBody) ||  // e.g. response to a HEAD request
+        status_  / 100 == 1 ||   // 1xx e.g. Continue
+        status_ == 204 ||        // No Content
+        status_ == 304)          // Not Modified
+    {
+        // VFALCO Content-Length may be present, but we
+        //        treat the message as not having a body.
+        //        https://github.com/boostorg/beast/issues/692
+        state_ = state::complete;
+    }
+    else if(f_ & flagContentLength)
+    {
+        if(len_ > body_limit_)
+        {
+            ec = error::body_limit;
+            return;
+        }
+        if(len_ > 0)
+        {
+            f_ |= flagHasBody;
+            state_ = state::body0;
+        }
+        else
+        {
+            state_ = state::complete;
+        }
+    }
+    else if(f_ & flagChunked)
+    {
+        f_ |= flagHasBody;
+        state_ = state::chunk_header0;
+    }
+    else
+    {
+        f_ |= flagHasBody;
+        f_ |= flagNeedEOF;
+        state_ = state::body_to_eof0;
+    }
+
+    impl().on_header_impl(ec);
+    if(ec)
+        return;
+    if(state_ == state::complete)
+    {
+        impl().on_finish_impl(ec);
+        if(ec)
+            return;
+    }
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+parse_body(char const*& p,
+    std::size_t n, error_code& ec)
+{
+    n = impl().on_body_impl(string_view{p,
+        beast::detail::clamp(len_, n)}, ec);
+    p += n;
+    len_ -= n;
+    if(ec)
+        return;
+    if(len_ > 0)
+        return;
+    impl().on_finish_impl(ec);
+    if(ec)
+        return;
+    state_ = state::complete;
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+parse_body_to_eof(char const*& p,
+    std::size_t n, error_code& ec)
+{
+    if(n > body_limit_)
+    {
+        ec = error::body_limit;
+        return;
+    }
+    body_limit_ = body_limit_ - n;
+    n = impl().on_body_impl(string_view{p, n}, ec);
+    p += n;
+    if(ec)
+        return;
+}
+
+template<bool isRequest, class Derived>
+void
+basic_parser<isRequest, Derived>::
+parse_chunk_header(char const*& p0,
+    std::size_t n, error_code& ec)
+{
+/*
+    chunked-body   = *chunk last-chunk trailer-part CRLF
+
+    chunk          = chunk-size [ chunk-ext ] CRLF chunk-data CRLF
+    last-chunk     = 1*("0") [ chunk-ext ] CRLF
+    trailer-part   = *( header-field CRLF )
+
+    chunk-size     = 1*HEXDIG
+    chunk-data     = 1*OCTET ; a sequence of chunk-size octets
+    chunk-ext      = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
+    chunk-ext-name = token
+    chunk-ext-val  = token / quoted-string
+*/
+
+    auto p = p0;
+    auto const pend = p + n;
+    char const* eol;
+
+    if(! (f_ & flagFinalChunk))
+    {
+        if(n < skip_ + 2)
+        {
+            ec = error::need_more;
+            return;
+        }
+        if(f_ & flagExpectCRLF)
+        {
+            // Treat the last CRLF in a chunk as
+            // part of the next chunk, so p can
+            // be parsed in one call instead of two.
+            if(! parse_crlf(p))
+            {
+                ec = error::bad_chunk;
+                return;
+            }
+        }
+        eol = find_eol(p0 + skip_, pend, ec);
+        if(ec)
+            return;
+        if(! eol)
+        {
+            ec = error::need_more;
+            skip_ = n - 1;
+            return;
+        }
+        skip_ = static_cast<
+            std::size_t>(eol - 2 - p0);
+
+        std::uint64_t size;
+        if(! parse_hex(p, size))
+        {
+            ec = error::bad_chunk;
+            return;
+        }
+        if(size != 0)
+        {
+            if(size > body_limit_)
+            {
+                ec = error::body_limit;
+                return;
+            }
+            body_limit_ -= size;
+            auto const start = p;
+            parse_chunk_extensions(p, pend, ec);
+            if(ec)
+                return;
+            if(p != eol -2 )
+            {
+                ec = error::bad_chunk_extension;
+                return;
+            }
+            auto const ext = make_string(start, p);
+            impl().on_chunk_header_impl(size, ext, ec);
+            if(ec)
+                return;
+            len_ = size;
+            skip_ = 2;
+            p0 = eol;
+            f_ |= flagExpectCRLF;
+            state_ = state::chunk_body;
+            return;
+        }
+
+        f_ |= flagFinalChunk;
+    }
+    else
+    {
+        BOOST_ASSERT(n >= 5);
+        if(f_ & flagExpectCRLF)
+            BOOST_VERIFY(parse_crlf(p));
+        std::uint64_t size;
+        BOOST_VERIFY(parse_hex(p, size));
+        eol = find_eol(p, pend, ec);
+        BOOST_ASSERT(! ec);
+    }
+
+    auto eom = find_eom(p0 + skip_, pend);
+    if(! eom)
+    {
+        BOOST_ASSERT(n >= 3);
+        skip_ = n - 3;
+        ec = error::need_more;
+        return;
+    }
+
+    auto const start = p;
+    parse_chunk_extensions(p, pend, ec);
+    if(ec)
+        return;
+    if(p != eol - 2)
+    {
+        ec = error::bad_chunk_extension;
+        return;
+    }
+    auto const ext = make_string(start, p);
+    impl().on_chunk_header_impl(0, ext, ec);
+    if(ec)
+        return;
+    p = eol;
+    parse_fields(p, eom, ec);
+    if(ec)
+        return;
+    BOOST_ASSERT(p == eom);
+    p0 = eom;
+
+    impl().on_finish_impl(ec);
+    if(ec)
+        return;
+    state_ = state::complete;
+}
+
+template<bool isRequest, class Derived>
+inline
+void
+basic_parser<isRequest, Derived>::
+parse_chunk_body(char const*& p,
+    std::size_t n, error_code& ec)
+{
+    n = impl().on_chunk_body_impl(
+        len_, string_view{p,
+            beast::detail::clamp(len_, n)}, ec);
+    p += n;
+    len_ -= n;
+    if(len_ == 0)
+        state_ = state::chunk_header;
+}
+
+template<bool isRequest, class Derived>
+void
+basic_parser<isRequest, Derived>::
+do_field(field f,
+    string_view value, error_code& ec)
+{
+    // Connection
+    if(f == field::connection ||
+        f == field::proxy_connection)
+    {
+        auto const list = opt_token_list{value};
+        if(! validate_list(list))
+        {
+            // VFALCO Should this be a field specific error?
+            ec = error::bad_value;
+            return;
+        }
+        for(auto const& s : list)
+        {
+            if(iequals({"close", 5}, s))
+            {
+                f_ |= flagConnectionClose;
+                continue;
+            }
+
+            if(iequals({"keep-alive", 10}, s))
+            {
+                f_ |= flagConnectionKeepAlive;
+                continue;
+            }
+
+            if(iequals({"upgrade", 7}, s))
+            {
+                f_ |= flagConnectionUpgrade;
+                continue;
+            }
+        }
+        ec.assign(0, ec.category());
+        return;
+    }
+
+    // Content-Length
+    if(f == field::content_length)
+    {
+        if(f_ & flagContentLength)
+        {
+            // duplicate
+            ec = error::bad_content_length;
+            return;
+        }
+
+        if(f_ & flagChunked)
+        {
+            // conflicting field
+            ec = error::bad_content_length;
+            return;
+        }
+
+        std::uint64_t v;
+        if(! parse_dec(
+            value.begin(), value.end(), v))
+        {
+            ec = error::bad_content_length;
+            return;
+        }
+
+        ec.assign(0, ec.category());
+        len_ = v;
+        f_ |= flagContentLength;
+        return;
+    }
+
+    // Transfer-Encoding
+    if(f == field::transfer_encoding)
+    {
+        if(f_ & flagChunked)
+        {
+            // duplicate
+            ec = error::bad_transfer_encoding;
+            return;
+        }
+
+        if(f_ & flagContentLength)
+        {
+            // conflicting field
+            ec = error::bad_transfer_encoding;
+            return;
+        }
+
+        ec.assign(0, ec.category());
+        auto const v = token_list{value};
+        auto const p = std::find_if(v.begin(), v.end(),
+            [&](typename token_list::value_type const& s)
+            {
+                return iequals({"chunked", 7}, s);
+            });
+        if(p == v.end())
+            return;
+        if(std::next(p) != v.end())
+            return;
+        len_ = 0;
+        f_ |= flagChunked;
+        return;
+    }
+
+    // Upgrade
+    if(f == field::upgrade)
+    {
+        ec.assign(0, ec.category());
+        f_ |= flagUpgrade;
+        return;
+    }
+
+    ec.assign(0, ec.category());
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/chunk_encode.ipp b/boost/beast/http/impl/chunk_encode.ipp
new file mode 100644
index 0000000000..51296041f7
--- /dev/null
+++ b/boost/beast/http/impl/chunk_encode.ipp
@@ -0,0 +1,707 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_CHUNK_ENCODE_IPP
+#define BOOST_BEAST_HTTP_IMPL_CHUNK_ENCODE_IPP
+
+#include <boost/beast/core/detail/varint.hpp>
+#include <boost/beast/http/error.hpp>
+#include <boost/beast/http/detail/rfc7230.hpp>
+#include <algorithm>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+inline
+chunk_header::
+chunk_header(std::size_t size)
+    : view_(
+        size,
+        boost::asio::const_buffer{nullptr, 0},
+        chunk_crlf{})
+{
+    BOOST_ASSERT(size > 0);
+}
+
+inline
+chunk_header::
+chunk_header(
+    std::size_t size,
+    string_view extensions)
+    : view_(
+        size,
+        boost::asio::const_buffer{
+            extensions.data(), extensions.size()},
+        chunk_crlf{})
+{
+    BOOST_ASSERT(size > 0);
+}
+
+template<class ChunkExtensions, class>
+chunk_header::
+chunk_header(
+    std::size_t size,
+    ChunkExtensions&& extensions)
+    : exts_(std::make_shared<detail::chunk_extensions_impl<
+        typename std::decay<ChunkExtensions>::type>>(
+            std::forward<ChunkExtensions>(extensions)))
+    , view_(
+        size,
+        exts_->str(),
+        chunk_crlf{})
+{
+    static_assert(
+        detail::is_chunk_extensions<ChunkExtensions>::value,
+        "ChunkExtensions requirements not met");
+    BOOST_ASSERT(size > 0);
+}
+
+template<class ChunkExtensions, class Allocator, class>
+chunk_header::
+chunk_header(
+    std::size_t size,
+    ChunkExtensions&& extensions,
+    Allocator const& allocator)
+    : exts_(std::allocate_shared<detail::chunk_extensions_impl<
+        typename std::decay<ChunkExtensions>::type>>(allocator,
+            std::forward<ChunkExtensions>(extensions)))
+    , view_(
+        size,
+        exts_->str(),
+        chunk_crlf{})
+{
+    static_assert(
+        detail::is_chunk_extensions<ChunkExtensions>::value,
+        "ChunkExtensions requirements not met");
+    BOOST_ASSERT(size > 0);
+}
+
+//------------------------------------------------------------------------------
+
+template<class ConstBufferSequence>
+chunk_body<ConstBufferSequence>::
+chunk_body(ConstBufferSequence const& buffers)
+    : view_(
+        boost::asio::buffer_size(buffers),
+        boost::asio::const_buffer{nullptr, 0},
+        chunk_crlf{},
+        buffers,
+        chunk_crlf{})
+{
+}
+
+template<class ConstBufferSequence>
+chunk_body<ConstBufferSequence>::
+chunk_body(
+    ConstBufferSequence const& buffers,
+    string_view extensions)
+    : view_(
+        boost::asio::buffer_size(buffers),
+        boost::asio::const_buffer{
+            extensions.data(), extensions.size()},
+        chunk_crlf{},
+        buffers,
+        chunk_crlf{})
+{
+}
+
+template<class ConstBufferSequence>
+template<class ChunkExtensions, class>
+chunk_body<ConstBufferSequence>::
+chunk_body(
+    ConstBufferSequence const& buffers,
+    ChunkExtensions&& extensions)
+    : exts_(std::make_shared<detail::chunk_extensions_impl<
+        typename std::decay<ChunkExtensions>::type>>(
+            std::forward<ChunkExtensions>(extensions)))
+    , view_(
+        boost::asio::buffer_size(buffers),
+        exts_->str(),
+        chunk_crlf{},
+        buffers,
+        chunk_crlf{})
+{
+}
+
+template<class ConstBufferSequence>
+template<class ChunkExtensions, class Allocator, class>
+chunk_body<ConstBufferSequence>::
+chunk_body(
+    ConstBufferSequence const& buffers,
+    ChunkExtensions&& extensions,
+    Allocator const& allocator)
+    : exts_(std::allocate_shared<detail::chunk_extensions_impl<
+        typename std::decay<ChunkExtensions>::type>>(allocator,
+            std::forward<ChunkExtensions>(extensions)))
+    , view_(
+        boost::asio::buffer_size(buffers),
+        exts_->str(),
+        chunk_crlf{},
+        buffers,
+        chunk_crlf{})
+{
+}
+
+//------------------------------------------------------------------------------
+
+template<class Trailer>
+template<class Allocator>
+auto
+chunk_last<Trailer>::
+prepare(Trailer const& trailer, Allocator const& allocator) ->
+    buffers_type
+{
+    auto sp = std::allocate_shared<typename
+        Trailer::writer>(allocator, trailer);
+    sp_ = sp;
+    return sp->get();
+}
+
+template<class Trailer>
+auto
+chunk_last<Trailer>::
+prepare(Trailer const& trailer, std::true_type) ->
+    buffers_type
+{
+    auto sp = std::make_shared<
+        typename Trailer::writer>(trailer);
+    sp_ = sp;
+    return sp->get();
+}
+
+template<class Trailer>
+auto
+chunk_last<Trailer>::
+prepare(Trailer const& trailer, std::false_type) ->
+    buffers_type
+{
+    return trailer;
+}
+
+template<class Trailer>
+chunk_last<Trailer>::
+chunk_last()
+    : view_(
+        detail::chunk_size0{},
+        Trailer{})
+{
+}
+
+template<class Trailer>
+chunk_last<Trailer>::
+chunk_last(Trailer const& trailer)
+    : view_(
+        detail::chunk_size0{},
+        prepare(trailer, is_fields<Trailer>{}))
+{
+}
+
+template<class Trailer>
+template<class DeducedTrailer, class Allocator, class>
+chunk_last<Trailer>::
+chunk_last(
+    DeducedTrailer const& trailer, Allocator const& allocator)
+    : view_(
+        detail::chunk_size0{},
+        prepare(trailer, allocator))
+{
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+class basic_chunk_extensions<Allocator>::const_iterator
+{
+    friend class basic_chunk_extensions;
+
+    using iter_type = char const*;
+
+    iter_type it_;
+    typename basic_chunk_extensions::value_type value_;
+
+    explicit
+    const_iterator(iter_type it)
+        : it_(it)
+    {
+    }
+
+    void
+    increment();
+
+public:
+    using value_type = typename
+        basic_chunk_extensions::value_type;
+    using pointer = value_type const*;
+    using reference = value_type const&;
+    using difference_type = std::ptrdiff_t;
+    using iterator_category =
+        std::forward_iterator_tag;
+
+    const_iterator() = default;
+    const_iterator(const_iterator&& other) = default;
+    const_iterator(const_iterator const& other) = default;
+    const_iterator& operator=(const_iterator&& other) = default;
+    const_iterator& operator=(const_iterator const& other) = default;
+
+    bool
+    operator==(const_iterator const& other) const
+    {
+        return it_ == other.it_;
+    }
+
+    bool
+    operator!=(const_iterator const& other) const
+    {
+        return !(*this == other);
+    }
+
+    reference
+    operator*();
+
+    pointer
+    operator->()
+    {
+        return &(**this);
+    }
+
+    const_iterator&
+    operator++()
+    {
+        increment();
+        return *this;
+    }
+
+    const_iterator
+    operator++(int)
+    {
+        auto temp = *this;
+        increment();
+        return temp;
+    }
+};
+
+template<class Allocator>
+void
+basic_chunk_extensions<Allocator>::
+const_iterator::
+increment()
+{
+    using beast::detail::varint_read;
+    auto n = varint_read(it_);
+    it_ += n;
+    n = varint_read(it_);
+    it_ += n;
+}
+
+template<class Allocator>
+auto
+basic_chunk_extensions<Allocator>::
+const_iterator::
+operator*() ->
+    reference
+{
+    using beast::detail::varint_read;
+    auto it = it_;
+    auto n = varint_read(it);
+    value_.first = string_view{it, n};
+    it += n;
+    n = varint_read(it);
+    value_.second = string_view{it, n};
+    return value_;
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+template<class FwdIt>
+FwdIt
+basic_chunk_extensions<Allocator>::
+do_parse(FwdIt it, FwdIt last, error_code& ec)
+{
+/*
+    chunk-ext       = *( BWS  ";" BWS chunk-ext-name [ BWS  "=" BWS chunk-ext-val ] )
+    BWS             = *( SP / HTAB ) ; "Bad White Space"
+    chunk-ext-name  = token
+    chunk-ext-val   = token / quoted-string
+    token           = 1*tchar
+    quoted-string   = DQUOTE *( qdtext / quoted-pair ) DQUOTE
+    qdtext          = HTAB / SP / "!" / %x23-5B ; '#'-'[' / %x5D-7E ; ']'-'~' / obs-text
+    quoted-pair     = "\" ( HTAB / SP / VCHAR / obs-text )
+    obs-text        = %x80-FF
+
+    https://www.rfc-editor.org/errata_search.php?rfc=7230&eid=4667
+*/
+    using beast::detail::varint_size;
+    using beast::detail::varint_write;
+    using CharT = char;
+    using Traits = std::char_traits<CharT>;
+    range_.reserve(static_cast<std::size_t>(
+        std::distance(it, last) * 1.2));
+    range_.resize(0);
+    auto const emit_string =
+        [this](FwdIt from, FwdIt to)
+        {
+            auto const len =
+                std::distance(from, to);
+            auto const offset = range_.size();
+            range_.resize(
+                offset +
+                varint_size(len) +
+                len);
+            auto dest = &range_[offset];
+            varint_write(dest, len);
+            Traits::copy(dest, from, len);
+        };
+    auto const emit_string_plus_empty =
+        [this](FwdIt from, FwdIt to)
+        {
+            auto const len =
+                std::distance(from, to);
+            auto const offset = range_.size();
+            range_.resize(
+                offset +
+                varint_size(len) +
+                len +
+                varint_size(0));
+            auto dest = &range_[offset];
+            varint_write(dest, len);
+            Traits::copy(dest, from, len);
+            dest += len;
+            varint_write(dest, 0);
+        };
+    auto const emit_empty_string =
+        [this]
+        {
+            auto const offset = range_.size();
+            range_.resize(offset + varint_size(0));
+            auto dest = &range_[offset];
+            varint_write(dest, 0);
+        };
+loop:
+    if(it == last)
+    {
+        ec.assign(0, ec.category());
+        return it;
+    }
+    // BWS
+    if(*it == ' ' || *it == '\t')
+    {
+        for(;;)
+        {
+            ++it;
+            if(it == last)
+            {
+                ec = error::bad_chunk_extension;
+                return it;
+            }
+            if(*it != ' ' && *it != '\t')
+                break;
+        }
+    }
+    // ';'
+    if(*it != ';')
+    {
+        ec = error::bad_chunk_extension;
+        return it;
+    }
+semi:
+    ++it; // skip ';'
+    // BWS
+    for(;;)
+    {
+        if(it == last)
+        {
+            ec = error::bad_chunk_extension;
+            return it;
+        }
+        if(*it != ' ' && *it != '\t')
+            break;
+        ++it;
+    }
+    // chunk-ext-name
+    {
+        if(! detail::is_token_char(*it))
+        {
+            ec = error::bad_chunk_extension;
+            return it;
+        }
+        auto const first = it;
+        for(;;)
+        {
+            ++it;
+            if(it == last)
+            {
+                emit_string_plus_empty(first, it);
+                return it;
+            }
+            if(! detail::is_token_char(*it))
+                break;
+        }
+        emit_string(first, it);
+    }
+    // BWS [ ";" / "=" ]
+    for(;;)
+    {
+        if(*it != ' ' && *it != '\t')
+            break;
+        ++it;
+        if(it == last)
+        {
+            ec = error::bad_chunk_extension;
+            return it;
+        }
+    }
+    if(*it == ';')
+    {
+        emit_empty_string();
+        goto semi;
+    }
+    if(*it != '=')
+    {
+        ec = error::bad_chunk_extension;
+        return it;
+    }
+    ++it; // skip '='
+    // BWS
+    for(;;)
+    {
+        if(it == last)
+        {
+            ec = error::bad_chunk_extension;
+            return it;
+        }
+        if(*it != ' ' && *it != '\t')
+            break;
+        ++it;
+    }
+    // chunk-ext-val
+    if(*it != '"')
+    {
+        // token
+        if(! detail::is_token_char(*it))
+        {
+            ec = error::bad_chunk_extension;
+            return it;
+        }
+        auto const first = it;
+        for(;;)
+        {
+            ++it;
+            if(it == last)
+                break;
+            if(! detail::is_token_char(*it))
+                break;
+        }
+        emit_string(first, it);
+        if(it == last)
+            return it;
+    }
+    else
+    {
+        // quoted-string
+        auto const first = ++it; // skip DQUOTE
+        // first pass, count chars
+        std::size_t len = 0;
+        for(;;)
+        {
+            if(it == last)
+            {
+                ec = error::bad_chunk_extension;
+                return it;
+            }
+            if(*it == '"')
+                break;
+            if(*it == '\\')
+            {
+                ++it;
+                if(it == last)
+                {
+                    ec = error::bad_chunk_extension;
+                    return it;
+                }
+            }
+            ++len;
+            ++it;
+        }
+        // now build the string
+        auto const offset = range_.size();
+        range_.resize(
+            offset +
+            varint_size(len) +
+            len);
+        auto dest = &range_[offset];
+        varint_write(dest, len);
+        it = first;
+        for(;;)
+        {
+            BOOST_ASSERT(it != last);
+            if(*it == '"')
+                break;
+            if(*it == '\\')
+            {
+                ++it;
+                BOOST_ASSERT(it != last);
+            }
+            Traits::assign(*dest++, *it++);
+        }
+        ++it; // skip DQUOTE
+    }
+    goto loop;
+}
+
+template<class Allocator>
+void
+basic_chunk_extensions<Allocator>::
+do_insert(string_view name, string_view value)
+{
+/*
+    chunk-ext       = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
+    chunk-ext-name  = token
+    chunk-ext-val   = token / quoted-string
+    token           = 1*tchar
+    quoted-string   = DQUOTE *( qdtext / quoted-pair ) DQUOTE
+    qdtext          = HTAB / SP / "!" / %x23-5B ; '#'-'[' / %x5D-7E ; ']'-'~' / obs-text
+    quoted-pair     = "\" ( HTAB / SP / VCHAR / obs-text )
+    obs-text        = %x80-FF
+*/
+    if(value.empty())
+    {
+        s_.reserve(1 + name.size());
+        s_.push_back(';');
+        s_.append(name.data(), name.size());
+        return;
+    }
+
+    bool is_token = true;
+    for(auto const c : value)
+    {
+        if(! detail::is_token_char(c))
+        {
+            is_token = false;
+            break;
+        }
+    }
+    if(is_token)
+    {
+        // token
+        s_.reserve(1 + name.size() + 1 + value.size());
+        s_.push_back(';');
+        s_.append(name.data(), name.size());
+        s_.push_back('=');
+        s_.append(value.data(), value.size());
+    }
+    else
+    {
+        // quoted-string
+        s_.reserve(
+            1 + name.size() + 1 +
+            1 + value.size() + 20 + 1);
+        s_.push_back(';');
+        s_.append(name.data(), name.size());
+        s_.append("=\"", 2);
+        for(auto const c : value)
+        {
+            if(c == '\\')
+                s_.append(R"(\\)", 2);
+            else if(c == '\"')
+                s_.append(R"(\")", 2);
+            else
+                s_.push_back(c);
+        }
+        s_.push_back('"');
+    }
+}
+
+template<class Allocator>
+void
+basic_chunk_extensions<Allocator>::
+parse(string_view s, error_code& ec)
+{
+    do_parse(s.data(), s.data() + s.size(), ec);
+    if(! ec)
+    {
+        s_.clear();
+        for(auto const& v : *this)
+            do_insert(v.first, v.second);
+    }
+}
+
+template<class Allocator>
+void
+basic_chunk_extensions<Allocator>::
+insert(string_view name)
+{
+    do_insert(name, {});
+
+    using beast::detail::varint_size;
+    using beast::detail::varint_write;
+    auto const offset = range_.size();
+    range_.resize(
+        offset +
+        varint_size(name.size()) +
+        name.size() +
+        varint_size(0));
+    auto dest = &range_[offset];
+    varint_write(dest, name.size());
+    std::memcpy(dest, name.data(), name.size());
+    dest += name.size();
+    varint_write(dest, 0);
+}
+
+template<class Allocator>
+void
+basic_chunk_extensions<Allocator>::
+insert(string_view name, string_view value)
+{
+    do_insert(name, value);
+
+    using beast::detail::varint_size;
+    using beast::detail::varint_write;
+    auto const offset = range_.size();
+    range_.resize(
+        offset +
+        varint_size(name.size()) +
+        name.size() +
+        varint_size(value.size()) +
+        value.size());
+    auto dest = &range_[offset];
+    varint_write(dest, name.size());
+    std::memcpy(dest, name.data(), name.size());
+    dest += name.size();
+    varint_write(dest, value.size());
+    std::memcpy(dest, value.data(), value.size());
+}
+
+template<class Allocator>
+inline
+auto
+basic_chunk_extensions<Allocator>::
+begin() const ->
+    const_iterator
+{
+    return const_iterator{range_.data()};
+}
+
+template<class Allocator>
+inline
+auto
+basic_chunk_extensions<Allocator>::
+end() const ->
+    const_iterator
+{
+    return const_iterator{
+        range_.data() + range_.size()};
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/error.ipp b/boost/beast/http/impl/error.ipp
new file mode 100644
index 0000000000..45075f5c18
--- /dev/null
+++ b/boost/beast/http/impl/error.ipp
@@ -0,0 +1,120 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_ERROR_IPP
+#define BOOST_BEAST_HTTP_IMPL_ERROR_IPP
+
+#include <type_traits>
+
+namespace boost {
+
+namespace system {
+template<>
+struct is_error_code_enum<beast::http::error>
+{
+    static bool const value = true;
+};
+} // system
+
+namespace beast {
+namespace http {
+namespace detail {
+
+class http_error_category : public error_category
+{
+public:
+    const char*
+    name() const noexcept override
+    {
+        return "beast.http";
+    }
+
+    std::string
+    message(int ev) const override
+    {
+        switch(static_cast<error>(ev))
+        {
+        case error::end_of_stream: return "end of stream";
+        case error::partial_message: return "partial message";
+        case error::need_more: return "need more";
+        case error::unexpected_body: return "unexpected body";
+        case error::need_buffer: return "need buffer";
+        case error::end_of_chunk: return "end of chunk";
+        case error::buffer_overflow: return "buffer overflow";
+        case error::header_limit: return "header limit exceeded";
+        case error::body_limit: return "body limit exceeded";
+        case error::bad_alloc: return "bad alloc";
+        case error::bad_line_ending: return "bad line ending";
+        case error::bad_method: return "bad method";
+        case error::bad_target: return "bad target";
+        case error::bad_version: return "bad version";
+        case error::bad_status: return "bad status";
+        case error::bad_reason: return "bad reason";
+        case error::bad_field: return "bad field";
+        case error::bad_value: return "bad value";
+        case error::bad_content_length: return "bad Content-Length";
+        case error::bad_transfer_encoding: return "bad Transfer-Encoding";
+        case error::bad_chunk: return "bad chunk";
+        case error::bad_chunk_extension: return "bad chunk extension";
+        case error::bad_obs_fold: return "bad obs-fold";
+
+        default:
+            return "beast.http error";
+        }
+    }
+
+    error_condition
+    default_error_condition(
+        int ev) const noexcept override
+    {
+        return error_condition{ev, *this};
+    }
+
+    bool
+    equivalent(int ev,
+        error_condition const& condition
+            ) const noexcept override
+    {
+        return condition.value() == ev &&
+            &condition.category() == this;
+    }
+
+    bool
+    equivalent(error_code const& error,
+        int ev) const noexcept override
+    {
+        return error.value() == ev &&
+            &error.category() == this;
+    }
+};
+
+inline
+error_category const&
+get_http_error_category()
+{
+    static http_error_category const cat{};
+    return cat;
+}
+
+} // detail
+
+inline
+error_code
+make_error_code(error ev)
+{
+    return error_code{
+        static_cast<std::underlying_type<error>::type>(ev),
+            detail::get_http_error_category()};
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/field.ipp b/boost/beast/http/impl/field.ipp
new file mode 100644
index 0000000000..8da470ff24
--- /dev/null
+++ b/boost/beast/http/impl/field.ipp
@@ -0,0 +1,561 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_FIELD_IPP
+#define BOOST_BEAST_HTTP_IMPL_FIELD_IPP
+
+#include <boost/beast/core/string.hpp>
+#include <algorithm>
+#include <array>
+#include <unordered_map>
+#include <vector>
+#include <boost/assert.hpp>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+namespace detail {
+
+struct field_table
+{
+    using array_type =
+        std::array<string_view, 352>;
+
+    struct hash
+    {
+        std::size_t
+        operator()(string_view s) const
+        {
+            auto const n = s.size();
+            return
+                beast::detail::ascii_tolower(s[0]) *
+                beast::detail::ascii_tolower(s[n/2]) ^
+                beast::detail::ascii_tolower(s[n-1]);   // hist[] = 331, 10, max_load_factor = 0.15f
+        }
+    };
+
+    struct iequal
+    {
+        // assumes inputs have equal length
+        bool
+        operator()(
+            string_view lhs,
+            string_view rhs) const
+        {
+            auto p1 = lhs.data();
+            auto p2 = rhs.data();
+            auto pend = lhs.end();
+            char a, b;
+            while(p1 < pend)
+            {
+                a = *p1++;
+                b = *p2++;
+                if(a != b)
+                    goto slow;
+            }
+            return true;
+
+            while(p1 < pend)
+            {
+            slow:
+                if( beast::detail::ascii_tolower(a) !=
+                    beast::detail::ascii_tolower(b))
+                    return false;
+                a = *p1++;
+                b = *p2++;
+            }
+            return true;
+        }
+    };
+
+    using map_type = std::unordered_map<
+        string_view, field, hash, iequal>;
+
+    array_type by_name_;
+    std::vector<map_type> by_size_;
+/*
+    From:
+    
+    https://www.iana.org/assignments/message-headers/message-headers.xhtml
+*/
+    field_table()
+        : by_name_({{
+            "<unknown-field>",
+            "A-IM",
+            "Accept",
+            "Accept-Additions",
+            "Accept-Charset",
+            "Accept-Datetime",
+            "Accept-Encoding",
+            "Accept-Features",
+            "Accept-Language",
+            "Accept-Patch",
+            "Accept-Post",
+            "Accept-Ranges",
+            "Access-Control",
+            "Access-Control-Allow-Credentials",
+            "Access-Control-Allow-Headers",
+            "Access-Control-Allow-Methods",
+            "Access-Control-Allow-Origin",
+            "Access-Control-Max-Age",
+            "Access-Control-Request-Headers",
+            "Access-Control-Request-Method",
+            "Age",
+            "Allow",
+            "ALPN",
+            "Also-Control",
+            "Alt-Svc",
+            "Alt-Used",
+            "Alternate-Recipient",
+            "Alternates",
+            "Apparently-To",
+            "Apply-To-Redirect-Ref",
+            "Approved",
+            "Archive",
+            "Archived-At",
+            "Article-Names",
+            "Article-Updates",
+            "Authentication-Control",
+            "Authentication-Info",
+            "Authentication-Results",
+            "Authorization",
+            "Auto-Submitted",
+            "Autoforwarded",
+            "Autosubmitted",
+            "Base",
+            "Bcc",
+            "Body",
+            "C-Ext",
+            "C-Man",
+            "C-Opt",
+            "C-PEP",
+            "C-PEP-Info",
+            "Cache-Control",
+            "CalDAV-Timezones",
+            "Cancel-Key",
+            "Cancel-Lock",
+            "Cc",
+            "Close",
+            "Comments",
+            "Compliance",
+            "Connection",
+            "Content-Alternative",
+            "Content-Base",
+            "Content-Description",
+            "Content-Disposition",
+            "Content-Duration",
+            "Content-Encoding",
+            "Content-features",
+            "Content-ID",
+            "Content-Identifier",
+            "Content-Language",
+            "Content-Length",
+            "Content-Location",
+            "Content-MD5",
+            "Content-Range",
+            "Content-Return",
+            "Content-Script-Type",
+            "Content-Style-Type",
+            "Content-Transfer-Encoding",
+            "Content-Type",
+            "Content-Version",
+            "Control",
+            "Conversion",
+            "Conversion-With-Loss",
+            "Cookie",
+            "Cookie2",
+            "Cost",
+            "DASL",
+            "Date",
+            "Date-Received",
+            "DAV",
+            "Default-Style",
+            "Deferred-Delivery",
+            "Delivery-Date",
+            "Delta-Base",
+            "Depth",
+            "Derived-From",
+            "Destination",
+            "Differential-ID",
+            "Digest",
+            "Discarded-X400-IPMS-Extensions",
+            "Discarded-X400-MTS-Extensions",
+            "Disclose-Recipients",
+            "Disposition-Notification-Options",
+            "Disposition-Notification-To",
+            "Distribution",
+            "DKIM-Signature",
+            "DL-Expansion-History",
+            "Downgraded-Bcc",
+            "Downgraded-Cc",
+            "Downgraded-Disposition-Notification-To",
+            "Downgraded-Final-Recipient",
+            "Downgraded-From",
+            "Downgraded-In-Reply-To",
+            "Downgraded-Mail-From",
+            "Downgraded-Message-Id",
+            "Downgraded-Original-Recipient",
+            "Downgraded-Rcpt-To",
+            "Downgraded-References",
+            "Downgraded-Reply-To",
+            "Downgraded-Resent-Bcc",
+            "Downgraded-Resent-Cc",
+            "Downgraded-Resent-From",
+            "Downgraded-Resent-Reply-To",
+            "Downgraded-Resent-Sender",
+            "Downgraded-Resent-To",
+            "Downgraded-Return-Path",
+            "Downgraded-Sender",
+            "Downgraded-To",
+            "EDIINT-Features",
+            "Eesst-Version",
+            "Encoding",
+            "Encrypted",
+            "Errors-To",
+            "ETag",
+            "Expect",
+            "Expires",
+            "Expiry-Date",
+            "Ext",
+            "Followup-To",
+            "Forwarded",
+            "From",
+            "Generate-Delivery-Report",
+            "GetProfile",
+            "Hobareg",
+            "Host",
+            "HTTP2-Settings",
+            "If",
+            "If-Match",
+            "If-Modified-Since",
+            "If-None-Match",
+            "If-Range",
+            "If-Schedule-Tag-Match",
+            "If-Unmodified-Since",
+            "IM",
+            "Importance",
+            "In-Reply-To",
+            "Incomplete-Copy",
+            "Injection-Date",
+            "Injection-Info",
+            "Jabber-ID",
+            "Keep-Alive",
+            "Keywords",
+            "Label",
+            "Language",
+            "Last-Modified",
+            "Latest-Delivery-Time",
+            "Lines",
+            "Link",
+            "List-Archive",
+            "List-Help",
+            "List-ID",
+            "List-Owner",
+            "List-Post",
+            "List-Subscribe",
+            "List-Unsubscribe",
+            "List-Unsubscribe-Post",
+            "Location",
+            "Lock-Token",
+            "Man",
+            "Max-Forwards",
+            "Memento-Datetime",
+            "Message-Context",
+            "Message-ID",
+            "Message-Type",
+            "Meter",
+            "Method-Check",
+            "Method-Check-Expires",
+            "MIME-Version",
+            "MMHS-Acp127-Message-Identifier",
+            "MMHS-Authorizing-Users",
+            "MMHS-Codress-Message-Indicator",
+            "MMHS-Copy-Precedence",
+            "MMHS-Exempted-Address",
+            "MMHS-Extended-Authorisation-Info",
+            "MMHS-Handling-Instructions",
+            "MMHS-Message-Instructions",
+            "MMHS-Message-Type",
+            "MMHS-Originator-PLAD",
+            "MMHS-Originator-Reference",
+            "MMHS-Other-Recipients-Indicator-CC",
+            "MMHS-Other-Recipients-Indicator-To",
+            "MMHS-Primary-Precedence",
+            "MMHS-Subject-Indicator-Codes",
+            "MT-Priority",
+            "Negotiate",
+            "Newsgroups",
+            "NNTP-Posting-Date",
+            "NNTP-Posting-Host",
+            "Non-Compliance",
+            "Obsoletes",
+            "Opt",
+            "Optional",
+            "Optional-WWW-Authenticate",
+            "Ordering-Type",
+            "Organization",
+            "Origin",
+            "Original-Encoded-Information-Types",
+            "Original-From",
+            "Original-Message-ID",
+            "Original-Recipient",
+            "Original-Sender",
+            "Original-Subject",
+            "Originator-Return-Address",
+            "Overwrite",
+            "P3P",
+            "Path",
+            "PEP",
+            "Pep-Info",
+            "PICS-Label",
+            "Position",
+            "Posting-Version",
+            "Pragma",
+            "Prefer",
+            "Preference-Applied",
+            "Prevent-NonDelivery-Report",
+            "Priority",
+            "Privicon",
+            "ProfileObject",
+            "Protocol",
+            "Protocol-Info",
+            "Protocol-Query",
+            "Protocol-Request",
+            "Proxy-Authenticate",
+            "Proxy-Authentication-Info",
+            "Proxy-Authorization",
+            "Proxy-Connection",
+            "Proxy-Features",
+            "Proxy-Instruction",
+            "Public",
+            "Public-Key-Pins",
+            "Public-Key-Pins-Report-Only",
+            "Range",
+            "Received",
+            "Received-SPF",
+            "Redirect-Ref",
+            "References",
+            "Referer",
+            "Referer-Root",
+            "Relay-Version",
+            "Reply-By",
+            "Reply-To",
+            "Require-Recipient-Valid-Since",
+            "Resent-Bcc",
+            "Resent-Cc",
+            "Resent-Date",
+            "Resent-From",
+            "Resent-Message-ID",
+            "Resent-Reply-To",
+            "Resent-Sender",
+            "Resent-To",
+            "Resolution-Hint",
+            "Resolver-Location",
+            "Retry-After",
+            "Return-Path",
+            "Safe",
+            "Schedule-Reply",
+            "Schedule-Tag",
+            "Sec-WebSocket-Accept",
+            "Sec-WebSocket-Extensions",
+            "Sec-WebSocket-Key",
+            "Sec-WebSocket-Protocol",
+            "Sec-WebSocket-Version",
+            "Security-Scheme",
+            "See-Also",
+            "Sender",
+            "Sensitivity",
+            "Server",
+            "Set-Cookie",
+            "Set-Cookie2",
+            "SetProfile",
+            "SIO-Label",
+            "SIO-Label-History",
+            "SLUG",
+            "SoapAction",
+            "Solicitation",
+            "Status-URI",
+            "Strict-Transport-Security",
+            "Subject",
+            "SubOK",
+            "Subst",
+            "Summary",
+            "Supersedes",
+            "Surrogate-Capability",
+            "Surrogate-Control",
+            "TCN",
+            "TE",
+            "Timeout",
+            "Title",
+            "To",
+            "Topic",
+            "Trailer",
+            "Transfer-Encoding",
+            "TTL",
+            "UA-Color",
+            "UA-Media",
+            "UA-Pixels",
+            "UA-Resolution",
+            "UA-Windowpixels",
+            "Upgrade",
+            "Urgency",
+            "URI",
+            "User-Agent",
+            "Variant-Vary",
+            "Vary",
+            "VBR-Info",
+            "Version",
+            "Via",
+            "Want-Digest",
+            "Warning",
+            "WWW-Authenticate",
+            "X-Archived-At",
+            "X-Device-Accept",
+            "X-Device-Accept-Charset",
+            "X-Device-Accept-Encoding",
+            "X-Device-Accept-Language",
+            "X-Device-User-Agent",
+            "X-Frame-Options",
+            "X-Mittente",
+            "X-PGP-Sig",
+            "X-Ricevuta",
+            "X-Riferimento-Message-ID",
+            "X-TipoRicevuta",
+            "X-Trasporto",
+            "X-VerificaSicurezza",
+            "X400-Content-Identifier",
+            "X400-Content-Return",
+            "X400-Content-Type",
+            "X400-MTS-Identifier",
+            "X400-Originator",
+            "X400-Received",
+            "X400-Recipients",
+            "X400-Trace",
+            "Xref"
+        }})
+    {
+        // find the longest field length
+        std::size_t high = 0;
+        for(auto const& s : by_name_)
+            if(high < s.size())
+                high = s.size();
+        // build by_size map
+        // skip field::unknown
+        by_size_.resize(high + 1);
+        for(auto& map : by_size_)
+            map.max_load_factor(.15f);
+        for(std::size_t i = 1;
+            i < by_name_.size(); ++i)
+        {
+            auto const& s = by_name_[i];
+            by_size_[s.size()].emplace(
+                s, static_cast<field>(i));
+        }
+
+#if 0
+        // This snippet calculates the performance
+        // of the hash function and map settings
+        {
+            std::vector<std::size_t> hist;
+            for(auto const& map : by_size_)
+            {
+                for(std::size_t i = 0; i < map.bucket_count(); ++i)
+                {
+                    auto const n = map.bucket_size(i);
+                    if(n > 0)
+                    {
+                        if(hist.size() < n)
+                            hist.resize(n);
+                        ++hist[n-1];
+                    }
+                }
+            }
+        }
+#endif
+    }
+
+    field
+    string_to_field(string_view s) const
+    {
+        if(s.size() >= by_size_.size())
+            return field::unknown;
+        auto const& map = by_size_[s.size()];
+        if(map.empty())
+            return field::unknown;
+        auto it = map.find(s);
+        if(it == map.end())
+            return field::unknown;
+        return it->second;
+    }
+
+    //
+    // Deprecated
+    //
+
+    using const_iterator =
+    array_type::const_iterator; 
+
+    std::size_t
+    size() const
+    {
+        return by_name_.size();
+    }
+
+    const_iterator
+    begin() const
+    {
+        return by_name_.begin();
+    }
+
+    const_iterator
+    end() const
+    {
+        return by_name_.end();
+    }
+};
+
+inline
+field_table const&
+get_field_table()
+{
+    static field_table const tab;
+    return tab;
+}
+
+template<class = void>
+string_view
+to_string(field f)
+{
+    auto const& v = get_field_table();
+    BOOST_ASSERT(static_cast<unsigned>(f) < v.size());
+    return v.begin()[static_cast<unsigned>(f)];
+}
+
+} // detail
+
+inline
+string_view
+to_string(field f)
+{
+    return detail::to_string(f);
+}
+
+inline
+field
+string_to_field(string_view s)
+{
+    return detail::get_field_table().string_to_field(s);
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/fields.ipp b/boost/beast/http/impl/fields.ipp
new file mode 100644
index 0000000000..67d7cc45b4
--- /dev/null
+++ b/boost/beast/http/impl/fields.ipp
@@ -0,0 +1,1380 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_FIELDS_IPP
+#define BOOST_BEAST_HTTP_IMPL_FIELDS_IPP
+
+#include <boost/beast/core/buffers_cat.hpp>
+#include <boost/beast/core/string.hpp>
+#include <boost/beast/core/static_string.hpp>
+#include <boost/beast/core/detail/buffers_ref.hpp>
+#include <boost/beast/http/verb.hpp>
+#include <boost/beast/http/rfc7230.hpp>
+#include <boost/beast/http/status.hpp>
+#include <boost/beast/http/chunk_encode.hpp>
+#include <boost/throw_exception.hpp>
+#include <stdexcept>
+#include <string>
+
+#if defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 60000
+    // Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56437
+#ifndef BOOST_BEAST_HTTP_NO_FIELDS_BASIC_STRING_ALLOCATOR
+#define BOOST_BEAST_HTTP_NO_FIELDS_BASIC_STRING_ALLOCATOR
+#endif
+#endif
+
+namespace boost {
+namespace beast {
+namespace http {
+
+template<class Allocator>
+class basic_fields<Allocator>::writer
+{
+public:
+    using iter_type = typename list_t::const_iterator;
+
+    struct field_iterator
+    {
+        iter_type it_;
+
+        using value_type = boost::asio::const_buffer;
+        using pointer = value_type const*;
+        using reference = value_type const;
+        using difference_type = std::ptrdiff_t;
+        using iterator_category =
+            std::bidirectional_iterator_tag;
+
+        field_iterator() = default;
+        field_iterator(field_iterator&& other) = default;
+        field_iterator(field_iterator const& other) = default;
+        field_iterator& operator=(field_iterator&& other) = default;
+        field_iterator& operator=(field_iterator const& other) = default;
+
+        explicit
+        field_iterator(iter_type it)
+            : it_(it)
+        {
+        }
+
+        bool
+        operator==(field_iterator const& other) const
+        {
+            return it_ == other.it_;
+        }
+
+        bool
+        operator!=(field_iterator const& other) const
+        {
+            return !(*this == other);
+        }
+
+        reference
+        operator*() const
+        {
+            return it_->buffer();
+        }
+
+        field_iterator&
+        operator++()
+        {
+            ++it_;
+            return *this;
+        }
+
+        field_iterator
+        operator++(int)
+        {
+            auto temp = *this;
+            ++(*this);
+            return temp;
+        }
+
+        field_iterator&
+        operator--()
+        {
+            --it_;
+            return *this;
+        }
+
+        field_iterator
+        operator--(int)
+        {
+            auto temp = *this;
+            --(*this);
+            return temp;
+        }
+    };
+
+    class field_range
+    {
+        field_iterator first_;
+        field_iterator last_;
+
+    public:
+        using const_iterator =
+            field_iterator;
+
+        using value_type =
+            typename const_iterator::value_type;
+
+        field_range(iter_type first, iter_type last)
+            : first_(first)
+            , last_(last)
+        {
+        }
+
+        const_iterator
+        begin() const
+        {
+            return first_;
+        }
+
+        const_iterator
+        end() const
+        {
+            return last_;
+        }
+    };
+
+    using view_type = buffers_cat_view<
+        boost::asio::const_buffer,
+        boost::asio::const_buffer,
+        boost::asio::const_buffer,
+        field_range,
+        chunk_crlf>;
+
+    basic_fields const& f_;
+    boost::optional<view_type> view_;
+    char buf_[13];
+
+public:
+    using const_buffers_type =
+        beast::detail::buffers_ref<view_type>;
+
+    writer(basic_fields const& f,
+        unsigned version, verb v);
+
+    writer(basic_fields const& f,
+        unsigned version, unsigned code);
+
+    writer(basic_fields const& f);
+
+    const_buffers_type
+    get() const
+    {
+        return const_buffers_type(*view_);
+    }
+};
+
+template<class Allocator>
+basic_fields<Allocator>::writer::
+writer(basic_fields const& f)
+    : f_(f)
+{
+    view_.emplace(
+        boost::asio::const_buffer{nullptr, 0},
+        boost::asio::const_buffer{nullptr, 0},
+        boost::asio::const_buffer{nullptr, 0},
+        field_range(f_.list_.begin(), f_.list_.end()),
+        chunk_crlf());
+}
+
+template<class Allocator>
+basic_fields<Allocator>::writer::
+writer(basic_fields const& f,
+        unsigned version, verb v)
+    : f_(f)
+{
+/*
+    request
+        "<method>"
+        " <target>"
+        " HTTP/X.Y\r\n" (11 chars)
+*/
+    string_view sv;
+    if(v == verb::unknown)
+        sv = f_.get_method_impl();
+    else
+        sv = to_string(v);
+
+    // target_or_reason_ has a leading SP
+
+    buf_[0] = ' ';
+    buf_[1] = 'H';
+    buf_[2] = 'T';
+    buf_[3] = 'T';
+    buf_[4] = 'P';
+    buf_[5] = '/';
+    buf_[6] = '0' + static_cast<char>(version / 10);
+    buf_[7] = '.';
+    buf_[8] = '0' + static_cast<char>(version % 10);
+    buf_[9] = '\r';
+    buf_[10]= '\n';
+
+    view_.emplace(
+        boost::asio::const_buffer{sv.data(), sv.size()},
+        boost::asio::const_buffer{
+            f_.target_or_reason_.data(),
+            f_.target_or_reason_.size()},
+        boost::asio::const_buffer{buf_, 11},
+        field_range(f_.list_.begin(), f_.list_.end()),
+        chunk_crlf());
+}
+
+template<class Allocator>
+basic_fields<Allocator>::writer::
+writer(basic_fields const& f,
+        unsigned version, unsigned code)
+    : f_(f)
+{
+/*
+    response
+        "HTTP/X.Y ### " (13 chars)
+        "<reason>"
+        "\r\n"
+*/
+    buf_[0] = 'H';
+    buf_[1] = 'T';
+    buf_[2] = 'T';
+    buf_[3] = 'P';
+    buf_[4] = '/';
+    buf_[5] = '0' + static_cast<char>(version / 10);
+    buf_[6] = '.';
+    buf_[7] = '0' + static_cast<char>(version % 10);
+    buf_[8] = ' ';
+    buf_[9] = '0' + static_cast<char>(code / 100);
+    buf_[10]= '0' + static_cast<char>((code / 10) % 10);
+    buf_[11]= '0' + static_cast<char>(code % 10);
+    buf_[12]= ' ';
+
+    string_view sv;
+    if(! f_.target_or_reason_.empty())
+        sv = f_.target_or_reason_;
+    else
+        sv = obsolete_reason(static_cast<status>(code));
+
+    view_.emplace(
+        boost::asio::const_buffer{buf_, 13},
+        boost::asio::const_buffer{sv.data(), sv.size()},
+        boost::asio::const_buffer{"\r\n", 2},
+        field_range(f_.list_.begin(), f_.list_.end()),
+        chunk_crlf{});
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+basic_fields<Allocator>::
+value_type::
+value_type(field name,
+        string_view sname, string_view value)
+    : off_(static_cast<off_t>(sname.size() + 2))
+    , len_(static_cast<off_t>(value.size()))
+    , f_(name)
+{
+    //BOOST_ASSERT(name == field::unknown ||
+    //    iequals(sname, to_string(name)));
+    char* p = reinterpret_cast<char*>(this + 1);
+    p[off_-2] = ':';
+    p[off_-1] = ' ';
+    p[off_ + len_] = '\r';
+    p[off_ + len_ + 1] = '\n';
+    std::memcpy(p, sname.data(), sname.size());
+    std::memcpy(p + off_, value.data(), value.size());
+}
+
+template<class Allocator>
+inline
+field const
+basic_fields<Allocator>::
+value_type::
+name() const
+{
+    return f_;
+}
+
+template<class Allocator>
+inline
+string_view const
+basic_fields<Allocator>::
+value_type::
+name_string() const
+{
+    return {reinterpret_cast<
+        char const*>(this + 1),
+            static_cast<std::size_t>(off_ - 2)};
+}
+
+template<class Allocator>
+inline
+string_view const
+basic_fields<Allocator>::
+value_type::
+value() const
+{
+    return {reinterpret_cast<
+        char const*>(this + 1) + off_,
+            static_cast<std::size_t>(len_)};
+}
+
+template<class Allocator>
+inline
+boost::asio::const_buffer
+basic_fields<Allocator>::
+value_type::
+buffer() const
+{
+    return boost::asio::const_buffer{
+        reinterpret_cast<char const*>(this + 1),
+        static_cast<std::size_t>(off_) + len_ + 2};
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+basic_fields<Allocator>::
+~basic_fields()
+{
+    delete_list();
+    realloc_string(method_, {});
+    realloc_string(
+        target_or_reason_, {});
+}
+
+template<class Allocator>
+basic_fields<Allocator>::
+basic_fields(Allocator const& alloc)
+    : alloc_(alloc)
+{
+}
+
+template<class Allocator>
+basic_fields<Allocator>::
+basic_fields(basic_fields&& other)
+    : alloc_(std::move(other.alloc_))
+    , set_(std::move(other.set_))
+    , list_(std::move(other.list_))
+    , method_(other.method_)
+    , target_or_reason_(other.target_or_reason_)
+{
+    other.method_.clear();
+    other.target_or_reason_.clear();
+}
+
+template<class Allocator>
+basic_fields<Allocator>::
+basic_fields(basic_fields&& other, Allocator const& alloc)
+    : alloc_(alloc)
+{
+    if(alloc_ != other.alloc_)
+    {
+        copy_all(other);
+        other.clear_all();
+    }
+    else
+    {
+        set_ = std::move(other.set_);
+        list_ = std::move(other.list_);
+        method_ = other.method_;
+        target_or_reason_ = other.target_or_reason_;
+    }
+}
+
+template<class Allocator>
+basic_fields<Allocator>::
+basic_fields(basic_fields const& other)
+    : alloc_(alloc_traits::
+        select_on_container_copy_construction(other.alloc_))
+{
+    copy_all(other);
+}
+
+template<class Allocator>
+basic_fields<Allocator>::
+basic_fields(basic_fields const& other,
+        Allocator const& alloc)
+    : alloc_(alloc)
+{
+    copy_all(other);
+}
+
+template<class Allocator>
+template<class OtherAlloc>
+basic_fields<Allocator>::
+basic_fields(basic_fields<OtherAlloc> const& other)
+{
+    copy_all(other);
+}
+
+template<class Allocator>
+template<class OtherAlloc>
+basic_fields<Allocator>::
+basic_fields(basic_fields<OtherAlloc> const& other,
+        Allocator const& alloc)
+    : alloc_(alloc)
+{
+    copy_all(other);
+}
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+operator=(basic_fields&& other) ->
+    basic_fields&
+{
+    if(this == &other)
+        return *this;
+    move_assign(other, std::integral_constant<bool,
+        alloc_traits:: propagate_on_container_move_assignment::value>{});
+    return *this;
+}
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+operator=(basic_fields const& other) ->
+    basic_fields&
+{
+    copy_assign(other, std::integral_constant<bool,
+        alloc_traits::propagate_on_container_copy_assignment::value>{});
+    return *this;
+}
+
+template<class Allocator>
+template<class OtherAlloc>
+auto
+basic_fields<Allocator>::
+operator=(basic_fields<OtherAlloc> const& other) ->
+    basic_fields&
+{
+    clear_all();
+    copy_all(other);
+    return *this;
+}
+
+//------------------------------------------------------------------------------
+//
+// Element access
+//
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+string_view const
+basic_fields<Allocator>::
+at(field name) const
+{
+    BOOST_ASSERT(name != field::unknown);
+    auto const it = find(name);
+    if(it == end())
+        BOOST_THROW_EXCEPTION(std::out_of_range{
+            "field not found"});
+    return it->value();
+}
+
+template<class Allocator>
+string_view const
+basic_fields<Allocator>::
+at(string_view name) const
+{
+    auto const it = find(name);
+    if(it == end())
+        BOOST_THROW_EXCEPTION(std::out_of_range{
+            "field not found"});
+    return it->value();
+}
+
+template<class Allocator>
+string_view const
+basic_fields<Allocator>::
+operator[](field name) const
+{
+    BOOST_ASSERT(name != field::unknown);
+    auto const it = find(name);
+    if(it == end())
+        return {};
+    return it->value();
+}
+
+template<class Allocator>
+string_view const
+basic_fields<Allocator>::
+operator[](string_view name) const
+{
+    auto const it = find(name);
+    if(it == end())
+        return {};
+    return it->value();
+}
+
+//------------------------------------------------------------------------------
+//
+// Modifiers
+//
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+clear()
+{
+    delete_list();
+    set_.clear();
+    list_.clear();
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+insert(field name, string_param const& value)
+{
+    BOOST_ASSERT(name != field::unknown);
+    insert(name, to_string(name), value);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+insert(string_view sname, string_param const& value)
+{
+    auto const name =
+        string_to_field(sname);
+    insert(name, sname, value);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+insert(field name,
+    string_view sname, string_param const& value)
+{
+    auto& e = new_element(name, sname,
+        static_cast<string_view>(value));
+    auto const before =
+        set_.upper_bound(sname, key_compare{});
+    if(before == set_.begin())
+    {
+        BOOST_ASSERT(count(sname) == 0);
+        set_.insert_before(before, e);
+        list_.push_back(e);
+        return;
+    }
+    auto const last = std::prev(before);
+    // VFALCO is it worth comparing `field name` first?
+    if(! iequals(sname, last->name_string()))
+    {
+        BOOST_ASSERT(count(sname) == 0);
+        set_.insert_before(before, e);
+        list_.push_back(e);
+        return;
+    }
+    // keep duplicate fields together in the list
+    set_.insert_before(before, e);
+    list_.insert(++list_.iterator_to(*last), e);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set(field name, string_param const& value)
+{
+    BOOST_ASSERT(name != field::unknown);
+    set_element(new_element(name, to_string(name),
+        static_cast<string_view>(value)));
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set(string_view sname, string_param const& value)
+{
+    set_element(new_element(
+        string_to_field(sname), sname,
+            static_cast<string_view>(value)));
+}
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+erase(const_iterator pos) ->
+    const_iterator
+{
+    auto next = pos.iter();
+    auto& e = *next++;
+    set_.erase(e);
+    list_.erase(e);
+    delete_element(e);
+    return next;
+}
+
+template<class Allocator>
+std::size_t
+basic_fields<Allocator>::
+erase(field name)
+{
+    BOOST_ASSERT(name != field::unknown);
+    return erase(to_string(name));
+}
+
+template<class Allocator>
+std::size_t
+basic_fields<Allocator>::
+erase(string_view name)
+{
+    std::size_t n =0;
+    set_.erase_and_dispose(name, key_compare{},
+        [&](value_type* e)
+        {
+            ++n;
+            list_.erase(list_.iterator_to(*e));
+            delete_element(*e);
+        });
+    return n;
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+swap(basic_fields<Allocator>& other)
+{
+    swap(other, std::integral_constant<bool,
+        alloc_traits::propagate_on_container_swap::value>{});
+}
+
+template<class Allocator>
+void
+swap(
+    basic_fields<Allocator>& lhs,
+    basic_fields<Allocator>& rhs)
+{
+    lhs.swap(rhs);
+}
+
+//------------------------------------------------------------------------------
+//
+// Lookup
+//
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+inline
+std::size_t
+basic_fields<Allocator>::
+count(field name) const
+{
+    BOOST_ASSERT(name != field::unknown);
+    return count(to_string(name));
+}
+
+template<class Allocator>
+std::size_t
+basic_fields<Allocator>::
+count(string_view name) const
+{
+    return set_.count(name, key_compare{});
+}
+
+template<class Allocator>
+inline
+auto
+basic_fields<Allocator>::
+find(field name) const ->
+    const_iterator
+{
+    BOOST_ASSERT(name != field::unknown);
+    return find(to_string(name));
+}
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+find(string_view name) const ->
+    const_iterator
+{
+    auto const it = set_.find(
+        name, key_compare{});
+    if(it == set_.end())
+        return list_.end();
+    return list_.iterator_to(*it);
+}
+
+template<class Allocator>
+inline
+auto
+basic_fields<Allocator>::
+equal_range(field name) const ->
+    std::pair<const_iterator, const_iterator>
+{
+    BOOST_ASSERT(name != field::unknown);
+    return equal_range(to_string(name));
+}
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+equal_range(string_view name) const ->
+    std::pair<const_iterator, const_iterator>
+{
+    auto result =
+        set_.equal_range(name, key_compare{});
+    if(result.first == result.second)
+        return {list_.end(), list_.end()};
+    return {
+        list_.iterator_to(*result.first),
+        ++list_.iterator_to(*(--result.second))};
+}
+
+//------------------------------------------------------------------------------
+
+namespace detail {
+
+// Filter a token list
+//
+template<class String, class Pred>
+void
+filter_token_list(
+    String& s,
+    string_view value,
+    Pred&& pred)
+{
+    token_list te{value};
+    auto it = te.begin();
+    auto last = te.end();
+    if(it == last)
+        return;
+    while(pred(*it))
+        if(++it == last)
+            return;
+    s.append(it->data(), it->size());
+    while(++it != last)
+    {
+        if(! pred(*it))
+        {
+            s.append(", ");
+            s.append(it->data(), it->size());
+        }
+    }
+}
+
+// Filter the last item in a token list
+template<class String, class Pred>
+void
+filter_token_list_last(
+    String& s,
+    string_view value,
+    Pred&& pred)
+{
+    token_list te{value};
+    if(te.begin() != te.end())
+    {
+        auto it = te.begin();
+        auto next = std::next(it);
+        if(next == te.end())
+        {
+            if(! pred(*it))
+                s.append(it->data(), it->size());
+            return;
+        }
+        s.append(it->data(), it->size());
+        for(;;)
+        {
+            it = next;
+            next = std::next(it);
+            if(next == te.end())
+            {
+                if(! pred(*it))
+                {
+                    s.append(", ");
+                    s.append(it->data(), it->size());
+                }
+                return;
+            }
+            s.append(", ");
+            s.append(it->data(), it->size());
+        }
+    }
+}
+
+template<class String>
+void
+keep_alive_impl(
+    String& s, string_view value,
+    unsigned version, bool keep_alive)
+{
+    if(version < 11)
+    {
+        if(keep_alive)
+        {
+            // remove close
+            filter_token_list(s, value,
+                [](string_view s)
+                {
+                    return iequals(s, "close");
+                });
+            // add keep-alive
+            if(s.empty())
+                s.append("keep-alive");
+            else if(! token_list{value}.exists("keep-alive"))
+                s.append(", keep-alive");
+        }
+        else
+        {
+            // remove close and keep-alive
+            filter_token_list(s, value,
+                [](string_view s)
+                {
+                    return
+                        iequals(s, "close") ||
+                        iequals(s, "keep-alive");
+                });
+        }
+    }
+    else
+    {
+        if(keep_alive)
+        {
+            // remove close and keep-alive
+            filter_token_list(s, value,
+                [](string_view s)
+                {
+                    return
+                        iequals(s, "close") ||
+                        iequals(s, "keep-alive");
+                });
+        }
+        else
+        {
+            // remove keep-alive
+            filter_token_list(s, value,
+                [](string_view s)
+                {
+                    return iequals(s, "keep-alive");
+                });
+            // add close
+            if(s.empty())
+                s.append("close");
+            else if(! token_list{value}.exists("close"))
+                s.append(", close");
+        }
+    }
+}
+
+} // detail
+
+//------------------------------------------------------------------------------
+
+// Fields
+
+template<class Allocator>
+inline
+string_view
+basic_fields<Allocator>::
+get_method_impl() const
+{
+    return method_;
+}
+
+template<class Allocator>
+inline
+string_view
+basic_fields<Allocator>::
+get_target_impl() const
+{
+    if(target_or_reason_.empty())
+        return target_or_reason_;
+    return {
+        target_or_reason_.data() + 1,
+        target_or_reason_.size() - 1};
+}
+
+template<class Allocator>
+inline
+string_view
+basic_fields<Allocator>::
+get_reason_impl() const
+{
+    return target_or_reason_;
+}
+
+template<class Allocator>
+bool
+basic_fields<Allocator>::
+get_chunked_impl() const
+{
+    auto const te = token_list{
+        (*this)[field::transfer_encoding]};
+    for(auto it = te.begin(); it != te.end();)
+    {
+        auto const next = std::next(it);
+        if(next == te.end())
+            return iequals(*it, "chunked");
+        it = next;
+    }
+    return false;
+}
+
+template<class Allocator>
+bool
+basic_fields<Allocator>::
+get_keep_alive_impl(unsigned version) const
+{
+    auto const it = find(field::connection);
+    if(version < 11)
+    {
+        if(it == end())
+            return false;
+        return token_list{
+            it->value()}.exists("keep-alive");
+    }
+    if(it == end())
+        return true;
+    return ! token_list{
+        it->value()}.exists("close");
+}
+
+template<class Allocator>
+bool
+basic_fields<Allocator>::
+has_content_length_impl() const
+{
+    return count(field::content_length) > 0;
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+set_method_impl(string_view s)
+{
+    realloc_string(method_, s);
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+set_target_impl(string_view s)
+{
+    realloc_target(
+        target_or_reason_, s);
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+set_reason_impl(string_view s)
+{
+    realloc_string(
+        target_or_reason_, s);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set_chunked_impl(bool value)
+{
+    auto it = find(field::transfer_encoding);
+    if(value)
+    {
+        // append "chunked"
+        if(it == end())
+        {
+            set(field::transfer_encoding, "chunked");
+            return;
+        }
+        auto const te = token_list{it->value()};
+        for(auto itt = te.begin();;)
+        {
+            auto const next = std::next(itt);
+            if(next == te.end())
+            {
+                if(iequals(*itt, "chunked"))
+                    return; // already set
+                break;
+            }
+            itt = next;
+        }
+        static_string<max_static_buffer> buf;
+        if(it->value().size() <= buf.size() + 9)
+        {
+            buf.append(it->value().data(), it->value().size());
+            buf.append(", chunked", 9);
+            set(field::transfer_encoding, buf);
+        }
+        else
+        {
+        #ifdef BOOST_BEAST_HTTP_NO_FIELDS_BASIC_STRING_ALLOCATOR
+            // Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56437
+            std::string s;
+        #else
+            using rebind_type =
+                typename beast::detail::allocator_traits<
+                    Allocator>::template rebind_alloc<char>;
+            std::basic_string<
+                char,
+                std::char_traits<char>,
+                rebind_type> s{rebind_type{alloc_}};
+        #endif
+            s.reserve(it->value().size() + 9);
+            s.append(it->value().data(), it->value().size());
+            s.append(", chunked", 9);
+            set(field::transfer_encoding, s);
+        }
+        return;
+    }
+    // filter "chunked"
+    if(it == end())
+        return;
+    try
+    {
+        static_string<max_static_buffer> buf;
+        detail::filter_token_list_last(buf, it->value(),
+            [](string_view s)
+            {
+                return iequals(s, "chunked");
+            });
+        if(! buf.empty())
+            set(field::transfer_encoding, buf);
+        else
+            erase(field::transfer_encoding);
+    }
+    catch(std::length_error const&)
+    {
+    #ifdef BOOST_BEAST_HTTP_NO_FIELDS_BASIC_STRING_ALLOCATOR
+        // Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56437
+        std::string s;
+    #else
+        using rebind_type =
+            typename beast::detail::allocator_traits<
+                Allocator>::template rebind_alloc<char>;
+        std::basic_string<
+            char,
+            std::char_traits<char>,
+            rebind_type> s{rebind_type{alloc_}};
+    #endif
+        s.reserve(it->value().size());
+        detail::filter_token_list_last(s, it->value(),
+            [](string_view s)
+            {
+                return iequals(s, "chunked");
+            });
+        if(! s.empty())
+            set(field::transfer_encoding, s);
+        else
+            erase(field::transfer_encoding);
+    }
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set_content_length_impl(
+    boost::optional<std::uint64_t> const& value)
+{
+    if(! value)
+        erase(field::content_length);
+    else
+        set(field::content_length, *value);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set_keep_alive_impl(
+    unsigned version, bool keep_alive)
+{
+    // VFALCO What about Proxy-Connection ?
+    auto const value = (*this)[field::connection];
+    try
+    {
+        static_string<max_static_buffer> buf;
+        detail::keep_alive_impl(
+            buf, value, version, keep_alive);
+        if(buf.empty())
+            erase(field::connection);
+        else
+            set(field::connection, buf);
+    }
+    catch(std::length_error const&)
+    {
+    #ifdef BOOST_BEAST_HTTP_NO_FIELDS_BASIC_STRING_ALLOCATOR
+        // Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56437
+        std::string s;
+    #else
+        using rebind_type =
+            typename beast::detail::allocator_traits<
+                Allocator>::template rebind_alloc<char>;
+        std::basic_string<
+            char,
+            std::char_traits<char>,
+            rebind_type> s{rebind_type{alloc_}};
+    #endif
+        s.reserve(value.size());
+        detail::keep_alive_impl(
+            s, value, version, keep_alive);
+        if(s.empty())
+            erase(field::connection);
+        else
+            set(field::connection, s);
+    }
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+auto
+basic_fields<Allocator>::
+new_element(field name,
+    string_view sname, string_view value) ->
+        value_type&
+{
+    if(sname.size() + 2 >
+            (std::numeric_limits<off_t>::max)())
+        BOOST_THROW_EXCEPTION(std::length_error{
+            "field name too large"});
+    if(value.size() + 2 >
+            (std::numeric_limits<off_t>::max)())
+        BOOST_THROW_EXCEPTION(std::length_error{
+            "field value too large"});
+    value = detail::trim(value);
+    std::uint16_t const off =
+        static_cast<off_t>(sname.size() + 2);
+    std::uint16_t const len =
+        static_cast<off_t>(value.size());
+    auto const p = alloc_traits::allocate(alloc_,
+        1 + (off + len + 2 + sizeof(value_type) - 1) /
+            sizeof(value_type));
+    // VFALCO allocator can't call the constructor because its private
+    //alloc_traits::construct(alloc_, p, name, sname, value);
+    new(p) value_type{name, sname, value};
+    return *p;
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+delete_element(value_type& e)
+{
+    auto const n = 1 + (e.off_ + e.len_ + 2 +
+        sizeof(value_type) - 1) / sizeof(value_type);
+    alloc_traits::destroy(alloc_, &e);
+    alloc_traits::deallocate(alloc_, &e, n);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+set_element(value_type& e)
+{
+    auto it = set_.lower_bound(
+        e.name_string(), key_compare{});
+    if(it == set_.end() || ! iequals(
+        e.name_string(), it->name_string()))
+    {
+        set_.insert_before(it, e);
+        list_.push_back(e);
+        return;
+    }
+    for(;;)
+    {
+        auto next = it;
+        ++next;
+        set_.erase(it);
+        list_.erase(list_.iterator_to(*it));
+        delete_element(*it);
+        it = next;
+        if(it == set_.end() ||
+            ! iequals(e.name_string(), it->name_string()))
+            break;
+    }
+    set_.insert_before(it, e);
+    list_.push_back(e);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+realloc_string(string_view& dest, string_view s)
+{
+    if(dest.empty() && s.empty())
+        return;
+    auto a = typename beast::detail::allocator_traits<
+        Allocator>::template rebind_alloc<
+            char>(alloc_);
+    if(! dest.empty())
+    {
+        a.deallocate(const_cast<char*>(
+            dest.data()), dest.size());
+        dest.clear();
+    }
+    if(! s.empty())
+    {
+        auto const p = a.allocate(s.size());
+        std::memcpy(p, s.data(), s.size());
+        dest = {p, s.size()};
+    }
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+realloc_target(
+    string_view& dest, string_view s)
+{
+    // The target string are stored with an
+    // extra space at the beginning to help
+    // the writer class.
+    if(dest.empty() && s.empty())
+        return;
+    auto a = typename beast::detail::allocator_traits<
+        Allocator>::template rebind_alloc<
+            char>(alloc_);
+    if(! dest.empty())
+    {
+        a.deallocate(const_cast<char*>(
+            dest.data()), dest.size());
+        dest.clear();
+    }
+    if(! s.empty())
+    {
+        auto const p = a.allocate(1 + s.size());
+        p[0] = ' ';
+        std::memcpy(p + 1, s.data(), s.size());
+        dest = {p, 1 + s.size()};
+    }
+}
+
+template<class Allocator>
+template<class OtherAlloc>
+void
+basic_fields<Allocator>::
+copy_all(basic_fields<OtherAlloc> const& other)
+{
+    for(auto const& e : other.list_)
+        insert(e.name(), e.name_string(), e.value());
+    realloc_string(method_, other.method_);
+    realloc_string(target_or_reason_,
+        other.target_or_reason_);
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+clear_all()
+{
+    clear();
+    realloc_string(method_, {});
+    realloc_string(target_or_reason_, {});
+}
+
+template<class Allocator>
+void
+basic_fields<Allocator>::
+delete_list()
+{
+    for(auto it = list_.begin(); it != list_.end();)
+        delete_element(*it++);
+}
+
+//------------------------------------------------------------------------------
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+move_assign(basic_fields& other, std::true_type)
+{
+    clear_all();
+    set_ = std::move(other.set_);
+    list_ = std::move(other.list_);
+    method_ = other.method_;
+    target_or_reason_ = other.target_or_reason_;
+    other.method_.clear();
+    other.target_or_reason_.clear();
+    alloc_ = other.alloc_;
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+move_assign(basic_fields& other, std::false_type)
+{
+    clear_all();
+    if(alloc_ != other.alloc_)
+    {
+        copy_all(other);
+        other.clear_all();
+    }
+    else
+    {
+        set_ = std::move(other.set_);
+        list_ = std::move(other.list_);
+        method_ = other.method_;
+        target_or_reason_ = other.target_or_reason_;
+        other.method_.clear();
+        other.target_or_reason_.clear();
+    }
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+copy_assign(basic_fields const& other, std::true_type)
+{
+    clear_all();
+    alloc_ = other.alloc_;
+    copy_all(other);
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+copy_assign(basic_fields const& other, std::false_type)
+{
+    clear_all();
+    copy_all(other);
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+swap(basic_fields& other, std::true_type)
+{
+    using std::swap;
+    swap(alloc_, other.alloc_);
+    swap(set_, other.set_);
+    swap(list_, other.list_);
+    swap(method_, other.method_);
+    swap(target_or_reason_, other.target_or_reason_);
+}
+
+template<class Allocator>
+inline
+void
+basic_fields<Allocator>::
+swap(basic_fields& other, std::false_type)
+{
+    BOOST_ASSERT(alloc_ == other.alloc_);
+    using std::swap;
+    swap(set_, other.set_);
+    swap(list_, other.list_);
+    swap(method_, other.method_);
+    swap(target_or_reason_, other.target_or_reason_);
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/file_body_win32.ipp b/boost/beast/http/impl/file_body_win32.ipp
new file mode 100644
index 0000000000..e11c443ed2
--- /dev/null
+++ b/boost/beast/http/impl/file_body_win32.ipp
@@ -0,0 +1,584 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_FILE_BODY_WIN32_IPP
+#define BOOST_BEAST_HTTP_IMPL_FILE_BODY_WIN32_IPP
+
+#if BOOST_BEAST_USE_WIN32_FILE
+
+#include <boost/beast/core/bind_handler.hpp>
+#include <boost/beast/core/type_traits.hpp>
+#include <boost/beast/core/detail/clamp.hpp>
+#include <boost/beast/http/serializer.hpp>
+#include <boost/asio/associated_allocator.hpp>
+#include <boost/asio/associated_executor.hpp>
+#include <boost/asio/async_result.hpp>
+#include <boost/asio/basic_stream_socket.hpp>
+#include <boost/asio/handler_continuation_hook.hpp>
+#include <boost/asio/windows/overlapped_ptr.hpp>
+#include <boost/make_unique.hpp>
+#include <boost/smart_ptr/make_shared_array.hpp>
+#include <boost/winapi/basic_types.hpp>
+#include <algorithm>
+#include <cstring>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+namespace detail {
+template<class, class, bool, class>
+class write_some_win32_op;
+} // detail
+
+template<>
+struct basic_file_body<file_win32>
+{
+    using file_type = file_win32;
+
+    class writer;
+    class reader;
+
+    //--------------------------------------------------------------------------
+
+    class value_type
+    {
+        friend class writer;
+        friend class reader;
+        friend struct basic_file_body<file_win32>;
+
+        template<class, class, bool, class>
+        friend class detail::write_some_win32_op;
+        template<
+            class Protocol, bool isRequest, class Fields>
+        friend
+        std::size_t
+        write_some(
+            boost::asio::basic_stream_socket<Protocol>& sock,
+            serializer<isRequest,
+                basic_file_body<file_win32>, Fields>& sr,
+            error_code& ec);
+
+        file_win32 file_;
+        std::uint64_t size_ = 0;    // cached file size
+        std::uint64_t first_;       // starting offset of the range
+        std::uint64_t last_;        // ending offset of the range
+
+    public:
+        ~value_type() = default;
+        value_type() = default;
+        value_type(value_type&& other) = default;
+        value_type& operator=(value_type&& other) = default;
+
+        bool
+        is_open() const
+        {
+            return file_.is_open();
+        }
+
+        std::uint64_t
+        size() const
+        {
+            return size_;
+        }
+
+        void
+        close();
+
+        void
+        open(char const* path, file_mode mode, error_code& ec);
+
+        void
+        reset(file_win32&& file, error_code& ec);
+    };
+
+    //--------------------------------------------------------------------------
+
+    class writer
+    {
+        template<class, class, bool, class>
+        friend class detail::write_some_win32_op;
+        template<
+            class Protocol, bool isRequest, class Fields>
+        friend
+        std::size_t
+        write_some(
+            boost::asio::basic_stream_socket<Protocol>& sock,
+            serializer<isRequest,
+                basic_file_body<file_win32>, Fields>& sr,
+            error_code& ec);
+
+        value_type& body_;  // The body we are reading from
+        std::uint64_t pos_; // The current position in the file
+        char buf_[4096];    // Small buffer for reading
+
+    public:
+        using const_buffers_type =
+            boost::asio::const_buffer;
+
+        template<bool isRequest, class Fields>
+        writer(message<isRequest,
+                basic_file_body<file_win32>, Fields>& m)
+            : body_(m.body())
+        {
+        }
+
+        void
+        init(error_code&)
+        {
+            BOOST_ASSERT(body_.file_.is_open());
+            pos_ = body_.first_;
+        }
+
+        boost::optional<std::pair<const_buffers_type, bool>>
+        get(error_code& ec)
+        {
+            std::size_t const n = (std::min)(sizeof(buf_),
+                beast::detail::clamp(body_.last_ - pos_));
+            if(n == 0)
+            {
+                ec.assign(0, ec.category());
+                return boost::none;
+            }
+            auto const nread = body_.file_.read(buf_, n, ec);
+            if(ec)
+                return boost::none;
+            BOOST_ASSERT(nread != 0);
+            pos_ += nread;
+            ec.assign(0, ec.category());
+            return {{
+                {buf_, nread},          // buffer to return.
+                pos_ < body_.last_}};   // `true` if there are more buffers.
+        }
+    };
+
+    //--------------------------------------------------------------------------
+
+    class reader
+    {
+        value_type& body_;
+
+    public:
+        template<bool isRequest, class Fields>
+        explicit
+        reader(message<isRequest, basic_file_body, Fields>& m)
+            : body_(m.body())
+        {
+        }
+
+        void
+        init(boost::optional<
+            std::uint64_t> const& content_length,
+                error_code& ec)
+        {
+            // VFALCO We could reserve space in the file
+            boost::ignore_unused(content_length);
+            BOOST_ASSERT(body_.file_.is_open());
+            ec.assign(0, ec.category());
+        }
+
+        template<class ConstBufferSequence>
+        std::size_t
+        put(ConstBufferSequence const& buffers,
+            error_code& ec)
+        {
+            std::size_t nwritten = 0;
+            for(auto buffer : beast::detail::buffers_range(buffers))
+            {
+                nwritten += body_.file_.write(
+                    buffer.data(), buffer.size(), ec);
+                if(ec)
+                    return nwritten;
+            }
+            ec.assign(0, ec.category());
+            return nwritten;
+        }
+
+        void
+        finish(error_code& ec)
+        {
+            ec.assign(0, ec.category());
+        }
+    };
+
+    //--------------------------------------------------------------------------
+
+    static
+    std::uint64_t
+    size(value_type const& body)
+    {
+        return body.size();
+    }
+};
+
+//------------------------------------------------------------------------------
+
+inline
+void
+basic_file_body<file_win32>::
+value_type::
+close()
+{
+    error_code ignored;
+    file_.close(ignored);
+}
+
+inline
+void
+basic_file_body<file_win32>::
+value_type::
+open(char const* path, file_mode mode, error_code& ec)
+{
+    file_.open(path, mode, ec);
+    if(ec)
+        return;
+    size_ = file_.size(ec);
+    if(ec)
+    {
+        close();
+        return;
+    }
+    first_ = 0;
+    last_ = size_;
+}
+
+inline
+void
+basic_file_body<file_win32>::
+value_type::
+reset(file_win32&& file, error_code& ec)
+{
+    if(file_.is_open())
+    {
+        error_code ignored;
+        file_.close(ignored);
+    }
+    file_ = std::move(file);
+    if(file_.is_open())
+    {
+        size_ = file_.size(ec);
+        if(ec)
+        {
+            close();
+            return;
+        }
+        first_ = 0;
+        last_ = size_;
+    }
+}
+
+//------------------------------------------------------------------------------
+
+namespace detail {
+
+template<class Unsigned>
+inline
+boost::winapi::DWORD_
+lowPart(Unsigned n)
+{
+    return static_cast<
+        boost::winapi::DWORD_>(
+            n & 0xffffffff);
+}
+
+template<class Unsigned>
+inline
+boost::winapi::DWORD_
+highPart(Unsigned n, std::true_type)
+{
+    return static_cast<
+        boost::winapi::DWORD_>(
+            (n>>32)&0xffffffff);
+}
+
+template<class Unsigned>
+inline
+boost::winapi::DWORD_
+highPart(Unsigned, std::false_type)
+{
+    return 0;
+}
+
+template<class Unsigned>
+inline
+boost::winapi::DWORD_
+highPart(Unsigned n)
+{
+    return highPart(n, std::integral_constant<
+        bool, (sizeof(Unsigned)>4)>{});
+}
+
+class null_lambda
+{
+public:
+    template<class ConstBufferSequence>
+    void
+    operator()(error_code&,
+        ConstBufferSequence const&) const
+    {
+        BOOST_ASSERT(false);
+    }
+};
+
+//------------------------------------------------------------------------------
+
+#if BOOST_ASIO_HAS_WINDOWS_OVERLAPPED_PTR
+
+template<
+    class Protocol, class Handler,
+    bool isRequest, class Fields>
+class write_some_win32_op
+{
+    boost::asio::basic_stream_socket<Protocol>& sock_;
+    serializer<isRequest,
+        basic_file_body<file_win32>, Fields>& sr_;
+    std::size_t bytes_transferred_ = 0;
+    Handler h_;
+    bool header_ = false;
+
+public:
+    write_some_win32_op(write_some_win32_op&&) = default;
+    write_some_win32_op(write_some_win32_op const&) = default;
+
+    template<class DeducedHandler>
+    write_some_win32_op(
+        DeducedHandler&& h,
+        boost::asio::basic_stream_socket<Protocol>& s,
+        serializer<isRequest,
+            basic_file_body<file_win32>,Fields>& sr)
+        : sock_(s)
+        , sr_(sr)
+        , h_(std::forward<DeducedHandler>(h))
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(h_);
+    }
+
+    using executor_type =
+        boost::asio::associated_executor_t<Handler, decltype(std::declval<
+            boost::asio::basic_stream_socket<Protocol>&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            h_, sock_.get_executor());
+    }
+
+    void
+    operator()();
+
+    void
+    operator()(
+        error_code ec,
+        std::size_t bytes_transferred = 0);
+
+    friend
+    bool asio_handler_is_continuation(write_some_win32_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return asio_handler_is_continuation(
+            std::addressof(op->h_));
+    }
+};
+
+template<
+    class Protocol, class Handler,
+    bool isRequest, class Fields>
+void
+write_some_win32_op<
+    Protocol, Handler, isRequest, Fields>::
+operator()()
+{
+    if(! sr_.is_header_done())
+    {
+        header_ = true;
+        sr_.split(true);
+        return detail::async_write_some(
+            sock_, sr_, std::move(*this));
+    }
+    if(sr_.get().chunked())
+    {
+        return detail::async_write_some(
+            sock_, sr_, std::move(*this));
+    }
+    auto& r = sr_.reader_impl();
+    boost::winapi::DWORD_ const nNumberOfBytesToWrite =
+        static_cast<boost::winapi::DWORD_>(
+        (std::min<std::uint64_t>)(
+            (std::min<std::uint64_t>)(r.body_.last_ - r.pos_, sr_.limit()),
+            (std::numeric_limits<boost::winapi::DWORD_>::max)()));
+    boost::asio::windows::overlapped_ptr overlapped{
+        sock_.get_executor().context(), *this};
+    auto& ov = *overlapped.get();
+    ov.Offset = lowPart(r.pos_);
+    ov.OffsetHigh = highPart(r.pos_);
+    auto const bSuccess = ::TransmitFile(
+        sock_.native_handle(),
+        sr_.get().body().file_.native_handle(),
+        nNumberOfBytesToWrite,
+        0,
+        overlapped.get(),
+        nullptr,
+        0);
+    auto const dwError = ::GetLastError();
+    if(! bSuccess && dwError !=
+        boost::winapi::ERROR_IO_PENDING_)
+    {
+        // VFALCO This needs review, is 0 the right number?
+        // completed immediately (with error?)
+        overlapped.complete(error_code{static_cast<int>(
+            boost::winapi::GetLastError()),
+                system_category()}, 0);
+        return;
+    }
+    overlapped.release();
+}
+
+template<
+    class Protocol, class Handler,
+    bool isRequest, class Fields>
+void
+write_some_win32_op<
+    Protocol, Handler, isRequest, Fields>::
+operator()(
+    error_code ec, std::size_t bytes_transferred)
+{
+    bytes_transferred_ += bytes_transferred;
+    if(! ec)
+    {
+        if(header_)
+        {
+            header_ = false;
+            return (*this)();
+        }
+        auto& r = sr_.reader_impl();
+        r.pos_ += bytes_transferred;
+        BOOST_ASSERT(r.pos_ <= r.body_.last_);
+        if(r.pos_ >= r.body_.last_)
+        {
+            sr_.next(ec, null_lambda{});
+            BOOST_ASSERT(! ec);
+            BOOST_ASSERT(sr_.is_done());
+        }
+    }
+    h_(ec, bytes_transferred_);
+}
+
+#endif
+
+} // detail
+
+//------------------------------------------------------------------------------
+
+template<class Protocol, bool isRequest, class Fields>
+std::size_t
+write_some(
+    boost::asio::basic_stream_socket<Protocol>& sock,
+    serializer<isRequest,
+        basic_file_body<file_win32>, Fields>& sr,
+    error_code& ec)
+{
+    if(! sr.is_header_done())
+    {
+        sr.split(true);
+        auto const bytes_transferred =
+            detail::write_some(sock, sr, ec);
+        if(ec)
+            return bytes_transferred;
+        return bytes_transferred;
+    }
+    if(sr.get().chunked())
+    {
+        auto const bytes_transferred =
+            detail::write_some(sock, sr, ec);
+        if(ec)
+            return bytes_transferred;
+        return bytes_transferred;
+    }
+    auto& r = sr.reader_impl();
+    r.body_.file_.seek(r.pos_, ec);
+    if(ec)
+        return 0;
+    boost::winapi::DWORD_ const nNumberOfBytesToWrite =
+        static_cast<boost::winapi::DWORD_>(
+        (std::min<std::uint64_t>)(
+            (std::min<std::uint64_t>)(r.body_.last_ - r.pos_, sr.limit()),
+            (std::numeric_limits<boost::winapi::DWORD_>::max)()));
+    auto const bSuccess = ::TransmitFile(
+        sock.native_handle(),
+        r.body_.file_.native_handle(),
+        nNumberOfBytesToWrite,
+        0,
+        nullptr,
+        nullptr,
+        0);
+    if(! bSuccess)
+    {
+        ec.assign(static_cast<int>(
+            boost::winapi::GetLastError()),
+                system_category());
+        return 0;
+    }
+    r.pos_ += nNumberOfBytesToWrite;
+    BOOST_ASSERT(r.pos_ <= r.body_.last_);
+    if(r.pos_ < r.body_.last_)
+    {
+        ec.assign(0, ec.category());
+    }
+    else
+    {
+        sr.next(ec, detail::null_lambda{});
+        BOOST_ASSERT(! ec);
+        BOOST_ASSERT(sr.is_done());
+    }
+    return nNumberOfBytesToWrite;
+}
+
+#if BOOST_ASIO_HAS_WINDOWS_OVERLAPPED_PTR
+
+template<
+    class Protocol,
+    bool isRequest, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write_some(
+    boost::asio::basic_stream_socket<Protocol>& sock,
+    serializer<isRequest,
+        basic_file_body<file_win32>, Fields>& sr,
+    WriteHandler&& handler)
+{
+    boost::asio::async_completion<WriteHandler,
+        void(error_code)> init{handler};
+    detail::write_some_win32_op<
+        Protocol,
+        BOOST_ASIO_HANDLER_TYPE(WriteHandler,
+            void(error_code, std::size_t)),
+        isRequest, Fields>{
+            init.completion_handler, sock, sr}();
+    return init.result.get();
+}
+
+#endif
+
+} // http
+} // beast
+} // boost
+
+#endif
+
+#endif
diff --git a/boost/beast/http/impl/message.ipp b/boost/beast/http/impl/message.ipp
new file mode 100644
index 0000000000..64d96eb6f1
--- /dev/null
+++ b/boost/beast/http/impl/message.ipp
@@ -0,0 +1,437 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_MESSAGE_IPP
+#define BOOST_BEAST_HTTP_IMPL_MESSAGE_IPP
+
+#include <boost/beast/core/error.hpp>
+#include <boost/beast/core/detail/type_traits.hpp>
+#include <boost/assert.hpp>
+#include <boost/throw_exception.hpp>
+#include <stdexcept>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+template<class Fields>
+template<class Arg1, class... ArgN, class>
+header<true, Fields>::
+header(Arg1&& arg1, ArgN&&... argn)
+    : Fields(std::forward<Arg1>(arg1),
+        std::forward<ArgN>(argn)...)
+{
+}
+
+template<class Fields>
+inline
+verb
+header<true, Fields>::
+method() const
+{
+    return method_;
+}
+
+template<class Fields>
+void
+header<true, Fields>::
+method(verb v)
+{
+    if(v == verb::unknown)
+        BOOST_THROW_EXCEPTION(
+            std::invalid_argument{"unknown method"});
+    method_ = v;
+    this->set_method_impl({});
+}
+
+template<class Fields>
+string_view
+header<true, Fields>::
+method_string() const
+{
+    if(method_ != verb::unknown)
+        return to_string(method_);
+    return this->get_method_impl();
+}
+
+template<class Fields>
+void
+header<true, Fields>::
+method_string(string_view s)
+{
+    method_ = string_to_verb(s);
+    if(method_ != verb::unknown)
+        this->set_method_impl({});
+    else
+        this->set_method_impl(s);
+}
+
+template<class Fields>
+inline
+string_view
+header<true, Fields>::
+target() const
+{
+    return this->get_target_impl();
+}
+
+template<class Fields>
+inline
+void
+header<true, Fields>::
+target(string_view s)
+{
+    this->set_target_impl(s);
+}
+
+template<class Fields>
+void
+swap(
+    header<true, Fields>& h1,
+    header<true, Fields>& h2)
+{
+    using std::swap;
+    swap(
+        static_cast<Fields&>(h1),
+        static_cast<Fields&>(h2));
+    swap(h1.version_, h2.version_);
+    swap(h1.method_, h2.method_);
+}
+
+//------------------------------------------------------------------------------
+
+template<class Fields>
+template<class Arg1, class... ArgN, class>
+header<false, Fields>::
+header(Arg1&& arg1, ArgN&&... argn)
+    : Fields(std::forward<Arg1>(arg1),
+        std::forward<ArgN>(argn)...)
+{
+}
+
+template<class Fields>
+inline
+status
+header<false, Fields>::
+result() const
+{
+    return int_to_status(
+        static_cast<int>(result_));
+}
+
+template<class Fields>
+inline
+void
+header<false, Fields>::
+result(status v)
+{
+    result_ = v;
+}
+
+template<class Fields>
+inline
+void
+header<false, Fields>::
+result(unsigned v)
+{
+    if(v > 999)
+        BOOST_THROW_EXCEPTION(
+            std::invalid_argument{
+                "invalid status-code"});
+    result_ = static_cast<status>(v);
+}
+
+template<class Fields>
+inline
+unsigned
+header<false, Fields>::
+result_int() const
+{
+    return static_cast<unsigned>(result_);
+}
+
+template<class Fields>
+string_view
+header<false, Fields>::
+reason() const
+{
+    auto const s = this->get_reason_impl();
+    if(! s.empty())
+        return s;
+    return obsolete_reason(result_);
+}
+
+template<class Fields>
+inline
+void
+header<false, Fields>::
+reason(string_view s)
+{
+    this->set_reason_impl(s);
+}
+
+template<class Fields>
+void
+swap(
+    header<false, Fields>& h1,
+    header<false, Fields>& h2)
+{
+    using std::swap;
+    swap(
+        static_cast<Fields&>(h1),
+        static_cast<Fields&>(h2));
+    swap(h1.version_, h2.version_);
+    swap(h1.result_, h2.result_);
+}
+
+//------------------------------------------------------------------------------
+
+template<bool isRequest, class Body, class Fields>
+template<class... BodyArgs>
+message<isRequest, Body, Fields>::
+message(header_type&& h, BodyArgs&&... body_args)
+    : header_type(std::move(h))
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArgs>(body_args)...)
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class... BodyArgs>
+message<isRequest, Body, Fields>::
+message(header_type const& h, BodyArgs&&... body_args)
+    : header_type(h)
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArgs>(body_args)...)
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class>
+message<isRequest, Body, Fields>::
+message(verb method, string_view target, Version version)
+    : header_type(method, target, version)
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class BodyArg, class>
+message<isRequest, Body, Fields>::
+message(verb method, string_view target,
+        Version version, BodyArg&& body_arg)
+    : header_type(method, target, version)
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArg>(body_arg))
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class BodyArg, class FieldsArg, class>
+message<isRequest, Body, Fields>::
+message(
+    verb method, string_view target, Version version,
+    BodyArg&& body_arg,
+    FieldsArg&& fields_arg)
+    : header_type(method, target, version,
+        std::forward<FieldsArg>(fields_arg))
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArg>(body_arg))
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class>
+message<isRequest, Body, Fields>::
+message(status result, Version version)
+    : header_type(result, version)
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class BodyArg, class>
+message<isRequest, Body, Fields>::
+message(status result, Version version,
+    BodyArg&& body_arg)
+    : header_type(result, version)
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArg>(body_arg))
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class Version, class BodyArg, class FieldsArg, class>
+message<isRequest, Body, Fields>::
+message(status result, Version version,
+    BodyArg&& body_arg, FieldsArg&& fields_arg)
+    : header_type(result, version,
+        std::forward<FieldsArg>(fields_arg))
+    , beast::detail::empty_base_optimization<
+        typename Body::value_type>(
+            std::forward<BodyArg>(body_arg))
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+message<isRequest, Body, Fields>::
+message(std::piecewise_construct_t)
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class... BodyArgs>
+message<isRequest, Body, Fields>::
+message(std::piecewise_construct_t,
+        std::tuple<BodyArgs...> body_args)
+    : message(std::piecewise_construct,
+        body_args,
+        beast::detail::make_index_sequence<
+            sizeof...(BodyArgs)>{})
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+template<class... BodyArgs, class... FieldsArgs>
+message<isRequest, Body, Fields>::
+message(std::piecewise_construct_t,
+    std::tuple<BodyArgs...> body_args,
+    std::tuple<FieldsArgs...> fields_args)
+    : message(std::piecewise_construct,
+        body_args,
+        fields_args,
+        beast::detail::make_index_sequence<
+            sizeof...(BodyArgs)>{},
+        beast::detail::make_index_sequence<
+            sizeof...(FieldsArgs)>{})
+{
+}
+
+template<bool isRequest, class Body, class Fields>
+void
+message<isRequest, Body, Fields>::
+chunked(bool value)
+{
+    this->set_chunked_impl(value);
+    this->set_content_length_impl(boost::none);
+}
+
+template<bool isRequest, class Body, class Fields>
+void
+message<isRequest, Body, Fields>::
+content_length(
+    boost::optional<std::uint64_t> const& value)
+{
+    this->set_content_length_impl(value);
+    this->set_chunked_impl(false);
+}
+
+template<bool isRequest, class Body, class Fields>
+boost::optional<std::uint64_t>
+message<isRequest, Body, Fields>::
+payload_size() const
+{
+    return payload_size(detail::is_body_sized<Body>{});
+}
+
+template<bool isRequest, class Body, class Fields>
+bool
+message<isRequest, Body, Fields>::
+need_eof(std::false_type) const
+{
+    // VFALCO Do we need a way to let the caller say "the body is intentionally skipped"?
+    if( this->result() == status::no_content ||
+        this->result() == status::not_modified ||
+        to_status_class(this->result()) ==
+            status_class::informational ||
+        has_content_length() ||
+        chunked())
+        return ! keep_alive();
+    return true;
+}
+
+template<bool isRequest, class Body, class Fields>
+void
+message<isRequest, Body, Fields>::
+prepare_payload(std::true_type)
+{
+    auto const n = payload_size();
+    if(this->method() == verb::trace && (! n || *n > 0))
+        BOOST_THROW_EXCEPTION(std::invalid_argument{
+            "invalid request body"});
+    if(n)
+    {
+        if(*n > 0 ||
+            this->method() == verb::options ||
+            this->method() == verb::put ||
+            this->method() == verb::post)
+        {
+            this->content_length(n);
+        }
+        else
+        {
+            this->chunked(false);
+        }
+    }
+    else if(this->version() == 11)
+    {
+        this->chunked(true);
+    }
+    else
+    {
+        this->chunked(false);
+    }
+}
+
+template<bool isRequest, class Body, class Fields>
+void
+message<isRequest, Body, Fields>::
+prepare_payload(std::false_type)
+{
+    auto const n = payload_size();
+    if( (! n || *n > 0) && (
+        (status_class(this->result()) == status_class::informational ||
+        this->result() == status::no_content ||
+        this->result() == status::not_modified)))
+    {
+        // The response body MUST be empty for this case
+        BOOST_THROW_EXCEPTION(std::invalid_argument{
+            "invalid response body"});
+    }
+    if(n)
+        this->content_length(n);
+    else if(this->version() == 11)
+        this->chunked(true);
+    else
+        this->chunked(false);
+}
+
+//------------------------------------------------------------------------------
+
+template<bool isRequest, class Body, class Fields>
+void
+swap(
+    message<isRequest, Body, Fields>& m1,
+    message<isRequest, Body, Fields>& m2)
+{
+    using std::swap;
+    swap(
+        static_cast<header<isRequest, Fields>&>(m1),
+        static_cast<header<isRequest, Fields>&>(m2));
+    swap(m1.body(), m2.body());
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/parser.ipp b/boost/beast/http/impl/parser.ipp
new file mode 100644
index 0000000000..99745da3f0
--- /dev/null
+++ b/boost/beast/http/impl/parser.ipp
@@ -0,0 +1,56 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_PARSER_IPP
+#define BOOST_BEAST_HTTP_IMPL_PARSER_IPP
+
+#include <boost/throw_exception.hpp>
+#include <stdexcept>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+template<bool isRequest, class Body, class Allocator>
+parser<isRequest, Body, Allocator>::
+parser()
+    : wr_(m_)
+{
+}
+
+template<bool isRequest, class Body, class Allocator>
+template<class Arg1, class... ArgN, class>
+parser<isRequest, Body, Allocator>::
+parser(Arg1&& arg1, ArgN&&... argn)
+    : m_(std::forward<Arg1>(arg1),
+        std::forward<ArgN>(argn)...)
+    , wr_(m_)
+{
+    m_.clear();
+}
+
+template<bool isRequest, class Body, class Allocator>
+template<class OtherBody, class... Args, class>
+parser<isRequest, Body, Allocator>::
+parser(parser<isRequest, OtherBody, Allocator>&& other,
+        Args&&... args)
+    : base_type(std::move(other))
+    , m_(other.release(), std::forward<Args>(args)...)
+    , wr_(m_)
+{
+    if(other.rd_inited_)
+        BOOST_THROW_EXCEPTION(std::invalid_argument{
+            "moved-from parser has a body"});
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/read.ipp b/boost/beast/http/impl/read.ipp
new file mode 100644
index 0000000000..5ecfae7d8b
--- /dev/null
+++ b/boost/beast/http/impl/read.ipp
@@ -0,0 +1,821 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_READ_IPP_HPP
+#define BOOST_BEAST_HTTP_IMPL_READ_IPP_HPP
+
+#include <boost/beast/http/type_traits.hpp>
+#include <boost/beast/http/error.hpp>
+#include <boost/beast/http/parser.hpp>
+#include <boost/beast/http/read.hpp>
+#include <boost/beast/core/bind_handler.hpp>
+#include <boost/beast/core/handler_ptr.hpp>
+#include <boost/beast/core/read_size.hpp>
+#include <boost/beast/core/type_traits.hpp>
+#include <boost/asio/associated_allocator.hpp>
+#include <boost/asio/associated_executor.hpp>
+#include <boost/asio/handler_continuation_hook.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/optional.hpp>
+#include <boost/throw_exception.hpp>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+namespace detail {
+
+//------------------------------------------------------------------------------
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Derived, class Handler>
+class read_some_op
+{
+    int state_ = 0;
+    Stream& s_;
+    DynamicBuffer& b_;
+    basic_parser<isRequest, Derived>& p_;
+    boost::optional<typename
+        DynamicBuffer::mutable_buffers_type> mb_;
+    std::size_t bytes_transferred_ = 0;
+    Handler h_;
+
+public:
+    read_some_op(read_some_op&&) = default;
+    read_some_op(read_some_op const&) = default;
+
+    template<class DeducedHandler>
+    read_some_op(DeducedHandler&& h, Stream& s,
+        DynamicBuffer& b, basic_parser<isRequest, Derived>& p)
+        : s_(s)
+        , b_(b)
+        , p_(p)
+        , h_(std::forward<DeducedHandler>(h))
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(h_);
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            h_, s_.get_executor());
+    }
+
+    void
+    operator()(
+        error_code ec = {},
+        std::size_t bytes_transferred = 0);
+
+    friend
+    bool asio_handler_is_continuation(read_some_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return op->state_ >= 2 ? true :
+            asio_handler_is_continuation(
+                std::addressof(op->h_));
+    }
+};
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Derived, class Handler>
+void
+read_some_op<Stream, DynamicBuffer,
+    isRequest, Derived, Handler>::
+operator()(
+    error_code ec,
+    std::size_t bytes_transferred)
+{
+    switch(state_)
+    {
+    case 0:
+        state_ = 1;
+        if(b_.size() == 0)
+            goto do_read;
+        goto do_parse;
+
+    case 1:
+        state_ = 2;
+    case 2:
+        if(ec == boost::asio::error::eof)
+        {
+            BOOST_ASSERT(bytes_transferred == 0);
+            if(p_.got_some())
+            {
+                // caller sees EOF on next read
+                ec.assign(0, ec.category());
+                p_.put_eof(ec);
+                if(ec)
+                    goto upcall;
+                BOOST_ASSERT(p_.is_done());
+                goto upcall;
+            }
+            ec = error::end_of_stream;
+            goto upcall;
+        }
+        if(ec)
+            goto upcall;
+        b_.commit(bytes_transferred);
+
+    do_parse:
+    {
+        auto const used = p_.put(b_.data(), ec);
+        bytes_transferred_ += used;
+        b_.consume(used);
+        if(! ec || ec != http::error::need_more)
+            goto do_upcall;
+        ec.assign(0, ec.category());
+    }
+
+    do_read:
+        try
+        {
+            mb_.emplace(b_.prepare(
+                read_size_or_throw(b_, 65536)));
+        }
+        catch(std::length_error const&)
+        {
+            ec = error::buffer_overflow;
+            goto do_upcall;
+        }
+        return s_.async_read_some(*mb_, std::move(*this));
+
+    do_upcall:
+        if(state_ >= 2)
+            goto upcall;
+        state_ = 3;
+        return boost::asio::post(
+            s_.get_executor(),
+            bind_handler(std::move(*this), ec, 0));
+
+    case 3:
+        break;
+    }
+upcall:
+    h_(ec, bytes_transferred_);
+}
+
+//------------------------------------------------------------------------------
+
+struct parser_is_done
+{
+    template<bool isRequest, class Derived>
+    bool
+    operator()(basic_parser<
+        isRequest, Derived> const& p) const
+    {
+        return p.is_done();
+    }
+};
+
+struct parser_is_header_done
+{
+    template<bool isRequest, class Derived>
+    bool
+    operator()(basic_parser<
+        isRequest, Derived> const& p) const
+    {
+        return p.is_header_done();
+    }
+};
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Derived, class Condition,
+        class Handler>
+class read_op
+{
+    int state_ = 0;
+    Stream& s_;
+    DynamicBuffer& b_;
+    basic_parser<isRequest, Derived>& p_;
+    std::size_t bytes_transferred_ = 0;
+    Handler h_;
+
+public:
+    read_op(read_op&&) = default;
+    read_op(read_op const&) = default;
+
+    template<class DeducedHandler>
+    read_op(DeducedHandler&& h, Stream& s,
+        DynamicBuffer& b, basic_parser<isRequest,
+            Derived>& p)
+        : s_(s)
+        , b_(b)
+        , p_(p)
+        , h_(std::forward<DeducedHandler>(h))
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(h_);
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            h_, s_.get_executor());
+    }
+
+    void
+    operator()(
+        error_code ec = {},
+        std::size_t bytes_transferred = 0);
+
+    friend
+    bool asio_handler_is_continuation(read_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return op->state_ >= 3 ? true :
+            asio_handler_is_continuation(
+                std::addressof(op->h_));
+    }
+};
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Derived, class Condition,
+        class Handler>
+void
+read_op<Stream, DynamicBuffer,
+    isRequest, Derived, Condition, Handler>::
+operator()(
+    error_code ec,
+    std::size_t bytes_transferred)
+{
+    switch(state_)
+    {
+    case 0:
+        if(Condition{}(p_))
+        {
+            state_ = 1;
+            return boost::asio::post(
+                s_.get_executor(),
+                bind_handler(std::move(*this), ec));
+        }
+        state_ = 2;
+
+    do_read:
+        return async_read_some(
+            s_, b_, p_, std::move(*this));
+
+    case 1:
+        goto upcall;
+
+    case 2:
+    case 3:
+        if(ec)
+            goto upcall;
+        bytes_transferred_ += bytes_transferred;
+        if(Condition{}(p_))
+            goto upcall;
+        state_ = 3;
+        goto do_read;
+    }
+upcall:
+    h_(ec, bytes_transferred_);
+}
+
+//------------------------------------------------------------------------------
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Body, class Allocator,
+        class Handler>
+class read_msg_op
+{
+    using parser_type =
+        parser<isRequest, Body, Allocator>;
+
+    using message_type =
+        typename parser_type::value_type;
+
+    struct data
+    {
+        int state = 0;
+        Stream& s;
+        DynamicBuffer& b;
+        message_type& m;
+        parser_type p;
+        std::size_t bytes_transferred = 0;
+
+        data(Handler&, Stream& s_,
+                DynamicBuffer& b_, message_type& m_)
+            : s(s_)
+            , b(b_)
+            , m(m_)
+            , p(std::move(m))
+        {
+            p.eager(true);
+        }
+    };
+
+    handler_ptr<data, Handler> d_;
+
+public:
+    read_msg_op(read_msg_op&&) = default;
+    read_msg_op(read_msg_op const&) = default;
+
+    template<class DeducedHandler, class... Args>
+    read_msg_op(DeducedHandler&& h, Stream& s, Args&&... args)
+        : d_(std::forward<DeducedHandler>(h),
+            s, std::forward<Args>(args)...)
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(d_.handler());
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            d_.handler(), d_->s.get_executor());
+    }
+
+    void
+    operator()(
+        error_code ec = {},
+        std::size_t bytes_transferred = 0);
+
+    friend
+    bool asio_handler_is_continuation(read_msg_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return op->d_->state >= 2 ? true :
+            asio_handler_is_continuation(
+                std::addressof(op->d_.handler()));
+    }
+};
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Body, class Allocator,
+        class Handler>
+void
+read_msg_op<Stream, DynamicBuffer,
+    isRequest, Body, Allocator, Handler>::
+operator()(
+    error_code ec,
+    std::size_t bytes_transferred)
+{
+    auto& d = *d_;
+    switch(d.state)
+    {
+    case 0:
+        d.state = 1;
+
+    do_read:
+        return async_read_some(
+            d.s, d.b, d.p, std::move(*this));
+
+    case 1:
+    case 2:
+        if(ec)
+            goto upcall;
+        d.bytes_transferred +=
+            bytes_transferred;
+        if(d.p.is_done())
+        {
+            d.m = d.p.release();
+            goto upcall;
+        }
+        d.state = 2;
+        goto do_read;
+    }
+upcall:
+    bytes_transferred = d.bytes_transferred;
+    d_.invoke(ec, bytes_transferred);
+}
+
+} // detail
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read_some(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    BOOST_ASSERT(! parser.is_done());
+    error_code ec;
+    auto const bytes_transferred =
+        read_some(stream, buffer, parser, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read_some(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    error_code& ec)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    BOOST_ASSERT(! parser.is_done());
+    std::size_t bytes_transferred = 0;
+    if(buffer.size() == 0)
+        goto do_read;
+    for(;;)
+    {
+        // invoke parser
+        {
+            auto const n = parser.put(buffer.data(), ec);
+            bytes_transferred += n;
+            buffer.consume(n);
+            if(! ec)
+                break;
+            if(ec != http::error::need_more)
+                break;
+        }
+    do_read:
+        boost::optional<typename
+            DynamicBuffer::mutable_buffers_type> b;
+        try
+        {
+            b.emplace(buffer.prepare(
+                read_size_or_throw(buffer, 65536)));
+        }
+        catch(std::length_error const&)
+        {
+            ec = error::buffer_overflow;
+            return bytes_transferred;
+        }
+        auto const n = stream.read_some(*b, ec);
+        if(ec == boost::asio::error::eof)
+        {
+            BOOST_ASSERT(n == 0);
+            if(parser.got_some())
+            {
+                // caller sees EOF on next read
+                parser.put_eof(ec);
+                if(ec)
+                    break;
+                BOOST_ASSERT(parser.is_done());
+                break;
+            }
+            ec = error::end_of_stream;
+            break;
+        }
+        if(ec)
+            break;
+        buffer.commit(n);
+    }
+    return bytes_transferred;
+}
+
+template<
+    class AsyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived,
+    class ReadHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    ReadHandler, void(error_code, std::size_t))
+async_read_some(
+    AsyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    ReadHandler&& handler)
+{
+    static_assert(is_async_read_stream<AsyncReadStream>::value,
+        "AsyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    BOOST_ASSERT(! parser.is_done());
+    boost::asio::async_completion<ReadHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::read_some_op<AsyncReadStream,
+        DynamicBuffer, isRequest, Derived, BOOST_ASIO_HANDLER_TYPE(
+            ReadHandler, void(error_code, std::size_t))>{
+                init.completion_handler, stream, buffer, parser}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read_header(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        read_header(stream, buffer, parser, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read_header(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    error_code& ec)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    parser.eager(false);
+    if(parser.is_header_done())
+    {
+        ec.assign(0, ec.category());
+        return 0;
+    }
+    std::size_t bytes_transferred = 0;
+    do
+    {
+        bytes_transferred += read_some(
+            stream, buffer, parser, ec);
+        if(ec)
+            return bytes_transferred;
+    }
+    while(! parser.is_header_done());
+    return bytes_transferred;
+}
+
+template<
+    class AsyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived,
+    class ReadHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    ReadHandler, void(error_code, std::size_t))
+async_read_header(
+    AsyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    ReadHandler&& handler)
+{
+    static_assert(is_async_read_stream<AsyncReadStream>::value,
+        "AsyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    parser.eager(false);
+    boost::asio::async_completion<ReadHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::read_op<AsyncReadStream, DynamicBuffer,
+        isRequest, Derived, detail::parser_is_header_done,
+            BOOST_ASIO_HANDLER_TYPE(ReadHandler, void(error_code, std::size_t))>{
+                init.completion_handler, stream, buffer, parser}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        read(stream, buffer, parser, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived>
+std::size_t
+read(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    error_code& ec)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    parser.eager(true);
+    if(parser.is_done())
+    {
+        ec.assign(0, ec.category());
+        return 0;
+    }
+    std::size_t bytes_transferred = 0;
+    do
+    {
+        bytes_transferred += read_some(
+            stream, buffer, parser, ec);
+        if(ec)
+            return bytes_transferred;
+    }
+    while(! parser.is_done());
+    return bytes_transferred;
+}
+
+template<
+    class AsyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Derived,
+    class ReadHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    ReadHandler, void(error_code, std::size_t))
+async_read(
+    AsyncReadStream& stream,
+    DynamicBuffer& buffer,
+    basic_parser<isRequest, Derived>& parser,
+    ReadHandler&& handler)
+{
+    static_assert(is_async_read_stream<AsyncReadStream>::value,
+        "AsyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    parser.eager(true);
+    boost::asio::async_completion<
+        ReadHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::read_op<AsyncReadStream, DynamicBuffer,
+        isRequest, Derived, detail::parser_is_done,
+            BOOST_ASIO_HANDLER_TYPE(ReadHandler, void(error_code, std::size_t))>{
+                init.completion_handler, stream, buffer, parser}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Body, class Allocator>
+std::size_t
+read(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    message<isRequest, Body, basic_fields<Allocator>>& msg)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_reader<Body>::value,
+        "BodyReader requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        read(stream, buffer, msg, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Body, class Allocator>
+std::size_t
+read(
+    SyncReadStream& stream,
+    DynamicBuffer& buffer,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
+    error_code& ec)
+{
+    static_assert(is_sync_read_stream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_reader<Body>::value,
+        "BodyReader requirements not met");
+    parser<isRequest, Body, Allocator> p{std::move(msg)};
+    p.eager(true);
+    auto const bytes_transferred =
+        read(stream, buffer, p.base(), ec);
+    if(ec)
+        return bytes_transferred;
+    msg = p.release();
+    return bytes_transferred;
+}
+
+template<
+    class AsyncReadStream,
+    class DynamicBuffer,
+    bool isRequest, class Body, class Allocator,
+    class ReadHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    ReadHandler, void(error_code, std::size_t))
+async_read(
+    AsyncReadStream& stream,
+    DynamicBuffer& buffer,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
+    ReadHandler&& handler)
+{
+    static_assert(is_async_read_stream<AsyncReadStream>::value,
+        "AsyncReadStream requirements not met");
+    static_assert(
+        boost::asio::is_dynamic_buffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_reader<Body>::value,
+        "BodyReader requirements not met");
+    boost::asio::async_completion<
+        ReadHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::read_msg_op<
+        AsyncReadStream,
+        DynamicBuffer,
+        isRequest, Body, Allocator,
+        BOOST_ASIO_HANDLER_TYPE(
+            ReadHandler, void(error_code, std::size_t))>{
+                init.completion_handler, stream, buffer, msg}();
+    return init.result.get();
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/rfc7230.ipp b/boost/beast/http/impl/rfc7230.ipp
new file mode 100644
index 0000000000..96ec902ceb
--- /dev/null
+++ b/boost/beast/http/impl/rfc7230.ipp
@@ -0,0 +1,572 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_RFC7230_IPP
+#define BOOST_BEAST_HTTP_IMPL_RFC7230_IPP
+
+#include <boost/beast/http/detail/rfc7230.hpp>
+#include <iterator>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+class param_list::const_iterator
+{
+    using iter_type = string_view::const_iterator;
+
+    std::string s_;
+    detail::param_iter pi_;
+
+public:
+    using value_type = param_list::value_type;
+    using pointer = value_type const*;
+    using reference = value_type const&;
+    using difference_type = std::ptrdiff_t;
+    using iterator_category = std::input_iterator_tag;
+
+    const_iterator() = default;
+
+    bool
+    operator==(const_iterator const& other) const
+    {
+        return
+            other.pi_.it == pi_.it &&
+            other.pi_.last == pi_.last &&
+            other.pi_.first == pi_.first;
+    }
+
+    bool
+    operator!=(const_iterator const& other) const
+    {
+        return !(*this == other);
+    }
+
+    reference
+    operator*() const
+    {
+        return pi_.v;
+    }
+
+    pointer
+    operator->() const
+    {
+        return &*(*this);
+    }
+
+    const_iterator&
+    operator++()
+    {
+        increment();
+        return *this;
+    }
+
+    const_iterator
+    operator++(int)
+    {
+        auto temp = *this;
+        ++(*this);
+        return temp;
+    }
+
+private:
+    friend class param_list;
+
+    const_iterator(iter_type first, iter_type last)
+    {
+        pi_.it = first;
+        pi_.first = first;
+        pi_.last = last;
+        increment();
+    }
+
+    template<class = void>
+    static
+    std::string
+    unquote(string_view sr);
+
+    template<class = void>
+    void
+    increment();
+};
+
+inline
+auto
+param_list::
+begin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+param_list::
+end() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+inline
+auto
+param_list::
+cbegin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+param_list::
+cend() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+template<class>
+std::string
+param_list::const_iterator::
+unquote(string_view sr)
+{
+    std::string s;
+    s.reserve(sr.size());
+    auto it = sr.begin() + 1;
+    auto end = sr.end() - 1;
+    while(it != end)
+    {
+        if(*it == '\\')
+            ++it;
+        s.push_back(*it);
+        ++it;
+    }
+    return s;
+}
+
+template<class>
+void
+param_list::const_iterator::
+increment()
+{
+    s_.clear();
+    pi_.increment();
+    if(pi_.empty())
+    {
+        pi_.it = pi_.last;
+        pi_.first = pi_.last;
+    }
+    else if(! pi_.v.second.empty() &&
+        pi_.v.second.front() == '"')
+    {
+        s_ = unquote(pi_.v.second);
+        pi_.v.second = string_view{
+            s_.data(), s_.size()};
+    }
+}
+
+//------------------------------------------------------------------------------
+
+class ext_list::const_iterator
+{
+    ext_list::value_type v_;
+    iter_type it_;
+    iter_type first_;
+    iter_type last_;
+
+public:
+    using value_type = ext_list::value_type;
+    using pointer = value_type const*;
+    using reference = value_type const&;
+    using difference_type = std::ptrdiff_t;
+    using iterator_category = std::forward_iterator_tag;
+
+    const_iterator() = default;
+
+    bool
+    operator==(const_iterator const& other) const
+    {
+        return
+            other.it_ == it_ &&
+            other.first_ == first_ &&
+            other.last_ == last_;
+    }
+
+    bool
+    operator!=(const_iterator const& other) const
+    {
+        return !(*this == other);
+    }
+
+    reference
+    operator*() const
+    {
+        return v_;
+    }
+
+    pointer
+    operator->() const
+    {
+        return &*(*this);
+    }
+
+    const_iterator&
+    operator++()
+    {
+        increment();
+        return *this;
+    }
+
+    const_iterator
+    operator++(int)
+    {
+        auto temp = *this;
+        ++(*this);
+        return temp;
+    }
+
+private:
+    friend class ext_list;
+
+    const_iterator(iter_type begin, iter_type end)
+    {
+        it_ = begin;
+        first_ = begin;
+        last_ = end;
+        increment();
+    }
+
+    template<class = void>
+    void
+    increment();
+};
+
+inline
+auto
+ext_list::
+begin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+ext_list::
+end() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+inline
+auto
+ext_list::
+cbegin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+ext_list::
+cend() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+template<class T>
+auto
+ext_list::
+find(T const& s) ->
+    const_iterator
+{
+    return std::find_if(begin(), end(),
+        [&s](value_type const& v)
+        {
+            return iequals(s, v.first);
+        });
+}
+
+template<class T>
+bool
+ext_list::
+exists(T const& s)
+{
+    return find(s) != end();
+}
+
+template<class>
+void
+ext_list::const_iterator::
+increment()
+{
+    /*
+        ext-list    = *( "," OWS ) ext *( OWS "," [ OWS ext ] )
+        ext         = token param-list
+        param-list  = *( OWS ";" OWS param )
+        param       = token OWS "=" OWS ( token / quoted-string )
+
+        chunked;a=b;i=j,gzip;windowBits=12
+        x,y
+        ,,,,,chameleon
+    */
+    auto const err =
+        [&]
+        {
+            it_ = last_;
+            first_ = last_;
+        };
+    auto need_comma = it_ != first_;
+    v_.first = {};
+    first_ = it_;
+    for(;;)
+    {
+        detail::skip_ows(it_, last_);
+        if(it_ == last_)
+            return err();
+        auto const c = *it_;
+        if(detail::is_token_char(c))
+        {
+            if(need_comma)
+                return err();
+            auto const p0 = it_;
+            for(;;)
+            {
+                ++it_;
+                if(it_ == last_)
+                    break;
+                if(! detail::is_token_char(*it_))
+                    break;
+            }
+            v_.first = string_view{&*p0,
+                static_cast<std::size_t>(it_ - p0)};
+            detail::param_iter pi;
+            pi.it = it_;
+            pi.first = it_;
+            pi.last = last_;
+            for(;;)
+            {
+                pi.increment();
+                if(pi.empty())
+                    break;
+            }
+            v_.second = param_list{string_view{&*it_,
+                static_cast<std::size_t>(pi.it - it_)}};
+            it_ = pi.it;
+            return;
+        }
+        if(c != ',')
+            return err();
+        need_comma = false;
+        ++it_;
+    }
+}
+
+//------------------------------------------------------------------------------
+
+class token_list::const_iterator
+{
+    token_list::value_type v_;
+    iter_type it_;
+    iter_type first_;
+    iter_type last_;
+
+public:
+    using value_type = token_list::value_type;
+    using pointer = value_type const*;
+    using reference = value_type const&;
+    using difference_type = std::ptrdiff_t;
+    using iterator_category = std::forward_iterator_tag;
+
+    const_iterator() = default;
+
+    bool
+    operator==(const_iterator const& other) const
+    {
+        return
+            other.it_ == it_ &&
+            other.first_ == first_ &&
+            other.last_ == last_;
+    }
+
+    bool
+    operator!=(const_iterator const& other) const
+    {
+        return !(*this == other);
+    }
+
+    reference
+    operator*() const
+    {
+        return v_;
+    }
+
+    pointer
+    operator->() const
+    {
+        return &*(*this);
+    }
+
+    const_iterator&
+    operator++()
+    {
+        increment();
+        return *this;
+    }
+
+    const_iterator
+    operator++(int)
+    {
+        auto temp = *this;
+        ++(*this);
+        return temp;
+    }
+
+private:
+    friend class token_list;
+
+    const_iterator(iter_type begin, iter_type end)
+    {
+        it_ = begin;
+        first_ = begin;
+        last_ = end;
+        increment();
+    }
+
+    template<class = void>
+    void
+    increment();
+};
+
+inline
+auto
+token_list::
+begin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+token_list::
+end() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+inline
+auto
+token_list::
+cbegin() const ->
+    const_iterator
+{
+    return const_iterator{s_.begin(), s_.end()};
+}
+
+inline
+auto
+token_list::
+cend() const ->
+    const_iterator
+{
+    return const_iterator{s_.end(), s_.end()};
+}
+
+template<class>
+void
+token_list::const_iterator::
+increment()
+{
+    /*
+        token-list  = *( "," OWS ) token *( OWS "," [ OWS ext ] )
+    */
+    auto const err =
+        [&]
+        {
+            it_ = last_;
+            first_ = last_;
+        };
+    auto need_comma = it_ != first_;
+    v_ = {};
+    first_ = it_;
+    for(;;)
+    {
+        detail::skip_ows(it_, last_);
+        if(it_ == last_)
+            return err();
+        auto const c = *it_;
+        if(detail::is_token_char(c))
+        {
+            if(need_comma)
+                return err();
+            auto const p0 = it_;
+            for(;;)
+            {
+                ++it_;
+                if(it_ == last_)
+                    break;
+                if(! detail::is_token_char(*it_))
+                    break;
+            }
+            v_ = string_view{&*p0,
+                static_cast<std::size_t>(it_ - p0)};
+            return;
+        }
+        if(c != ',')
+            return err();
+        need_comma = false;
+        ++it_;
+    }
+}
+
+template<class T>
+bool
+token_list::
+exists(T const& s)
+{
+    return std::find_if(begin(), end(),
+        [&s](value_type const& v)
+        {
+            return iequals(s, v);
+        }
+    ) != end();
+}
+
+template<class Policy>
+bool
+validate_list(detail::basic_parsed_list<
+    Policy> const& list)
+{
+    auto const last = list.end();
+    auto it = list.begin();
+    if(it.error())
+        return false;
+    while(it != last)
+    {
+        ++it;
+        if(it.error())
+            return false;
+        if(it == last)
+            break;
+    }
+    return true;
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
+
diff --git a/boost/beast/http/impl/serializer.ipp b/boost/beast/http/impl/serializer.ipp
new file mode 100644
index 0000000000..11cf857845
--- /dev/null
+++ b/boost/beast/http/impl/serializer.ipp
@@ -0,0 +1,430 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_SERIALIZER_IPP
+#define BOOST_BEAST_HTTP_IMPL_SERIALIZER_IPP
+
+#include <boost/beast/core/detail/buffers_ref.hpp>
+#include <boost/beast/http/error.hpp>
+#include <boost/beast/http/status.hpp>
+#include <boost/beast/core/detail/config.hpp>
+#include <boost/assert.hpp>
+#include <ostream>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+template<
+    bool isRequest, class Body, class Fields>
+void
+serializer<isRequest, Body, Fields>::
+frdinit(std::true_type)
+{
+    frd_.emplace(m_, m_.version(), m_.method());
+}
+
+template<
+    bool isRequest, class Body, class Fields>
+void
+serializer<isRequest, Body, Fields>::
+frdinit(std::false_type)
+{
+    frd_.emplace(m_, m_.version(), m_.result_int());
+}
+
+template<
+    bool isRequest, class Body, class Fields>
+template<std::size_t I, class Visit>
+inline
+void
+serializer<isRequest, Body, Fields>::
+do_visit(error_code& ec, Visit& visit)
+{
+    pv_.template emplace<I>(limit_, v_.template get<I>());
+    visit(ec, beast::detail::make_buffers_ref(
+        pv_.template get<I>()));
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    bool isRequest, class Body, class Fields>
+serializer<isRequest, Body, Fields>::
+serializer(value_type& m)
+    : m_(m)
+    , rd_(m_)
+{
+}
+
+template<
+    bool isRequest, class Body, class Fields>
+template<class Visit>
+void
+serializer<isRequest, Body, Fields>::
+next(error_code& ec, Visit&& visit)
+{
+    using boost::asio::buffer_size;
+    switch(s_)
+    {
+    case do_construct:
+    {
+        frdinit(std::integral_constant<bool,
+            isRequest>{});
+        if(m_.chunked())
+            goto go_init_c;
+        s_ = do_init;
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case do_init:
+    {
+        rd_.init(ec);
+        if(ec)
+            return;
+        if(split_)
+            goto go_header_only;
+        auto result = rd_.get(ec);
+        if(ec == error::need_more)
+            goto go_header_only;
+        if(ec)
+            return;
+        if(! result)
+            goto go_header_only;
+        more_ = result->second;
+        v_.template emplace<2>(
+            boost::in_place_init,
+            frd_->get(),
+            result->first);
+        s_ = do_header;
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case do_header:
+        do_visit<2>(ec, visit);
+        break;
+
+    go_header_only:
+        v_.template emplace<1>(frd_->get());
+        s_ = do_header_only;
+        BOOST_BEAST_FALLTHROUGH;
+    case do_header_only:
+        do_visit<1>(ec, visit);
+        break;
+
+    case do_body:
+        s_ = do_body + 1;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case do_body + 1:
+    {
+        auto result = rd_.get(ec);
+        if(ec)
+            return;
+        if(! result)
+            goto go_complete;
+        more_ = result->second;
+        v_.template emplace<3>(result->first);
+        s_ = do_body + 2;
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case do_body + 2:
+        do_visit<3>(ec, visit);
+        break;
+
+    //----------------------------------------------------------------------
+
+        go_init_c:
+        s_ = do_init_c;
+        BOOST_BEAST_FALLTHROUGH;
+    case do_init_c:
+    {
+        rd_.init(ec);
+        if(ec)
+            return;
+        if(split_)
+            goto go_header_only_c;
+        auto result = rd_.get(ec);
+        if(ec == error::need_more)
+            goto go_header_only_c;
+        if(ec)
+            return;
+        if(! result)
+            goto go_header_only_c;
+        more_ = result->second;
+        if(! more_)
+        {
+            // do it all in one buffer
+            v_.template emplace<7>(
+                boost::in_place_init,
+                frd_->get(),
+                buffer_size(result->first),
+                boost::asio::const_buffer{nullptr, 0},
+                chunk_crlf{},
+                result->first,
+                chunk_crlf{},
+                detail::chunk_last(),
+                boost::asio::const_buffer{nullptr, 0},
+                chunk_crlf{});
+            goto go_all_c;
+        }
+        v_.template emplace<4>(
+            boost::in_place_init,
+            frd_->get(),
+            buffer_size(result->first),
+            boost::asio::const_buffer{nullptr, 0},
+            chunk_crlf{},
+            result->first,
+            chunk_crlf{});
+        s_ = do_header_c;
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case do_header_c:
+        do_visit<4>(ec, visit);
+        break;
+
+    go_header_only_c:
+        v_.template emplace<1>(frd_->get());
+        s_ = do_header_only_c;
+    case do_header_only_c:
+        do_visit<1>(ec, visit);
+        break;
+
+    case do_body_c:
+        s_ = do_body_c + 1;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case do_body_c + 1:
+    {
+        auto result = rd_.get(ec);
+        if(ec)
+            return;
+        if(! result)
+            goto go_final_c;
+        more_ = result->second;
+        if(! more_)
+        {
+            // do it all in one buffer
+            v_.template emplace<6>(
+                boost::in_place_init,
+                buffer_size(result->first),
+                boost::asio::const_buffer{nullptr, 0},
+                chunk_crlf{},
+                result->first,
+                chunk_crlf{},
+                detail::chunk_last(),
+                boost::asio::const_buffer{nullptr, 0},
+                chunk_crlf{});
+            goto go_body_final_c;
+        }
+        v_.template emplace<5>(
+            boost::in_place_init,
+            buffer_size(result->first),
+            boost::asio::const_buffer{nullptr, 0},
+            chunk_crlf{},
+            result->first,
+            chunk_crlf{});
+        s_ = do_body_c + 2;
+        BOOST_BEAST_FALLTHROUGH;
+    }
+
+    case do_body_c + 2:
+        do_visit<5>(ec, visit);
+        break;
+
+    go_body_final_c:
+        s_ = do_body_final_c;
+        BOOST_BEAST_FALLTHROUGH;
+    case do_body_final_c:
+        do_visit<6>(ec, visit);
+        break;
+
+    go_all_c:
+        s_ = do_all_c;
+        BOOST_BEAST_FALLTHROUGH;
+    case do_all_c:
+        do_visit<7>(ec, visit);
+        break;
+
+    go_final_c:
+    case do_final_c:
+        v_.template emplace<8>(
+            boost::in_place_init,
+            detail::chunk_last(),
+            boost::asio::const_buffer{nullptr, 0},
+            chunk_crlf{});
+        s_ = do_final_c + 1;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case do_final_c + 1:
+        do_visit<8>(ec, visit);
+        break;
+
+    //----------------------------------------------------------------------
+
+    default:
+    case do_complete:
+        BOOST_ASSERT(false);
+        break;
+
+    go_complete:
+        s_ = do_complete;
+        break;
+    }
+}
+
+template<
+    bool isRequest, class Body, class Fields>
+void
+serializer<isRequest, Body, Fields>::
+consume(std::size_t n)
+{
+    using boost::asio::buffer_size;
+    switch(s_)
+    {
+    case do_header:
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<2>()));
+        v_.template get<2>().consume(n);
+        if(buffer_size(v_.template get<2>()) > 0)
+            break;
+        header_done_ = true;
+        v_.reset();
+        if(! more_)
+            goto go_complete;
+        s_ = do_body + 1;
+        break;
+
+    case do_header_only:
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<1>()));
+        v_.template get<1>().consume(n);
+        if(buffer_size(v_.template get<1>()) > 0)
+            break;
+        frd_ = boost::none;
+        header_done_ = true;
+        if(! split_)
+            goto go_complete;
+        s_ = do_body;
+        break;
+
+    case do_body + 2:
+    {
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<3>()));
+        v_.template get<3>().consume(n);
+        if(buffer_size(v_.template get<3>()) > 0)
+            break;
+        v_.reset();
+        if(! more_)
+            goto go_complete;
+        s_ = do_body + 1;
+        break;
+    }
+
+    //----------------------------------------------------------------------
+
+    case do_header_c:
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<4>()));
+        v_.template get<4>().consume(n);
+        if(buffer_size(v_.template get<4>()) > 0)
+            break;
+        header_done_ = true;
+        v_.reset();
+        if(more_)
+            s_ = do_body_c + 1;
+        else
+            s_ = do_final_c;
+        break;
+
+    case do_header_only_c:
+    {
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<1>()));
+        v_.template get<1>().consume(n);
+        if(buffer_size(v_.template get<1>()) > 0)
+            break;
+        frd_ = boost::none;
+        header_done_ = true;
+        if(! split_)
+        {
+            s_ = do_final_c;
+            break;
+        }
+        s_ = do_body_c;
+        break;
+    }
+
+    case do_body_c + 2:
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<5>()));
+        v_.template get<5>().consume(n);
+        if(buffer_size(v_.template get<5>()) > 0)
+            break;
+        v_.reset();
+        if(more_)
+            s_ = do_body_c + 1;
+        else
+            s_ = do_final_c;
+        break;
+
+    case do_body_final_c:
+    {
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<6>()));
+        v_.template get<6>().consume(n);
+        if(buffer_size(v_.template get<6>()) > 0)
+            break;
+        v_.reset();
+        s_ = do_complete;
+        break;
+    }
+
+    case do_all_c:
+    {
+        BOOST_ASSERT(
+            n <= buffer_size(v_.template get<7>()));
+        v_.template get<7>().consume(n);
+        if(buffer_size(v_.template get<7>()) > 0)
+            break;
+        header_done_ = true;
+        v_.reset();
+        s_ = do_complete;
+        break;
+    }
+
+    case do_final_c + 1:
+        BOOST_ASSERT(buffer_size(v_.template get<8>()));
+        v_.template get<8>().consume(n);
+        if(buffer_size(v_.template get<8>()) > 0)
+            break;
+        v_.reset();
+        goto go_complete;
+
+    //----------------------------------------------------------------------
+
+    default:
+        BOOST_ASSERT(false);
+    case do_complete:
+        break;
+
+    go_complete:
+        s_ = do_complete;
+        break;
+    }
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/status.ipp b/boost/beast/http/impl/status.ipp
new file mode 100644
index 0000000000..1cc8f34b63
--- /dev/null
+++ b/boost/beast/http/impl/status.ipp
@@ -0,0 +1,252 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_STATUS_IPP
+#define BOOST_BEAST_HTTP_IMPL_STATUS_IPP
+
+#include <boost/beast/core/detail/config.hpp>
+#include <boost/throw_exception.hpp>
+
+namespace boost {
+namespace beast {
+namespace http {
+namespace detail {
+
+template<class = void>
+status
+int_to_status(unsigned v)
+{
+    switch(static_cast<status>(v))
+    {
+    // 1xx
+    case status::continue_:
+    case status::switching_protocols:
+    case status::processing:
+        BOOST_BEAST_FALLTHROUGH;
+
+    // 2xx
+    case status::ok:
+    case status::created:
+    case status::accepted:
+    case status::non_authoritative_information:
+    case status::no_content:
+    case status::reset_content:
+    case status::partial_content:
+    case status::multi_status:
+    case status::already_reported:
+    case status::im_used:
+        BOOST_BEAST_FALLTHROUGH;
+
+    // 3xx
+    case status::multiple_choices:
+    case status::moved_permanently:
+    case status::found:
+    case status::see_other:
+    case status::not_modified:
+    case status::use_proxy:
+    case status::temporary_redirect:
+    case status::permanent_redirect:
+        BOOST_BEAST_FALLTHROUGH;
+
+    // 4xx
+    case status::bad_request:
+    case status::unauthorized:
+    case status::payment_required:
+    case status::forbidden:
+    case status::not_found:
+    case status::method_not_allowed:
+    case status::not_acceptable:
+    case status::proxy_authentication_required:
+    case status::request_timeout:
+    case status::conflict:
+    case status::gone:
+    case status::length_required:
+    case status::precondition_failed:
+    case status::payload_too_large:
+    case status::uri_too_long:
+    case status::unsupported_media_type:
+    case status::range_not_satisfiable:
+    case status::expectation_failed:
+    case status::misdirected_request:
+    case status::unprocessable_entity:
+    case status::locked:
+    case status::failed_dependency:
+    case status::upgrade_required:
+    case status::precondition_required:
+    case status::too_many_requests:
+    case status::request_header_fields_too_large:
+    case status::connection_closed_without_response:
+    case status::unavailable_for_legal_reasons:
+    case status::client_closed_request:
+        BOOST_BEAST_FALLTHROUGH;
+
+    // 5xx
+    case status::internal_server_error:
+    case status::not_implemented:
+    case status::bad_gateway:
+    case status::service_unavailable:
+    case status::gateway_timeout:
+    case status::http_version_not_supported:
+    case status::variant_also_negotiates:
+    case status::insufficient_storage:
+    case status::loop_detected:
+    case status::not_extended:
+    case status::network_authentication_required:
+    case status::network_connect_timeout_error:
+        return static_cast<status>(v);
+
+    default:
+        break;
+    }
+    return status::unknown;
+}
+
+template<class = void>
+string_view
+status_to_string(unsigned v)
+{
+    switch(static_cast<status>(v))
+    {
+    // 1xx
+    case status::continue_:                             return "Continue";
+    case status::switching_protocols:                   return "Switching Protocols";
+    case status::processing:                            return "Processing";
+
+    // 2xx
+    case status::ok:                                    return "OK";
+    case status::created:                               return "Created";
+    case status::accepted:                              return "Accepted";
+    case status::non_authoritative_information:         return "Non-Authoritative Information";
+    case status::no_content:                            return "No Content";
+    case status::reset_content:                         return "Reset Content";
+    case status::partial_content:                       return "Partial Content";
+    case status::multi_status:                          return "Multi-Status";
+    case status::already_reported:                      return "Already Reported";
+    case status::im_used:                               return "IM Used";
+
+    // 3xx
+    case status::multiple_choices:                      return "Multiple Choices";
+    case status::moved_permanently:                     return "Moved Permanently";
+    case status::found:                                 return "Found";
+    case status::see_other:                             return "See Other";
+    case status::not_modified:                          return "Not Modified";
+    case status::use_proxy:                             return "Use Proxy";
+    case status::temporary_redirect:                    return "Temporary Redirect";
+    case status::permanent_redirect:                    return "Permanent Redirect";
+
+    // 4xx
+    case status::bad_request:                           return "Bad Request";
+    case status::unauthorized:                          return "Unauthorized";
+    case status::payment_required:                      return "Payment Required";
+    case status::forbidden:                             return "Forbidden";
+    case status::not_found:                             return "Not Found";
+    case status::method_not_allowed:                    return "Method Not Allowed";
+    case status::not_acceptable:                        return "Not Acceptable";
+    case status::proxy_authentication_required:         return "Proxy Authentication Required";
+    case status::request_timeout:                       return "Request Timeout";
+    case status::conflict:                              return "Conflict";
+    case status::gone:                                  return "Gone";
+    case status::length_required:                       return "Length Required";
+    case status::precondition_failed:                   return "Precondition Failed";
+    case status::payload_too_large:                     return "Payload Too Large";
+    case status::uri_too_long:                          return "URI Too Long";
+    case status::unsupported_media_type:                return "Unsupported Media Type";
+    case status::range_not_satisfiable:                 return "Range Not Satisfiable";
+    case status::expectation_failed:                    return "Expectation Failed";
+    case status::misdirected_request:                   return "Misdirected Request";
+    case status::unprocessable_entity:                  return "Unprocessable Entity";
+    case status::locked:                                return "Locked";
+    case status::failed_dependency:                     return "Failed Dependency";
+    case status::upgrade_required:                      return "Upgrade Required";
+    case status::precondition_required:                 return "Precondition Required";
+    case status::too_many_requests:                     return "Too Many Requests";
+    case status::request_header_fields_too_large:       return "Request Header Fields Too Large";
+    case status::connection_closed_without_response:    return "Connection Closed Without Response";
+    case status::unavailable_for_legal_reasons:         return "Unavailable For Legal Reasons";
+    case status::client_closed_request:                 return "Client Closed Request";
+    // 5xx
+    case status::internal_server_error:                 return "Internal Server Error";
+    case status::not_implemented:                       return "Not Implemented";
+    case status::bad_gateway:                           return "Bad Gateway";
+    case status::service_unavailable:                   return "Service Unavailable";
+    case status::gateway_timeout:                       return "Gateway Timeout";
+    case status::http_version_not_supported:            return "HTTP Version Not Supported";
+    case status::variant_also_negotiates:               return "Variant Also Negotiates";
+    case status::insufficient_storage:                  return "Insufficient Storage";
+    case status::loop_detected:                         return "Loop Detected";
+    case status::not_extended:                          return "Not Extended";
+    case status::network_authentication_required:       return "Network Authentication Required";
+    case status::network_connect_timeout_error:         return "Network Connect Timeout Error";
+
+    default:
+        break;
+    }
+    return "<unknown-status>";
+}
+
+template<class = void>
+status_class
+to_status_class(unsigned v)
+{
+    switch(v / 100)
+    {
+    case 1: return status_class::informational;
+    case 2: return status_class::successful;
+    case 3: return status_class::redirection;
+    case 4: return status_class::client_error;
+    case 5: return status_class::server_error;
+    default:
+        break;
+    }
+    return status_class::unknown;
+}
+
+} // detail
+
+inline
+status
+int_to_status(unsigned v)
+{
+    return detail::int_to_status(v);
+}
+
+inline
+status_class
+to_status_class(unsigned v)
+{
+    return detail::to_status_class(v);
+}
+
+inline
+status_class
+to_status_class(status v)
+{
+    return to_status_class(static_cast<int>(v));
+}
+
+inline
+string_view
+obsolete_reason(status v)
+{
+    return detail::status_to_string(
+        static_cast<unsigned>(v));
+}
+
+inline
+std::ostream&
+operator<<(std::ostream& os, status v)
+{
+    return os << obsolete_reason(v);
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/verb.ipp b/boost/beast/http/impl/verb.ipp
new file mode 100644
index 0000000000..820609165b
--- /dev/null
+++ b/boost/beast/http/impl/verb.ipp
@@ -0,0 +1,337 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_VERB_IPP
+#define BOOST_BEAST_HTTP_IMPL_VERB_IPP
+
+#include <boost/beast/core/detail/config.hpp>
+#include <boost/throw_exception.hpp>
+#include <stdexcept>
+
+namespace boost {
+namespace beast {
+namespace http {
+
+namespace detail {
+
+template<class = void>
+inline
+string_view
+verb_to_string(verb v)
+{
+    switch(v)
+    {
+    case verb::delete_:       return "DELETE";
+    case verb::get:           return "GET";
+    case verb::head:          return "HEAD";
+    case verb::post:          return "POST";
+    case verb::put:           return "PUT";
+    case verb::connect:       return "CONNECT";
+    case verb::options:       return "OPTIONS";
+    case verb::trace:         return "TRACE";
+
+    case verb::copy:          return "COPY";
+    case verb::lock:          return "LOCK";
+    case verb::mkcol:         return "MKCOL";
+    case verb::move:          return "MOVE";
+    case verb::propfind:      return "PROPFIND";
+    case verb::proppatch:     return "PROPPATCH";
+    case verb::search:        return "SEARCH";
+    case verb::unlock:        return "UNLOCK";
+    case verb::bind:          return "BIND";
+    case verb::rebind:        return "REBIND";
+    case verb::unbind:        return "UNBIND";
+    case verb::acl:           return "ACL";
+
+    case verb::report:        return "REPORT";
+    case verb::mkactivity:    return "MKACTIVITY";
+    case verb::checkout:      return "CHECKOUT";
+    case verb::merge:         return "MERGE";
+
+    case verb::msearch:       return "M-SEARCH";
+    case verb::notify:        return "NOTIFY";
+    case verb::subscribe:     return "SUBSCRIBE";
+    case verb::unsubscribe:   return "UNSUBSCRIBE";
+
+    case verb::patch:         return "PATCH";
+    case verb::purge:         return "PURGE";
+
+    case verb::mkcalendar:    return "MKCALENDAR";
+
+    case verb::link:          return "LINK";
+    case verb::unlink:        return "UNLINK";
+    
+    case verb::unknown:
+        return "<unknown>";
+    }
+
+    BOOST_THROW_EXCEPTION(std::invalid_argument{"unknown verb"});
+}
+
+template<class = void>
+verb
+string_to_verb(string_view v)
+{
+/*
+    ACL
+    BIND
+    CHECKOUT
+    CONNECT
+    COPY
+    DELETE
+    GET
+    HEAD
+    LINK
+    LOCK
+    M-SEARCH
+    MERGE
+    MKACTIVITY
+    MKCALENDAR
+    MKCOL
+    MOVE
+    NOTIFY
+    OPTIONS
+    PATCH
+    POST
+    PROPFIND
+    PROPPATCH
+    PURGE
+    PUT
+    REBIND
+    REPORT
+    SEARCH
+    SUBSCRIBE
+    TRACE
+    UNBIND
+    UNLINK
+    UNLOCK
+    UNSUBSCRIBE
+*/
+    if(v.size() < 3)
+        return verb::unknown;
+    // s must be null terminated
+    auto const eq =
+        [](string_view sv, char const* s)
+        {
+            auto p = sv.data();
+            for(;;)
+            {
+                if(*s != *p)
+                    return false;
+                ++s;
+                ++p;
+                if(! *s)
+                    return p == sv.end();
+            }
+        };
+    auto c = v[0];
+    v.remove_prefix(1);
+    switch(c)
+    {
+    case 'A':
+        if(v == "CL")
+            return verb::acl;
+        break;
+
+    case 'B':
+        if(v == "IND")
+            return verb::bind;
+        break;
+
+    case 'C':
+        c = v[0];
+        v.remove_prefix(1);
+        switch(c)
+        {
+        case 'H':
+            if(eq(v, "ECKOUT"))
+                return verb::checkout;
+            break;
+
+        case 'O':
+            if(eq(v, "NNECT"))
+                return verb::connect;
+            if(eq(v, "PY"))
+                return verb::copy;
+            BOOST_BEAST_FALLTHROUGH;
+
+        default:
+            break;
+        }
+        break;
+
+    case 'D':
+        if(eq(v, "ELETE"))
+            return verb::delete_;
+        break;
+
+    case 'G':
+        if(eq(v, "ET"))
+            return verb::get;
+        break;
+
+    case 'H':
+        if(eq(v, "EAD"))
+            return verb::head;
+        break;
+
+    case 'L':
+        if(eq(v, "INK"))
+            return verb::link;
+        if(eq(v, "OCK"))
+            return verb::lock;
+        break;
+
+    case 'M':
+        c = v[0];
+        v.remove_prefix(1);
+        switch(c)
+        {
+        case '-':
+            if(eq(v, "SEARCH"))
+                return verb::msearch;
+            break;
+
+        case 'E':
+            if(eq(v, "RGE"))
+                return verb::merge;
+            break;
+
+        case 'K':
+            if(eq(v, "ACTIVITY"))
+                return verb::mkactivity;
+            if(v[0] == 'C')
+            {
+                v.remove_prefix(1);
+                if(eq(v, "ALENDAR"))
+                    return verb::mkcalendar;
+                if(eq(v, "OL"))
+                    return verb::mkcol;
+                break;
+            }
+            break;
+        
+        case 'O':
+            if(eq(v, "VE"))
+                return verb::move;
+            BOOST_BEAST_FALLTHROUGH;
+
+        default:
+            break;
+        }
+        break;
+
+    case 'N':
+        if(eq(v, "OTIFY"))
+            return verb::notify;
+        break;
+
+    case 'O':
+        if(eq(v, "PTIONS"))
+            return verb::options;
+        break;
+
+    case 'P':
+        c = v[0];
+        v.remove_prefix(1);
+        switch(c)
+        {
+        case 'A':
+            if(eq(v, "TCH"))
+                return verb::patch;
+            break;
+
+        case 'O':
+            if(eq(v, "ST"))
+                return verb::post;
+            break;
+
+        case 'R':
+            if(eq(v, "OPFIND"))
+                return verb::propfind;
+            if(eq(v, "OPPATCH"))
+                return verb::proppatch;
+            break;
+
+        case 'U':
+            if(eq(v, "RGE"))
+                return verb::purge;
+            if(eq(v, "T"))
+                return verb::put;
+            BOOST_BEAST_FALLTHROUGH;
+
+        default:
+            break;
+        }
+        break;
+
+    case 'R':
+        if(v[0] != 'E')
+            break;
+        v.remove_prefix(1);
+        if(eq(v, "BIND"))
+            return verb::rebind;
+        if(eq(v, "PORT"))
+            return verb::report;
+        break;
+
+    case 'S':
+        if(eq(v, "EARCH"))
+            return verb::search;
+        if(eq(v, "UBSCRIBE"))
+            return verb::subscribe;
+        break;
+
+    case 'T':
+        if(eq(v, "RACE"))
+            return verb::trace;
+        break;
+
+    case 'U':
+        if(v[0] != 'N')
+            break;
+        v.remove_prefix(1);
+        if(eq(v, "BIND"))
+            return verb::unbind;
+        if(eq(v, "LINK"))
+            return verb::unlink;
+        if(eq(v, "LOCK"))
+            return verb::unlock;
+        if(eq(v, "SUBSCRIBE"))
+            return verb::unsubscribe;
+        break;
+
+    default:
+        break;
+    }
+
+    return verb::unknown;
+}
+
+} // detail
+
+inline
+string_view
+to_string(verb v)
+{
+    return detail::verb_to_string(v);
+}
+
+inline
+verb
+string_to_verb(string_view s)
+{
+    return detail::string_to_verb(s);
+}
+
+} // http
+} // beast
+} // boost
+
+#endif
diff --git a/boost/beast/http/impl/write.ipp b/boost/beast/http/impl/write.ipp
new file mode 100644
index 0000000000..9d5be277ec
--- /dev/null
+++ b/boost/beast/http/impl/write.ipp
@@ -0,0 +1,887 @@
+//
+// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/beast
+//
+
+#ifndef BOOST_BEAST_HTTP_IMPL_WRITE_IPP
+#define BOOST_BEAST_HTTP_IMPL_WRITE_IPP
+
+#include <boost/beast/http/type_traits.hpp>
+#include <boost/beast/core/bind_handler.hpp>
+#include <boost/beast/core/ostream.hpp>
+#include <boost/beast/core/handler_ptr.hpp>
+#include <boost/beast/core/type_traits.hpp>
+#include <boost/beast/core/detail/config.hpp>
+#include <boost/asio/associated_allocator.hpp>
+#include <boost/asio/associated_executor.hpp>
+#include <boost/asio/handler_continuation_hook.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/write.hpp>
+#include <boost/optional.hpp>
+#include <boost/throw_exception.hpp>
+#include <ostream>
+#include <sstream>
+
+namespace boost {
+namespace beast {
+namespace http {
+namespace detail {
+
+template<
+    class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+class write_some_op
+{
+    Stream& s_;
+    serializer<isRequest,Body, Fields>& sr_;
+    Handler h_;
+
+    class lambda
+    {
+        write_some_op& op_;
+
+    public:
+        bool invoked = false;
+
+        explicit
+        lambda(write_some_op& op)
+            : op_(op)
+        {
+        }
+
+        template<class ConstBufferSequence>
+        void
+        operator()(error_code& ec,
+            ConstBufferSequence const& buffers)
+        {
+            invoked = true;
+            ec.assign(0, ec.category());
+            return op_.s_.async_write_some(
+                buffers, std::move(op_));
+        }
+    };
+
+public:
+    write_some_op(write_some_op&&) = default;
+    write_some_op(write_some_op const&) = default;
+
+    template<class DeducedHandler>
+    write_some_op(DeducedHandler&& h, Stream& s,
+            serializer<isRequest, Body, Fields>& sr)
+        : s_(s)
+        , sr_(sr)
+        , h_(std::forward<DeducedHandler>(h))
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(h_);
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            h_, s_.get_executor());
+    }
+
+    void
+    operator()();
+
+    void
+    operator()(
+        error_code ec,
+        std::size_t bytes_transferred);
+
+    friend
+    bool asio_handler_is_continuation(write_some_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return asio_handler_is_continuation(
+            std::addressof(op->h_));
+    }
+};
+
+template<
+    class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+void
+write_some_op<
+    Stream, Handler, isRequest, Body, Fields>::
+operator()()
+{
+    error_code ec;
+    if(! sr_.is_done())
+    {
+        lambda f{*this};
+        sr_.next(ec, f);
+        if(ec)
+        {
+            BOOST_ASSERT(! f.invoked);
+            return boost::asio::post(
+                s_.get_executor(),
+                bind_handler(std::move(*this), ec, 0));
+        }
+        if(f.invoked)
+        {
+            // *this has been moved from,
+            // cannot access members here.
+            return;
+        }
+        // What else could it be?
+        BOOST_ASSERT(sr_.is_done());
+    }
+    return boost::asio::post(
+        s_.get_executor(),
+        bind_handler(std::move(*this), ec, 0));
+}
+
+template<
+    class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+void
+write_some_op<
+    Stream, Handler, isRequest, Body, Fields>::
+operator()(
+    error_code ec, std::size_t bytes_transferred)
+{
+    if(! ec)
+        sr_.consume(bytes_transferred);
+    h_(ec, bytes_transferred);
+}
+
+//------------------------------------------------------------------------------
+
+struct serializer_is_header_done
+{
+    template<
+        bool isRequest, class Body, class Fields>
+    bool
+    operator()(
+        serializer<isRequest, Body, Fields>& sr) const
+    {
+        return sr.is_header_done();
+    }
+};
+
+struct serializer_is_done
+{
+    template<
+        bool isRequest, class Body, class Fields>
+    bool
+    operator()(
+        serializer<isRequest, Body, Fields>& sr) const
+    {
+        return sr.is_done();
+    }
+};
+
+//------------------------------------------------------------------------------
+
+template<
+    class Stream, class Handler, class Predicate,
+    bool isRequest, class Body, class Fields>
+class write_op
+{
+    int state_ = 0;
+    Stream& s_;
+    serializer<isRequest, Body, Fields>& sr_;
+    std::size_t bytes_transferred_ = 0;
+    Handler h_;
+
+public:
+    write_op(write_op&&) = default;
+    write_op(write_op const&) = default;
+
+    template<class DeducedHandler>
+    write_op(DeducedHandler&& h, Stream& s,
+            serializer<isRequest, Body, Fields>& sr)
+        : s_(s)
+        , sr_(sr)
+        , h_(std::forward<DeducedHandler>(h))
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(h_);
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            h_, s_.get_executor());
+    }
+
+    void
+    operator()(
+        error_code ec = {},
+        std::size_t bytes_transferred = 0);
+
+    friend
+    bool asio_handler_is_continuation(write_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return op->state_ >= 3 ||
+            asio_handler_is_continuation(
+                std::addressof(op->h_));
+    }
+};
+
+template<
+    class Stream, class Handler, class Predicate,
+    bool isRequest, class Body, class Fields>
+void
+write_op<Stream, Handler, Predicate,
+    isRequest, Body, Fields>::
+operator()(
+    error_code ec, std::size_t bytes_transferred)
+{
+    if(ec)
+        goto upcall;
+    switch(state_)
+    {
+    case 0:
+    {
+        if(Predicate{}(sr_))
+        {
+            state_ = 1;
+            return boost::asio::post(
+                s_.get_executor(),
+                bind_handler(std::move(*this), ec, 0));
+        }
+        state_ = 2;
+        return beast::http::async_write_some(
+            s_, sr_, std::move(*this));
+    }
+
+    case 1:
+        goto upcall;
+
+    case 2:
+        state_ = 3;
+        BOOST_BEAST_FALLTHROUGH;
+
+    case 3:
+    {
+        bytes_transferred_ += bytes_transferred;
+        if(Predicate{}(sr_))
+            goto upcall;
+        return beast::http::async_write_some(
+            s_, sr_, std::move(*this));
+    }
+    }
+upcall:
+    h_(ec, bytes_transferred_);
+}
+
+//------------------------------------------------------------------------------
+
+template<class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+class write_msg_op
+{
+    struct data
+    {
+        Stream& s;
+        serializer<isRequest, Body, Fields> sr;
+
+        data(Handler&, Stream& s_, message<
+                isRequest, Body, Fields>& m_)
+            : s(s_)
+            , sr(m_)
+        {
+        }
+    };
+
+    handler_ptr<data, Handler> d_;
+
+public:
+    write_msg_op(write_msg_op&&) = default;
+    write_msg_op(write_msg_op const&) = default;
+
+    template<class DeducedHandler, class... Args>
+    write_msg_op(DeducedHandler&& h, Stream& s, Args&&... args)
+        : d_(std::forward<DeducedHandler>(h),
+            s, std::forward<Args>(args)...)
+    {
+    }
+
+    using allocator_type =
+        boost::asio::associated_allocator_t<Handler>;
+
+    allocator_type
+    get_allocator() const noexcept
+    {
+        return boost::asio::get_associated_allocator(d_.handler());
+    }
+
+    using executor_type = boost::asio::associated_executor_t<
+        Handler, decltype(std::declval<Stream&>().get_executor())>;
+
+    executor_type
+    get_executor() const noexcept
+    {
+        return boost::asio::get_associated_executor(
+            d_.handler(), d_->s.get_executor());
+    }
+
+    void
+    operator()();
+
+    void
+    operator()(
+        error_code ec, std::size_t bytes_transferred);
+
+    friend
+    bool asio_handler_is_continuation(write_msg_op* op)
+    {
+        using boost::asio::asio_handler_is_continuation;
+        return asio_handler_is_continuation(
+            std::addressof(op->d_.handler()));
+    }
+};
+
+template<class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+void
+write_msg_op<
+    Stream, Handler, isRequest, Body, Fields>::
+operator()()
+{
+    auto& d = *d_;
+    return async_write(d.s, d.sr, std::move(*this));
+}
+
+template<class Stream, class Handler,
+    bool isRequest, class Body, class Fields>
+void
+write_msg_op<
+    Stream, Handler, isRequest, Body, Fields>::
+operator()(error_code ec, std::size_t bytes_transferred)
+{
+    d_.invoke(ec, bytes_transferred);
+}
+
+//------------------------------------------------------------------------------
+
+template<class Stream>
+class write_some_lambda
+{
+    Stream& stream_;
+
+public:
+    bool invoked = false;
+    std::size_t bytes_transferred = 0;
+
+    explicit
+    write_some_lambda(Stream& stream)
+        : stream_(stream)
+    {
+    }
+
+    template<class ConstBufferSequence>
+    void
+    operator()(error_code& ec,
+        ConstBufferSequence const& buffers)
+    {
+        invoked = true;
+        bytes_transferred =
+            stream_.write_some(buffers, ec);
+    }
+};
+
+template<class Stream>
+class write_lambda
+{
+    Stream& stream_;
+
+public:
+    bool invoked = false;
+    std::size_t bytes_transferred = 0;
+
+    explicit
+    write_lambda(Stream& stream)
+        : stream_(stream)
+    {
+    }
+
+    template<class ConstBufferSequence>
+    void
+    operator()(error_code& ec,
+        ConstBufferSequence const& buffers)
+    {
+        invoked = true;
+        bytes_transferred = boost::asio::write(
+            stream_, buffers, ec);
+    }
+};
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write_some(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    error_code& ec)
+{
+    if(! sr.is_done())
+    {
+        write_some_lambda<SyncWriteStream> f{stream};
+        sr.next(ec, f);
+        if(ec)
+            return f.bytes_transferred;
+        if(f.invoked)
+            sr.consume(f.bytes_transferred);
+        return f.bytes_transferred;
+    }
+    ec.assign(0, ec.category());
+    return 0;
+}
+
+template<
+    class AsyncWriteStream,
+    bool isRequest, class Body, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write_some(
+    AsyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    WriteHandler&& handler)
+{
+    boost::asio::async_completion<
+        WriteHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::write_some_op<
+        AsyncWriteStream,
+        BOOST_ASIO_HANDLER_TYPE(WriteHandler,
+            void(error_code, std::size_t)),
+        isRequest, Body, Fields>{
+            init.completion_handler, stream, sr}();
+    return init.result.get();
+}
+
+} // detail
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write_some(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        write_some(stream, sr, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write_some(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    error_code& ec)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    return detail::write_some(stream, sr, ec);
+}
+
+template<
+    class AsyncWriteStream,
+    bool isRequest, class Body, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write_some(
+    AsyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    WriteHandler&& handler)
+{
+    static_assert(is_async_write_stream<
+            AsyncWriteStream>::value,
+        "AsyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    return detail::async_write_some(stream, sr,
+        std::forward<WriteHandler>(handler));
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write_header(SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        write_header(stream, sr, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write_header(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    error_code& ec)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    sr.split(true);
+    std::size_t bytes_transferred = 0;
+    if(! sr.is_header_done())
+    {
+        detail::write_lambda<SyncWriteStream> f{stream};
+        do
+        {
+            sr.next(ec, f);
+            bytes_transferred += f.bytes_transferred;
+            if(ec)
+                return bytes_transferred;
+            BOOST_ASSERT(f.invoked);
+            sr.consume(f.bytes_transferred);
+        }
+        while(! sr.is_header_done());
+    }
+    else
+    {
+        ec.assign(0, ec.category());
+    }
+    return bytes_transferred;
+}
+
+template<
+    class AsyncWriteStream,
+    bool isRequest, class Body, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write_header(
+    AsyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    WriteHandler&& handler)
+{
+    static_assert(is_async_write_stream<
+            AsyncWriteStream>::value,
+        "AsyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    sr.split(true);
+    boost::asio::async_completion<
+        WriteHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::write_op<
+        AsyncWriteStream,
+        BOOST_ASIO_HANDLER_TYPE(WriteHandler,
+            void(error_code, std::size_t)),
+        detail::serializer_is_header_done,
+        isRequest, Body, Fields>{
+        init.completion_handler, stream, sr}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        write(stream, sr, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write(
+    SyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    error_code& ec)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    std::size_t bytes_transferred = 0;
+    sr.split(false);
+    for(;;)
+    {
+        bytes_transferred +=
+            write_some(stream, sr, ec);
+        if(ec)
+            return bytes_transferred;
+        if(sr.is_done())
+            break;
+    }
+    return bytes_transferred;
+}
+
+template<
+    class AsyncWriteStream,
+    bool isRequest, class Body, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write(
+    AsyncWriteStream& stream,
+    serializer<isRequest, Body, Fields>& sr,
+    WriteHandler&& handler)
+{
+    static_assert(is_async_write_stream<
+            AsyncWriteStream>::value,
+        "AsyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    sr.split(false);
+    boost::asio::async_completion<
+        WriteHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::write_op<
+        AsyncWriteStream,
+        BOOST_ASIO_HANDLER_TYPE(WriteHandler,
+            void(error_code, std::size_t)),
+        detail::serializer_is_done,
+        isRequest, Body, Fields>{
+            init.completion_handler, stream, sr}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write(
+    SyncWriteStream& stream,
+    message<isRequest, Body, Fields> const& msg)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    error_code ec;
+    auto const bytes_transferred =
+        write(stream, msg, ec);
+    if(ec)
+        BOOST_THROW_EXCEPTION(system_error{ec});
+    return bytes_transferred;
+}
+
+template<
+    class SyncWriteStream,
+    bool isRequest, class Body, class Fields>
+std::size_t
+write(
+    SyncWriteStream& stream,
+    message<isRequest, Body, Fields> const& msg,
+    error_code& ec)
+{
+    static_assert(is_sync_write_stream<SyncWriteStream>::value,
+        "SyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    serializer<isRequest, Body, Fields> sr{msg};
+    return write(stream, sr, ec);
+}
+
+template<
+    class AsyncWriteStream,
+    bool isRequest, class Body, class Fields,
+    class WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(
+    WriteHandler, void(error_code, std::size_t))
+async_write(
+    AsyncWriteStream& stream,
+    message<isRequest, Body, Fields>& msg,
+    WriteHandler&& handler)
+{
+    static_assert(
+        is_async_write_stream<AsyncWriteStream>::value,
+        "AsyncWriteStream requirements not met");
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    boost::asio::async_completion<
+        WriteHandler,
+        void(error_code, std::size_t)> init{handler};
+    detail::write_msg_op<
+        AsyncWriteStream,
+        BOOST_ASIO_HANDLER_TYPE(WriteHandler,
+            void(error_code, std::size_t)),
+        isRequest, Body, Fields>{
+            init.completion_handler, stream, msg}();
+    return init.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+namespace detail {
+
+template<class Serializer>
+class write_ostream_lambda
+{
+    std::ostream& os_;
+    Serializer& sr_;
+
+public:
+    write_ostream_lambda(std::ostream& os,
+            Serializer& sr)
+        : os_(os)
+        , sr_(sr)
+    {
+    }
+
+    template<class ConstBufferSequence>
+    void
+    operator()(error_code& ec,
+        ConstBufferSequence const& buffers) const
+    {
+        ec.assign(0, ec.category());
+        if(os_.fail())
+            return;
+        std::size_t bytes_transferred = 0;
+        for(auto b : buffers_range(buffers))
+        {
+            os_.write(reinterpret_cast<char const*>(
+                b.data()), b.size());
+            if(os_.fail())
+                return;
+            bytes_transferred += b.size();
+        }
+        sr_.consume(bytes_transferred);
+    }
+};
+
+} // detail
+
+template<class Fields>
+std::ostream&
+operator<<(std::ostream& os,
+    header<true, Fields> const& h)
+{
+    typename Fields::writer fr{
+        h, h.version(), h.method()};
+    return os << buffers(fr.get());
+}
+
+template<class Fields>
+std::ostream&
+operator<<(std::ostream& os,
+    header<false, Fields> const& h)
+{
+    typename Fields::writer fr{
+        h, h.version(), h.result_int()};
+    return os << buffers(fr.get());
+}
+
+template<bool isRequest, class Body, class Fields>
+std::ostream&
+operator<<(std::ostream& os,
+    message<isRequest, Body, Fields> const& msg)
+{
+    static_assert(is_body<Body>::value,
+        "Body requirements not met");
+    static_assert(is_body_writer<Body>::value,
+        "BodyWriter requirements not met");
+    serializer<isRequest, Body, Fields> sr{msg};
+    error_code ec;
+    detail::write_ostream_lambda<decltype(sr)> f{os, sr};
+    do
+    {
+        sr.next(ec, f);
+        if(os.fail())
+            break;
+        if(ec)
+        {
+            os.setstate(std::ios::failbit);
+            break;
+        }   
+    }
+    while(! sr.is_done());
+    return os;
+}
+
+} // http
+} // beast
+} // boost
+
+#endif