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//
// posix_chat_client.cpp
// ~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff 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)
//
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <boost/array.hpp>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include "chat_message.hpp"
#if defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
using boost::asio::ip::tcp;
namespace posix = boost::asio::posix;
class posix_chat_client
{
public:
posix_chat_client(boost::asio::io_context& io_context,
const tcp::resolver::results_type& endpoints)
: socket_(io_context),
input_(io_context, ::dup(STDIN_FILENO)),
output_(io_context, ::dup(STDOUT_FILENO)),
input_buffer_(chat_message::max_body_length)
{
boost::asio::async_connect(socket_, endpoints,
boost::bind(&posix_chat_client::handle_connect, this,
boost::asio::placeholders::error));
}
private:
void handle_connect(const boost::system::error_code& error)
{
if (!error)
{
// Read the fixed-length header of the next message from the server.
boost::asio::async_read(socket_,
boost::asio::buffer(read_msg_.data(), chat_message::header_length),
boost::bind(&posix_chat_client::handle_read_header, this,
boost::asio::placeholders::error));
// Read a line of input entered by the user.
boost::asio::async_read_until(input_, input_buffer_, '\n',
boost::bind(&posix_chat_client::handle_read_input, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
}
void handle_read_header(const boost::system::error_code& error)
{
if (!error && read_msg_.decode_header())
{
// Read the variable-length body of the message from the server.
boost::asio::async_read(socket_,
boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
boost::bind(&posix_chat_client::handle_read_body, this,
boost::asio::placeholders::error));
}
else
{
close();
}
}
void handle_read_body(const boost::system::error_code& error)
{
if (!error)
{
// Write out the message we just received, terminated by a newline.
static char eol[] = { '\n' };
boost::array<boost::asio::const_buffer, 2> buffers = {{
boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
boost::asio::buffer(eol) }};
boost::asio::async_write(output_, buffers,
boost::bind(&posix_chat_client::handle_write_output, this,
boost::asio::placeholders::error));
}
else
{
close();
}
}
void handle_write_output(const boost::system::error_code& error)
{
if (!error)
{
// Read the fixed-length header of the next message from the server.
boost::asio::async_read(socket_,
boost::asio::buffer(read_msg_.data(), chat_message::header_length),
boost::bind(&posix_chat_client::handle_read_header, this,
boost::asio::placeholders::error));
}
else
{
close();
}
}
void handle_read_input(const boost::system::error_code& error,
std::size_t length)
{
if (!error)
{
// Write the message (minus the newline) to the server.
write_msg_.body_length(length - 1);
input_buffer_.sgetn(write_msg_.body(), length - 1);
input_buffer_.consume(1); // Remove newline from input.
write_msg_.encode_header();
boost::asio::async_write(socket_,
boost::asio::buffer(write_msg_.data(), write_msg_.length()),
boost::bind(&posix_chat_client::handle_write, this,
boost::asio::placeholders::error));
}
else if (error == boost::asio::error::not_found)
{
// Didn't get a newline. Send whatever we have.
write_msg_.body_length(input_buffer_.size());
input_buffer_.sgetn(write_msg_.body(), input_buffer_.size());
write_msg_.encode_header();
boost::asio::async_write(socket_,
boost::asio::buffer(write_msg_.data(), write_msg_.length()),
boost::bind(&posix_chat_client::handle_write, this,
boost::asio::placeholders::error));
}
else
{
close();
}
}
void handle_write(const boost::system::error_code& error)
{
if (!error)
{
// Read a line of input entered by the user.
boost::asio::async_read_until(input_, input_buffer_, '\n',
boost::bind(&posix_chat_client::handle_read_input, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
close();
}
}
void close()
{
// Cancel all outstanding asynchronous operations.
socket_.close();
input_.close();
output_.close();
}
private:
tcp::socket socket_;
posix::stream_descriptor input_;
posix::stream_descriptor output_;
chat_message read_msg_;
chat_message write_msg_;
boost::asio::streambuf input_buffer_;
};
int main(int argc, char* argv[])
{
try
{
if (argc != 3)
{
std::cerr << "Usage: posix_chat_client <host> <port>\n";
return 1;
}
boost::asio::io_context io_context;
tcp::resolver resolver(io_context);
tcp::resolver::results_type endpoints = resolver.resolve(argv[1], argv[2]);
posix_chat_client c(io_context, endpoints);
io_context.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
#else // defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
int main() {}
#endif // defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
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