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diff --git a/tts-mqtt-test/src/paho-mqtt/MQTTClient.h b/tts-mqtt-test/src/paho-mqtt/MQTTClient.h new file mode 100644 index 0000000..346cbd4 --- /dev/null +++ b/tts-mqtt-test/src/paho-mqtt/MQTTClient.h @@ -0,0 +1,1414 @@ +/******************************************************************************* + * Copyright (c) 2009, 2018 IBM Corp. + * + * All rights reserved. This program and the accompanying materials + * are made available under the terms of the Eclipse Public License v1.0 + * and Eclipse Distribution License v1.0 which accompany this distribution. + * + * The Eclipse Public License is available at + * http://www.eclipse.org/legal/epl-v10.html + * and the Eclipse Distribution License is available at + * http://www.eclipse.org/org/documents/edl-v10.php. + * + * Contributors: + * Ian Craggs - initial API and implementation and/or initial documentation + * Ian Craggs, Allan Stockdill-Mander - SSL updates + * Ian Craggs - multiple server connection support + * Ian Craggs - MQTT 3.1.1 support + * Ian Craggs - remove const from eyecatchers #168 + *******************************************************************************/ + +/** + * @cond MQTTClient_internal + * @mainpage MQTT Client Library Internals + * In the beginning there was one MQTT C client library, MQTTClient, as implemented in MQTTClient.c + * This library was designed to be easy to use for applications which didn't mind if some of the calls + * blocked for a while. For instance, the MQTTClient_connect call will block until a successful + * connection has completed, or a connection has failed, which could be as long as the "connection + * timeout" interval, whose default is 30 seconds. + * + * However in mobile devices and other windowing environments, blocking on the GUI thread is a bad + * thing as it causes the user interface to freeze. Hence a new API, MQTTAsync, implemented + * in MQTTAsync.c, was devised. There are no blocking calls in this library, so it is well suited + * to GUI and mobile environments, at the expense of some extra complexity. + * + * Both libraries are designed to be sparing in the use of threads. So multiple client objects are + * handled by one or two threads, with a select call in Socket_getReadySocket(), used to determine + * when a socket has incoming data. This API is thread safe: functions may be called by multiple application + * threads, with the exception of ::MQTTClient_yield and ::MQTTClient_receive, which are intended + * for single threaded environments only. + * + * @endcond + * @cond MQTTClient_main + * @mainpage MQTT Client library for C + * © Copyright IBM Corp. 2009, 2017 + * + * @brief An MQTT client library in C. + * + * These pages describe the original more synchronous API which might be + * considered easier to use. Some of the calls will block. For the new + * totally asynchronous API where no calls block, which is especially suitable + * for use in windowed environments, see the + * <a href="../../MQTTAsync/html/index.html">MQTT C Client Asynchronous API Documentation</a>. + * The MQTTClient API is not thread safe, whereas the MQTTAsync API is. + * + * An MQTT client application connects to MQTT-capable servers. + * A typical client is responsible for collecting information from a telemetry + * device and publishing the information to the server. It can also subscribe + * to topics, receive messages, and use this information to control the + * telemetry device. + * + * MQTT clients implement the published MQTT v3 protocol. You can write your own + * API to the MQTT protocol using the programming language and platform of your + * choice. This can be time-consuming and error-prone. + * + * To simplify writing MQTT client applications, this library encapsulates + * the MQTT v3 protocol for you. Using this library enables a fully functional + * MQTT client application to be written in a few lines of code. + * The information presented here documents the API provided + * by the MQTT Client library for C. + * + * <b>Using the client</b><br> + * Applications that use the client library typically use a similar structure: + * <ul> + * <li>Create a client object</li> + * <li>Set the options to connect to an MQTT server</li> + * <li>Set up callback functions if multi-threaded (asynchronous mode) + * operation is being used (see @ref async).</li> + * <li>Subscribe to any topics the client needs to receive</li> + * <li>Repeat until finished:</li> + * <ul> + * <li>Publish any messages the client needs to</li> + * <li>Handle any incoming messages</li> + * </ul> + * <li>Disconnect the client</li> + * <li>Free any memory being used by the client</li> + * </ul> + * Some simple examples are shown here: + * <ul> + * <li>@ref pubsync</li> + * <li>@ref pubasync</li> + * <li>@ref subasync</li> + * </ul> + * Additional information about important concepts is provided here: + * <ul> + * <li>@ref async</li> + * <li>@ref wildcard</li> + * <li>@ref qos</li> + * <li>@ref tracing</li> + * </ul> + * @endcond + */ + +/* +/// @cond EXCLUDE +*/ +#if defined(__cplusplus) + extern "C" { +#endif +#if !defined(MQTTCLIENT_H) +#define MQTTCLIENT_H + +#if defined(WIN32) || defined(WIN64) + #define DLLImport __declspec(dllimport) + #define DLLExport __declspec(dllexport) +#else + #define DLLImport extern + #define DLLExport __attribute__ ((visibility ("default"))) +#endif + +#include <stdio.h> +/* +/// @endcond +*/ + +#if !defined(NO_PERSISTENCE) +#include "../paho-mqtt/MQTTClientPersistence.h" +#endif + +/** + * Return code: No error. Indicates successful completion of an MQTT client + * operation. + */ +#define MQTTCLIENT_SUCCESS 0 +/** + * Return code: A generic error code indicating the failure of an MQTT client + * operation. + */ +#define MQTTCLIENT_FAILURE -1 + +/* error code -2 is MQTTCLIENT_PERSISTENCE_ERROR */ + +/** + * Return code: The client is disconnected. + */ +#define MQTTCLIENT_DISCONNECTED -3 +/** + * Return code: The maximum number of messages allowed to be simultaneously + * in-flight has been reached. + */ +#define MQTTCLIENT_MAX_MESSAGES_INFLIGHT -4 +/** + * Return code: An invalid UTF-8 string has been detected. + */ +#define MQTTCLIENT_BAD_UTF8_STRING -5 +/** + * Return code: A NULL parameter has been supplied when this is invalid. + */ +#define MQTTCLIENT_NULL_PARAMETER -6 +/** + * Return code: The topic has been truncated (the topic string includes + * embedded NULL characters). String functions will not access the full topic. + * Use the topic length value to access the full topic. + */ +#define MQTTCLIENT_TOPICNAME_TRUNCATED -7 +/** + * Return code: A structure parameter does not have the correct eyecatcher + * and version number. + */ +#define MQTTCLIENT_BAD_STRUCTURE -8 +/** + * Return code: A QoS value that falls outside of the acceptable range (0,1,2) + */ +#define MQTTCLIENT_BAD_QOS -9 +/** + * Return code: Attempting SSL connection using non-SSL version of library + */ +#define MQTTCLIENT_SSL_NOT_SUPPORTED -10 +/** + * Return code: protocol prefix in serverURI should be tcp:// or ssl:// + */ +#define MQTTCLIENT_BAD_PROTOCOL -14 + +/** + * Default MQTT version to connect with. Use 3.1.1 then fall back to 3.1 + */ +#define MQTTVERSION_DEFAULT 0 +/** + * MQTT version to connect with: 3.1 + */ +#define MQTTVERSION_3_1 3 +/** + * MQTT version to connect with: 3.1.1 + */ +#define MQTTVERSION_3_1_1 4 +/** + * Bad return code from subscribe, as defined in the 3.1.1 specification + */ +#define MQTT_BAD_SUBSCRIBE 0x80 + +/** + * Initialization options + */ +typedef struct +{ + /** The eyecatcher for this structure. Must be MQTG. */ + char struct_id[4]; + /** The version number of this structure. Must be 0 */ + int struct_version; + /** 1 = we do openssl init, 0 = leave it to the application */ + int do_openssl_init; +} MQTTClient_init_options; + +#define MQTTClient_init_options_initializer { {'M', 'Q', 'T', 'G'}, 0, 0 } + +/** + * Global init of mqtt library. Call once on program start to set global behaviour. + * do_openssl_init - if mqtt library should initialize OpenSSL (1) or rely on the caller to do it before using the library (0) + */ +DLLExport void MQTTClient_global_init(MQTTClient_init_options* inits); + +/** + * A handle representing an MQTT client. A valid client handle is available + * following a successful call to MQTTClient_create(). + */ +typedef void* MQTTClient; +/** + * A value representing an MQTT message. A delivery token is returned to the + * client application when a message is published. The token can then be used to + * check that the message was successfully delivered to its destination (see + * MQTTClient_publish(), + * MQTTClient_publishMessage(), + * MQTTClient_deliveryComplete(), + * MQTTClient_waitForCompletion() and + * MQTTClient_getPendingDeliveryTokens()). + */ +typedef int MQTTClient_deliveryToken; +typedef int MQTTClient_token; + +/** + * A structure representing the payload and attributes of an MQTT message. The + * message topic is not part of this structure (see MQTTClient_publishMessage(), + * MQTTClient_publish(), MQTTClient_receive(), MQTTClient_freeMessage() + * and MQTTClient_messageArrived()). + */ +typedef struct +{ + /** The eyecatcher for this structure. must be MQTM. */ + char struct_id[4]; + /** The version number of this structure. Must be 0 */ + int struct_version; + /** The length of the MQTT message payload in bytes. */ + int payloadlen; + /** A pointer to the payload of the MQTT message. */ + void* payload; + /** + * The quality of service (QoS) assigned to the message. + * There are three levels of QoS: + * <DL> + * <DT><B>QoS0</B></DT> + * <DD>Fire and forget - the message may not be delivered</DD> + * <DT><B>QoS1</B></DT> + * <DD>At least once - the message will be delivered, but may be + * delivered more than once in some circumstances.</DD> + * <DT><B>QoS2</B></DT> + * <DD>Once and one only - the message will be delivered exactly once.</DD> + * </DL> + */ + int qos; + /** + * The retained flag serves two purposes depending on whether the message + * it is associated with is being published or received. + * + * <b>retained = true</b><br> + * For messages being published, a true setting indicates that the MQTT + * server should retain a copy of the message. The message will then be + * transmitted to new subscribers to a topic that matches the message topic. + * For subscribers registering a new subscription, the flag being true + * indicates that the received message is not a new one, but one that has + * been retained by the MQTT server. + * + * <b>retained = false</b> <br> + * For publishers, this ndicates that this message should not be retained + * by the MQTT server. For subscribers, a false setting indicates this is + * a normal message, received as a result of it being published to the + * server. + */ + int retained; + /** + * The dup flag indicates whether or not this message is a duplicate. + * It is only meaningful when receiving QoS1 messages. When true, the + * client application should take appropriate action to deal with the + * duplicate message. + */ + int dup; + /** The message identifier is normally reserved for internal use by the + * MQTT client and server. + */ + int msgid; +} MQTTClient_message; + +#define MQTTClient_message_initializer { {'M', 'Q', 'T', 'M'}, 0, 0, NULL, 0, 0, 0, 0 } + +/** + * This is a callback function. The client application + * must provide an implementation of this function to enable asynchronous + * receipt of messages. The function is registered with the client library by + * passing it as an argument to MQTTClient_setCallbacks(). It is + * called by the client library when a new message that matches a client + * subscription has been received from the server. This function is executed on + * a separate thread to the one on which the client application is running. + * @param context A pointer to the <i>context</i> value originally passed to + * MQTTClient_setCallbacks(), which contains any application-specific context. + * @param topicName The topic associated with the received message. + * @param topicLen The length of the topic if there are one + * more NULL characters embedded in <i>topicName</i>, otherwise <i>topicLen</i> + * is 0. If <i>topicLen</i> is 0, the value returned by <i>strlen(topicName)</i> + * can be trusted. If <i>topicLen</i> is greater than 0, the full topic name + * can be retrieved by accessing <i>topicName</i> as a byte array of length + * <i>topicLen</i>. + * @param message The MQTTClient_message structure for the received message. + * This structure contains the message payload and attributes. + * @return This function must return a boolean value indicating whether or not + * the message has been safely received by the client application. Returning + * true indicates that the message has been successfully handled. + * Returning false indicates that there was a problem. In this + * case, the client library will reinvoke MQTTClient_messageArrived() to + * attempt to deliver the message to the application again. + */ +typedef int MQTTClient_messageArrived(void* context, char* topicName, int topicLen, MQTTClient_message* message); + +/** + * This is a callback function. The client application + * must provide an implementation of this function to enable asynchronous + * notification of delivery of messages. The function is registered with the + * client library by passing it as an argument to MQTTClient_setCallbacks(). + * It is called by the client library after the client application has + * published a message to the server. It indicates that the necessary + * handshaking and acknowledgements for the requested quality of service (see + * MQTTClient_message.qos) have been completed. This function is executed on a + * separate thread to the one on which the client application is running. + * <b>Note:</b>MQTTClient_deliveryComplete() is not called when messages are + * published at QoS0. + * @param context A pointer to the <i>context</i> value originally passed to + * MQTTClient_setCallbacks(), which contains any application-specific context. + * @param dt The ::MQTTClient_deliveryToken associated with + * the published message. Applications can check that all messages have been + * correctly published by matching the delivery tokens returned from calls to + * MQTTClient_publish() and MQTTClient_publishMessage() with the tokens passed + * to this callback. + */ +typedef void MQTTClient_deliveryComplete(void* context, MQTTClient_deliveryToken dt); + +/** + * This is a callback function. The client application + * must provide an implementation of this function to enable asynchronous + * notification of the loss of connection to the server. The function is + * registered with the client library by passing it as an argument to + * MQTTClient_setCallbacks(). It is called by the client library if the client + * loses its connection to the server. The client application must take + * appropriate action, such as trying to reconnect or reporting the problem. + * This function is executed on a separate thread to the one on which the + * client application is running. + * @param context A pointer to the <i>context</i> value originally passed to + * MQTTClient_setCallbacks(), which contains any application-specific context. + * @param cause The reason for the disconnection. + * Currently, <i>cause</i> is always set to NULL. + */ +typedef void MQTTClient_connectionLost(void* context, char* cause); + +/** + * This function sets the callback functions for a specific client. + * If your client application doesn't use a particular callback, set the + * relevant parameter to NULL. Calling MQTTClient_setCallbacks() puts the + * client into multi-threaded mode. Any necessary message acknowledgements and + * status communications are handled in the background without any intervention + * from the client application. See @ref async for more information. + * + * <b>Note:</b> The MQTT client must be disconnected when this function is + * called. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param context A pointer to any application-specific context. The + * the <i>context</i> pointer is passed to each of the callback functions to + * provide access to the context information in the callback. + * @param cl A pointer to an MQTTClient_connectionLost() callback + * function. You can set this to NULL if your application doesn't handle + * disconnections. + * @param ma A pointer to an MQTTClient_messageArrived() callback + * function. This callback function must be specified when you call + * MQTTClient_setCallbacks(). + * @param dc A pointer to an MQTTClient_deliveryComplete() callback + * function. You can set this to NULL if your application publishes + * synchronously or if you do not want to check for successful delivery. + * @return ::MQTTCLIENT_SUCCESS if the callbacks were correctly set, + * ::MQTTCLIENT_FAILURE if an error occurred. + */ +DLLExport int MQTTClient_setCallbacks(MQTTClient handle, void* context, MQTTClient_connectionLost* cl, + MQTTClient_messageArrived* ma, MQTTClient_deliveryComplete* dc); + + +/** + * This function creates an MQTT client ready for connection to the + * specified server and using the specified persistent storage (see + * MQTTClient_persistence). See also MQTTClient_destroy(). + * @param handle A pointer to an ::MQTTClient handle. The handle is + * populated with a valid client reference following a successful return from + * this function. + * @param serverURI A null-terminated string specifying the server to + * which the client will connect. It takes the form <i>protocol://host:port</i>. + * Currently, <i>protocol</i> must be <i>tcp</i> or <i>ssl</i>. + * For <i>host</i>, you can + * specify either an IP address or a host name. For instance, to connect to + * a server running on the local machines with the default MQTT port, specify + * <i>tcp://localhost:1883</i>. + * @param clientId The client identifier passed to the server when the + * client connects to it. It is a null-terminated UTF-8 encoded string. + * @param persistence_type The type of persistence to be used by the client: + * <br> + * ::MQTTCLIENT_PERSISTENCE_NONE: Use in-memory persistence. If the device or + * system on which the client is running fails or is switched off, the current + * state of any in-flight messages is lost and some messages may not be + * delivered even at QoS1 and QoS2. + * <br> + * ::MQTTCLIENT_PERSISTENCE_DEFAULT: Use the default (file system-based) + * persistence mechanism. Status about in-flight messages is held in persistent + * storage and provides some protection against message loss in the case of + * unexpected failure. + * <br> + * ::MQTTCLIENT_PERSISTENCE_USER: Use an application-specific persistence + * implementation. Using this type of persistence gives control of the + * persistence mechanism to the application. The application has to implement + * the MQTTClient_persistence interface. + * @param persistence_context If the application uses + * ::MQTTCLIENT_PERSISTENCE_NONE persistence, this argument is unused and should + * be set to NULL. For ::MQTTCLIENT_PERSISTENCE_DEFAULT persistence, it + * should be set to the location of the persistence directory (if set + * to NULL, the persistence directory used is the working directory). + * Applications that use ::MQTTCLIENT_PERSISTENCE_USER persistence set this + * argument to point to a valid MQTTClient_persistence structure. + * @return ::MQTTCLIENT_SUCCESS if the client is successfully created, otherwise + * an error code is returned. + */ +DLLExport int MQTTClient_create(MQTTClient* handle, const char* serverURI, const char* clientId, + int persistence_type, void* persistence_context); + +/** + * MQTTClient_willOptions defines the MQTT "Last Will and Testament" (LWT) settings for + * the client. In the event that a client unexpectedly loses its connection to + * the server, the server publishes the LWT message to the LWT topic on + * behalf of the client. This allows other clients (subscribed to the LWT topic) + * to be made aware that the client has disconnected. To enable the LWT + * function for a specific client, a valid pointer to an MQTTClient_willOptions + * structure is passed in the MQTTClient_connectOptions structure used in the + * MQTTClient_connect() call that connects the client to the server. The pointer + * to MQTTClient_willOptions can be set to NULL if the LWT function is not + * required. + */ +typedef struct +{ + /** The eyecatcher for this structure. must be MQTW. */ + char struct_id[4]; + /** The version number of this structure. Must be 0 or 1 + 0 means there is no binary payload option + */ + int struct_version; + /** The LWT topic to which the LWT message will be published. */ + const char* topicName; + /** The LWT payload in string form. */ + const char* message; + /** + * The retained flag for the LWT message (see MQTTClient_message.retained). + */ + int retained; + /** + * The quality of service setting for the LWT message (see + * MQTTClient_message.qos and @ref qos). + */ + int qos; + /** The LWT payload in binary form. This is only checked and used if the message option is NULL */ + struct + { + int len; /**< binary payload length */ + const void* data; /**< binary payload data */ + } payload; +} MQTTClient_willOptions; + +#define MQTTClient_willOptions_initializer { {'M', 'Q', 'T', 'W'}, 1, NULL, NULL, 0, 0, {0, NULL} } + +#define MQTT_SSL_VERSION_DEFAULT 0 +#define MQTT_SSL_VERSION_TLS_1_0 1 +#define MQTT_SSL_VERSION_TLS_1_1 2 +#define MQTT_SSL_VERSION_TLS_1_2 3 + +/** +* MQTTClient_sslProperties defines the settings to establish an SSL/TLS connection using the +* OpenSSL library. It covers the following scenarios: +* - Server authentication: The client needs the digital certificate of the server. It is included +* in a store containting trusted material (also known as "trust store"). +* - Mutual authentication: Both client and server are authenticated during the SSL handshake. In +* addition to the digital certificate of the server in a trust store, the client will need its own +* digital certificate and the private key used to sign its digital certificate stored in a "key store". +* - Anonymous connection: Both client and server do not get authenticated and no credentials are needed +* to establish an SSL connection. Note that this scenario is not fully secure since it is subject to +* man-in-the-middle attacks. +*/ +typedef struct +{ + /** The eyecatcher for this structure. Must be MQTS */ + char struct_id[4]; + /** The version number of this structure. Must be 0, or 1 to enable TLS version selection. */ + int struct_version; + + /** The file in PEM format containing the public digital certificates trusted by the client. */ + const char* trustStore; + + /** The file in PEM format containing the public certificate chain of the client. It may also include + * the client's private key. + */ + const char* keyStore; + + /** If not included in the sslKeyStore, this setting points to the file in PEM format containing + * the client's private key. + */ + const char* privateKey; + /** The password to load the client's privateKey if encrypted. */ + const char* privateKeyPassword; + + /** + * The list of cipher suites that the client will present to the server during the SSL handshake. For a + * full explanation of the cipher list format, please see the OpenSSL on-line documentation: + * http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT + * If this setting is ommitted, its default value will be "ALL", that is, all the cipher suites -excluding + * those offering no encryption- will be considered. + * This setting can be used to set an SSL anonymous connection ("aNULL" string value, for instance). + */ + const char* enabledCipherSuites; + + /** True/False option to enable verification of the server certificate **/ + int enableServerCertAuth; + + /** The SSL/TLS version to use. Specify one of MQTT_SSL_VERSION_DEFAULT (0), + * MQTT_SSL_VERSION_TLS_1_0 (1), MQTT_SSL_VERSION_TLS_1_1 (2) or MQTT_SSL_VERSION_TLS_1_2 (3). + * Only used if struct_version is >= 1. + */ + int sslVersion; + + /** + * Whether to carry out post-connect checks, including that a certificate + * matches the given host name. + * Exists only if struct_version >= 2 + */ + int verify; + + /** + * From the OpenSSL documentation: + * If CApath is not NULL, it points to a directory containing CA certificates in PEM format. + * Exists only if struct_version >= 2 + */ + const char* CApath; + +} MQTTClient_SSLOptions; + +#define MQTTClient_SSLOptions_initializer { {'M', 'Q', 'T', 'S'}, 2, NULL, NULL, NULL, NULL, NULL, 1, MQTT_SSL_VERSION_DEFAULT, 0, NULL } + +/** + * MQTTClient_connectOptions defines several settings that control the way the + * client connects to an MQTT server. + * + * <b>Note:</b> Default values are not defined for members of + * MQTTClient_connectOptions so it is good practice to specify all settings. + * If the MQTTClient_connectOptions structure is defined as an automatic + * variable, all members are set to random values and thus must be set by the + * client application. If the MQTTClient_connectOptions structure is defined + * as a static variable, initialization (in compliant compilers) sets all + * values to 0 (NULL for pointers). A #keepAliveInterval setting of 0 prevents + * correct operation of the client and so you <b>must</b> at least set a value + * for #keepAliveInterval. + */ +typedef struct +{ + /** The eyecatcher for this structure. must be MQTC. */ + char struct_id[4]; + /** The version number of this structure. Must be 0, 1, 2, 3, 4 or 5. + * 0 signifies no SSL options and no serverURIs + * 1 signifies no serverURIs + * 2 signifies no MQTTVersion + * 3 signifies no returned values + * 4 signifies no binary password option + */ + int struct_version; + /** The "keep alive" interval, measured in seconds, defines the maximum time + * that should pass without communication between the client and the server + * The client will ensure that at least one message travels across the + * network within each keep alive period. In the absence of a data-related + * message during the time period, the client sends a very small MQTT + * "ping" message, which the server will acknowledge. The keep alive + * interval enables the client to detect when the server is no longer + * available without having to wait for the long TCP/IP timeout. + */ + int keepAliveInterval; + /** + * This is a boolean value. The cleansession setting controls the behaviour + * of both the client and the server at connection and disconnection time. + * The client and server both maintain session state information. This + * information is used to ensure "at least once" and "exactly once" + * delivery, and "exactly once" receipt of messages. Session state also + * includes subscriptions created by an MQTT client. You can choose to + * maintain or discard state information between sessions. + * + * When cleansession is true, the state information is discarded at + * connect and disconnect. Setting cleansession to false keeps the state + * information. When you connect an MQTT client application with + * MQTTClient_connect(), the client identifies the connection using the + * client identifier and the address of the server. The server checks + * whether session information for this client + * has been saved from a previous connection to the server. If a previous + * session still exists, and cleansession=true, then the previous session + * information at the client and server is cleared. If cleansession=false, + * the previous session is resumed. If no previous session exists, a new + * session is started. + */ + int cleansession; + /** + * This is a boolean value that controls how many messages can be in-flight + * simultaneously. Setting <i>reliable</i> to true means that a published + * message must be completed (acknowledgements received) before another + * can be sent. Attempts to publish additional messages receive an + * ::MQTTCLIENT_MAX_MESSAGES_INFLIGHT return code. Setting this flag to + * false allows up to 10 messages to be in-flight. This can increase + * overall throughput in some circumstances. + */ + int reliable; + /** + * This is a pointer to an MQTTClient_willOptions structure. If your + * application does not make use of the Last Will and Testament feature, + * set this pointer to NULL. + */ + MQTTClient_willOptions* will; + /** + * MQTT servers that support the MQTT v3.1.1 protocol provide authentication + * and authorisation by user name and password. This is the user name + * parameter. + */ + const char* username; + /** + * MQTT servers that support the MQTT v3.1.1 protocol provide authentication + * and authorisation by user name and password. This is the password + * parameter. + */ + const char* password; + /** + * The time interval in seconds to allow a connect to complete. + */ + int connectTimeout; + /** + * The time interval in seconds + */ + int retryInterval; + /** + * This is a pointer to an MQTTClient_SSLOptions structure. If your + * application does not make use of SSL, set this pointer to NULL. + */ + MQTTClient_SSLOptions* ssl; + /** + * The number of entries in the optional serverURIs array. Defaults to 0. + */ + int serverURIcount; + /** + * An optional array of null-terminated strings specifying the servers to + * which the client will connect. Each string takes the form <i>protocol://host:port</i>. + * <i>protocol</i> must be <i>tcp</i> or <i>ssl</i>. For <i>host</i>, you can + * specify either an IP address or a host name. For instance, to connect to + * a server running on the local machines with the default MQTT port, specify + * <i>tcp://localhost:1883</i>. + * If this list is empty (the default), the server URI specified on MQTTClient_create() + * is used. + */ + char* const* serverURIs; + /** + * Sets the version of MQTT to be used on the connect. + * MQTTVERSION_DEFAULT (0) = default: start with 3.1.1, and if that fails, fall back to 3.1 + * MQTTVERSION_3_1 (3) = only try version 3.1 + * MQTTVERSION_3_1_1 (4) = only try version 3.1.1 + */ + int MQTTVersion; + /** + * Returned from the connect when the MQTT version used to connect is 3.1.1 + */ + struct + { + const char* serverURI; /**< the serverURI connected to */ + int MQTTVersion; /**< the MQTT version used to connect with */ + int sessionPresent; /**< if the MQTT version is 3.1.1, the value of sessionPresent returned in the connack */ + } returned; + /** + * Optional binary password. Only checked and used if the password option is NULL + */ + struct { + int len; /**< binary password length */ + const void* data; /**< binary password data */ + } binarypwd; +} MQTTClient_connectOptions; + +#define MQTTClient_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 5, 60, 1, 1, NULL, NULL, NULL, 30, 20, NULL, 0, NULL, 0, {NULL, 0, 0}, {0, NULL} } + +/** + * MQTTClient_libraryInfo is used to store details relating to the currently used + * library such as the version in use, the time it was built and relevant openSSL + * options. + * There is one static instance of this struct in MQTTClient.c + */ + +typedef struct +{ + const char* name; + const char* value; +} MQTTClient_nameValue; + +/** + * This function returns version information about the library. + * no trace information will be returned. + * @return an array of strings describing the library. The last entry is a NULL pointer. + */ +DLLExport MQTTClient_nameValue* MQTTClient_getVersionInfo(void); + +/** + * This function attempts to connect a previously-created client (see + * MQTTClient_create()) to an MQTT server using the specified options. If you + * want to enable asynchronous message and status notifications, you must call + * MQTTClient_setCallbacks() prior to MQTTClient_connect(). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param options A pointer to a valid MQTTClient_connectOptions + * structure. + * @return ::MQTTCLIENT_SUCCESS if the client successfully connects to the + * server. An error code is returned if the client was unable to connect to + * the server. + * Error codes greater than 0 are returned by the MQTT protocol:<br><br> + * <b>1</b>: Connection refused: Unacceptable protocol version<br> + * <b>2</b>: Connection refused: Identifier rejected<br> + * <b>3</b>: Connection refused: Server unavailable<br> + * <b>4</b>: Connection refused: Bad user name or password<br> + * <b>5</b>: Connection refused: Not authorized<br> + * <b>6-255</b>: Reserved for future use<br> + */ +DLLExport int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions* options); + +/** + * This function attempts to disconnect the client from the MQTT + * server. In order to allow the client time to complete handling of messages + * that are in-flight when this function is called, a timeout period is + * specified. When the timeout period has expired, the client disconnects even + * if there are still outstanding message acknowledgements. + * The next time the client connects to the same server, any QoS 1 or 2 + * messages which have not completed will be retried depending on the + * cleansession settings for both the previous and the new connection (see + * MQTTClient_connectOptions.cleansession and MQTTClient_connect()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param timeout The client delays disconnection for up to this time (in + * milliseconds) in order to allow in-flight message transfers to complete. + * @return ::MQTTCLIENT_SUCCESS if the client successfully disconnects from + * the server. An error code is returned if the client was unable to disconnect + * from the server + */ +DLLExport int MQTTClient_disconnect(MQTTClient handle, int timeout); + +/** + * This function allows the client application to test whether or not a + * client is currently connected to the MQTT server. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @return Boolean true if the client is connected, otherwise false. + */ +DLLExport int MQTTClient_isConnected(MQTTClient handle); + + +/* Subscribe is synchronous. QoS list parameter is changed on return to granted QoSs. + Returns return code, MQTTCLIENT_SUCCESS == success, non-zero some sort of error (TBD) */ + +/** + * This function attempts to subscribe a client to a single topic, which may + * contain wildcards (see @ref wildcard). This call also specifies the + * @ref qos requested for the subscription + * (see also MQTTClient_subscribeMany()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param topic The subscription topic, which may include wildcards. + * @param qos The requested quality of service for the subscription. + * @return ::MQTTCLIENT_SUCCESS if the subscription request is successful. + * An error code is returned if there was a problem registering the + * subscription. + */ +DLLExport int MQTTClient_subscribe(MQTTClient handle, const char* topic, int qos); + +/** + * This function attempts to subscribe a client to a list of topics, which may + * contain wildcards (see @ref wildcard). This call also specifies the + * @ref qos requested for each topic (see also MQTTClient_subscribe()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param count The number of topics for which the client is requesting + * subscriptions. + * @param topic An array (of length <i>count</i>) of pointers to + * topics, each of which may include wildcards. + * @param qos An array (of length <i>count</i>) of @ref qos + * values. qos[n] is the requested QoS for topic[n]. + * @return ::MQTTCLIENT_SUCCESS if the subscription request is successful. + * An error code is returned if there was a problem registering the + * subscriptions. + */ +DLLExport int MQTTClient_subscribeMany(MQTTClient handle, int count, char* const* topic, int* qos); + +/** + * This function attempts to remove an existing subscription made by the + * specified client. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param topic The topic for the subscription to be removed, which may + * include wildcards (see @ref wildcard). + * @return ::MQTTCLIENT_SUCCESS if the subscription is removed. + * An error code is returned if there was a problem removing the + * subscription. + */ +DLLExport int MQTTClient_unsubscribe(MQTTClient handle, const char* topic); + +/** + * This function attempts to remove existing subscriptions to a list of topics + * made by the specified client. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param count The number subscriptions to be removed. + * @param topic An array (of length <i>count</i>) of pointers to the topics of + * the subscriptions to be removed, each of which may include wildcards. + * @return ::MQTTCLIENT_SUCCESS if the subscriptions are removed. + * An error code is returned if there was a problem removing the subscriptions. + */ +DLLExport int MQTTClient_unsubscribeMany(MQTTClient handle, int count, char* const* topic); + +/** + * This function attempts to publish a message to a given topic (see also + * MQTTClient_publishMessage()). An ::MQTTClient_deliveryToken is issued when + * this function returns successfully. If the client application needs to + * test for succesful delivery of QoS1 and QoS2 messages, this can be done + * either asynchronously or synchronously (see @ref async, + * ::MQTTClient_waitForCompletion and MQTTClient_deliveryComplete()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param topicName The topic associated with this message. + * @param payloadlen The length of the payload in bytes. + * @param payload A pointer to the byte array payload of the message. + * @param qos The @ref qos of the message. + * @param retained The retained flag for the message. + * @param dt A pointer to an ::MQTTClient_deliveryToken. This is populated + * with a token representing the message when the function returns + * successfully. If your application does not use delivery tokens, set this + * argument to NULL. + * @return ::MQTTCLIENT_SUCCESS if the message is accepted for publication. + * An error code is returned if there was a problem accepting the message. + */ +DLLExport int MQTTClient_publish(MQTTClient handle, const char* topicName, int payloadlen, void* payload, int qos, int retained, + MQTTClient_deliveryToken* dt); +/** + * This function attempts to publish a message to a given topic (see also + * MQTTClient_publish()). An ::MQTTClient_deliveryToken is issued when + * this function returns successfully. If the client application needs to + * test for succesful delivery of QoS1 and QoS2 messages, this can be done + * either asynchronously or synchronously (see @ref async, + * ::MQTTClient_waitForCompletion and MQTTClient_deliveryComplete()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param topicName The topic associated with this message. + * @param msg A pointer to a valid MQTTClient_message structure containing + * the payload and attributes of the message to be published. + * @param dt A pointer to an ::MQTTClient_deliveryToken. This is populated + * with a token representing the message when the function returns + * successfully. If your application does not use delivery tokens, set this + * argument to NULL. + * @return ::MQTTCLIENT_SUCCESS if the message is accepted for publication. + * An error code is returned if there was a problem accepting the message. + */ +DLLExport int MQTTClient_publishMessage(MQTTClient handle, const char* topicName, MQTTClient_message* msg, MQTTClient_deliveryToken* dt); + + +/** + * This function is called by the client application to synchronize execution + * of the main thread with completed publication of a message. When called, + * MQTTClient_waitForCompletion() blocks execution until the message has been + * successful delivered or the specified timeout has expired. See @ref async. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param dt The ::MQTTClient_deliveryToken that represents the message being + * tested for successful delivery. Delivery tokens are issued by the + * publishing functions MQTTClient_publish() and MQTTClient_publishMessage(). + * @param timeout The maximum time to wait in milliseconds. + * @return ::MQTTCLIENT_SUCCESS if the message was successfully delivered. + * An error code is returned if the timeout expires or there was a problem + * checking the token. + */ +DLLExport int MQTTClient_waitForCompletion(MQTTClient handle, MQTTClient_deliveryToken dt, unsigned long timeout); + + +/** + * This function sets a pointer to an array of delivery tokens for + * messages that are currently in-flight (pending completion). + * + * <b>Important note:</b> The memory used to hold the array of tokens is + * malloc()'d in this function. The client application is responsible for + * freeing this memory when it is no longer required. + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param tokens The address of a pointer to an ::MQTTClient_deliveryToken. + * When the function returns successfully, the pointer is set to point to an + * array of tokens representing messages pending completion. The last member of + * the array is set to -1 to indicate there are no more tokens. If no tokens + * are pending, the pointer is set to NULL. + * @return ::MQTTCLIENT_SUCCESS if the function returns successfully. + * An error code is returned if there was a problem obtaining the list of + * pending tokens. + */ +DLLExport int MQTTClient_getPendingDeliveryTokens(MQTTClient handle, MQTTClient_deliveryToken **tokens); + +/** + * When implementing a single-threaded client, call this function periodically + * to allow processing of message retries and to send MQTT keepalive pings. + * If the application is calling MQTTClient_receive() regularly, then it is + * not necessary to call this function. + */ +DLLExport void MQTTClient_yield(void); + +/** + * This function performs a synchronous receive of incoming messages. It should + * be used only when the client application has not set callback methods to + * support asynchronous receipt of messages (see @ref async and + * MQTTClient_setCallbacks()). Using this function allows a single-threaded + * client subscriber application to be written. When called, this function + * blocks until the next message arrives or the specified timeout expires + *(see also MQTTClient_yield()). + * + * <b>Important note:</b> The application must free() the memory allocated + * to the topic and the message when processing is complete (see + * MQTTClient_freeMessage()). + * @param handle A valid client handle from a successful call to + * MQTTClient_create(). + * @param topicName The address of a pointer to a topic. This function + * allocates the memory for the topic and returns it to the application + * by setting <i>topicName</i> to point to the topic. + * @param topicLen The length of the topic. If the return code from this + * function is ::MQTTCLIENT_TOPICNAME_TRUNCATED, the topic contains embedded + * NULL characters and the full topic should be retrieved by using + * <i>topicLen</i>. + * @param message The address of a pointer to the received message. This + * function allocates the memory for the message and returns it to the + * application by setting <i>message</i> to point to the received message. + * The pointer is set to NULL if the timeout expires. + * @param timeout The length of time to wait for a message in milliseconds. + * @return ::MQTTCLIENT_SUCCESS or ::MQTTCLIENT_TOPICNAME_TRUNCATED if a + * message is received. ::MQTTCLIENT_SUCCESS can also indicate that the + * timeout expired, in which case <i>message</i> is NULL. An error code is + * returned if there was a problem trying to receive a message. + */ +DLLExport int MQTTClient_receive(MQTTClient handle, char** topicName, int* topicLen, MQTTClient_message** message, + unsigned long timeout); + +/** + * This function frees memory allocated to an MQTT message, including the + * additional memory allocated to the message payload. The client application + * calls this function when the message has been fully processed. <b>Important + * note:</b> This function does not free the memory allocated to a message + * topic string. It is the responsibility of the client application to free + * this memory using the MQTTClient_free() library function. + * @param msg The address of a pointer to the ::MQTTClient_message structure + * to be freed. + */ +DLLExport void MQTTClient_freeMessage(MQTTClient_message** msg); + +/** + * This function frees memory allocated by the MQTT C client library, especially the + * topic name. This is needed on Windows when the client libary and application + * program have been compiled with different versions of the C compiler. It is + * thus good policy to always use this function when freeing any MQTT C client- + * allocated memory. + * @param ptr The pointer to the client library storage to be freed. + */ +DLLExport void MQTTClient_free(void* ptr); + +/** + * This function frees the memory allocated to an MQTT client (see + * MQTTClient_create()). It should be called when the client is no longer + * required. + * @param handle A pointer to the handle referring to the ::MQTTClient + * structure to be freed. + */ +DLLExport void MQTTClient_destroy(MQTTClient* handle); + +#endif +#ifdef __cplusplus + } +#endif + +/** + * @cond MQTTClient_main + * @page async Asynchronous vs synchronous client applications + * The client library supports two modes of operation. These are referred to + * as <b>synchronous</b> and <b>asynchronous</b> modes. If your application + * calls MQTTClient_setCallbacks(), this puts the client into asynchronous + * mode, otherwise it operates in synchronous mode. + * + * In synchronous mode, the client application runs on a single thread. + * Messages are published using the MQTTClient_publish() and + * MQTTClient_publishMessage() functions. To determine that a QoS1 or QoS2 + * (see @ref qos) message has been successfully delivered, the application + * must call the MQTTClient_waitForCompletion() function. An example showing + * synchronous publication is shown in @ref pubsync. Receiving messages in + * synchronous mode uses the MQTTClient_receive() function. Client applications + * must call either MQTTClient_receive() or MQTTClient_yield() relatively + * frequently in order to allow processing of acknowledgements and the MQTT + * "pings" that keep the network connection to the server alive. + * + * In asynchronous mode, the client application runs on several threads. The + * main program calls functions in the client library to publish and subscribe, + * just as for the synchronous mode. Processing of handshaking and maintaining + * the network connection is performed in the background, however. + * Notifications of status and message reception are provided to the client + * application using callbacks registered with the library by the call to + * MQTTClient_setCallbacks() (see MQTTClient_messageArrived(), + * MQTTClient_connectionLost() and MQTTClient_deliveryComplete()). + * This API is not thread safe however - it is not possible to call it from multiple + * threads without synchronization. You can use the MQTTAsync API for that. + * + * @page wildcard Subscription wildcards + * Every MQTT message includes a topic that classifies it. MQTT servers use + * topics to determine which subscribers should receive messages published to + * the server. + * + * Consider the server receiving messages from several environmental sensors. + * Each sensor publishes its measurement data as a message with an associated + * topic. Subscribing applications need to know which sensor originally + * published each received message. A unique topic is thus used to identify + * each sensor and measurement type. Topics such as SENSOR1TEMP, + * SENSOR1HUMIDITY, SENSOR2TEMP and so on achieve this but are not very + * flexible. If additional sensors are added to the system at a later date, + * subscribing applications must be modified to receive them. + * + * To provide more flexibility, MQTT supports a hierarchical topic namespace. + * This allows application designers to organize topics to simplify their + * management. Levels in the hierarchy are delimited by the '/' character, + * such as SENSOR/1/HUMIDITY. Publishers and subscribers use these + * hierarchical topics as already described. + * + * For subscriptions, two wildcard characters are supported: + * <ul> + * <li>A '#' character represents a complete sub-tree of the hierarchy and + * thus must be the last character in a subscription topic string, such as + * SENSOR/#. This will match any topic starting with SENSOR/, such as + * SENSOR/1/TEMP and SENSOR/2/HUMIDITY.</li> + * <li> A '+' character represents a single level of the hierarchy and is + * used between delimiters. For example, SENSOR/+/TEMP will match + * SENSOR/1/TEMP and SENSOR/2/TEMP.</li> + * </ul> + * Publishers are not allowed to use the wildcard characters in their topic + * names. + * + * Deciding on your topic hierarchy is an important step in your system design. + * + * @page qos Quality of service + * The MQTT protocol provides three qualities of service for delivering + * messages between clients and servers: "at most once", "at least once" and + * "exactly once". + * + * Quality of service (QoS) is an attribute of an individual message being + * published. An application sets the QoS for a specific message by setting the + * MQTTClient_message.qos field to the required value. + * + * A subscribing client can set the maximum quality of service a server uses + * to send messages that match the client subscriptions. The + * MQTTClient_subscribe() and MQTTClient_subscribeMany() functions set this + * maximum. The QoS of a message forwarded to a subscriber thus might be + * different to the QoS given to the message by the original publisher. + * The lower of the two values is used to forward a message. + * + * The three levels are: + * + * <b>QoS0, At most once:</b> The message is delivered at most once, or it + * may not be delivered at all. Its delivery across the network is not + * acknowledged. The message is not stored. The message could be lost if the + * client is disconnected, or if the server fails. QoS0 is the fastest mode of + * transfer. It is sometimes called "fire and forget". + * + * The MQTT protocol does not require servers to forward publications at QoS0 + * to a client. If the client is disconnected at the time the server receives + * the publication, the publication might be discarded, depending on the + * server implementation. + * + * <b>QoS1, At least once:</b> The message is always delivered at least once. + * It might be delivered multiple times if there is a failure before an + * acknowledgment is received by the sender. The message must be stored + * locally at the sender, until the sender receives confirmation that the + * message has been published by the receiver. The message is stored in case + * the message must be sent again. + * + * <b>QoS2, Exactly once:</b> The message is always delivered exactly once. + * The message must be stored locally at the sender, until the sender receives + * confirmation that the message has been published by the receiver. The + * message is stored in case the message must be sent again. QoS2 is the + * safest, but slowest mode of transfer. A more sophisticated handshaking + * and acknowledgement sequence is used than for QoS1 to ensure no duplication + * of messages occurs. + * @page pubsync Synchronous publication example +@code +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "MQTTClient.h" + +#define ADDRESS "tcp://localhost:1883" +#define CLIENTID "ExampleClientPub" +#define TOPIC "MQTT Examples" +#define PAYLOAD "Hello World!" +#define QOS 1 +#define TIMEOUT 10000L + +int main(int argc, char* argv[]) +{ + MQTTClient client; + MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer; + MQTTClient_message pubmsg = MQTTClient_message_initializer; + MQTTClient_deliveryToken token; + int rc; + + MQTTClient_create(&client, ADDRESS, CLIENTID, + MQTTCLIENT_PERSISTENCE_NONE, NULL); + conn_opts.keepAliveInterval = 20; + conn_opts.cleansession = 1; + + if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) + { + printf("Failed to connect, return code %d\n", rc); + exit(EXIT_FAILURE); + } + pubmsg.payload = PAYLOAD; + pubmsg.payloadlen = strlen(PAYLOAD); + pubmsg.qos = QOS; + pubmsg.retained = 0; + MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token); + printf("Waiting for up to %d seconds for publication of %s\n" + "on topic %s for client with ClientID: %s\n", + (int)(TIMEOUT/1000), PAYLOAD, TOPIC, CLIENTID); + rc = MQTTClient_waitForCompletion(client, token, TIMEOUT); + printf("Message with delivery token %d delivered\n", token); + MQTTClient_disconnect(client, 10000); + MQTTClient_destroy(&client); + return rc; +} + + * @endcode + * + * @page pubasync Asynchronous publication example +@code{.c} +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "MQTTClient.h" + +#define ADDRESS "tcp://localhost:1883" +#define CLIENTID "ExampleClientPub" +#define TOPIC "MQTT Examples" +#define PAYLOAD "Hello World!" +#define QOS 1 +#define TIMEOUT 10000L + +volatile MQTTClient_deliveryToken deliveredtoken; + +void delivered(void *context, MQTTClient_deliveryToken dt) +{ + printf("Message with token value %d delivery confirmed\n", dt); + deliveredtoken = dt; +} + +int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message) +{ + int i; + char* payloadptr; + + printf("Message arrived\n"); + printf(" topic: %s\n", topicName); + printf(" message: "); + + payloadptr = message->payload; + for(i=0; i<message->payloadlen; i++) + { + putchar(*payloadptr++); + } + putchar('\n'); + MQTTClient_freeMessage(&message); + MQTTClient_free(topicName); + return 1; +} + +void connlost(void *context, char *cause) +{ + printf("\nConnection lost\n"); + printf(" cause: %s\n", cause); +} + +int main(int argc, char* argv[]) +{ + MQTTClient client; + MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer; + MQTTClient_message pubmsg = MQTTClient_message_initializer; + MQTTClient_deliveryToken token; + int rc; + + MQTTClient_create(&client, ADDRESS, CLIENTID, + MQTTCLIENT_PERSISTENCE_NONE, NULL); + conn_opts.keepAliveInterval = 20; + conn_opts.cleansession = 1; + + MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered); + + if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) + { + printf("Failed to connect, return code %d\n", rc); + exit(EXIT_FAILURE); + } + pubmsg.payload = PAYLOAD; + pubmsg.payloadlen = strlen(PAYLOAD); + pubmsg.qos = QOS; + pubmsg.retained = 0; + deliveredtoken = 0; + MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token); + printf("Waiting for publication of %s\n" + "on topic %s for client with ClientID: %s\n", + PAYLOAD, TOPIC, CLIENTID); + while(deliveredtoken != token); + MQTTClient_disconnect(client, 10000); + MQTTClient_destroy(&client); + return rc; +} + + * @endcode + * @page subasync Asynchronous subscription example +@code +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "MQTTClient.h" + +#define ADDRESS "tcp://localhost:1883" +#define CLIENTID "ExampleClientSub" +#define TOPIC "MQTT Examples" +#define PAYLOAD "Hello World!" +#define QOS 1 +#define TIMEOUT 10000L + +volatile MQTTClient_deliveryToken deliveredtoken; + +void delivered(void *context, MQTTClient_deliveryToken dt) +{ + printf("Message with token value %d delivery confirmed\n", dt); + deliveredtoken = dt; +} + +int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message) +{ + int i; + char* payloadptr; + + printf("Message arrived\n"); + printf(" topic: %s\n", topicName); + printf(" message: "); + + payloadptr = message->payload; + for(i=0; i<message->payloadlen; i++) + { + putchar(*payloadptr++); + } + putchar('\n'); + MQTTClient_freeMessage(&message); + MQTTClient_free(topicName); + return 1; +} + +void connlost(void *context, char *cause) +{ + printf("\nConnection lost\n"); + printf(" cause: %s\n", cause); +} + +int main(int argc, char* argv[]) +{ + MQTTClient client; + MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer; + int rc; + int ch; + + MQTTClient_create(&client, ADDRESS, CLIENTID, + MQTTCLIENT_PERSISTENCE_NONE, NULL); + conn_opts.keepAliveInterval = 20; + conn_opts.cleansession = 1; + + MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered); + + if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) + { + printf("Failed to connect, return code %d\n", rc); + exit(EXIT_FAILURE); + } + printf("Subscribing to topic %s\nfor client %s using QoS%d\n\n" + "Press Q<Enter> to quit\n\n", TOPIC, CLIENTID, QOS); + MQTTClient_subscribe(client, TOPIC, QOS); + + do + { + ch = getchar(); + } while(ch!='Q' && ch != 'q'); + + MQTTClient_disconnect(client, 10000); + MQTTClient_destroy(&client); + return rc; +} + + * @endcode + * @page tracing Tracing + * + * Runtime tracing is controlled by environment variables. + * + * Tracing is switched on by setting MQTT_C_CLIENT_TRACE. A value of ON, or stdout, prints to + * stdout, any other value is interpreted as a file name to use. + * + * The amount of trace detail is controlled with the MQTT_C_CLIENT_TRACE_LEVEL environment + * variable - valid values are ERROR, PROTOCOL, MINIMUM, MEDIUM and MAXIMUM + * (from least to most verbose). + * + * The variable MQTT_C_CLIENT_TRACE_MAX_LINES limits the number of lines of trace that are output + * to a file. Two files are used at most, when they are full, the last one is overwritten with the + * new trace entries. The default size is 1000 lines. + * + * ### MQTT Packet Tracing + * + * A feature that can be very useful is printing the MQTT packets that are sent and received. To + * achieve this, use the following environment variable settings: + * @code + MQTT_C_CLIENT_TRACE=ON + MQTT_C_CLIENT_TRACE_LEVEL=PROTOCOL + * @endcode + * The output you should see looks like this: + * @code + 20130528 155936.813 3 stdout-subscriber -> CONNECT cleansession: 1 (0) + 20130528 155936.813 3 stdout-subscriber <- CONNACK rc: 0 + 20130528 155936.813 3 stdout-subscriber -> SUBSCRIBE msgid: 1 (0) + 20130528 155936.813 3 stdout-subscriber <- SUBACK msgid: 1 + 20130528 155941.818 3 stdout-subscriber -> DISCONNECT (0) + * @endcode + * where the fields are: + * 1. date + * 2. time + * 3. socket number + * 4. client id + * 5. direction (-> from client to server, <- from server to client) + * 6. packet details + * + * ### Default Level Tracing + * + * This is an extract of a default level trace of a call to connect: + * @code + 19700101 010000.000 (1152206656) (0)> MQTTClient_connect:893 + 19700101 010000.000 (1152206656) (1)> MQTTClient_connectURI:716 + 20130528 160447.479 Connecting to serverURI localhost:1883 + 20130528 160447.479 (1152206656) (2)> MQTTProtocol_connect:98 + 20130528 160447.479 (1152206656) (3)> MQTTProtocol_addressPort:48 + 20130528 160447.479 (1152206656) (3)< MQTTProtocol_addressPort:73 + 20130528 160447.479 (1152206656) (3)> Socket_new:599 + 20130528 160447.479 New socket 4 for localhost, port 1883 + 20130528 160447.479 (1152206656) (4)> Socket_addSocket:163 + 20130528 160447.479 (1152206656) (5)> Socket_setnonblocking:73 + 20130528 160447.479 (1152206656) (5)< Socket_setnonblocking:78 (0) + 20130528 160447.479 (1152206656) (4)< Socket_addSocket:176 (0) + 20130528 160447.479 (1152206656) (4)> Socket_error:95 + 20130528 160447.479 (1152206656) (4)< Socket_error:104 (115) + 20130528 160447.479 Connect pending + 20130528 160447.479 (1152206656) (3)< Socket_new:683 (115) + 20130528 160447.479 (1152206656) (2)< MQTTProtocol_connect:131 (115) + * @endcode + * where the fields are: + * 1. date + * 2. time + * 3. thread id + * 4. function nesting level + * 5. function entry (>) or exit (<) + * 6. function name : line of source code file + * 7. return value (if there is one) + * + * ### Memory Allocation Tracing + * + * Setting the trace level to maximum causes memory allocations and frees to be traced along with + * the default trace entries, with messages like the following: + * @code + 20130528 161819.657 Allocating 16 bytes in heap at file /home/icraggs/workspaces/mqrtc/mqttv3c/src/MQTTPacket.c line 177 ptr 0x179f930 + + 20130528 161819.657 Freeing 16 bytes in heap at file /home/icraggs/workspaces/mqrtc/mqttv3c/src/MQTTPacket.c line 201, heap use now 896 bytes + * @endcode + * When the last MQTT client object is destroyed, if the trace is being recorded + * and all memory allocated by the client library has not been freed, an error message will be + * written to the trace. This can help with fixing memory leaks. The message will look like this: + * @code + 20130528 163909.208 Some memory not freed at shutdown, possible memory leak + 20130528 163909.208 Heap scan start, total 880 bytes + 20130528 163909.208 Heap element size 32, line 354, file /home/icraggs/workspaces/mqrtc/mqttv3c/src/MQTTPacket.c, ptr 0x260cb00 + 20130528 163909.208 Content + 20130528 163909.209 Heap scan end + * @endcode + * @endcond + */ |