cc
MQTTClient.h
- Committer:
- icraggs
- Date:
- 2014-08-15
- Revision:
- 41:b7e86fa6dbb8
- Parent:
- 40:9623a2c9c8ac
- Child:
- 42:f5beda831651
File content as of revision 41:b7e86fa6dbb8:
/******************************************************************************* * Copyright (c) 2014 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 *******************************************************************************/ /* TODO: ensure publish packets are retried on reconnect */ #if !defined(MQTTCLIENT_H) #define MQTTCLIENT_H #include "FP.h" #include "MQTTPacket.h" #include "stdio.h" #include "MQTT_logging.h" namespace MQTT { enum QoS { QOS0, QOS1, QOS2 }; // all failure return codes must be negative enum returnCode { BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 }; struct Message { enum QoS qos; bool retained; bool dup; unsigned short id; void *payload; size_t payloadlen; }; struct MessageData { MessageData(MQTTString &aTopicName, struct Message &aMessage) : message(aMessage), topicName(aTopicName) { } struct Message &message; MQTTString &topicName; }; class PacketId { public: PacketId() { next = 0; } int getNext() { return next = (next == MAX_PACKET_ID) ? 1 : ++next; } private: static const int MAX_PACKET_ID = 65535; int next; }; class QoS2 { public: private: }; /** * @class Client * @brief blocking, non-threaded MQTT client API * * This version of the API blocks on all method calls, until they are complete. This means that only one * MQTT request can be in process at any one time. * @param Network a network class which supports send, receive * @param Timer a timer class with the methods: */ template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE = 100, int MAX_MESSAGE_HANDLERS = 5> class Client { public: typedef void (*messageHandler)(MessageData&); /** Construct the client * @param network - pointer to an instance of the Network class - must be connected to the endpoint * before calling MQTT connect * @param limits an instance of the Limit class - to alter limits as required */ Client(Network& network, unsigned int command_timeout_ms = 30000); /** Set the default message handling callback - used for any message which does not match a subscription message handler * @param mh - pointer to the callback function */ void setDefaultMessageHandler(messageHandler mh) { defaultMessageHandler.attach(mh); } /** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack * The nework object must be connected to the network endpoint before calling this * @param options - connect options * @return success code - */ int connect(MQTTPacket_connectData* options = 0); /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs * @param topic - the topic to publish to * @param message - the message to send * @return success code - */ int publish(const char* topicName, Message* message); /** MQTT Subscribe - send an MQTT subscribe packet and wait for the suback * @param topicFilter - a topic pattern which can include wildcards * @param qos - the MQTT QoS to subscribe at * @param mh - the callback function to be invoked when a message is received for this subscription * @return success code - */ int subscribe(const char* topicFilter, enum QoS qos, messageHandler mh); /** MQTT Unsubscribe - send an MQTT unsubscribe packet and wait for the unsuback * @param topicFilter - a topic pattern which can include wildcards * @return success code - */ int unsubscribe(const char* topicFilter); /** MQTT Disconnect - send an MQTT disconnect packet, and clean up any state * @return success code - */ int disconnect(); /** A call to this API must be made within the keepAlive interval to keep the MQTT connection alive * yield can be called if no other MQTT operation is needed. This will also allow messages to be * received. * @param timeout_ms the time to wait, in milliseconds * @return success code - on failure, this means the client has disconnected */ int yield(int timeout_ms = 1000); private: int cycle(Timer& timer); int waitfor(int packet_type, Timer& timer); int keepalive(); int decodePacket(int* value, int timeout); int readPacket(Timer& timer); int sendPacket(int length, Timer& timer); int deliverMessage(MQTTString& topicName, Message& message); bool isTopicMatched(char* topicFilter, MQTTString& topicName); Network& ipstack; unsigned int command_timeout_ms; unsigned char buf[MAX_MQTT_PACKET_SIZE]; unsigned char readbuf[MAX_MQTT_PACKET_SIZE]; Timer ping_timer; unsigned int keepAliveInterval; bool ping_outstanding; PacketId packetid; struct MessageHandlers { const char* topicFilter; FP<void, MessageData&> fp; } messageHandlers[MAX_MESSAGE_HANDLERS]; // Message handlers are indexed by subscription topic FP<void, MessageData&> defaultMessageHandler; bool isconnected; #if 0 struct { bool used; int id; } QoS2messages[MAX_QOS2_MESSAGES]; #endif }; } template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS> MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::Client(Network& network, unsigned int command_timeout_ms) : ipstack(network), packetid() { ping_timer = Timer(); ping_outstanding = 0; for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i) messageHandlers[i].topicFilter = 0; this->command_timeout_ms = command_timeout_ms; isconnected = false; } template<class Network, class Timer, int a, int b> int MQTT::Client<Network, Timer, a, b>::sendPacket(int length, Timer& timer) { int rc = FAILURE, sent = 0; while (sent < length && !timer.expired()) { rc = ipstack.write(&buf[sent], length, timer.left_ms()); if (rc < 0) // there was an error writing the data break; sent += rc; } if (sent == length) { ping_timer.countdown(this->keepAliveInterval); // record the fact that we have successfully sent the packet rc = SUCCESS; } else rc = FAILURE; return rc; } template<class Network, class Timer, int a, int b> int MQTT::Client<Network, Timer, a, b>::decodePacket(int* value, int timeout) { unsigned char c; int multiplier = 1; int len = 0; const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4; *value = 0; do { int rc = MQTTPACKET_READ_ERROR; if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES) { rc = MQTTPACKET_READ_ERROR; /* bad data */ goto exit; } rc = ipstack.read(&c, 1, timeout); if (rc != 1) goto exit; *value += (c & 127) * multiplier; multiplier *= 128; } while ((c & 128) != 0); exit: return len; } /** * If any read fails in this method, then we should disconnect from the network, as on reconnect * the packets can be retried. * @param timeout the max time to wait for the packet read to complete, in milliseconds * @return the MQTT packet type, or -1 if none */ template<class Network, class Timer, int a, int b> int MQTT::Client<Network, Timer, a, b>::readPacket(Timer& timer) { int rc = FAILURE; MQTTHeader header = {0}; int len = 0; int rem_len = 0; /* 1. read the header byte. This has the packet type in it */ if (ipstack.read(readbuf, 1, timer.left_ms()) != 1) goto exit; len = 1; /* 2. read the remaining length. This is variable in itself */ decodePacket(&rem_len, timer.left_ms()); len += MQTTPacket_encode(readbuf + 1, rem_len); /* put the original remaining length back into the buffer */ /* 3. read the rest of the buffer using a callback to supply the rest of the data */ if (ipstack.read(readbuf + len, rem_len, timer.left_ms()) != rem_len) goto exit; header.byte = readbuf[0]; rc = header.bits.type; exit: return rc; } // assume topic filter and name is in correct format // # can only be at end // + and # can only be next to separator template<class Network, class Timer, int a, int b> bool MQTT::Client<Network, Timer, a, b>::isTopicMatched(char* topicFilter, MQTTString& topicName) { char* curf = topicFilter; char* curn = topicName.lenstring.data; char* curn_end = curn + topicName.lenstring.len; while (*curf && curn < curn_end) { if (*curn == '/' && *curf != '/') break; if (*curf != '+' && *curf != '#' && *curf != *curn) break; if (*curf == '+') { // skip until we meet the next separator, or end of string char* nextpos = curn + 1; while (nextpos < curn_end && *nextpos != '/') nextpos = ++curn + 1; } else if (*curf == '#') curn = curn_end - 1; // skip until end of string curf++; curn++; }; return (curn == curn_end) && (*curf == '\0'); } template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS> int MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::deliverMessage(MQTTString& topicName, Message& message) { int rc = FAILURE; // we have to find the right message handler - indexed by topic for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i) { if (messageHandlers[i].topicFilter != 0 && (MQTTPacket_equals(&topicName, (char*)messageHandlers[i].topicFilter) || isTopicMatched((char*)messageHandlers[i].topicFilter, topicName))) { if (messageHandlers[i].fp.attached()) { MessageData md(topicName, message); messageHandlers[i].fp(md); rc = SUCCESS; } } } if (rc == FAILURE && defaultMessageHandler.attached()) { MessageData md(topicName, message); defaultMessageHandler(md); rc = SUCCESS; } return rc; } template<class Network, class Timer, int a, int b> int MQTT::Client<Network, Timer, a, b>::yield(int timeout_ms) { int rc = SUCCESS; Timer timer = Timer(); timer.countdown_ms(timeout_ms); while (!timer.expired()) { if (cycle(timer) == FAILURE) { rc = FAILURE; break; } } return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::cycle(Timer& timer) { /* get one piece of work off the wire and one pass through */ // read the socket, see what work is due unsigned short packet_type = readPacket(timer); int len = 0, rc = SUCCESS; switch (packet_type) { case CONNACK: case PUBACK: case SUBACK: break; case PUBLISH: MQTTString topicName; Message msg; if (MQTTDeserialize_publish((unsigned char*)&msg.dup, (int*)&msg.qos, (unsigned char*)&msg.retained, (unsigned short*)&msg.id, &topicName, (unsigned char**)&msg.payload, (int*)&msg.payloadlen, readbuf, MAX_MQTT_PACKET_SIZE) != 1) goto exit; // if (msg.qos != QOS2) deliverMessage(topicName, msg); #if 0 else if (isQoS2msgidFree(msg.id)) { UseQoS2msgid(msg.id); deliverMessage(topicName, msg); } #endif if (msg.qos != QOS0) { if (msg.qos == QOS1) len = MQTTSerialize_ack(buf, MAX_MQTT_PACKET_SIZE, PUBACK, 0, msg.id); else if (msg.qos == QOS2) len = MQTTSerialize_ack(buf, MAX_MQTT_PACKET_SIZE, PUBREC, 0, msg.id); if (len <= 0) rc = FAILURE; else rc = sendPacket(len, timer); if (rc == FAILURE) goto exit; // there was a problem } break; case PUBREC: unsigned short mypacketid; unsigned char dup, type; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1) rc = FAILURE; else if ((len = MQTTSerialize_ack(buf, MAX_MQTT_PACKET_SIZE, PUBREL, 0, mypacketid)) <= 0) rc = FAILURE; else if ((rc = sendPacket(len, timer)) != SUCCESS) // send the PUBREL packet rc = FAILURE; // there was a problem if (rc == FAILURE) goto exit; // there was a problem break; case PUBCOMP: break; case PINGRESP: ping_outstanding = false; break; } keepalive(); exit: if (rc == SUCCESS) rc = packet_type; return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::keepalive() { int rc = FAILURE; if (keepAliveInterval == 0) { rc = SUCCESS; goto exit; } if (ping_timer.expired()) { if (!ping_outstanding) { Timer timer = Timer(1000); int len = MQTTSerialize_pingreq(buf, MAX_MQTT_PACKET_SIZE); if (len > 0 && (rc = sendPacket(len, timer)) == SUCCESS) // send the ping packet ping_outstanding = true; } } exit: return rc; } // only used in single-threaded mode where one command at a time is in process template<class Network, class Timer, int a, int b> int MQTT::Client<Network, Timer, a, b>::waitfor(int packet_type, Timer& timer) { int rc = FAILURE; do { if (timer.expired()) break; // we timed out } while ((rc = cycle(timer)) != packet_type); return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::connect(MQTTPacket_connectData* options) { Timer connect_timer = Timer(command_timeout_ms); int rc = FAILURE; MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer; int len = 0; if (isconnected) // don't send connect packet again if we are already connected goto exit; if (options == 0) options = &default_options; // set default options if none were supplied this->keepAliveInterval = options->keepAliveInterval; ping_timer.countdown(this->keepAliveInterval); if ((len = MQTTSerialize_connect(buf, MAX_MQTT_PACKET_SIZE, options)) <= 0) goto exit; if ((rc = sendPacket(len, connect_timer)) != SUCCESS) // send the connect packet goto exit; // there was a problem // this will be a blocking call, wait for the connack if (waitfor(CONNACK, connect_timer) == CONNACK) { unsigned char connack_rc = 255; bool sessionPresent = false; if (MQTTDeserialize_connack((unsigned char*)&sessionPresent, &connack_rc, readbuf, MAX_MQTT_PACKET_SIZE) == 1) rc = connack_rc; else rc = FAILURE; } else rc = FAILURE; exit: if (rc == SUCCESS) isconnected = true; return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::subscribe(const char* topicFilter, enum QoS qos, messageHandler messageHandler) { int rc = FAILURE; Timer timer = Timer(command_timeout_ms); int len = 0; MQTTString topic = {(char*)topicFilter, 0, 0}; if (!isconnected) goto exit; len = MQTTSerialize_subscribe(buf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int*)&qos); if (len <= 0) goto exit; if ((rc = sendPacket(len, timer)) != SUCCESS) // send the subscribe packet goto exit; // there was a problem if (waitfor(SUBACK, timer) == SUBACK) // wait for suback { int count = 0, grantedQoS = -1; unsigned short mypacketid; if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, readbuf, MAX_MQTT_PACKET_SIZE) == 1) rc = grantedQoS; // 0, 1, 2 or 0x80 if (rc != 0x80) { for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i) { if (messageHandlers[i].topicFilter == 0) { messageHandlers[i].topicFilter = topicFilter; messageHandlers[i].fp.attach(messageHandler); rc = 0; break; } } } } else rc = FAILURE; exit: return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::unsubscribe(const char* topicFilter) { int rc = FAILURE; Timer timer = Timer(command_timeout_ms); MQTTString topic = {(char*)topicFilter, 0, 0}; int len = 0; if (!isconnected) goto exit; if ((len = MQTTSerialize_unsubscribe(buf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic)) <= 0) goto exit; if ((rc = sendPacket(len, timer)) != SUCCESS) // send the subscribe packet goto exit; // there was a problem if (waitfor(UNSUBACK, timer) == UNSUBACK) { unsigned short mypacketid; // should be the same as the packetid above if (MQTTDeserialize_unsuback(&mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) == 1) rc = 0; } else rc = FAILURE; exit: return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::publish(const char* topicName, Message* message) { int rc = FAILURE; Timer timer = Timer(command_timeout_ms); MQTTString topicString = {(char*)topicName, 0, 0}; int len = 0; if (!isconnected) goto exit; if (message->qos == QOS1 || message->qos == QOS2) message->id = packetid.getNext(); len = MQTTSerialize_publish(buf, MAX_MQTT_PACKET_SIZE, 0, message->qos, message->retained, message->id, topicString, (unsigned char*)message->payload, message->payloadlen); if (len <= 0) goto exit; if ((rc = sendPacket(len, timer)) != SUCCESS) // send the subscribe packet goto exit; // there was a problem if (message->qos == QOS1) { if (waitfor(PUBACK, timer) == PUBACK) { unsigned short mypacketid; unsigned char dup, type; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1) rc = FAILURE; } else rc = FAILURE; } else if (message->qos == QOS2) { if (waitfor(PUBCOMP, timer) == PUBCOMP) { unsigned short mypacketid; unsigned char dup, type; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1) rc = FAILURE; } else rc = FAILURE; } exit: return rc; } template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b> int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::disconnect() { int rc = FAILURE; Timer timer = Timer(command_timeout_ms); // we might wait for incomplete incoming publishes to complete int len = MQTTSerialize_disconnect(buf, MAX_MQTT_PACKET_SIZE); if (len > 0) rc = sendPacket(len, timer); // send the disconnect packet isconnected = false; return rc; } #endif