Program to send NTP data to MQTT broker
Fork of MQTT by
MQTTClient.h
- Committer:
- icraggs
- Date:
- 2014-04-28
- Revision:
- 20:cad3d54d7ecf
- Parent:
- 19:57f6f976e878
- Child:
- 21:e918525e529d
File content as of revision 20:cad3d54d7ecf:
/******************************************************************************* * 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 *******************************************************************************/ #if !defined(MQTTCLIENT_H) #define MQTTCLIENT_H #include "FP.h" #include "MQTTPacket.h" #include "stdio.h" namespace MQTT { enum QoS { QOS0, QOS1, QOS2 }; struct Message { enum QoS qos; bool retained; bool dup; unsigned short id; void *payload; size_t payloadlen; }; struct MessageData { struct Message message; char* topicName; }; class PacketId { public: PacketId(); int getNext(); private: static const int MAX_PACKET_ID = 65535; int next; }; typedef void (*messageHandler)(Message*); typedef struct limits { int MAX_MQTT_PACKET_SIZE; // int MAX_MESSAGE_HANDLERS; // each subscription requires a message handler long command_timeout_ms; limits() { MAX_MQTT_PACKET_SIZE = 100; MAX_MESSAGE_HANDLERS = 5; command_timeout_ms = 30000; } } Limits; template<class Network, class Timer> class Client { public: /** 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, const Limits limits = Limits()); typedef struct { Client* client; Network* network; } connectionLostInfo; typedef int (*connectionLostHandlers)(connectionLostInfo*); /** Set the connection lost callback - called whenever the connection is lost and we should be connected * @param clh - pointer to the callback function */ void setConnectionLostHandler(connectionLostHandlers clh) { connectionLostHandler.attach(clh); } /** 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 * @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. */ void yield(int timeout); 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* topic, Message* message); Network* ipstack; Limits limits; char* buf; char* readbuf; Timer ping_timer; unsigned int keepAliveInterval; bool ping_outstanding; PacketId packetid; typedef FP<void, Message*> messageHandlerFP; struct MessageHandlers { const char* topic; messageHandlerFP fp; } *messageHandlers; // Message handlers are indexed by subscription topic messageHandlerFP defaultMessageHandler; typedef FP<int, connectionLostInfo*> connectionLostFP; connectionLostFP connectionLostHandler; }; } template<class Network, class Timer> MQTT::Client<Network, Timer>::Client(Network* network, Limits limits) : limits(limits), packetid() { this->ipstack = network; this->ping_timer = Timer(); this->ping_outstanding = 0; // How to make these memory allocations portable? I was hoping to avoid the heap buf = new char[limits.MAX_MQTT_PACKET_SIZE]; readbuf = new char[limits.MAX_MQTT_PACKET_SIZE]; this->messageHandlers = new struct MessageHandlers[limits.MAX_MESSAGE_HANDLERS]; for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) messageHandlers[i].topic = 0; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::sendPacket(int length, Timer& timer) { int sent = 0; while (sent < length) sent += ipstack->write(&buf[sent], length, timer.left_ms()); if (sent == length) ping_timer.countdown(this->keepAliveInterval); // record the fact that we have successfully sent the packet return sent; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::decodePacket(int* value, int timeout) { 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 MQTT::Client<Network, Timer>::readPacket(Timer& timer) { int rc = -1; 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; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::deliverMessage(MQTTString* topic, Message* message) { int rc = -1; // we have to find the right message handler - indexed by topic for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) { if (messageHandlers[i].topic != 0 && MQTTPacket_equals(topic, (char*)messageHandlers[i].topic)) { messageHandlers[i].fp(message); rc = 0; break; } } if (rc == -1) defaultMessageHandler(message); return rc; } template<class Network, class Timer> void MQTT::Client<Network, Timer>::yield(int timeout) { Timer timer = Timer(); timer.countdown_ms(timeout); while (!timer.expired()) cycle(timer); } template<class Network, class Timer> int MQTT::Client<Network, Timer>::cycle(Timer& timer) { /* get one piece of work off the wire and one pass through */ // read the socket, see what work is due int packet_type = readPacket(timer); int len, rc; switch (packet_type) { case CONNACK: case PUBACK: case SUBACK: break; case PUBLISH: MQTTString topicName; Message msg; rc = MQTTDeserialize_publish((int*)&msg.dup, (int*)&msg.qos, (int*)&msg.retained, (int*)&msg.id, &topicName, (char**)&msg.payload, (int*)&msg.payloadlen, readbuf, limits.MAX_MQTT_PACKET_SIZE);; deliverMessage(&topicName, &msg); if (msg.qos != QOS0) { if (msg.qos == QOS1) len = MQTTSerialize_ack(buf, limits.MAX_MQTT_PACKET_SIZE, PUBACK, 0, msg.id); else if (msg.qos == QOS2) len = MQTTSerialize_ack(buf, limits.MAX_MQTT_PACKET_SIZE, PUBREC, 0, msg.id); rc = sendPacket(len, timer); if (rc != len) goto exit; // there was a problem } break; case PUBREC: int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) ; len = MQTTSerialize_ack(buf, limits.MAX_MQTT_PACKET_SIZE, PUBREL, 0, mypacketid); rc = sendPacket(len, timer); // send the PUBREL packet if (rc != len) goto exit; // there was a problem break; case PUBCOMP: break; case PINGRESP: ping_outstanding = false; break; } keepalive(); exit: return packet_type; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::keepalive() { int rc = 0; if (keepAliveInterval == 0) goto exit; if (ping_timer.expired()) { if (ping_outstanding) rc = -1; else { Timer timer = Timer(1000); int len = MQTTSerialize_pingreq(buf, limits.MAX_MQTT_PACKET_SIZE); rc = sendPacket(len, timer); // send the ping packet if (rc != len) rc = -1; // indicate there's a problem else 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 MQTT::Client<Network, Timer>::waitfor(int packet_type, Timer& timer) { int rc = -1; do { if (timer.expired()) break; // we timed out } while ((rc = cycle(timer)) != packet_type); return rc; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::connect(MQTTPacket_connectData* options) { Timer connect_timer = Timer(limits.command_timeout_ms); MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer; if (options == 0) options = &default_options; // set default options if none were supplied this->keepAliveInterval = options->keepAliveInterval; ping_timer.countdown(this->keepAliveInterval); int len = MQTTSerialize_connect(buf, limits.MAX_MQTT_PACKET_SIZE, options); int rc = sendPacket(len, connect_timer); // send the connect packet if (rc != len) goto exit; // there was a problem // this will be a blocking call, wait for the connack if (waitfor(CONNACK, connect_timer) == CONNACK) { int connack_rc = -1; if (MQTTDeserialize_connack(&connack_rc, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) rc = connack_rc; } exit: return rc; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::subscribe(const char* topicFilter, enum QoS qos, messageHandler messageHandler) { int len = -1; Timer timer = Timer(limits.command_timeout_ms); MQTTString topic = {(char*)topicFilter, 0, 0}; int rc = MQTTSerialize_subscribe(buf, limits.MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int*)&qos); if (rc <= 0) goto exit; len = rc; if ((rc = sendPacket(len, timer)) != len) // send the subscribe packet goto exit; // there was a problem if (waitfor(SUBACK, timer) == SUBACK) // wait for suback { int count = 0, grantedQoS = -1, mypacketid; if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) rc = grantedQoS; // 0, 1, 2 or 0x80 if (rc != 0x80) { for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) { if (messageHandlers[i].topic == 0) { messageHandlers[i].topic = topicFilter; messageHandlers[i].fp.attach(messageHandler); rc = 0; break; } } } } exit: return rc; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::unsubscribe(const char* topicFilter) { int len = -1; Timer timer = Timer(limits.command_timeout_ms); MQTTString topic = {(char*)topicFilter, 0, 0}; int rc = MQTTSerialize_unsubscribe(buf, limits.MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic); if (rc <= 0) goto exit; len = rc; if ((rc = sendPacket(len, timer)) != len) // send the subscribe packet goto exit; // there was a problem if (waitfor(UNSUBACK, timer) == UNSUBACK) { int mypacketid; // should be the same as the packetid above if (MQTTDeserialize_unsuback(&mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) rc = 0; } exit: return rc; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::publish(const char* topicName, Message* message) { Timer timer = Timer(limits.command_timeout_ms); MQTTString topicString = {(char*)topicName, 0, 0}; if (message->qos == QOS1 || message->qos == QOS2) message->id = packetid.getNext(); int len = MQTTSerialize_publish(buf, limits.MAX_MQTT_PACKET_SIZE, 0, message->qos, message->retained, message->id, topicString, (char*)message->payload, message->payloadlen); int rc = sendPacket(len, timer); // send the subscribe packet if (rc != len) goto exit; // there was a problem if (message->qos == QOS1) { if (waitfor(PUBACK, timer) == PUBACK) { int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) rc = 0; } } else if (message->qos == QOS2) { if (waitfor(PUBCOMP, timer) == PUBCOMP) { int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) rc = 0; } } exit: return rc; } template<class Network, class Timer> int MQTT::Client<Network, Timer>::disconnect() { Timer timer = Timer(limits.command_timeout_ms); // we might wait for incomplete incoming publishes to complete int len = MQTTSerialize_disconnect(buf, limits.MAX_MQTT_PACKET_SIZE); int rc = sendPacket(len, timer); // send the disconnect packet return rc; } #endif