Program to send NTP data to MQTT broker
Fork of MQTT by
MQTTClient.h
- Committer:
- icraggs
- Date:
- 2014-04-14
- Revision:
- 16:91c2f9a144d4
- Parent:
- 15:64a57183aa03
- Child:
- 19:57f6f976e878
File content as of revision 16:91c2f9a144d4:
/******************************************************************************* * 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; }; 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 int MAX_CONCURRENT_OPERATIONS; // each command which runs concurrently can have a result handler, when we are in multi-threaded mode int command_timeout; limits() { MAX_MQTT_PACKET_SIZE = 100; MAX_MESSAGE_HANDLERS = 5; MAX_CONCURRENT_OPERATIONS = 1; // 1 indicates single-threaded mode - set to >1 for multithreaded mode command_timeout = 30; } } Limits; template<class Network, class Timer, class Thread, class Mutex> class Client { public: struct Result { /* success or failure result data */ Client<Network, Timer, Thread, Mutex>* client; int connack_rc; }; typedef void (*resultHandler)(Result*); Client(Network* network, const Limits limits = Limits()); int connect(MQTTPacket_connectData* options = 0, resultHandler fn = 0); template<class T> int connect(MQTTPacket_connectData* options = 0, T *item = 0, void(T::*method)(Result *) = 0); // alternative to pass in pointer to member function int publish(const char* topic, Message* message, resultHandler rh = 0); int subscribe(const char* topicFilter, enum QoS qos, messageHandler mh, resultHandler rh = 0); int unsubscribe(const char* topicFilter, resultHandler rh = 0); int disconnect(int timeout, resultHandler rh = 0); void run(void const *argument); private: int cycle(int timeout); int waitfor(int packet_type, Timer& atimer); int keepalive(); int findFreeOperation(); int decodePacket(int* value, int timeout); int readPacket(int timeout); int sendPacket(int length, int timeout); int deliverMessage(MQTTString* topic, Message* message); Thread* thread; Network* ipstack; Limits limits; char* buf; char* readbuf; Timer ping_timer, connect_timer; unsigned int keepAliveInterval; bool ping_outstanding; PacketId packetid; typedef FP<void, Result*> resultHandlerFP; resultHandlerFP connectHandler; typedef FP<void, Message*> messageHandlerFP; struct MessageHandlers { const char* topic; messageHandlerFP fp; } *messageHandlers; // Message handlers are indexed by subscription topic // how many concurrent operations should we allow? Each one will require a function pointer struct Operations { unsigned short id; resultHandlerFP fp; const char* topic; // if this is a publish, store topic name in case republishing is required Message* message; // for publish, Timer timer; // to check if the command has timed out } *operations; // result handlers are indexed by packet ids static void threadfn(void* arg); }; } template<class Network, class Timer, class Thread, class Mutex> void MQTT::Client<Network, Timer, Thread, Mutex>::threadfn(void* arg) { ((Client<Network, Timer, Thread, Mutex>*) arg)->run(NULL); } template<class Network, class Timer, class Thread, class Mutex> MQTT::Client<Network, Timer, Thread, Mutex>::Client(Network* network, Limits limits) : limits(limits), packetid() { this->thread = 0; 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->operations = new struct Operations[limits.MAX_CONCURRENT_OPERATIONS]; for (int i = 0; i < limits.MAX_CONCURRENT_OPERATIONS; ++i) operations[i].id = 0; 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, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::sendPacket(int length, int timeout) { int sent = 0; while (sent < length) sent += ipstack->write(&buf[sent], length, timeout); 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, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::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, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::readPacket(int timeout) { 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, timeout) != 1) goto exit; len = 1; /* 2. read the remaining length. This is variable in itself */ decodePacket(&rem_len, timeout); 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, timeout) != rem_len) goto exit; header.byte = readbuf[0]; rc = header.bits.type; exit: return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::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 && MQTTPacket_equals(topic, (char*)messageHandlers[i].topic)) { messageHandlers[i].fp(message); rc = 0; break; } } return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::cycle(int timeout) { /* get one piece of work off the wire and one pass through */ // read the socket, see what work is due int packet_type = readPacket(timeout); printf("packet type %d\n", packet_type); int len, rc; switch (packet_type) { case CONNACK: if (this->thread) { Result res = {this, 0}; if (MQTTDeserialize_connack(&res.connack_rc, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) ; connectHandler(&res); connectHandler.detach(); // only invoke the callback once } break; case PUBACK: if (this->thread) ; //call resultHandler 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); if (msg.qos == QOS0) deliverMessage(&topicName, &msg); break; case PUBREC: int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) ; // must lock this access against the application thread, if we are multi-threaded len = MQTTSerialize_ack(buf, limits.MAX_MQTT_PACKET_SIZE, PUBREL, 0, mypacketid); rc = sendPacket(len, timeout); // 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, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::keepalive() { int rc = 0; if (keepAliveInterval == 0) goto exit; if (ping_timer.expired()) { if (ping_outstanding) rc = -1; else { int len = MQTTSerialize_pingreq(buf, limits.MAX_MQTT_PACKET_SIZE); rc = sendPacket(len, 1000); // send the ping packet if (rc != len) rc = -1; // indicate there's a problem else ping_outstanding = true; } } exit: return rc; } template<class Network, class Timer, class Thread, class Mutex> void MQTT::Client<Network, Timer, Thread, Mutex>::run(void const *argument) { while (true) cycle(ping_timer.left_ms()); } // only used in single-threaded mode where one command at a time is in process template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::waitfor(int packet_type, Timer& atimer) { int rc = -1; do { if (atimer.expired()) break; // we timed out } while ((rc = cycle(atimer.left_ms())) != packet_type); return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::connect(MQTTPacket_connectData* options, resultHandler resultHandler) { connect_timer.countdown(limits.command_timeout); 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.left_ms()); // send the connect packet if (rc != len) goto exit; // there was a problem if (resultHandler == 0) // wait until the connack is received { // 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; } } else { // set connect response callback function connectHandler.attach(resultHandler); // start background thread this->thread = new Thread((void (*)(void const *argument))&MQTT::Client<Network, Timer, Thread, Mutex>::threadfn, (void*)this); } exit: return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::findFreeOperation() { int found = -1; for (int i = 0; i < limits.MAX_CONCURRENT_OPERATIONS; ++i) { if (operations[i].id == 0) { found = i; break; } } return found; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::subscribe(const char* topicFilter, enum QoS qos, messageHandler messageHandler, resultHandler resultHandler) { int index = 0; if (this->thread) index = findFreeOperation(); Timer& atimer = operations[index].timer; atimer.countdown(limits.command_timeout); MQTTString topic = {(char*)topicFilter, 0, 0}; int len = MQTTSerialize_subscribe(buf, limits.MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int*)&qos); int rc = sendPacket(len, atimer.left_ms()); // send the subscribe packet if (rc != len) goto exit; // there was a problem /* wait for suback */ if (resultHandler == 0) { // this will block if (waitfor(SUBACK, atimer) == 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; } } } } } else { // set subscribe response callback function } exit: return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::unsubscribe(const char* topicFilter, resultHandler resultHandler) { int index = 0; if (this->thread) index = findFreeOperation(); Timer& atimer = operations[index].timer; MQTTString topic = {(char*)topicFilter, 0, 0}; int len = MQTTSerialize_unsubscribe(buf, buflen, 0, packetid.getNext(), 1, &topic); int rc = sendPacket(len, atimer); // send the subscribe packet if (rc != len) goto exit; // there was a problem /* wait for unsuback */ if (resultHandler == 0) { // this will block if (waitfor(UNSUBACK) == UNSUBACK) { int mypacketid; if (MQTTDeserialize_unsuback(&mypacketid, readbuf, readbuflen) == 1) rc = 0; } } else { // set unsubscribe response callback function } exit: command_timer.stop(); command_timer.reset(); return rc; } template<class Network, class Timer, class Thread, class Mutex> int MQTT::Client<Network, Timer, Thread, Mutex>::publish(const char* topicName, Message* message, resultHandler resultHandler) { command_timer.start(); MQTTString topic = {(char*)topicName, 0, 0}; message->id = packetid.getNext(); int len = MQTTSerialize_publish(buf, buflen, 0, message->qos, message->retained, message->id, topic, message->payload, message->payloadlen); int rc = sendPacket(len); // send the subscribe packet if (rc != len) goto exit; // there was a problem /* wait for acks */ if (resultHandler == 0) { if (message->qos == QOS1) { if (waitfor(PUBACK) == PUBACK) { int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, readbuflen) == 1) rc = 0; } } else if (message->qos == QOS2) { if (waitfor(PUBCOMP) == PUBCOMP) { int type, dup, mypacketid; if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, readbuflen) == 1) rc = 0; } } } else { // set publish response callback function } exit: command_timer.stop(); command_timer.reset(); return rc; } #endif