Tarea 2
Embed:
(wiki syntax)
Show/hide line numbers
MQTTAsync.h
00001 /******************************************************************************* 00002 * Copyright (c) 2014 IBM Corp. 00003 * 00004 * All rights reserved. This program and the accompanying materials 00005 * are made available under the terms of the Eclipse Public License v1.0 00006 * and Eclipse Distribution License v1.0 which accompany this distribution. 00007 * 00008 * The Eclipse Public License is available at 00009 * http://www.eclipse.org/legal/epl-v10.html 00010 * and the Eclipse Distribution License is available at 00011 * http://www.eclipse.org/org/documents/edl-v10.php. 00012 * 00013 * Contributors: 00014 * Ian Craggs - initial API and implementation and/or initial documentation 00015 *******************************************************************************/ 00016 00017 #if !defined(MQTTASYNC_H) 00018 #define MQTTASYNC_H 00019 00020 #include "FP.h" 00021 #include "MQTTPacket.h" 00022 #include "stdio.h" 00023 00024 namespace MQTT 00025 { 00026 00027 00028 enum QoS { QOS0, QOS1, QOS2 }; 00029 00030 00031 struct Message 00032 { 00033 enum QoS qos; 00034 bool retained; 00035 bool dup; 00036 unsigned short id; 00037 void *payload; 00038 size_t payloadlen; 00039 }; 00040 00041 00042 class PacketId 00043 { 00044 public: 00045 PacketId(); 00046 00047 int getNext(); 00048 00049 private: 00050 static const int MAX_PACKET_ID = 65535; 00051 int next; 00052 }; 00053 00054 typedef void (*messageHandler)(Message*); 00055 00056 typedef struct limits 00057 { 00058 int MAX_MQTT_PACKET_SIZE; // 00059 int MAX_MESSAGE_HANDLERS; // each subscription requires a message handler 00060 int MAX_CONCURRENT_OPERATIONS; // each command which runs concurrently can have a result handler, when we are in multi-threaded mode 00061 int command_timeout_ms; 00062 00063 limits() 00064 { 00065 MAX_MQTT_PACKET_SIZE = 100; 00066 MAX_MESSAGE_HANDLERS = 5; 00067 MAX_CONCURRENT_OPERATIONS = 1; // 1 indicates single-threaded mode - set to >1 for multithreaded mode 00068 command_timeout_ms = 30000; 00069 } 00070 } Limits; 00071 00072 00073 /** 00074 * @class Async 00075 * @brief non-blocking, threaded MQTT client API 00076 * @param Network a network class which supports send, receive 00077 * @param Timer a timer class with the methods: 00078 */ 00079 template<class Network, class Timer, class Thread, class Mutex> class Async 00080 { 00081 00082 public: 00083 00084 struct Result 00085 { 00086 /* success or failure result data */ 00087 Async<Network, Timer, Thread, Mutex>* client; 00088 int rc; 00089 }; 00090 00091 typedef void (*resultHandler)(Result*); 00092 00093 Async(Network* network, const Limits limits = Limits()); 00094 00095 typedef struct 00096 { 00097 Async* client; 00098 Network* network; 00099 } connectionLostInfo; 00100 00101 typedef int (*connectionLostHandlers)(connectionLostInfo*); 00102 00103 /** Set the connection lost callback - called whenever the connection is lost and we should be connected 00104 * @param clh - pointer to the callback function 00105 */ 00106 void setConnectionLostHandler(connectionLostHandlers clh) 00107 { 00108 connectionLostHandler.attach(clh); 00109 } 00110 00111 /** Set the default message handling callback - used for any message which does not match a subscription message handler 00112 * @param mh - pointer to the callback function 00113 */ 00114 void setDefaultMessageHandler(messageHandler mh) 00115 { 00116 defaultMessageHandler.attach(mh); 00117 } 00118 00119 int connect(resultHandler fn, MQTTPacket_connectData* options = 0); 00120 00121 template<class T> 00122 int connect(void(T::*method)(Result *), MQTTPacket_connectData* options = 0, T *item = 0); // alternative to pass in pointer to member function 00123 00124 int publish(resultHandler rh, const char* topic, Message* message); 00125 00126 int subscribe(resultHandler rh, const char* topicFilter, enum QoS qos, messageHandler mh); 00127 00128 int unsubscribe(resultHandler rh, const char* topicFilter); 00129 00130 int disconnect(resultHandler rh); 00131 00132 private: 00133 00134 void run(void const *argument); 00135 int cycle(int timeout); 00136 int waitfor(int packet_type, Timer& atimer); 00137 int keepalive(); 00138 int findFreeOperation(); 00139 00140 int decodePacket(int* value, int timeout); 00141 int readPacket(int timeout); 00142 int sendPacket(int length, int timeout); 00143 int deliverMessage(MQTTString* topic, Message* message); 00144 00145 Thread* thread; 00146 Network* ipstack; 00147 00148 Limits limits; 00149 00150 char* buf; 00151 char* readbuf; 00152 00153 Timer ping_timer, connect_timer; 00154 unsigned int keepAliveInterval; 00155 bool ping_outstanding; 00156 00157 PacketId packetid; 00158 00159 typedef FP<void, Result*> resultHandlerFP; 00160 resultHandlerFP connectHandler; 00161 00162 typedef FP<void, Message*> messageHandlerFP; 00163 struct MessageHandlers 00164 { 00165 const char* topic; 00166 messageHandlerFP fp; 00167 } *messageHandlers; // Message handlers are indexed by subscription topic 00168 00169 // how many concurrent operations should we allow? Each one will require a function pointer 00170 struct Operations 00171 { 00172 unsigned short id; 00173 resultHandlerFP fp; 00174 const char* topic; // if this is a publish, store topic name in case republishing is required 00175 Message* message; // for publish, 00176 Timer timer; // to check if the command has timed out 00177 } *operations; // result handlers are indexed by packet ids 00178 00179 static void threadfn(void* arg); 00180 00181 messageHandlerFP defaultMessageHandler; 00182 00183 typedef FP<int, connectionLostInfo*> connectionLostFP; 00184 00185 connectionLostFP connectionLostHandler; 00186 00187 }; 00188 00189 } 00190 00191 00192 template<class Network, class Timer, class Thread, class Mutex> void MQTT::Async<Network, Timer, Thread, Mutex>::threadfn(void* arg) 00193 { 00194 ((Async<Network, Timer, Thread, Mutex>*) arg)->run(NULL); 00195 } 00196 00197 00198 template<class Network, class Timer, class Thread, class Mutex> MQTT::Async<Network, Timer, Thread, Mutex>::Async(Network* network, Limits limits) : limits(limits), packetid() 00199 { 00200 this->thread = 0; 00201 this->ipstack = network; 00202 this->ping_timer = Timer(); 00203 this->ping_outstanding = 0; 00204 00205 // How to make these memory allocations portable? I was hoping to avoid the heap 00206 buf = new char[limits.MAX_MQTT_PACKET_SIZE]; 00207 readbuf = new char[limits.MAX_MQTT_PACKET_SIZE]; 00208 this->operations = new struct Operations[limits.MAX_CONCURRENT_OPERATIONS]; 00209 for (int i = 0; i < limits.MAX_CONCURRENT_OPERATIONS; ++i) 00210 operations[i].id = 0; 00211 this->messageHandlers = new struct MessageHandlers[limits.MAX_MESSAGE_HANDLERS]; 00212 for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) 00213 messageHandlers[i].topic = 0; 00214 } 00215 00216 00217 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::sendPacket(int length, int timeout) 00218 { 00219 int sent = 0; 00220 00221 while (sent < length) 00222 sent += ipstack->write(&buf[sent], length, timeout); 00223 if (sent == length) 00224 ping_timer.countdown(this->keepAliveInterval); // record the fact that we have successfully sent the packet 00225 return sent; 00226 } 00227 00228 00229 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::decodePacket(int* value, int timeout) 00230 { 00231 char c; 00232 int multiplier = 1; 00233 int len = 0; 00234 const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4; 00235 00236 *value = 0; 00237 do 00238 { 00239 int rc = MQTTPACKET_READ_ERROR; 00240 00241 if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES) 00242 { 00243 rc = MQTTPACKET_READ_ERROR; /* bad data */ 00244 goto exit; 00245 } 00246 rc = ipstack->read(&c, 1, timeout); 00247 if (rc != 1) 00248 goto exit; 00249 *value += (c & 127) * multiplier; 00250 multiplier *= 128; 00251 } while ((c & 128) != 0); 00252 exit: 00253 return len; 00254 } 00255 00256 00257 /** 00258 * If any read fails in this method, then we should disconnect from the network, as on reconnect 00259 * the packets can be retried. 00260 * @param timeout the max time to wait for the packet read to complete, in milliseconds 00261 * @return the MQTT packet type, or -1 if none 00262 */ 00263 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::readPacket(int timeout) 00264 { 00265 int rc = -1; 00266 MQTTHeader header = {0}; 00267 int len = 0; 00268 int rem_len = 0; 00269 00270 /* 1. read the header byte. This has the packet type in it */ 00271 if (ipstack->read(readbuf, 1, timeout) != 1) 00272 goto exit; 00273 00274 len = 1; 00275 /* 2. read the remaining length. This is variable in itself */ 00276 decodePacket(&rem_len, timeout); 00277 len += MQTTPacket_encode(readbuf + 1, rem_len); /* put the original remaining length back into the buffer */ 00278 00279 /* 3. read the rest of the buffer using a callback to supply the rest of the data */ 00280 if (ipstack->read(readbuf + len, rem_len, timeout) != rem_len) 00281 goto exit; 00282 00283 header.byte = readbuf[0]; 00284 rc = header.bits.type; 00285 exit: 00286 return rc; 00287 } 00288 00289 00290 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::deliverMessage(MQTTString* topic, Message* message) 00291 { 00292 int rc = -1; 00293 00294 // we have to find the right message handler - indexed by topic 00295 for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) 00296 { 00297 if (messageHandlers[i].topic != 0 && MQTTPacket_equals(topic, (char*)messageHandlers[i].topic)) 00298 { 00299 messageHandlers[i].fp(message); 00300 rc = 0; 00301 break; 00302 } 00303 } 00304 00305 return rc; 00306 } 00307 00308 00309 00310 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::cycle(int timeout) 00311 { 00312 /* get one piece of work off the wire and one pass through */ 00313 00314 // read the socket, see what work is due 00315 int packet_type = readPacket(timeout); 00316 00317 int len, rc; 00318 switch (packet_type) 00319 { 00320 case CONNACK: 00321 if (this->thread) 00322 { 00323 Result res = {this, 0}; 00324 if (MQTTDeserialize_connack(&res.rc, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00325 ; 00326 connectHandler(&res); 00327 connectHandler.detach(); // only invoke the callback once 00328 } 00329 break; 00330 case PUBACK: 00331 if (this->thread) 00332 ; //call resultHandler 00333 case SUBACK: 00334 break; 00335 case PUBLISH: 00336 MQTTString topicName; 00337 Message msg; 00338 rc = MQTTDeserialize_publish((int*)&msg.dup, (int*)&msg.qos, (int*)&msg.retained, (int*)&msg.id, &topicName, 00339 (char**)&msg.payload, (int*)&msg.payloadlen, readbuf, limits.MAX_MQTT_PACKET_SIZE);; 00340 if (msg.qos == QOS0) 00341 deliverMessage(&topicName, &msg); 00342 break; 00343 case PUBREC: 00344 int type, dup, mypacketid; 00345 if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00346 ; 00347 // must lock this access against the application thread, if we are multi-threaded 00348 len = MQTTSerialize_ack(buf, limits.MAX_MQTT_PACKET_SIZE, PUBREL, 0, mypacketid); 00349 rc = sendPacket(len, timeout); // send the PUBREL packet 00350 if (rc != len) 00351 goto exit; // there was a problem 00352 00353 break; 00354 case PUBCOMP: 00355 break; 00356 case PINGRESP: 00357 ping_outstanding = false; 00358 break; 00359 } 00360 keepalive(); 00361 exit: 00362 return packet_type; 00363 } 00364 00365 00366 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::keepalive() 00367 { 00368 int rc = 0; 00369 00370 if (keepAliveInterval == 0) 00371 goto exit; 00372 00373 if (ping_timer.expired()) 00374 { 00375 if (ping_outstanding) 00376 rc = -1; 00377 else 00378 { 00379 int len = MQTTSerialize_pingreq(buf, limits.MAX_MQTT_PACKET_SIZE); 00380 rc = sendPacket(len, 1000); // send the ping packet 00381 if (rc != len) 00382 rc = -1; // indicate there's a problem 00383 else 00384 ping_outstanding = true; 00385 } 00386 } 00387 00388 exit: 00389 return rc; 00390 } 00391 00392 00393 template<class Network, class Timer, class Thread, class Mutex> void MQTT::Async<Network, Timer, Thread, Mutex>::run(void const *argument) 00394 { 00395 while (true) 00396 cycle(ping_timer.left_ms()); 00397 } 00398 00399 00400 // only used in single-threaded mode where one command at a time is in process 00401 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::waitfor(int packet_type, Timer& atimer) 00402 { 00403 int rc = -1; 00404 00405 do 00406 { 00407 if (atimer.expired()) 00408 break; // we timed out 00409 } 00410 while ((rc = cycle(atimer.left_ms())) != packet_type); 00411 00412 return rc; 00413 } 00414 00415 00416 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::connect(resultHandler resultHandler, MQTTPacket_connectData* options) 00417 { 00418 connect_timer.countdown(limits.command_timeout_ms); 00419 00420 MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer; 00421 if (options == 0) 00422 options = &default_options; // set default options if none were supplied 00423 00424 this->keepAliveInterval = options->keepAliveInterval; 00425 ping_timer.countdown(this->keepAliveInterval); 00426 int len = MQTTSerialize_connect(buf, limits.MAX_MQTT_PACKET_SIZE, options); 00427 int rc = sendPacket(len, connect_timer.left_ms()); // send the connect packet 00428 if (rc != len) 00429 goto exit; // there was a problem 00430 00431 if (resultHandler == 0) // wait until the connack is received 00432 { 00433 // this will be a blocking call, wait for the connack 00434 if (waitfor(CONNACK, connect_timer) == CONNACK) 00435 { 00436 int connack_rc = -1; 00437 if (MQTTDeserialize_connack(&connack_rc, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00438 rc = connack_rc; 00439 } 00440 } 00441 else 00442 { 00443 // set connect response callback function 00444 connectHandler.attach(resultHandler); 00445 00446 // start background thread 00447 this->thread = new Thread((void (*)(void const *argument))&MQTT::Async<Network, Timer, Thread, Mutex>::threadfn, (void*)this); 00448 } 00449 00450 exit: 00451 return rc; 00452 } 00453 00454 00455 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::findFreeOperation() 00456 { 00457 int found = -1; 00458 for (int i = 0; i < limits.MAX_CONCURRENT_OPERATIONS; ++i) 00459 { 00460 if (operations[i].id == 0) 00461 { 00462 found = i; 00463 break; 00464 } 00465 } 00466 return found; 00467 } 00468 00469 00470 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::subscribe(resultHandler resultHandler, const char* topicFilter, enum QoS qos, messageHandler messageHandler) 00471 { 00472 int index = 0; 00473 if (this->thread) 00474 index = findFreeOperation(); 00475 Timer& atimer = operations[index].timer; 00476 00477 atimer.countdown(limits.command_timeout_ms); 00478 MQTTString topic = {(char*)topicFilter, 0, 0}; 00479 00480 int len = MQTTSerialize_subscribe(buf, limits.MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int*)&qos); 00481 int rc = sendPacket(len, atimer.left_ms()); // send the subscribe packet 00482 if (rc != len) 00483 goto exit; // there was a problem 00484 00485 /* wait for suback */ 00486 if (resultHandler == 0) 00487 { 00488 // this will block 00489 if (waitfor(SUBACK, atimer) == SUBACK) 00490 { 00491 int count = 0, grantedQoS = -1, mypacketid; 00492 if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00493 rc = grantedQoS; // 0, 1, 2 or 0x80 00494 if (rc != 0x80) 00495 { 00496 for (int i = 0; i < limits.MAX_MESSAGE_HANDLERS; ++i) 00497 { 00498 if (messageHandlers[i].topic == 0) 00499 { 00500 messageHandlers[i].topic = topicFilter; 00501 messageHandlers[i].fp.attach(messageHandler); 00502 rc = 0; 00503 break; 00504 } 00505 } 00506 } 00507 } 00508 } 00509 else 00510 { 00511 // set subscribe response callback function 00512 00513 } 00514 00515 exit: 00516 return rc; 00517 } 00518 00519 00520 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::unsubscribe(resultHandler resultHandler, const char* topicFilter) 00521 { 00522 int index = 0; 00523 if (this->thread) 00524 index = findFreeOperation(); 00525 Timer& atimer = operations[index].timer; 00526 00527 atimer.countdown(limits.command_timeout_ms); 00528 MQTTString topic = {(char*)topicFilter, 0, 0}; 00529 00530 int len = MQTTSerialize_unsubscribe(buf, limits.MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic); 00531 int rc = sendPacket(len, atimer.left_ms()); // send the subscribe packet 00532 if (rc != len) 00533 goto exit; // there was a problem 00534 00535 // set unsubscribe response callback function 00536 00537 00538 exit: 00539 return rc; 00540 } 00541 00542 00543 00544 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::publish(resultHandler resultHandler, const char* topicName, Message* message) 00545 { 00546 int index = 0; 00547 if (this->thread) 00548 index = findFreeOperation(); 00549 Timer& atimer = operations[index].timer; 00550 00551 atimer.countdown(limits.command_timeout_ms); 00552 MQTTString topic = {(char*)topicName, 0, 0}; 00553 00554 if (message->qos == QOS1 || message->qos == QOS2) 00555 message->id = packetid.getNext(); 00556 00557 int len = MQTTSerialize_publish(buf, limits.MAX_MQTT_PACKET_SIZE, 0, message->qos, message->retained, message->id, topic, (char*)message->payload, message->payloadlen); 00558 int rc = sendPacket(len, atimer.left_ms()); // send the subscribe packet 00559 if (rc != len) 00560 goto exit; // there was a problem 00561 00562 /* wait for acks */ 00563 if (resultHandler == 0) 00564 { 00565 if (message->qos == QOS1) 00566 { 00567 if (waitfor(PUBACK, atimer) == PUBACK) 00568 { 00569 int type, dup, mypacketid; 00570 if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00571 rc = 0; 00572 } 00573 } 00574 else if (message->qos == QOS2) 00575 { 00576 if (waitfor(PUBCOMP, atimer) == PUBCOMP) 00577 { 00578 int type, dup, mypacketid; 00579 if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, limits.MAX_MQTT_PACKET_SIZE) == 1) 00580 rc = 0; 00581 } 00582 00583 } 00584 } 00585 else 00586 { 00587 // set publish response callback function 00588 00589 } 00590 00591 exit: 00592 return rc; 00593 } 00594 00595 00596 template<class Network, class Timer, class Thread, class Mutex> int MQTT::Async<Network, Timer, Thread, Mutex>::disconnect(resultHandler resultHandler) 00597 { 00598 Timer timer = Timer(limits.command_timeout_ms); // we might wait for incomplete incoming publishes to complete 00599 int len = MQTTSerialize_disconnect(buf, limits.MAX_MQTT_PACKET_SIZE); 00600 int rc = sendPacket(len, timer.left_ms()); // send the disconnect packet 00601 00602 return (rc == len) ? 0 : -1; 00603 } 00604 00605 00606 00607 #endif
Generated on Thu Dec 15 2022 05:38:19 by 1.7.2