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MQTT Client for mbed LPC1768 and Application Board over Ethernet; publish only.
Dependencies: C12832 MMA7660 MQTT
Fork of HelloMQTT by
Machine-to-Machine-Communication
Das Message Queue Telemetry Transport (MQTT) Protokoll ist ein effizientes Internet of Things (IoT) Protokoll mit wenig Protokolloverhead. Es wurde als lightweight publish/subscribe messaging transport entworfen. Es ist sinnvoll für Verbindungen mit Remote-Standorten, wo nur wenig Resourcen benötigt werden bzw. geringe Bandbreite zur Verfügung steht. Neben MQTT gibt es weitere IoT-Protokoll, wie HTTP, CoAP, XMPP, ... (Überischt über IoT Protokolle). Eine Beschreibung des MQTT ist z.B. hier zu finden.
MQTT implementiert das Publish/Subscribe-Pattern, daher wird ein Brocker für die Vermittlung der Nachrichten (topics) benötigt. Neben vielen quelloffenen Implementierungen (z. B. mosquitto) gibt es auch kommerzielle bzw. freie Server (Broker), die unterschiedliche Features bereit stellen (z. B. den in Deutschland entwickelten HiveMQ).
Für die Programmierung der Clients bzw. Ebedded Systems stehen ebenso sehr viele Libaries in verschiedenen Programmiersprachen zur Verfügung.
Weitere Kommunikationsmöglichkeiten
main.cpp
- Committer:
- icraggs
- Date:
- 2014-05-20
- Revision:
- 8:a3e3113054a1
- Parent:
- 7:3de634f2d40c
- Child:
- 9:5beb8609e9f7
File content as of revision 8:a3e3113054a1:
/******************************************************************************* * 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 *******************************************************************************/ /** This is a sample program to illustrate the use of the MQTT Client library on the mbed platform. The Client class requires two classes which mediate access to system interfaces for networking and timing. As long as these two classes provide the required public programming interfaces, it does not matter what facilities they use underneath. In this program, they use the mbed system libraries. */ #include "C12832.h" C12832 lcd(p5, p7, p6, p8, p11); #include "MQTTEthernet.h" #include "MQTTClient.h" int arrivedcount = 0; void messageArrived(MQTT::Message* message) { lcd.cls(); lcd.locate(0,3); printf("Message arrived: qos %d, retained %d, dup %d, packetid %d\n", message->qos, message->retained, message->dup, message->id); printf("Payload %.*s\n", message->payloadlen, (char*)message->payload); ++arrivedcount; lcd.puts((char*)message->payload); } int main(int argc, char* argv[]) { MQTTEthernet ipstack = MQTTEthernet(); float version = 0.46; char* topic = "mbed-sample"; lcd.printf("Version is %f\n", version); printf("Version is %f\n", version); MQTT::Client<MQTTEthernet, Countdown> client = MQTT::Client<MQTTEthernet, Countdown>(ipstack); char* hostname = "m2m.eclipse.org"; int port = 1883; lcd.printf("Connecting to %s:%d\n", hostname, port); int rc = ipstack.connect(hostname, port); if (rc != 0) lcd.printf("rc from TCP connect is %d\n", rc); MQTTPacket_connectData data = MQTTPacket_connectData_initializer; data.MQTTVersion = 3; data.clientID.cstring = "mbed-sample"; if ((rc = client.connect(&data)) != 0) lcd.printf("rc from MQTT connect is %d\n", rc); if ((rc = client.subscribe(topic, MQTT::QOS1, messageArrived)) != 0) lcd.printf("rc from MQTT subscribe is %d\n", rc); MQTT::Message message; // QoS 0 char buf[100]; sprintf(buf, "Hello World! QoS 0 message from app version %f\n", version); message.qos = MQTT::QOS0; message.retained = false; message.dup = false; message.payload = (void*)buf; message.payloadlen = strlen(buf)+1; rc = client.publish(topic, &message); while (arrivedcount == 0) client.yield(100); // QoS 1 sprintf(buf, "Hello World! QoS 1 message from app version %f\n", version); message.qos = MQTT::QOS1; message.payloadlen = strlen(buf)+1; rc = client.publish(topic, &message); while (arrivedcount == 1) client.yield(100); // QoS 2 sprintf(buf, "Hello World! QoS 2 message from app version %f\n", version); message.qos = MQTT::QOS2; message.payloadlen = strlen(buf)+1; rc = client.publish(topic, &message); while (arrivedcount == 2) client.yield(100); if ((rc = client.unsubscribe(topic)) != 0) printf("rc from unsubscribe was %d\n", rc); if ((rc = client.disconnect()) != 0) printf("rc from disconnect was %d\n", rc); ipstack.disconnect(); lcd.cls(); lcd.locate(0,3); lcd.printf("Version %.2f: finish %d msgs\n", version, arrivedcount); printf("Finishing with %d messages received\n", arrivedcount); return 0; }