![](/media/cache/group/mqtt.png.50x50_q85.png)
Sample MQTT program - simple send and receive
This program and the MQTT libraries it uses are part of the EclipseTM Paho project; specifically the embedded client.
This example and API are working, but are still in progress. Please give us your feedback.
HelloMQTT is an example of using the MQTT API. The MQTT API is portable across network interface stacks. MQTT is designed to be used with TCP/IP, but any transport with similar characteristics should be suitable.
HelloMQTT uses the NetworkInterface APIs in mbed OS 5 to show how this works. The MQTT library contains an MQTTNetwork.h header, which is a wrapper around the mbed networking interface. To switch between connectivity methods (the default is Ethernet) the easy-connect library is provided in this example application. You can change the connectivity method in mbed_app.json
.
Adding new connectivity methods to the program is trivial, as long as they implement the mbed OS 5 NetworkStack
API.
main.cpp@20:49c9daf2b0ff, 2017-01-10 (annotated)
- Committer:
- Jan Jongboom
- Date:
- Tue Jan 10 18:10:17 2017 -0600
- Revision:
- 20:49c9daf2b0ff
- Parent:
- 19:7f7aba7a4a8b
- Child:
- 21:a68bd76740f9
Update to mbed OS 5, use NetworkInterface for multiple connectivity methods - not just ethernet
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
icraggs | 1:a1d5c7a6acbc | 1 | /******************************************************************************* |
icraggs | 17:0811bdbdd78a | 2 | * Copyright (c) 2014, 2015 IBM Corp. |
icraggs | 1:a1d5c7a6acbc | 3 | * |
icraggs | 1:a1d5c7a6acbc | 4 | * All rights reserved. This program and the accompanying materials |
icraggs | 1:a1d5c7a6acbc | 5 | * are made available under the terms of the Eclipse Public License v1.0 |
icraggs | 1:a1d5c7a6acbc | 6 | * and Eclipse Distribution License v1.0 which accompany this distribution. |
icraggs | 1:a1d5c7a6acbc | 7 | * |
icraggs | 1:a1d5c7a6acbc | 8 | * The Eclipse Public License is available at |
icraggs | 1:a1d5c7a6acbc | 9 | * http://www.eclipse.org/legal/epl-v10.html |
icraggs | 1:a1d5c7a6acbc | 10 | * and the Eclipse Distribution License is available at |
icraggs | 1:a1d5c7a6acbc | 11 | * http://www.eclipse.org/org/documents/edl-v10.php. |
icraggs | 1:a1d5c7a6acbc | 12 | * |
icraggs | 1:a1d5c7a6acbc | 13 | * Contributors: |
icraggs | 1:a1d5c7a6acbc | 14 | * Ian Craggs - initial API and implementation and/or initial documentation |
icraggs | 17:0811bdbdd78a | 15 | * Ian Craggs - make sure QoS2 processing works, and add device headers |
icraggs | 1:a1d5c7a6acbc | 16 | *******************************************************************************/ |
Jan Jongboom |
20:49c9daf2b0ff | 17 | |
icraggs | 2:638c854c0695 | 18 | /** |
icraggs | 2:638c854c0695 | 19 | This is a sample program to illustrate the use of the MQTT Client library |
icraggs | 2:638c854c0695 | 20 | on the mbed platform. The Client class requires two classes which mediate |
icraggs | 2:638c854c0695 | 21 | access to system interfaces for networking and timing. As long as these two |
icraggs | 2:638c854c0695 | 22 | classes provide the required public programming interfaces, it does not matter |
icraggs | 2:638c854c0695 | 23 | what facilities they use underneath. In this program, they use the mbed |
icraggs | 2:638c854c0695 | 24 | system libraries. |
Jan Jongboom |
20:49c9daf2b0ff | 25 | |
icraggs | 2:638c854c0695 | 26 | */ |
Jan Jongboom |
20:49c9daf2b0ff | 27 | |
icraggs | 18:07a79d8f01c3 | 28 | // change this to 0 to output messages to serial instead of LCD |
icraggs | 18:07a79d8f01c3 | 29 | #define USE_LCD 1 |
icraggs | 1:a1d5c7a6acbc | 30 | |
icraggs | 18:07a79d8f01c3 | 31 | #if USE_LCD |
icraggs | 17:0811bdbdd78a | 32 | #include "C12832.h" |
icraggs | 2:638c854c0695 | 33 | |
Jan Jongboom |
20:49c9daf2b0ff | 34 | // the actual pins are defined in mbed_app.json and can be overridden per target |
Jan Jongboom |
20:49c9daf2b0ff | 35 | C12832 lcd(LCD_MOSI, LCD_SCK, LCD_MISO, LCD_A0, LCD_NCS); |
icraggs | 17:0811bdbdd78a | 36 | |
Jan Jongboom |
20:49c9daf2b0ff | 37 | #define logMessage lcd.cls();lcd.printf |
Jan Jongboom |
20:49c9daf2b0ff | 38 | |
Jan Jongboom |
20:49c9daf2b0ff | 39 | #else |
Jan Jongboom |
20:49c9daf2b0ff | 40 | |
Jan Jongboom |
20:49c9daf2b0ff | 41 | #define logMessage printf |
icraggs | 18:07a79d8f01c3 | 42 | |
icraggs | 18:07a79d8f01c3 | 43 | #endif |
icraggs | 18:07a79d8f01c3 | 44 | |
icraggs | 17:0811bdbdd78a | 45 | #define MQTTCLIENT_QOS2 1 |
icraggs | 0:0cae29831d01 | 46 | |
Jan Jongboom |
20:49c9daf2b0ff | 47 | #include "easy-connect.h" |
Jan Jongboom |
20:49c9daf2b0ff | 48 | #include "MQTTNetwork.h" |
Jan Jongboom |
20:49c9daf2b0ff | 49 | #include "MQTTmbed.h" |
icraggs | 2:638c854c0695 | 50 | #include "MQTTClient.h" |
icraggs | 2:638c854c0695 | 51 | |
icraggs | 2:638c854c0695 | 52 | int arrivedcount = 0; |
icraggs | 2:638c854c0695 | 53 | |
icraggs | 8:a3e3113054a1 | 54 | |
icraggs | 9:5beb8609e9f7 | 55 | void messageArrived(MQTT::MessageData& md) |
icraggs | 2:638c854c0695 | 56 | { |
icraggs | 9:5beb8609e9f7 | 57 | MQTT::Message &message = md.message; |
Jan Jongboom |
20:49c9daf2b0ff | 58 | logMessage("Message arrived: qos %d, retained %d, dup %d, packetid %d\r\n", message.qos, message.retained, message.dup, message.id); |
Jan Jongboom |
20:49c9daf2b0ff | 59 | logMessage("Payload %.*s\r\n", message.payloadlen, (char*)message.payload); |
icraggs | 2:638c854c0695 | 60 | ++arrivedcount; |
icraggs | 2:638c854c0695 | 61 | } |
icraggs | 0:0cae29831d01 | 62 | |
icraggs | 2:638c854c0695 | 63 | |
icraggs | 2:638c854c0695 | 64 | int main(int argc, char* argv[]) |
Jan Jongboom |
20:49c9daf2b0ff | 65 | { |
Jan Jongboom |
20:49c9daf2b0ff | 66 | float version = 0.6; |
icraggs | 2:638c854c0695 | 67 | char* topic = "mbed-sample"; |
Jan Jongboom |
20:49c9daf2b0ff | 68 | |
Jan Jongboom |
20:49c9daf2b0ff | 69 | logMessage("HelloMQTT: version is %.2f\r\n", version); |
Jan Jongboom |
20:49c9daf2b0ff | 70 | |
Jan Jongboom |
20:49c9daf2b0ff | 71 | NetworkInterface* network = easy_connect(true); |
Jan Jongboom |
20:49c9daf2b0ff | 72 | if (!network) { |
Jan Jongboom |
20:49c9daf2b0ff | 73 | return -1; |
Jan Jongboom |
20:49c9daf2b0ff | 74 | } |
Jan Jongboom |
20:49c9daf2b0ff | 75 | |
Jan Jongboom |
20:49c9daf2b0ff | 76 | MQTTNetwork mqttNetwork(network); |
Jan Jongboom |
20:49c9daf2b0ff | 77 | |
Jan Jongboom |
20:49c9daf2b0ff | 78 | MQTT::Client<MQTTNetwork, Countdown> client = MQTT::Client<MQTTNetwork, Countdown>(mqttNetwork); |
Jan Jongboom |
20:49c9daf2b0ff | 79 | |
Jan Jongboom |
20:49c9daf2b0ff | 80 | const char* hostname = "m2m.eclipse.org"; |
icraggs | 6:e4c690c45021 | 81 | int port = 1883; |
Jan Jongboom |
20:49c9daf2b0ff | 82 | logMessage("Connecting to %s:%d\r\n", hostname, port); |
Jan Jongboom |
20:49c9daf2b0ff | 83 | int rc = mqttNetwork.connect(hostname, port); |
icraggs | 6:e4c690c45021 | 84 | if (rc != 0) |
Jan Jongboom |
20:49c9daf2b0ff | 85 | logMessage("rc from TCP connect is %d\r\n", rc); |
Jan Jongboom |
20:49c9daf2b0ff | 86 | |
Jan Jongboom |
20:49c9daf2b0ff | 87 | MQTTPacket_connectData data = MQTTPacket_connectData_initializer; |
icraggs | 6:e4c690c45021 | 88 | data.MQTTVersion = 3; |
icraggs | 8:a3e3113054a1 | 89 | data.clientID.cstring = "mbed-sample"; |
icraggs | 12:086a9314e8a5 | 90 | data.username.cstring = "testuser"; |
icraggs | 12:086a9314e8a5 | 91 | data.password.cstring = "testpassword"; |
icraggs | 16:28d062c5522b | 92 | if ((rc = client.connect(data)) != 0) |
Jan Jongboom |
20:49c9daf2b0ff | 93 | logMessage("rc from MQTT connect is %d\r\n", rc); |
Jan Jongboom |
20:49c9daf2b0ff | 94 | |
icraggs | 19:7f7aba7a4a8b | 95 | if ((rc = client.subscribe(topic, MQTT::QOS2, messageArrived)) != 0) |
Jan Jongboom |
20:49c9daf2b0ff | 96 | logMessage("rc from MQTT subscribe is %d\r\n", rc); |
icraggs | 2:638c854c0695 | 97 | |
icraggs | 2:638c854c0695 | 98 | MQTT::Message message; |
icraggs | 0:0cae29831d01 | 99 | |
icraggs | 2:638c854c0695 | 100 | // QoS 0 |
icraggs | 2:638c854c0695 | 101 | char buf[100]; |
Jan Jongboom |
20:49c9daf2b0ff | 102 | sprintf(buf, "Hello World! QoS 0 message from app version %f\r\n", version); |
icraggs | 2:638c854c0695 | 103 | message.qos = MQTT::QOS0; |
icraggs | 2:638c854c0695 | 104 | message.retained = false; |
icraggs | 2:638c854c0695 | 105 | message.dup = false; |
icraggs | 2:638c854c0695 | 106 | message.payload = (void*)buf; |
icraggs | 2:638c854c0695 | 107 | message.payloadlen = strlen(buf)+1; |
icraggs | 16:28d062c5522b | 108 | rc = client.publish(topic, message); |
icraggs | 12:086a9314e8a5 | 109 | while (arrivedcount < 1) |
icraggs | 2:638c854c0695 | 110 | client.yield(100); |
Jan Jongboom |
20:49c9daf2b0ff | 111 | |
icraggs | 2:638c854c0695 | 112 | // QoS 1 |
Jan Jongboom |
20:49c9daf2b0ff | 113 | sprintf(buf, "Hello World! QoS 1 message from app version %f\r\n", version); |
icraggs | 2:638c854c0695 | 114 | message.qos = MQTT::QOS1; |
icraggs | 2:638c854c0695 | 115 | message.payloadlen = strlen(buf)+1; |
icraggs | 16:28d062c5522b | 116 | rc = client.publish(topic, message); |
icraggs | 12:086a9314e8a5 | 117 | while (arrivedcount < 2) |
icraggs | 2:638c854c0695 | 118 | client.yield(100); |
Jan Jongboom |
20:49c9daf2b0ff | 119 | |
icraggs | 2:638c854c0695 | 120 | // QoS 2 |
Jan Jongboom |
20:49c9daf2b0ff | 121 | sprintf(buf, "Hello World! QoS 2 message from app version %f\r\n", version); |
icraggs | 2:638c854c0695 | 122 | message.qos = MQTT::QOS2; |
icraggs | 2:638c854c0695 | 123 | message.payloadlen = strlen(buf)+1; |
icraggs | 16:28d062c5522b | 124 | rc = client.publish(topic, message); |
icraggs | 12:086a9314e8a5 | 125 | while (arrivedcount < 3) |
icraggs | 2:638c854c0695 | 126 | client.yield(100); |
Jan Jongboom |
20:49c9daf2b0ff | 127 | |
icraggs | 17:0811bdbdd78a | 128 | if ((rc = client.unsubscribe(topic)) != 0) |
Jan Jongboom |
20:49c9daf2b0ff | 129 | logMessage("rc from unsubscribe was %d\r\n", rc); |
Jan Jongboom |
20:49c9daf2b0ff | 130 | |
icraggs | 8:a3e3113054a1 | 131 | if ((rc = client.disconnect()) != 0) |
Jan Jongboom |
20:49c9daf2b0ff | 132 | logMessage("rc from disconnect was %d\r\n", rc); |
Jan Jongboom |
20:49c9daf2b0ff | 133 | |
Jan Jongboom |
20:49c9daf2b0ff | 134 | mqttNetwork.disconnect(); |
Jan Jongboom |
20:49c9daf2b0ff | 135 | |
Jan Jongboom |
20:49c9daf2b0ff | 136 | logMessage("Version %.2f: finish %d msgs\r\n", version, arrivedcount); |
Jan Jongboom |
20:49c9daf2b0ff | 137 | |
icraggs | 0:0cae29831d01 | 138 | return 0; |
icraggs | 0:0cae29831d01 | 139 | } |