MQTT / Mbed OS HelloMQTT

Sample MQTT program - simple send and receive

Dependencies:   C12832 MQTT

Dependents:   MQTT_G_SENSOR

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.

MQTTNetwork.h@21:a68bd76740f9, 2017-09-07 (annotated)

Committer:
Jan Jongboom
Date:
Thu Sep 07 10:06:22 2017 +0100
Revision:
21:a68bd76740f9
Parent:
20:49c9daf2b0ff 
changeset: 21:6ab7c0b84d9e

tag: tip

user: Jan Jongboom <janjongboom@gmail.com>

date: Thu Sep 07 10:02:29 2017 +0100

summary: Update to mbed OS 5.5.6

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Jan Jongboom 20:49c9daf2b0ff 1 #ifndef _MQTTNETWORK_H_
Jan Jongboom 20:49c9daf2b0ff 2 #define _MQTTNETWORK_H_
Jan Jongboom 20:49c9daf2b0ff 3
Jan Jongboom 20:49c9daf2b0ff 4 #include "NetworkInterface.h"
Jan Jongboom 20:49c9daf2b0ff 5
Jan Jongboom 20:49c9daf2b0ff 6 class MQTTNetwork {
Jan Jongboom 20:49c9daf2b0ff 7 public:
Jan Jongboom 20:49c9daf2b0ff 8 MQTTNetwork(NetworkInterface* aNetwork) : network(aNetwork) {
Jan Jongboom 20:49c9daf2b0ff 9 socket = new TCPSocket();
Jan Jongboom 20:49c9daf2b0ff 10 }
Jan Jongboom 20:49c9daf2b0ff 11
Jan Jongboom 20:49c9daf2b0ff 12 ~MQTTNetwork() {
Jan Jongboom 20:49c9daf2b0ff 13 delete socket;
Jan Jongboom 20:49c9daf2b0ff 14 }
Jan Jongboom 20:49c9daf2b0ff 15
Jan Jongboom 20:49c9daf2b0ff 16 int read(unsigned char* buffer, int len, int timeout) {
Jan Jongboom 20:49c9daf2b0ff 17 return socket->recv(buffer, len);
Jan Jongboom 20:49c9daf2b0ff 18 }
Jan Jongboom 20:49c9daf2b0ff 19
Jan Jongboom 20:49c9daf2b0ff 20 int write(unsigned char* buffer, int len, int timeout) {
Jan Jongboom 20:49c9daf2b0ff 21 return socket->send(buffer, len);
Jan Jongboom 20:49c9daf2b0ff 22 }
Jan Jongboom 20:49c9daf2b0ff 23
Jan Jongboom 20:49c9daf2b0ff 24 int connect(const char* hostname, int port) {
Jan Jongboom 20:49c9daf2b0ff 25 socket->open(network);
Jan Jongboom 20:49c9daf2b0ff 26 return socket->connect(hostname, port);
Jan Jongboom 20:49c9daf2b0ff 27 }
Jan Jongboom 20:49c9daf2b0ff 28
Jan Jongboom 21:a68bd76740f9 29 int disconnect() {
Jan Jongboom 21:a68bd76740f9 30 return socket->close();
Jan Jongboom 20:49c9daf2b0ff 31 }
Jan Jongboom 20:49c9daf2b0ff 32
Jan Jongboom 20:49c9daf2b0ff 33 private:
Jan Jongboom 20:49c9daf2b0ff 34 NetworkInterface* network;
Jan Jongboom 20:49c9daf2b0ff 35 TCPSocket* socket;
Jan Jongboom 20:49c9daf2b0ff 36 };
Jan Jongboom 20:49c9daf2b0ff 37
Jan Jongboom 20:49c9daf2b0ff 38 #endif // _MQTTNETWORK_H_