Osamu Koizumi / Mbed OS HelloMQTT

HelloMQTT over TLS.

Dependencies:   MQTT

Fork of HelloMQTT by Osamu Koizumi

HelloMQTT over TLS

This program is a fork of HelloMQTT. Added TLS capability by using TLSSocket library. Tested on K64F.

This sample program connects to iot.eclipse.org:8883 by default. Verifies server identification. Subscribes a certain topic. Then publishes three messages with different QoSs, i.e. QoS0, QoS1, and QoS2.

Warning

Some brokers do not accept QoS2 and/or QoS1 message. For example, AWS IoT Message Broker doesn't accept QoS2. In such broker, this program doesn't work as is. Change QoS level.

Output from console

HelloMQTT: version is 0.70

Opening network interface...
Network interface opened successfully.

Connecting to host iot.eclipse.org:8883 ...
Connection established.

MQTT client is trying to connect the server ...
Client connected.

Client is trying to subscribe a topic "mbed-test".
Client has subscribed a topic "mbed-test".

Client publishes messages ...
Publishing message QoS 0.
QoS 0 message published.
! Message arrived: qos 0, retained 0, dup 0, packetid 6257
! Payload Hello World!  QoS 0 message from app version 0.700000

Publishing message QoS 1.
QoS 1 message published.
! Message arrived: qos 1, retained 0, dup 0, packetid 1
! Payload Hello World!  QoS 1 message from app version 0.700000

Publishing message QoS 2.
QoS 2 message published.
! Message arrived: qos 2, retained 0, dup 0, packetid 2
! Payload Hello World!  QoS 2 message from app version 0.700000

Version 0.70: finish 3 msgs

Known Issues

On K64F, when serial baud rate is changed from 9600 to 115200, program fails.

MQTTNetwork.h

Committer:
Osamu Koizumi
Date:
2018-06-13
Revision:
42:c88d777f2e00
Parent:
34:8f7a465c2192

File content as of revision 42:c88d777f2e00:

#ifndef _MQTTNETWORK_H_
#define _MQTTNETWORK_H_

#include "NetworkInterface.h"

#undef USE_TLS
#if defined(MBED_CONF_APP_USE_TLS) && (MBED_CONF_APP_USE_TLS == 1)
  #define USE_TLS
#endif

#ifdef USE_TLS
#include "TLSSocket.h"
#endif /* USE_TLS */

class MQTTNetwork {
public:
    MQTTNetwork(NetworkInterface* aNetwork) : network(aNetwork) {
#ifdef USE_TLS
        socket = new TLSSocket();
#else
        socket = new TCPSocket();
#endif /* USE_TLS */
    }

    ~MQTTNetwork() {
        delete socket;
    }

    int read(unsigned char* buffer, int len, int timeout) {
        return socket->recv(buffer, len);
    }

    int write(unsigned char* buffer, int len, int timeout) {
        return socket->send(buffer, len);
    }

    int connect(const char* hostname, int port, const char *ssl_ca_pem = NULL,
            const char *ssl_cli_pem = NULL, const char *ssl_pk_pem = NULL) {
        nsapi_error_t ret = 0;
        if((ret = socket->open(network)) != 0) {
            return ret;
        }
#ifdef USE_TLS
        socket->set_root_ca_cert(ssl_ca_pem);
        socket->set_client_cert_key(ssl_cli_pem, ssl_pk_pem);
#endif /* USE_TLS */
        return socket->connect(hostname, port);
    }

    int disconnect() {
        return socket->close();
    }

private:
    NetworkInterface* network;
#ifdef USE_TLS
    TLSSocket* socket;
#else
    TCPSocket* socket;
#endif /* USE_TLS */
};

#endif // _MQTTNETWORK_H_