Simple usage example of MQTTS library

Dependencies:   EthernetInterface MQTTS NTPClient SDFileSystem mbed-rtos mbed wolfSSL

Fork of HelloMQTT by MQTT

MQTT is light weight protocol for M2M, IoT. MQTTS adds TLS(SSL) security layer into the MQTT. This program shows simple usage example of MQTTS library.

Connect information has to be stored in SD file "connectInfo.txt", with following lines in it.

  • Host Name
  • User Name
  • Password
  • Client ID
  • Topic

The program asks following information on the terminal

  • Port Number to be connected. If the port is >8000 it assumes MQTTS.
  • Message to be published
  • Certificate file name, if MQTTS. Input file name on SD card. Simply Return key force it to no server verification. The program set up the realtime clock by NTP for certificate verification.

This program was tested with FRDM-K64F, against Sango MQTT server by Shiguredo. https://sango.shiguredo.jp/

References:

main_linux.cpp

Committer:
icraggs
Date:
2014-05-06
Revision:
3:7a6a899de7cc

File content as of revision 3:7a6a899de7cc:

/*******************************************************************************
 * 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 Linux.  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 Linux
  system libraries.
 
 */

#if defined(LINUX)

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>

#include <stdlib.h>
#include <string.h>
#include <signal.h>

#include "MQTTClient.h"
#include "FP.cpp"

#define DEFAULT_STACK_SIZE -1


class IPStack 
{
public:    
    IPStack()
    {

    }
    
	int Socket_error(const char* aString)
	{

		if (errno != EINTR && errno != EAGAIN && errno != EINPROGRESS && errno != EWOULDBLOCK)
		{
			if (strcmp(aString, "shutdown") != 0 || (errno != ENOTCONN && errno != ECONNRESET))
				printf("Socket error %s in %s for socket %d\n", strerror(errno), aString, mysock);
		}
		return errno;
	}

    int connect(const char* hostname, int port)
    {
		int type = SOCK_STREAM;
		struct sockaddr_in address;
		int rc = -1;
		sa_family_t family = AF_INET;
		struct addrinfo *result = NULL;
		struct addrinfo hints = {0, AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, 0, NULL, NULL, NULL};

		if ((rc = getaddrinfo(hostname, NULL, &hints, &result)) == 0)
		{
			struct addrinfo* res = result;

			/* prefer ip4 addresses */
			while (res)
			{
				if (res->ai_family == AF_INET)
				{
					result = res;
					break;
				}
				res = res->ai_next;
			}

			if (result->ai_family == AF_INET)
			{
				address.sin_port = htons(port);
				address.sin_family = family = AF_INET;
				address.sin_addr = ((struct sockaddr_in*)(result->ai_addr))->sin_addr;
			}
			else
				rc = -1;

			freeaddrinfo(result);
		}

		if (rc == 0)
		{
			mysock = socket(family, type, 0);
			if (mysock != -1)
			{
				int opt = 1;

				//if (setsockopt(mysock, SOL_SOCKET, SO_NOSIGPIPE, (void*)&opt, sizeof(opt)) != 0)
				//	printf("Could not set SO_NOSIGPIPE for socket %d", mysock);
				
				rc = ::connect(mysock, (struct sockaddr*)&address, sizeof(address));
			}
		}

        return rc;
    }

    int read(char* buffer, int len, int timeout_ms)
    {
		struct timeval interval = {timeout_ms / 1000, (timeout_ms % 1000) * 1000};
		if (interval.tv_sec < 0 || (interval.tv_sec == 0 && interval.tv_usec <= 0))
		{
			interval.tv_sec = 0;
			interval.tv_usec = 100;
		}

		setsockopt(mysock, SOL_SOCKET, SO_RCVTIMEO, (char *)&interval, sizeof(struct timeval));

		//printf("reading %d bytes\n", len);
		int rc = ::recv(mysock, buffer, (size_t)len, 0);
		if (rc == -1)
			Socket_error("read");
		//printf("read %d bytes\n", rc);
		return rc;
    }
    
    int write(char* buffer, int len, int timeout)
    {
		struct timeval tv;

		tv.tv_sec = 0;  /* 30 Secs Timeout */
		tv.tv_usec = timeout * 1000;  // Not init'ing this can cause strange errors

		setsockopt(mysock, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,sizeof(struct timeval));
		int	rc = ::write(mysock, buffer, len);
		//printf("write rc %d\n", rc);
		return rc;
    }

	int disconnect()
	{
		return ::close(mysock);
	}
    
private:

    int mysock; 
    
};


class Countdown
{
public:
    Countdown()
    { 
	
    }

    Countdown(int ms)
    { 
		countdown_ms(ms);
    }
    

    bool expired()
    {
		struct timeval now, res;
		gettimeofday(&now, NULL);
		timersub(&end_time, &now, &res);		
		//printf("left %d ms\n", (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000);
		//if (res.tv_sec > 0 || res.tv_usec > 0)
		//	printf("expired %d %d\n", res.tv_sec, res.tv_usec);
        return res.tv_sec < 0 || (res.tv_sec == 0 && res.tv_usec <= 0);
    }
    

    void countdown_ms(int ms)  
    {
		struct timeval now;
		gettimeofday(&now, NULL);
		struct timeval interval = {ms / 1000, (ms % 1000) * 1000};
		//printf("interval %d %d\n", interval.tv_sec, interval.tv_usec);
		timeradd(&now, &interval, &end_time);
    }

    
    void countdown(int seconds)
    {
		struct timeval now;
		gettimeofday(&now, NULL);
		struct timeval interval = {seconds, 0};
		timeradd(&now, &interval, &end_time);
    }

    
    int left_ms()
    {
		struct timeval now, res;
		gettimeofday(&now, NULL);
		timersub(&end_time, &now, &res);
		//printf("left %d ms\n", (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000);
        return (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000;
    }
    
private:

	struct timeval end_time;
};


int arrivedcount = 0;

void messageArrived(MQTT::Message* message)
{
	printf("Message %d arrived: qos %d, retained %d, dup %d, packetid %d\n", 
		++arrivedcount, message->qos, message->retained, message->dup, message->id);
    printf("Payload %.*s\n", message->payloadlen, (char*)message->payload);
}


int connect(MQTT::Client<IPStack, Countdown>::connectionLostInfo* info)
{
    const char* hostname = "localhost"; //"m2m.eclipse.org";
    int port = 1883;
    printf("Connecting to %s:%d\n", hostname, port);
    int rc = info->network->connect(hostname, port);
	if (rc != 0)
	    printf("rc from TCP connect is %d\n", rc);
 
    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;       
    data.MQTTVersion = 3;
    data.clientID.cstring = (char*)"mbed-icraggs";
    rc = info->client->connect(&data);
	if (rc != 0)
	    printf("rc from MQTT connect is %d\n", rc);
    
    return rc;
}


int main(int argc, char* argv[])
{   
    IPStack ipstack = IPStack();
    float version = 0.3;
    const char* topic = "mbed-sample";
    
    printf("Version is %f\n", version);
              
    MQTT::Client<IPStack, Countdown> client = MQTT::Client<IPStack, Countdown>(ipstack);
    
    client.setConnectionLostHandler(connect);

    MQTT::Client<IPStack, Countdown>::connectionLostInfo info = {&client, &ipstack};
    int rc = connect(&info);
    
    rc = client.subscribe(topic, MQTT::QOS2, messageArrived);   
    if (rc != 0)
        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", 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
	printf("Now QoS 1\n");
    sprintf(buf, "Hello World!  QoS 1 message from app version %f", 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", version);
    message.qos = MQTT::QOS2;
    message.payloadlen = strlen(buf)+1;
    rc = client.publish(topic, &message);
    while (arrivedcount == 2)
        client.yield(100);
    
    rc = client.unsubscribe(topic);
    if (rc != 0)
        printf("rc from unsubscribe was %d\n", rc);
    
    rc = client.disconnect();
    if (rc != 0)
        printf("rc from disconnect was %d\n", rc);
    
    ipstack.disconnect();
    
    printf("Finishing with %d messages received\n", arrivedcount);
    
    return 0;
}

#endif