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[paho-dev] MQTTClient or MQTTAsync ?
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Hi ,
I was going through samples for asynchronous publication and came across below 2 examples
As per reading adding setCallbacks will make the client asynchronous
2. MQTTAsync - (attaching file - ) I does almost the same except
while(deliveredtoken != token); ( as in 1 )
Difference between 1 and 2 is waiting for the delivery of the published messaged only ?
I wanted to have clear understanding how 1 and 2 are different.
What are advantages of using MQTTAsync instead of MQTTClient (using setCallbacks) for asynchronous publication.
--
cheerz,
Rajath
/*******************************************************************************
* Copyright (c) 2012, 2013 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 contribution
*******************************************************************************/
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "MQTTAsync.h"
#if defined(WIN32)
#include "windows.h"
#endif
#define ADDRESS "tcp://m2m.eclipse.org:1883"
#define CLIENTID "ExampleClientPub"
#define TOPIC "MQTT Examples"
#define PAYLOAD "Hello World!"
#define QOS 1
#define TIMEOUT 10000L
volatile MQTTAsync_token deliveredtoken;
int finished = 0;
void connlost(void *context, char *cause)
{
MQTTAsync client = (MQTTAsync)context;
MQTTAsync_connectOptions conn_opts = MQTTAsync_connectOptions_initializer;
int rc;
printf("\nConnection lost\n");
printf(" cause: %s\n", cause);
printf("Reconnecting\n");
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
{
printf("Failed to start connect, return code %d\n", rc);
finished = 1;
}
}
void onDisconnect(void* context, MQTTAsync_successData* response)
{
printf("Successful disconnection\n");
finished = 1;
}
void onSend(void* context, MQTTAsync_successData* response)
{
MQTTAsync client = (MQTTAsync)context;
MQTTAsync_disconnectOptions opts = MQTTAsync_disconnectOptions_initializer;
int rc;
printf("Message with token value %d delivery confirmed\n", response->token);
opts.onSuccess = onDisconnect;
opts.context = client;
if ((rc = MQTTAsync_disconnect(client, &opts)) != MQTTASYNC_SUCCESS)
{
printf("Failed to start sendMessage, return code %d\n", rc);
exit(-1);
}
}
void onConnectFailure(void* context, MQTTAsync_failureData* response)
{
printf("Connect failed, rc %d\n", response ? response->code : 0);
finished = 1;
}
void onConnect(void* context, MQTTAsync_successData* response)
{
MQTTAsync client = (MQTTAsync)context;
MQTTAsync_responseOptions opts = MQTTAsync_responseOptions_initializer;
MQTTAsync_message pubmsg = MQTTAsync_message_initializer;
int rc;
printf("Successful connection\n");
opts.onSuccess = onSend;
opts.context = client;
pubmsg.payload = PAYLOAD;
pubmsg.payloadlen = strlen(PAYLOAD);
pubmsg.qos = QOS;
pubmsg.retained = 0;
deliveredtoken = 0;
if ((rc = MQTTAsync_sendMessage(client, TOPIC, &pubmsg, &opts)) != MQTTASYNC_SUCCESS)
{
printf("Failed to start sendMessage, return code %d\n", rc);
exit(-1);
}
}
int main(int argc, char* argv[])
{
MQTTAsync client;
MQTTAsync_connectOptions conn_opts = MQTTAsync_connectOptions_initializer;
MQTTAsync_message pubmsg = MQTTAsync_message_initializer;
//MQTTAsync_token token;
int rc;
MQTTAsync_create(&client, ADDRESS, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL);
MQTTAsync_setCallbacks(client, NULL, connlost, NULL, NULL);
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
conn_opts.onSuccess = onConnect;
conn_opts.onFailure = onConnectFailure;
conn_opts.context = client;
if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
{
printf("Failed to start connect, return code %d\n", rc);
exit(-1);
}
printf("Waiting for publication of %s\n"
"on topic %s for client with ClientID: %s\n",
PAYLOAD, TOPIC, CLIENTID);
while (!finished)
#if defined(WIN32)
Sleep(100);
#else
usleep(10000L);
#endif
MQTTAsync_destroy(&client);
return rc;
}