MQTT over QUIC

/*******************************************************************************
 * Copyright (c) 2023-2025 EMQ Technologies Co., William Yang and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    https://www.eclipse.org/legal/epl-2.0/
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "MQTTAsync.h"

#if !defined(_WIN32)
#include <unistd.h>
#else
#include <windows.h>
#endif

#if defined(_WRS_KERNEL)
#include <OsWrapper.h>
#endif

#define ADDRESS     "quic://127.0.0.1:14567"
#define CLIENTID    "ExampleClientPub"
#define TOPIC       "MQTT Examples"
#define PAYLOAD     "Hello World!"
#define QOS         1
#define TIMEOUT     10000L

int finished = 0;

/* kept at file scope so the reconnect in connlost() can reuse them */
static const char* g_username = NULL;
static const char* g_password = NULL;
static MQTTAsync_SSLOptions g_sslopts = MQTTAsync_SSLOptions_initializer;

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;
	conn_opts.username = g_username;
	conn_opts.password = g_password;
	conn_opts.ssl = &g_sslopts;
	conn_opts.context = client;
	if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to start connect, return code %d\\n", rc);
		finished = 1;
	}
}

void onDisconnectFailure(void* context, MQTTAsync_failureData* response)
{
	printf("Disconnect failed\\n");
	finished = 1;
}

void onDisconnect(void* context, MQTTAsync_successData* response)
{
	printf("Successful disconnection\\n");
	finished = 1;
}

void onSendFailure(void* context, MQTTAsync_failureData* response)
{
	MQTTAsync client = (MQTTAsync)context;
	MQTTAsync_disconnectOptions opts = MQTTAsync_disconnectOptions_initializer;
	int rc;

	printf("Message send failed token %d error code %d\\n", response->token, response->code);
	opts.onSuccess = onDisconnect;
	opts.onFailure = onDisconnectFailure;
	opts.context = client;
	if ((rc = MQTTAsync_disconnect(client, &opts)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to start disconnect, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}
}

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.onFailure = onDisconnectFailure;
	opts.context = client;
	if ((rc = MQTTAsync_disconnect(client, &opts)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to start disconnect, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}
}


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.onFailure = onSendFailure;
	opts.context = client;
	pubmsg.payload = PAYLOAD;
	pubmsg.payloadlen = (int)strlen(PAYLOAD);
	pubmsg.qos = QOS;
	pubmsg.retained = 0;
	if ((rc = MQTTAsync_sendMessage(client, TOPIC, &pubmsg, &opts)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to start sendMessage, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}
}

int messageArrived(void* context, char* topicName, int topicLen, MQTTAsync_message* m)
{
	/* not expecting any messages */
	return 1;
}

void trace_callback(enum MQTTASYNC_TRACE_LEVELS level, char* message)
{
	fprintf(stdout, "Trace : %d, %s\\n", level, message);
}

int main(int argc, char* argv[])
{
	MQTTAsync client;
	MQTTAsync_setTraceCallback(trace_callback);
	MQTTAsync_setTraceLevel(MQTTASYNC_TRACE_MINIMUM);
	//MQTTAsync_setTraceLevel(MQTTASYNC_TRACE_PROTOCOL);
	MQTTAsync_connectOptions conn_opts = MQTTAsync_connectOptions_initializer;
	g_sslopts.enableServerCertAuth = 0; //for simplicity, we don't verify the server certificate
	int rc;

    const char* uri = (argc > 1) ? argv[1] : ADDRESS;
    g_username = (argc > 2) ? argv[2] : NULL;
    g_password = (argc > 3) ? argv[3] : NULL;


	if ((rc = MQTTAsync_create(&client, uri, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to create client object, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}

	if ((rc = MQTTAsync_setCallbacks(client, NULL, connlost, messageArrived, NULL)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to set callback, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}

	conn_opts.keepAliveInterval = 20;
	conn_opts.cleansession = 1;
	conn_opts.username = g_username;
	conn_opts.password = g_password;
	conn_opts.onSuccess = onConnect;
	conn_opts.onFailure = onConnectFailure;
	conn_opts.httpProxy = NULL;
	conn_opts.httpsProxy = NULL;
	conn_opts.context = client;
	conn_opts.ssl = &g_sslopts;
	if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
	{
		printf("Failed to start connect, return code %d\\n", rc);
		exit(EXIT_FAILURE);
	}

	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

	printf("Destroy client\\n");
	MQTTAsync_destroy(&client);
	return rc;
}