FreeRTOS/FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/mqtt/DemoTasks/SimpleMQTTExamples.c

/*
 * FreeRTOS Kernel V10.2.1
 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

/* Standard inclues. */
#include <string.h>
#include <stdio.h>

/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"

/* IoT SDK includes. */
#include "iot_mqtt.h"
#include "iot_taskpool.h"
#include "platform/iot_network_freertos.h"

/**
 * @brief The keep-alive interval used for this example.
 *
 * An MQTT ping request will be sent periodically at this interval.
 */
#define mqttexampleKEEP_ALIVE_SECONDS		( 60 )

/**
 * @brief The timeout for MQTT operations in this example.
 */
#define mqttexampleMQTT_TIMEOUT_MS			( 5000 )

/**
 * @brief The MQTT client identifier used in this example.
 */
#define mqttexampleCLIENT_IDENTIFIER		"mqttexampleclient"

/**
 * @brief Details of the MQTT broker to connect to.
 *
 * @note This example does not use TLS and therefore won't work with AWS IoT.
 *
 */
#define mqttexampleMQTT_BROKER_ENDPOINT		"test.mosquitto.org"
#define mqttexampleMQTT_BROKER_PORT			1883

/**
 * @brief The topic to subscribe and publish to in the example.
 */
#define mqttexampleTOPIC					"example/topic"

/**
 * @brief The MQTT message published in this example.
 */
#define mqttexampleMESSAGE					"Hello World!"

/**
 * @brief Paramters to control the retry behaviour in case a QoS1 publish
 * message gets lost.
 *
 * Retry every minutes up to a maximum of 5 retries.
 */
#define mqttexamplePUBLISH_RETRY_MS			( 1000 )
#define mqttexamplePUBLISH_RETRY_LIMIT		( 5 )

/**
 * @brief The bit which is set in the demo task's notification value from the
 * disconnect callback to inform the demo task about the MQTT disconnect.
 */
#define mqttexampleDISCONNECTED_BIT			( 1UL << 0UL )

/**
 * @brief The bit which is set in the demo task's notification value from the
 * publish callback to inform the demo task about the message received from the
 * MQTT broker.
 */
#define mqttexampleMESSAGE_RECEIVED_BIT		( 1UL << 1UL )
/*-----------------------------------------------------------*/

/**
 * @brief The MQTT connection handle used in this example.
 */
static IotMqttConnection_t xMQTTConnection = IOT_MQTT_CONNECTION_INITIALIZER;

/**
 * @brief Parameters used to create the system task pool.
 */
static const IotTaskPoolInfo_t xTaskPoolParameters = {
														/* Minimum number of threads in a task pool.
														 * Note the slimmed down version of the task
														 * pool used by this library does not autoscale
														 * the number of tasks in the pool so in this
														 * case this sets the number of tasks in the
														 * pool. */
														2,
														/* Maximum number of threads in a task pool.
														 * Note the slimmed down version of the task
														 * pool used by this library does not autoscale
														 * the number of tasks in the pool so in this
														 * case this parameter is just ignored. */
														2,
														/* Stack size for every task pool thread - in
														 * bytes, hence multiplying by the number of bytes
														 * in a word as configMINIMAL_STACK_SIZE is
														 * specified in words. */
														configMINIMAL_STACK_SIZE * sizeof( portSTACK_TYPE ),
														/* Priority for every task pool thread. */
														tskIDLE_PRIORITY,
													 };
/*-----------------------------------------------------------*/

/**
 * @brief The task used to demonstrate the MQTT API.
 *
 * @param[in] pvParameters Parmaters as passed at the time of task creation. Not
 * used in this example.
 */
static void prvMQTTDemoTask( void *pvParameters );

/**
 * @brief The callback invoked by the MQTT library when the MQTT connection gets
 * disconnected.
 *
 * @param[in] pvCallbackContext Callback context as provided at the time of
 * connect.
 * @param[in] pxCallbackParams Contains the reason why the MQTT connection was
 * disconnected.
 */
static void prvExample_OnDisconnect( void * pvCallbackContext,
									 IotMqttCallbackParam_t * pxCallbackParams );

/**
 * @brief The callback invoked by the MQTT library when a message is received on
 * a subscribed topic from the MQTT broker.
 *
 * @param[in] pvCallbackContext Callback context as provided at the time of
 * subscribe.
 * @param[in] pxCallbackParams Contain the details about the received message -
 * topic on which the message was received, the received message.
 */
static void prvExample_OnMessageReceived( void * pvCallbackContext,
										  IotMqttCallbackParam_t * pxCallbackParams );

/**
 * @brief Connects to the MQTT broker as specified in mqttexampleMQTT_BROKER_ENDPOINT
 * and mqttexampleMQTT_BROKER_PORT.
 *
 * @note This example does not use TLS and therefore will not work with MQTT.
 */
static void prvMQTTConnect( void );

/**
 * @brief Subscribes to the topic as specified in mqttexampleTOPIC.
 */
static void prvMQTTSubscribe( void );

/**
 * @brief Publishes a messages mqttexampleMESSAGE on mqttexampleTOPIC topic.
 */
static void prvMQTTPublish( void );

/**
 * @brief Unsubscribes from the mqttexampleTOPIC topic.
 */
static void prvMQTTUnsubscribe( void );

/**
 * @brief Disconnects from the MQTT broker gracefully by sending an MQTT
 * DISCONNECT message.
 */
static void prvMQTTDisconnect( void );
/*-----------------------------------------------------------*/

static void prvExample_OnDisconnect( void * pvCallbackContext,
										   IotMqttCallbackParam_t * pxCallbackParams )
{
TaskHandle_t xDemoTaskHandle = ( TaskHandle_t ) pvCallbackContext;

	/* Ensure that we initiated the disconnect. */
	configASSERT( pxCallbackParams->u.disconnectReason == IOT_MQTT_DISCONNECT_CALLED );

	/* Inform the demo task about the disconnect. */
	xTaskNotify( xDemoTaskHandle,
				mqttexampleDISCONNECTED_BIT,
				eSetBits /* Set the mqttexampleDISCONNECTED_BIT in the demo task's notification value. */
				);
}
/*-----------------------------------------------------------*/

static void prvExample_OnMessageReceived( void * pvCallbackContext,
										IotMqttCallbackParam_t * pxCallbackParams )
{
TaskHandle_t xDemoTaskHandle = ( TaskHandle_t ) pvCallbackContext;

	/* Ensure that the message is received on the expected topic. */
	configASSERT( pxCallbackParams->u.message.info.topicNameLength == strlen( mqttexampleTOPIC ) );
	configASSERT( strncmp( pxCallbackParams->u.message.info.pTopicName,
						   mqttexampleTOPIC,
						   strlen( mqttexampleTOPIC ) ) == 0 );

	/* Ensure that the expected message is received. */
	configASSERT( pxCallbackParams->u.message.info.payloadLength == strlen( mqttexampleMESSAGE ) );
	configASSERT( strncmp( pxCallbackParams->u.message.info.pPayload,
						   mqttexampleMESSAGE,
						   strlen( mqttexampleMESSAGE ) ) == 0 );

	/* Ensure that the message QoS is as expected. */
	configASSERT( pxCallbackParams->u.message.info.qos == IOT_MQTT_QOS_1 );

	/* Although this print uses the constants rather than the data from the
	message payload the asserts above have already checked the message payload
	equals the constants, and it is more efficient not to have to worry about
	lengths in the print. */
	configPRINTF( ( "Received %s from topic %s\r\n", mqttexampleMESSAGE, mqttexampleTOPIC ) );

	/* Inform the demo task about the message received from the MQTT broker. */
	xTaskNotify( xDemoTaskHandle,
				 mqttexampleMESSAGE_RECEIVED_BIT,
				 eSetBits /* Set the mqttexampleMESSAGE_RECEIVED_BIT in the demo task's notification value. */
				);
}
/*-----------------------------------------------------------*/

void vStartSimpleMQTTDemo( void )
{
	/* This example uses a single application task, which in turn is used to
	 * connect, subscribe, publish, unsubscribe and disconnect from the MQTT
	 * broker. */
	xTaskCreate( prvMQTTDemoTask,			/* Function that implements the task. */
				 "MQTTDemo",				/* Text name for the task - only used for debugging. */
				 configMINIMAL_STACK_SIZE,	/* Size of stack (in words, not bytes) to allocate for the task. */
				 NULL,						/* Task parameter - not used in this case. */
				 tskIDLE_PRIORITY,			/* Task priority, must be between 0 and configMAX_PRIORITIES - 1. */
				 NULL );					/* Used to pass out a handle to the created task - not used in this case. */
}
/*-----------------------------------------------------------*/

static void prvMQTTDemoTask( void *pvParameters )
{
IotMqttError_t xResult;
uint32_t ulNotificationValue = 0, ulIterations;
const uint32_t ulMaxIterations = 5UL;
const TickType_t xNoDelay = ( TickType_t ) 0;

	/* Remove compiler warnings about unused parameters. */
	( void ) pvParameters;

	/* The MQTT library needs a task pool, so create the system task pool. */
	xResult = IotTaskPool_CreateSystemTaskPool( &( xTaskPoolParameters ) );
	configASSERT( xResult == IOT_TASKPOOL_SUCCESS );

	/* MQTT library must be initialized before it can be used. This is just one
	 * time initialization. */
	xResult = IotMqtt_Init();
	configASSERT( xResult == IOT_MQTT_SUCCESS );

	for( ; ; )
	{
		/* Don't expect any notifications to be pending yet. */
		configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );


		/******************** CONNECT ****************************************/

		/* Establish a connection to the MQTT broker. This example connects to
		 * the MQTT broker as specified in mqttexampleMQTT_BROKER_ENDPOINT and
		 * mqttexampleMQTT_BROKER_PORT at the top of this file. Please change
		 * it to the MQTT broker you want to connect to. Note that this example
		 * does not use TLS and therefore will not work with AWS IoT. */
		prvMQTTConnect();
		configPRINTF( ( "Connected to %s\r\n", mqttexampleMQTT_BROKER_ENDPOINT ) );


		/******************* SUBSCRIBE ***************************************/

		/* The client is now connected to the broker.  Subscribe to the topic
		as specified in mqttexampleTOPIC at the top of this file.  This client
		will then publish to the same topic it subscribed to, so will expect
		all the messages it sends to the broker to be sent back to it from the
		broker. */
		prvMQTTSubscribe();
		configPRINTF( ( "Subscribed to %s\r\n", mqttexampleTOPIC ) );


		/******************* PUBLISH 5 TIMES *********************************/

		/* Publish a few messages while connected. */
		for( ulIterations = 0; ulIterations < ulMaxIterations; ulIterations++ )
		{
			/* Publish a message on the mqttexampleTOPIC topic as specified at the
			 * top of this file. */
			prvMQTTPublish();
			configPRINTF( ( "Published %s to %s\r\n", mqttexampleMESSAGE, mqttexampleTOPIC ) );

			/* Since we are subscribed on the same topic, we will get the same
			 * message back from the MQTT broker. Wait for the message to be
			 * received which is informed to us by the publish callback
			 * (prvExample_OnMessageReceived) by setting the
			 * mqttexampleMESSAGE_RECEIVED_BIT in this task's notification
			 value. */
			xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
							 mqttexampleMESSAGE_RECEIVED_BIT, /* Clear bit on exit. */
							 &( ulNotificationValue ), /* Obtain the notification value. */
							 pdMS_TO_TICKS( mqttexampleMQTT_TIMEOUT_MS ) );
			configASSERT( ( ulNotificationValue & mqttexampleMESSAGE_RECEIVED_BIT ) == mqttexampleMESSAGE_RECEIVED_BIT );
		}


		/******************* UNSUBSCRIBE AND DISCONNECT **********************/

		/* Unsubscribe from the topic mqttexampleTOPIC the disconnect
		gracefully. */
		prvMQTTUnsubscribe();
		prvMQTTDisconnect();
		configPRINTF( ( "Disconnected from from %s\r\n\r\n", mqttexampleMQTT_BROKER_ENDPOINT ) );

		/* Wait for the disconnect operation to complete which is informed to us
		 * by the disconnect callback (prvExample_OnDisconnect)by setting
		 * the mqttexampleDISCONNECTED_BIT in this task's notification value.
		 * Note that all bits are cleared in the task's notification value to
		 * ensure that it is ready for the next run. */
		xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
						 mqttexampleDISCONNECTED_BIT, /* Clear bit again on exit. */
						 &( ulNotificationValue ), /* Obtain the notification value. */
						 pdMS_TO_TICKS( mqttexampleMQTT_TIMEOUT_MS ) );
		configASSERT( ( ulNotificationValue & mqttexampleDISCONNECTED_BIT ) == mqttexampleDISCONNECTED_BIT );



		/* Wait for some time between two iterations to ensure that we do not
		 * bombard the public test mosquitto broker. */
		configPRINTF( ( "prvMQTTDemoTask() completed an iteration without hitting an assert.  Total free heap is %u\r\n\r\n", xPortGetFreeHeapSize() ) );
		vTaskDelay( pdMS_TO_TICKS( 5000 ) );
	}
}
/*-----------------------------------------------------------*/

static void prvMQTTConnect( void )
{
IotMqttError_t xResult;
IotNetworkServerInfo_t xMQTTBrokerInfo;
IotMqttNetworkInfo_t xNetworkInfo = IOT_MQTT_NETWORK_INFO_INITIALIZER;
IotMqttConnectInfo_t xConnectInfo = IOT_MQTT_CONNECT_INFO_INITIALIZER;

	/******************* Broker information setup. **********************/
	xMQTTBrokerInfo.pHostName = mqttexampleMQTT_BROKER_ENDPOINT;
	xMQTTBrokerInfo.port = mqttexampleMQTT_BROKER_PORT;

	/******************* Network information setup. **********************/
	/* No connection to the MQTT broker has been established yet and we want to
	 * establish a new connection. */
	xNetworkInfo.createNetworkConnection = true;
	xNetworkInfo.u.setup.pNetworkServerInfo = &( xMQTTBrokerInfo );

	/* This example does not use TLS and therefore pNetworkCredentialInfo must
	 * be set to NULL. */
	xNetworkInfo.u.setup.pNetworkCredentialInfo = NULL;

	/* Use FreeRTOS+TCP network. */
	xNetworkInfo.pNetworkInterface = IOT_NETWORK_INTERFACE_FREERTOS;

	/* Setup the callback which is called when the MQTT connection is disconnected. */
	xNetworkInfo.disconnectCallback.pCallbackContext = ( void * ) xTaskGetCurrentTaskHandle();//_RB_ Why the task handle?
	xNetworkInfo.disconnectCallback.function = prvExample_OnDisconnect;

	/****************** MQTT Connection information setup. ********************/
	/* Set this flag to true if connecting to the AWS IoT MQTT broker.  This
	example does not use TLS and therefore won't work with AWS IoT. */
	xConnectInfo.awsIotMqttMode = false;

	/* Start with a clean session i.e. direct the MQTT broker to discard any
	 * previous session data. Also, establishing a connection with clean session
	 * will ensure that the broker does not store any data when this client
	 * gets disconnected. */
	xConnectInfo.cleanSession = true;

	/* Since we are starting with a clean session, there are no previous
	 * subscriptions to be restored. */
	xConnectInfo.pPreviousSubscriptions = NULL;
	xConnectInfo.previousSubscriptionCount = 0;

	/* We do not want to publish Last Will and Testament (LWT) message if the
	 * client gets disconnected. */
	xConnectInfo.pWillInfo = NULL;

	/* Send an MQTT PING request every minute to keep the connection open if
	there is no other MQTT trafic. */
	xConnectInfo.keepAliveSeconds = mqttexampleKEEP_ALIVE_SECONDS;

	/* The client identifier is used to uniquely identify this MQTT client to
	 * the MQTT broker.  In a production device the identifier can be something
	 unique, such as a device serial number. */
	xConnectInfo.pClientIdentifier = mqttexampleCLIENT_IDENTIFIER;
	xConnectInfo.clientIdentifierLength = ( uint16_t ) strlen( mqttexampleCLIENT_IDENTIFIER );

	/* This example does not use any authentication and therefore username and
	 * password fields are not used. */
	xConnectInfo.pUserName = NULL;
	xConnectInfo.userNameLength = 0;
	xConnectInfo.pPassword = NULL;
	xConnectInfo.passwordLength = 0;

	/* Establish the connection to the MQTT broker - It is a blocking call and
	will return only when connection is complete or a timeout occurrs. */
	xResult = IotMqtt_Connect( &( xNetworkInfo ),
							   &( xConnectInfo ),
							   mqttexampleMQTT_TIMEOUT_MS,
							   &( xMQTTConnection ) );
	configASSERT( xResult == IOT_MQTT_SUCCESS );
}
/*-----------------------------------------------------------*/

static void prvMQTTSubscribe( void )
{
IotMqttError_t xResult;
IotMqttSubscription_t xMQTTSubscription;

	/* Subscribe to the mqttexampleTOPIC topic filter. */
	xMQTTSubscription.qos = IOT_MQTT_QOS_1;
	xMQTTSubscription.pTopicFilter = mqttexampleTOPIC;
	xMQTTSubscription.topicFilterLength = ( uint16_t ) strlen( mqttexampleTOPIC );
	xMQTTSubscription.callback.pCallbackContext = ( void * ) xTaskGetCurrentTaskHandle();
	xMQTTSubscription.callback.function = prvExample_OnMessageReceived;

	/* Use the synchronous API to subscribe - It is a blocking call and only
	 * returns when the subscribe operation is complete. */
	xResult = IotMqtt_TimedSubscribe( xMQTTConnection,
									  &( xMQTTSubscription ),
									  1, /* We are subscribing to one topic filter. */
									  0, /* flags - currently ignored. */
									  mqttexampleMQTT_TIMEOUT_MS );
	configASSERT( xResult == IOT_MQTT_SUCCESS );
}
/*-----------------------------------------------------------*/

static void prvMQTTPublish( void )
{
IotMqttError_t xResult;
IotMqttPublishInfo_t xMQTTPublishInfo;

	/* Publish a message with QoS1 on the mqttexampleTOPIC topic. Since we are
	 * subscribed to the same topic, the MQTT broker will send the same message
	 * back to us. It is verified in the publish callback. */
	xMQTTPublishInfo.qos = IOT_MQTT_QOS_1;
	xMQTTPublishInfo.retain = false;
	xMQTTPublishInfo.pTopicName = mqttexampleTOPIC;
	xMQTTPublishInfo.topicNameLength = ( uint16_t ) strlen( mqttexampleTOPIC );
	xMQTTPublishInfo.pPayload = mqttexampleMESSAGE;
	xMQTTPublishInfo.payloadLength = strlen( mqttexampleMESSAGE );
	xMQTTPublishInfo.retryMs = mqttexamplePUBLISH_RETRY_MS;
	xMQTTPublishInfo.retryLimit = mqttexamplePUBLISH_RETRY_LIMIT;

	/* Use the synchronous API to publish - It is a blocking call and only
	 * returns when the publish operation is complete. */
	xResult = IotMqtt_TimedPublish( xMQTTConnection,
									&( xMQTTPublishInfo ),
									0, /* flags - currently ignored. */
									mqttexampleMQTT_TIMEOUT_MS );
	configASSERT( xResult == IOT_MQTT_SUCCESS );
}
/*-----------------------------------------------------------*/

static void prvMQTTUnsubscribe( void )
{
IotMqttError_t xResult;
IotMqttSubscription_t xMQTTSubscription;

	/* Unsubscribe from the mqttexampleTOPIC topic filter. */
	xMQTTSubscription.pTopicFilter = mqttexampleTOPIC;
	xMQTTSubscription.topicFilterLength = ( uint16_t ) strlen( mqttexampleTOPIC );
	/* The following members of the IotMqttSubscription_t are ignored by the
	 * unsubscribe operation. Just initialize them to avoid "use of uninitialized
	 * variable" warnings. */
	xMQTTSubscription.qos = IOT_MQTT_QOS_1;
	xMQTTSubscription.callback.pCallbackContext = NULL;
	xMQTTSubscription.callback.function = NULL;

	/* Use the synchronous API to unsubscribe - It is a blocking call and only
	 * returns when the unsubscribe operation is complete. */
	xResult = IotMqtt_TimedUnsubscribe( xMQTTConnection,
										&( xMQTTSubscription ),
										1, /* We are unsubscribing from one topic filter. */
										0, /* flags - currently ignored. */
										mqttexampleMQTT_TIMEOUT_MS );
	configASSERT( xResult == IOT_MQTT_SUCCESS );
}
/*-----------------------------------------------------------*/

static void prvMQTTDisconnect( void )
{
	/* Send a MQTT DISCONNECT packet to the MQTT broker to do a graceful
	 * disconnect. */
	IotMqtt_Disconnect( xMQTTConnection,
						0 /* flags - 0 means a graceful disconnect by sending MQTT DISCONNECT. */
						);
}
/*-----------------------------------------------------------*/