aws_iot_mqtt_client_interface.h File Reference

Interface definition for MQTT client. More...

#include "stdio.h"
#include "stdbool.h"
#include "stdint.h"
#include "stddef.h"
#include "aws_iot_error.h"
#include "aws_iot_config.h"
#include "aws_iot_mqtt_client.h"
#include "network_interface.h"
#include "timer_interface.h"

Go to the source code of this file.

Functions
IoT_Error_t	aws_iot_mqtt_free (AWS_IoT_Client *pClient)
	Clean mqtt client from all dynamic memory allocate. More...
IoT_Error_t	aws_iot_mqtt_init (AWS_IoT_Client *pClient, IoT_Client_Init_Params *pInitParams)
	MQTT Client Initialization Function. More...
IoT_Error_t	aws_iot_mqtt_connect (AWS_IoT_Client *pClient, IoT_Client_Connect_Params *pConnectParams)
	MQTT Connection Function. More...
IoT_Error_t	aws_iot_mqtt_publish (AWS_IoT_Client *pClient, const char *pTopicName, uint16_t topicNameLen, IoT_Publish_Message_Params *pParams)
	Publish an MQTT message on a topic. More...
IoT_Error_t	aws_iot_mqtt_subscribe (AWS_IoT_Client *pClient, const char *pTopicName, uint16_t topicNameLen, QoS qos, pApplicationHandler_t pApplicationHandler, void *pApplicationHandlerData)
	Subscribe to an MQTT topic. More...
IoT_Error_t	aws_iot_mqtt_resubscribe (AWS_IoT_Client *pClient)
	Subscribe to an MQTT topic. More...
IoT_Error_t	aws_iot_mqtt_unsubscribe (AWS_IoT_Client *pClient, const char *pTopicFilter, uint16_t topicFilterLen)
	Unsubscribe to an MQTT topic. More...
IoT_Error_t	aws_iot_mqtt_disconnect (AWS_IoT_Client *pClient)
	Disconnect an MQTT Connection. More...
IoT_Error_t	aws_iot_mqtt_yield (AWS_IoT_Client *pClient, uint32_t timeout_ms)
	Yield to the MQTT client. More...
IoT_Error_t	aws_iot_mqtt_attempt_reconnect (AWS_IoT_Client *pClient)
	MQTT Manual Re-Connection Function. More...

Detailed Description

Interface definition for MQTT client.

Function Documentation

aws_iot_mqtt_free()

IoT_Error_t aws_iot_mqtt_free

(

AWS_IoT_Client *

pClient

)

Clean mqtt client from all dynamic memory allocate.

This function will free up memory that was dynamically allocated for the client.

Parameters

pClient

MQTT Client that was previously created by calling aws_iot_mqtt_init

Returns

An IoT Error Type defining successful/failed freeing

aws_iot_mqtt_init()

IoT_Error_t aws_iot_mqtt_init	(	AWS_IoT_Client *	pClient,
		IoT_Client_Init_Params *	pInitParams
	)

MQTT Client Initialization Function.

Called to initialize the MQTT Client

Parameters

pClient	Reference to the IoT Client
pInitParams	Pointer to MQTT connection parameters

Returns

IoT_Error_t Type defining successful/failed API call

aws_iot_mqtt_connect()

IoT_Error_t aws_iot_mqtt_connect	(	AWS_IoT_Client *	pClient,
		IoT_Client_Connect_Params *	pConnectParams
	)

MQTT Connection Function.

Called to establish an MQTT connection with the AWS IoT Service

Parameters

pClient	Reference to the IoT Client
pConnectParams	Pointer to MQTT connection parameters

Returns

An IoT Error Type defining successful/failed connection

Called to establish an MQTT connection with the AWS IoT Service This is the outer function which does the validations and calls the internal connect above to perform the actual operation. It is also responsible for client state changes

Parameters

pClient	Reference to the IoT Client
pConnectParams	Pointer to MQTT connection parameters

Returns

An IoT Error Type defining successful/failed connection

aws_iot_mqtt_publish()

IoT_Error_t aws_iot_mqtt_publish	(	AWS_IoT_Client *	pClient,
		const char *	pTopicName,
		uint16_t	topicNameLen,
		IoT_Publish_Message_Params *	pParams
	)

Publish an MQTT message on a topic.

Called to publish an MQTT message on a topic.

Note

Call is blocking. In the case of a QoS 0 message the function returns after the message was successfully passed to the TLS layer. In the case of QoS 1 the function returns after the receipt of the PUBACK control packet.

Parameters

pClient	Reference to the IoT Client
pTopicName	Topic Name to publish to
topicNameLen	Length of the topic name
pParams	Pointer to Publish Message parameters

Returns

An IoT Error Type defining successful/failed publish

aws_iot_mqtt_subscribe()

IoT_Error_t aws_iot_mqtt_subscribe	(	AWS_IoT_Client *	pClient,
		const char *	pTopicName,
		uint16_t	topicNameLen,
		QoS	qos,
		pApplicationHandler_t	pApplicationHandler,
		void *	pApplicationHandlerData
	)

Subscribe to an MQTT topic.

Called to send a subscribe message to the broker requesting a subscription to an MQTT topic.

Note

Call is blocking. The call returns after the receipt of the SUBACK control packet.

Warning

pTopicName and pApplicationHandlerData need to be static in memory.

Parameters

pClient	Reference to the IoT Client
pTopicName	Topic Name to publish to. pTopicName needs to be static in memory since no malloc is performed by the SDK
topicNameLen	Length of the topic name
qos	Quality of service for subscription
pApplicationHandler	Reference to the handler function for this subscription
pApplicationHandlerData	Point to data passed to the callback. pApplicationHandlerData also needs to be static in memory since no malloc is performed by the SDK

Returns

An IoT Error Type defining successful/failed subscription

aws_iot_mqtt_resubscribe()

IoT_Error_t aws_iot_mqtt_resubscribe

(

AWS_IoT_Client *

pClient

)

Subscribe to an MQTT topic.

Called to resubscribe to the topics that the client has active subscriptions on. Internally called when autoreconnect is enabled

Note

Call is blocking. The call returns after the receipt of the SUBACK control packet.

Parameters

pClient

Reference to the IoT Client

Returns

An IoT Error Type defining successful/failed subscription

aws_iot_mqtt_unsubscribe()

IoT_Error_t aws_iot_mqtt_unsubscribe	(	AWS_IoT_Client *	pClient,
		const char *	pTopicFilter,
		uint16_t	topicFilterLen
	)

Unsubscribe to an MQTT topic.

Called to send an unsubscribe message to the broker requesting removal of a subscription to an MQTT topic.

Note

Call is blocking. The call returns after the receipt of the UNSUBACK control packet.

Parameters

pClient	Reference to the IoT Client
pTopicFilter	Topic filter of subscription
topicFilterLen	Length of the topic filter

Returns

An IoT Error Type defining successful/failed unsubscribe call

aws_iot_mqtt_disconnect()

IoT_Error_t aws_iot_mqtt_disconnect

(

AWS_IoT_Client *

pClient

)

Disconnect an MQTT Connection.

Called to send a disconnect message to the broker.

Parameters

pClient

Reference to the IoT Client

Returns

An IoT Error Type defining successful/failed send of the disconnect control packet.

Called to send a disconnect message to the broker. This is the outer function which does the validations and calls the internal disconnect above to perform the actual operation. It is also responsible for client state changes

Parameters

pClient

Reference to the IoT Client

Returns

An IoT Error Type defining successful/failed send of the disconnect control packet.

aws_iot_mqtt_yield()

IoT_Error_t aws_iot_mqtt_yield	(	AWS_IoT_Client *	pClient,
		uint32_t	timeout_ms
	)

Yield to the MQTT client.

Called to yield the current thread to the underlying MQTT client. This time is used by the MQTT client to manage PING requests to monitor the health of the TCP connection as well as periodically check the socket receive buffer for subscribe messages. Yield() must be called at a rate faster than the keepalive interval. It must also be called at a rate faster than the incoming message rate as this is the only way the client receives processing time to manage incoming messages.

Parameters

pClient	Reference to the IoT Client
timeout_ms	Maximum number of milliseconds to pass thread execution to the client.

Returns

An IoT Error Type defining successful/failed client processing. If this call results in an error it is likely the MQTT connection has dropped. iot_is_mqtt_connected can be called to confirm.

aws_iot_mqtt_attempt_reconnect()

IoT_Error_t aws_iot_mqtt_attempt_reconnect

(

AWS_IoT_Client *

pClient

)

MQTT Manual Re-Connection Function.

Called to establish an MQTT connection with the AWS IoT Service using parameters from the last time a connection was attempted Use after disconnect to start the reconnect process manually Makes only one reconnect attempt Sets the client state to pending reconnect in case of failure

Parameters

pClient

Reference to the IoT Client

Returns

An IoT Error Type defining successful/failed connection

Called to establish an MQTT connection with the AWS IoT Service using parameters from the last time a connection was attempted Use after disconnect to start the reconnect process manually Makes only one reconnect attempt. Sets the client state to pending reconnect in case of failure

Parameters

pClient

Reference to the IoT Client

Returns

An IoT Error Type defining successful/failed connection