MQTT Client

Functions
int	ltrx_mqtt_client_connect (struct ltrx_mqtt_client *lmc)
	Establish client connection to MQTT broker. More...
struct ltrx_mqtt_client *	ltrx_mqtt_client_create (uint32_t command_timeout_ms, size_t sendbuf_size, size_t recvbuf_size)
	Create a MQTT client instance. More...
int	ltrx_mqtt_client_destroy (struct ltrx_mqtt_client *lmc)
	Destroy a MQTT client instance. More...
int	ltrx_mqtt_client_disconnect (struct ltrx_mqtt_client *lmc)
	Disconnect client connection from MQTT broker. More...
int	ltrx_mqtt_client_publish (struct ltrx_mqtt_client *lmc, const char *topic, struct ltrx_mqtt_message *msg)
	Publish a message to the MQTT broker. More...
int	ltrx_mqtt_client_set_cleansession (struct ltrx_mqtt_client *lmc, bool cleansession)
	Set cleansession flag for a MQTT client instance. More...
int	ltrx_mqtt_client_set_connect_info (struct ltrx_mqtt_client *lmc, const struct ltrx_mqtt_client_connect_info *lmcci)
	Set connection info for a MQTT client instance. More...
int	ltrx_mqtt_client_set_keepalive_interval (struct ltrx_mqtt_client *lmc, uint16_t keepalive_interval_sec)
	Set keepalive interval for a MQTT client instance. More...
int	ltrx_mqtt_client_set_log_verbosity (struct ltrx_mqtt_client *lmc, uint8_t verbosity)
	Set logging level for a MQTT client instance. More...
int	ltrx_mqtt_client_set_lwt (struct ltrx_mqtt_client *lmc, const char *topic, struct ltrx_mqtt_message *msg)
	Set Last Will and Testament for a MQTT client instance. More...
int	ltrx_mqtt_client_set_network_info (struct ltrx_mqtt_client *lmc, struct ltrx_mqtt_client_network_info *lmcni)
	Set network info for a MQTT client instance. More...
int	ltrx_mqtt_client_subscribe (struct ltrx_mqtt_client *lmc, const char *topic_filter, int max_qos, void(*callback)(struct ltrx_mqtt_message_data *))
	Subscribe to message topic(s) from a MQTT broker. More...
int	ltrx_mqtt_client_unsubscribe (struct ltrx_mqtt_client *lmc, const char *topic_filter)
	Unsubscribe from message topic(s) from a MQTT broker. More...

Detailed Description

MQTT Client is compliant with MQTT 3.1.1.

SSL Client is compliant with SSLv3, TLS 1.0, TLS 1.1, and TLS 1.2. Due to severe memory limitations, only a single connection instance is provided.

To use this API, follow these steps:

(1) Include the header file:

#include "mqtt_module_libs.h"

(2) Declare the global pointer:

const struct mqtt_external_functions *
    g_mqttExternalFunctionEntry_pointer = 0;

(3) Initialize the pointer in your _module_startup routine:

void <your_module>_module_startup(void)
{
    g_mqttExternalFunctionEntry_pointer =
        ltrx_module_functions_lookup("mqtt");
    // Your module startup goes here.
}

Function Documentation

int ltrx_mqtt_client_connect

(

struct ltrx_mqtt_client *

lmc

)

Establish client connection to MQTT broker.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]

lmc

Pointer to a MQTT client instance

struct ltrx_mqtt_client* ltrx_mqtt_client_create	(	uint32_t	command_timeout_ms,
		size_t	sendbuf_size,
		size_t	recvbuf_size
	)

Create a MQTT client instance.

Return values

non-NULL	Pointer to the new MQTT client instance.
NULL	Failed.

Parameters

[in]	command_timeout_ms	Timeout in ms to wait for ACK of sent command.
[in]	sendbuf_size	Size of send buffer in bytes.
[in]	recvbuf_size	Size of receive buffer in bytes.

int ltrx_mqtt_client_destroy

(

struct ltrx_mqtt_client *

lmc

)

Destroy a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]

lmc

Pointer to a MQTT client instance

int ltrx_mqtt_client_disconnect

(

struct ltrx_mqtt_client *

lmc

)

Disconnect client connection from MQTT broker.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]

lmc

Pointer to a MQTT client instance

int ltrx_mqtt_client_publish	(	struct ltrx_mqtt_client *	lmc,
		const char *	topic,
		struct ltrx_mqtt_message *	msg
	)

Publish a message to the MQTT broker.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	topic	The message topic
[in]	msg	The message info

int ltrx_mqtt_client_set_cleansession	(	struct ltrx_mqtt_client *	lmc,
		bool	cleansession
	)

Set cleansession flag for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	cleansession	cleansession flag.

int ltrx_mqtt_client_set_connect_info	(	struct ltrx_mqtt_client *	lmc,
		const struct ltrx_mqtt_client_connect_info *	lmcci
	)

Set connection info for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	lmcci	Connection info for MQTT session.

int ltrx_mqtt_client_set_keepalive_interval	(	struct ltrx_mqtt_client *	lmc,
		uint16_t	keepalive_interval_sec
	)

Set keepalive interval for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	keepalive_interval_sec	keepalive interval in seconds.

int ltrx_mqtt_client_set_log_verbosity	(	struct ltrx_mqtt_client *	lmc,
		uint8_t	verbosity
	)

Set logging level for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	verbosity	Requested verbosity.

int ltrx_mqtt_client_set_lwt	(	struct ltrx_mqtt_client *	lmc,
		const char *	topic,
		struct ltrx_mqtt_message *	msg
	)

Set Last Will and Testament for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	topic	The will message topic
[in]	msg	The will message info

int ltrx_mqtt_client_set_network_info	(	struct ltrx_mqtt_client *	lmc,
		struct ltrx_mqtt_client_network_info *	lmcni
	)

Set network info for a MQTT client instance.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	lmcni	Network connection info for MQTT session.

int ltrx_mqtt_client_subscribe	(	struct ltrx_mqtt_client *	lmc,
		const char *	topic_filter,
		int	max_qos,
		void(*)(struct ltrx_mqtt_message_data *)	callback
	)

Subscribe to message topic(s) from a MQTT broker.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	topic_filter	The message topic filter
[in]	max_qos	The max qos level at which the broker can send matching messages
[in]	callback	The message handler to call when a matching message is received

int ltrx_mqtt_client_unsubscribe	(	struct ltrx_mqtt_client *	lmc,
		const char *	topic_filter
	)

Unsubscribe from message topic(s) from a MQTT broker.

Return values

enum	ltrx_mqtt_client_return_code

Parameters

[in]	lmc	Pointer to a MQTT client instance
[in]	topic_filter	The message topic filter