MQTT Client

Lightweight MQTT 3.1.1 client for IoT pub/sub messaging. More...

Data Structures
struct	ove_mqtt_config_t
	MQTT connection configuration. More...

Macros
#define	OVE_MQTT_QOS0   ((ove_mqtt_qos_t)0)
#define	OVE_MQTT_QOS1   ((ove_mqtt_qos_t)1)

Typedefs
typedef uint8_t	ove_mqtt_qos_t
	MQTT QoS level.
typedef void(*	ove_mqtt_msg_cb) (const char *topic, size_t topic_len, const void *payload, size_t payload_len, void *user_data)
	MQTT message callback.

Functions
int	ove_mqtt_client_init (ove_mqtt_client_t *client, ove_mqtt_client_storage_t *storage)
	Initialise an MQTT client from caller-supplied storage.
void	ove_mqtt_client_deinit (ove_mqtt_client_t client)
	De-initialise an MQTT client.
int	ove_mqtt_connect (ove_mqtt_client_t client, const ove_mqtt_config_t *cfg)
	Connect to an MQTT broker.
void	ove_mqtt_disconnect (ove_mqtt_client_t client)
	Disconnect from the MQTT broker.
int	ove_mqtt_publish (ove_mqtt_client_t client, const char *topic, const void *payload, size_t payload_len, ove_mqtt_qos_t qos)
	Publish a message.
int	ove_mqtt_subscribe (ove_mqtt_client_t client, const char *topic, ove_mqtt_qos_t qos)
	Subscribe to a topic.
int	ove_mqtt_unsubscribe (ove_mqtt_client_t client, const char *topic)
	Unsubscribe from a topic.
int	ove_mqtt_loop (ove_mqtt_client_t client, uint64_t timeout_ns)
	Process incoming packets and send keep-alive pings.
int	ove_mqtt_client_create (ove_mqtt_client_t *client)
	Heap-allocate and initialise an MQTT client.
void	ove_mqtt_client_destroy (ove_mqtt_client_t client)
	Destroy a heap-allocated MQTT client.

Detailed Description

Lightweight MQTT 3.1.1 client for IoT pub/sub messaging.

Supports CONNECT, PUBLISH (QoS 0/1), SUBSCRIBE, keep-alive, and optional TLS. Uses the oveRTOS socket layer for transport.

Note

Requires CONFIG_OVE_NET_MQTT (implies CONFIG_OVE_NET). When disabled every function is replaced by a no-op stub.

Macro Definition Documentation

OVE_MQTT_QOS0

#define OVE_MQTT_QOS0   ((ove_mqtt_qos_t)0)

At most once.

OVE_MQTT_QOS1

#define OVE_MQTT_QOS1   ((ove_mqtt_qos_t)1)

At least once.

Typedef Documentation

ove_mqtt_msg_cb

typedef void(* ove_mqtt_msg_cb) (const char *topic, size_t topic_len, const void *payload, size_t payload_len, void *user_data)

MQTT message callback.

Parameters

[in]	topic	Topic string (not NUL-terminated).
[in]	topic_len	Topic length in bytes.
[in]	payload	Message payload.
[in]	payload_len	Payload length in bytes.
[in]	user_data	Opaque pointer supplied at connect time.

Function Documentation

ove_mqtt_client_init()

int ove_mqtt_client_init	(	ove_mqtt_client_t *	client,
		ove_mqtt_client_storage_t *	storage
	)

Initialise an MQTT client from caller-supplied storage.

Parameters

[out]	client	Handle written on success.
[in]	storage	Caller-allocated storage.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_client_deinit()

void ove_mqtt_client_deinit

(

ove_mqtt_client_t

client

)

De-initialise an MQTT client.

Parameters

[in]

client

Handle returned by ove_mqtt_client_init().

ove_mqtt_connect()

int ove_mqtt_connect	(	ove_mqtt_client_t	client,
		const ove_mqtt_config_t *	cfg
	)

Connect to an MQTT broker.

Parameters

[in]	client	MQTT client handle.
[in]	cfg	Connection configuration.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_disconnect()

void ove_mqtt_disconnect

(

ove_mqtt_client_t

client

)

Disconnect from the MQTT broker.

Parameters

[in]

client

MQTT client handle.

ove_mqtt_publish()

int ove_mqtt_publish	(	ove_mqtt_client_t	client,
		const char *	topic,
		const void *	payload,
		size_t	payload_len,
		ove_mqtt_qos_t	qos
	)

Publish a message.

Parameters

[in]	client	MQTT client handle.
[in]	topic	Topic string (NUL-terminated).
[in]	payload	Message payload.
[in]	payload_len	Payload length in bytes.
[in]	qos	QoS level.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_subscribe()

int ove_mqtt_subscribe	(	ove_mqtt_client_t	client,
		const char *	topic,
		ove_mqtt_qos_t	qos
	)

Subscribe to a topic.

Parameters

[in]	client	MQTT client handle.
[in]	topic	Topic filter (NUL-terminated).
[in]	qos	Maximum QoS level.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_unsubscribe()

int ove_mqtt_unsubscribe	(	ove_mqtt_client_t	client,
		const char *	topic
	)

Unsubscribe from a topic.

Parameters

[in]	client	MQTT client handle.
[in]	topic	Topic filter (NUL-terminated).

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_loop()

int ove_mqtt_loop	(	ove_mqtt_client_t	client,
		uint64_t	timeout_ns
	)

Process incoming packets and send keep-alive pings.

Must be called periodically (typically in a loop or timer).

Parameters

[in]	client	MQTT client handle.
[in]	timeout_ns	Maximum time to wait for incoming data.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_client_create()

int ove_mqtt_client_create

(

ove_mqtt_client_t *

client

)

Heap-allocate and initialise an MQTT client.

Parameters

[out]

client

Handle written on success.

Returns

OVE_OK on success, negative error code on failure.

ove_mqtt_client_destroy()

void ove_mqtt_client_destroy

(

ove_mqtt_client_t

client

)

Destroy a heap-allocated MQTT client.

Parameters

[in]

client

Handle returned by ove_mqtt_client_create().