ove::mqtt::Client Class Reference

RAII wrapper around an oveRTOS MQTT client handle. More...

#include <net_mqtt.hpp>

Public Types
using	MsgFn = void(*)(std::string_view topic, std::string_view payload)
	Stateless message callback type.

Public Member Functions
	Client ()
	Constructs and initialises the MQTT client.
	~Client () noexcept
	Destroys the MQTT client, releasing the underlying resource.
	Client (const Client &)=delete
Client &	operator= (const Client &)=delete
	Client (Client &&)=delete
Client &	operator= (Client &&)=delete
Result< void >	connect (const Config &cfg, MsgFn on_message=nullptr) noexcept
	Connects to an MQTT broker.
void	disconnect ()
	Disconnects from the MQTT broker.
Result< void >	publish (const char *topic, const void *payload, size_t len, Qos qos=Qos::AtMostOnce) noexcept
	Publishes a message (raw pointer + length).
Result< void >	publish (const char *topic, std::string_view payload, Qos qos=Qos::AtMostOnce) noexcept
	Publishes a message from a string_view.
Result< void >	subscribe (const char *topic, Qos qos=Qos::AtMostOnce) noexcept
	Subscribes to a topic.
Result< void >	unsubscribe (const char *topic) noexcept
	Unsubscribes from a topic.
Result< void >	loop (std::chrono::nanoseconds timeout=std::chrono::milliseconds{500}) noexcept
	Processes incoming packets and sends keep-alive pings.
bool	valid () const
	Returns true if the underlying client handle is non-null.
ove_mqtt_client_t	handle () const
	Returns the raw oveRTOS MQTT client handle.

Detailed Description

RAII wrapper around an oveRTOS MQTT client handle.

Constructs the underlying MQTT client on creation and destroys it on destruction. The message callback uses a static trampoline so that no heap-allocated closure is required; this makes the Client inherently per-instance and therefore non-movable even without CONFIG_OVE_ZERO_HEAP.

Note

Non-copyable and non-movable (static callback is per-instance).

Member Typedef Documentation

MsgFn

using ove::mqtt::Client::MsgFn = void (*)(std::string_view topic, std::string_view payload)

Stateless message callback type.

Must be a plain function pointer (or a stateless lambda convertible to one). Receives the topic and payload as std::string_view.

Constructor & Destructor Documentation

Client()

ove::mqtt::Client::Client ( )

inline

Constructs and initialises the MQTT client.

Calls ove_mqtt_client_init (zero-heap) or ove_mqtt_client_create (heap). Asserts at startup if initialisation fails.

~Client()

ove::mqtt::Client::~Client ( )

inlinenoexcept

Destroys the MQTT client, releasing the underlying resource.

If the handle is null the destructor is a no-op.

Member Function Documentation

connect()

Result< void > ove::mqtt::Client::connect ( const Config &  cfg, MsgFn  on_message = nullptr  )

inlinenoexcept

Connects to an MQTT broker.

Optionally registers a stateless message callback that is invoked for every incoming PUBLISH. The callback is stored in a static variable and dispatched via an internal trampoline.

Parameters

[in]	cfg	Connection configuration.
[in]	on_message	Message callback (nullptr to disable).

Returns

Empty Result<void> on success; unexpected Error on failure.

publish() [1/2]

Result< void > ove::mqtt::Client::publish ( const char *  topic, const void *  payload, size_t  len, Qos  qos = Qos::AtMostOnce  )

inlinenoexcept

Publishes a message (raw pointer + length).

Parameters

[in]	topic	Topic string (NUL-terminated).
[in]	payload	Message payload.
[in]	len	Payload length in bytes.
[in]	qos	QoS level (default: AtMostOnce).

Returns

Empty Result<void> on success; unexpected Error on failure.

publish() [2/2]

Result< void > ove::mqtt::Client::publish ( const char *  topic, std::string_view  payload, Qos  qos = Qos::AtMostOnce  )

inlinenoexcept

Publishes a message from a string_view.

Parameters

[in]	topic	Topic string (NUL-terminated).
[in]	payload	Message payload as a string_view.
[in]	qos	QoS level (default: AtMostOnce).

Returns

As publish(const char*, const void*, size_t, Qos).

subscribe()

Result< void > ove::mqtt::Client::subscribe ( const char *  topic, Qos  qos = Qos::AtMostOnce  )

inlinenoexcept

Subscribes to a topic.

Parameters

[in]	topic	Topic filter (NUL-terminated).
[in]	qos	Maximum QoS level (default: AtMostOnce).

Returns

Empty Result<void> on success; unexpected Error on failure.

unsubscribe()

Result< void > ove::mqtt::Client::unsubscribe ( const char *  topic )

inlinenoexcept

Unsubscribes from a topic.

Parameters

[in]

topic

Topic filter (NUL-terminated).

Returns

Empty Result<void> on success; unexpected Error on failure.

loop()

Result< void > ove::mqtt::Client::loop ( std::chrono::nanoseconds  timeout = std::chrono::milliseconds{500} )

inlinenoexcept

Processes incoming packets and sends keep-alive pings.

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

Parameters

[in]

timeout

Maximum time to wait for incoming data (any std::chrono::duration unit; defaults to 500 ms).

Returns

Empty Result<void> on success; unexpected Error on failure.

valid()

bool ove::mqtt::Client::valid ( ) const

inline

Returns true if the underlying client handle is non-null.

Returns

true when the client was successfully initialised.

handle()

ove_mqtt_client_t ove::mqtt::Client::handle ( ) const

inline

Returns the raw oveRTOS MQTT client handle.

Returns

The opaque ove_mqtt_client_t handle.

---

The documentation for this class was generated from the following file:

• bindings/cpp/ove/net_mqtt.hpp