MQTTComponent is the base class for all components that interact with MQTT to expose certain functionality or data from actuators or sensors to clients. More...

#include <mqtt_component.h>

Inheritance diagram for esphome::mqtt::MQTTComponent:

Public Member Functions
	MQTTComponent ()
	Constructs a MQTTComponent.

void	call_setup () override
	Override setup_ so that we can call send_discovery() when needed.

void	call_dump_config () override

virtual void	send_discovery (JsonObject root, SendDiscoveryConfig &config)=0
	Send discovery info the Home Assistant, override this.

virtual bool	send_initial_state ()=0

bool	is_internal () const
	Returns cached is_internal result (computed once during setup).

void	set_qos (uint8_t qos)
	Set QOS for state messages.

uint8_t	get_qos () const

void	set_retain (bool retain)
	Set whether state message should be retained.

bool	get_retain () const

void	disable_discovery ()
	Disable discovery. Sets friendly name to "".

bool	is_discovery_enabled () const

void	set_subscribe_qos (uint8_t qos)
	Set the QOS for subscribe messages (used in discovery).

virtual const char *	component_type () const =0
	Override this method to return the component type (e.g. "light", "sensor", ...)

template<typename T >
void	set_custom_state_topic (T &&custom_state_topic)
	Set a custom state topic. Do not set for default behavior.

template<typename T >
void	set_custom_command_topic (T &&custom_command_topic)

void	set_command_retain (bool command_retain)
	Set whether command message should be retained.

float	get_setup_priority () const override
	MQTT_COMPONENT setup priority.

void	set_availability (std::string topic, std::string payload_available, std::string payload_not_available)
	Set the Home Assistant availability data.

void	disable_availability ()

void	schedule_resend_state ()
	Internal method for the MQTT client base to schedule a resend of the state on reconnect.

void	process_resend ()
	Process pending resend if needed (called by MQTTClientComponent)

bool	publish (const std::string &topic, const std::string &payload)
	Send a MQTT message.

bool	publish (const std::string &topic, const char *payload, size_t payload_length)
	Send a MQTT message.

bool	publish (const std::string &topic, const char *payload)
	Send a MQTT message.

bool	publish (const char topic, const char payload, size_t payload_length)
	Send a MQTT message (no heap allocation for topic).

bool	publish (StringRef topic, const char *payload, size_t payload_length)
	Send a MQTT message (no heap allocation for topic).

bool	publish (const char topic, const char payload)
	Send a MQTT message (no heap allocation for topic).

bool	publish (StringRef topic, const char *payload)
	Send a MQTT message (no heap allocation for topic).

bool	publish (const std::string &topic, ProgmemStr payload)
	Send a MQTT message with a PROGMEM string payload.

bool	publish (const char *topic, ProgmemStr payload)
	Send a MQTT message with a PROGMEM string payload (no heap allocation for topic).

bool	publish (StringRef topic, ProgmemStr payload)
	Send a MQTT message with a PROGMEM string payload (no heap allocation for topic).

bool	publish_json (const std::string &topic, const json::json_build_t &f)
	Construct and send a JSON MQTT message.

bool	publish_json (const char *topic, const json::json_build_t &f)
	Construct and send a JSON MQTT message (no heap allocation for topic).

bool	publish_json (StringRef topic, const json::json_build_t &f)
	Construct and send a JSON MQTT message (no heap allocation for topic).

void	subscribe (const std::string &topic, mqtt_callback_t callback, uint8_t qos=0)
	Subscribe to a MQTT topic.

void	subscribe_json (const std::string &topic, const mqtt_json_callback_t &callback, uint8_t qos=0)
	Subscribe to a MQTT topic and automatically parse JSON payload.

Public Member Functions inherited from esphome::Component
virtual void	setup ()
	Where the component's initialization should happen.

virtual void	loop ()
	This method will be called repeatedly.

virtual void	dump_config ()

float	get_actual_setup_priority () const

void	set_setup_priority (float priority)

virtual float	get_loop_priority () const
	priority of loop().

void	call ()

virtual void	on_shutdown ()

virtual void	on_safe_shutdown ()

virtual bool	teardown ()
	Called during teardown to allow component to gracefully finish operations.

virtual void	on_powerdown ()
	Called after teardown is complete to power down hardware.

uint8_t	get_component_state () const

void	reset_to_construction_state ()
	Reset this component back to the construction state to allow setup to run again.

bool	is_in_loop_state () const
	Check if this component has completed setup and is in the loop state.

bool	is_idle () const
	Check if this component is idle.

virtual void	mark_failed ()
	Mark this component as failed.

	ESPDEPRECATED ("Use mark_failed(LOG_STR(\"static string literal\")) instead. Do NOT use .c_str() from temporary " "strings. Will stop working in 2026.6.0", "2025.12.0") void mark_failed(const char *message)

void	mark_failed (const LogString *message)

void	disable_loop ()
	Disable this component's loop.

void	enable_loop ()
	Enable this component's loop.

void	enable_loop_soon_any_context ()
	Thread and ISR-safe version of enable_loop() that can be called from any context.

bool	is_failed () const

bool	is_ready () const

virtual bool	can_proceed ()

bool	status_has_warning () const

bool	status_has_error () const

void	status_set_warning (const char *message=nullptr)

void	status_set_warning (const LogString *message)

void	status_set_error ()

	ESPDEPRECATED ("Use status_set_error(LOG_STR(\"static string literal\")) instead. Do NOT use .c_str() from temporary " "strings. Will stop working in 2026.6.0", "2025.12.0") void status_set_error(const char *message)

void	status_set_error (const LogString *message)

void	status_clear_warning ()

void	status_clear_error ()

void	status_momentary_warning (const char *name, uint32_t length=5000)
	Set warning status flag and automatically clear it after a timeout.

void	status_momentary_error (const char *name, uint32_t length=5000)
	Set error status flag and automatically clear it after a timeout.

bool	has_overridden_loop () const

void	set_component_source (const LogString *source)
	Set where this component was loaded from for some debug messages.

const LogString *	get_component_log_str () const
	Get the integration where this component was declared as a LogString for logging.

bool	should_warn_of_blocking (uint32_t blocking_time)

Protected Member Functions
StringRef	get_discovery_topic_to_ (std::span< char, MQTT_DISCOVERY_TOPIC_MAX_LEN > buf, const MQTTDiscoveryInfo &discovery_info) const
	Helper method to get the discovery topic for this component into a buffer.

StringRef	get_default_topic_for_to_ (std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN > buf, const char *suffix, size_t suffix_len) const
	Get this components state/command/... topic into a buffer.

std::string	get_default_topic_for_ (const std::string &suffix) const
	Get this components state/command/... topic (allocates std::string).

virtual const EntityBase *	get_entity () const =0
	Gets the Entity served by this MQTT component.

const StringRef &	friendly_name_ () const
	Get the friendly name of this MQTT component.

StringRef	get_icon_ref_ () const
	Get the icon field of this component as StringRef.

bool	is_disabled_by_default_ () const
	Get whether the underlying Entity is disabled by default.

StringRef	get_state_topic_to_ (std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN > buf) const
	Get the MQTT state topic into a buffer (no heap allocation for non-lambda custom topics).

StringRef	get_command_topic_to_ (std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN > buf) const
	Get the MQTT command topic into a buffer (no heap allocation for non-lambda custom topics).

std::string	get_state_topic_ () const
	Get the MQTT topic that new states will be shared to (allocates std::string).

std::string	get_command_topic_ () const
	Get the MQTT topic for listening to commands (allocates std::string).

bool	is_connected_ () const

bool	send_discovery_ ()
	Internal method to start sending discovery info, this will call send_discovery().

StringRef	get_default_object_id_to_ (std::span< char, OBJECT_ID_MAX_LEN > buf) const
	Get the object ID for this MQTT component, writing to the provided buffer.

bool	compute_is_internal_ ()
	Compute is_internal status based on topics and entity state.

Protected Member Functions inherited from esphome::Component
virtual void	call_loop ()

void	set_component_state_ (uint8_t state)
	Helper to set component state (clears state bits and sets new state)

void	set_interval (uint32_t id, uint32_t interval, std::function< void()> &&f)
	Set an interval function with a numeric ID (zero heap allocation).

void	set_interval (InternalSchedulerID id, uint32_t interval, std::function< void()> &&f)

void	set_interval (uint32_t interval, std::function< void()> &&f)

bool	cancel_interval (uint32_t id)

bool	cancel_interval (InternalSchedulerID id)

ESPDEPRECATED("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const std	ESPDEPRECATED ("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const char *name

	ESPDEPRECATED ("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(uint32_t id

	ESPDEPRECATED ("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(uint32_t initial_wait_time

ESPDEPRECATED("cancel_retry is deprecated and will be removed in 2026.8.0.", "2026.2.0") bool cancel_retry(const std	ESPDEPRECATED ("cancel_retry is deprecated and will be removed in 2026.8.0.", "2026.2.0") bool cancel_retry(const char *name)

	ESPDEPRECATED ("cancel_retry is deprecated and will be removed in 2026.8.0.", "2026.2.0") bool cancel_retry(uint32_t id)

void	set_timeout (uint32_t id, uint32_t timeout, std::function< void()> &&f)
	Set a timeout function with a numeric ID (zero heap allocation).

void	set_timeout (InternalSchedulerID id, uint32_t timeout, std::function< void()> &&f)

void	set_timeout (uint32_t timeout, std::function< void()> &&f)

bool	cancel_timeout (uint32_t id)

bool	cancel_timeout (InternalSchedulerID id)

void	defer (std::function< void()> &&f)
	Defer a callback to the next loop() call.

void	defer (uint32_t id, std::function< void()> &&f)
	Defer a callback with a numeric ID (zero heap allocation)

bool	cancel_defer (uint32_t id)

Protected Attributes
TemplatableValue< std::string >	custom_state_topic_ {}

TemplatableValue< std::string >	custom_command_topic_ {}

std::unique_ptr< Availability >	availability_

uint8_t	qos_: 2 {0}

uint8_t	subscribe_qos_: 2 {0}

bool	command_retain_: 1 {false}

bool	retain_: 1 {true}

bool	discovery_enabled_: 1 {true}

bool	resend_state_: 1 {false}

bool	is_internal_: 1 {false}
	Cached result of compute_is_internal_(), set during setup.

Protected Attributes inherited from esphome::Component
ESPDEPRECATED("Use const char* or uint32_t overload instead. Removed in 2026.7.0", "2026.1.0") void set_interval(const std voi	set_interval )(const char *name, uint32_t interval, std::function< void()> &&f)
	Set an interval function with a unique name.

ESPDEPRECATED("Use const char* or uint32_t overload instead. Removed in 2026.7.0", "2026.1.0") bool cancel_interval(const std boo	cancel_interval )(const char *name)
	Cancel an interval function.

ESPDEPRECATED("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const std uint32_t	initial_wait_time

ESPDEPRECATED("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const std uint32_t uint8_t	max_attempts

ESPDEPRECATED("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const std uint32_t uint8_t std::function< RetryResult(uint8_t)> &&	f

ESPDEPRECATED("set_retry is deprecated and will be removed in 2026.8.0. Use set_timeout or set_interval instead.", "2026.2.0") void set_retry(const std uint32_t uint8_t std::function< RetryResult(uint8_t)> float	backoff_increase_factor = 1.0f)

uint32_t	initial_wait_time

uint32_t uint8_t	max_attempts

uint32_t uint8_t std::function< RetryResult(uint8_t)> &&	f

uint32_t uint8_t std::function< RetryResult(uint8_t)> float	backoff_increase_factor = 1.0f)

uint8_t	max_attempts

uint8_t std::function< RetryResult(uint8_t)> &&	f

uint8_t std::function< RetryResult(uint8_t)> float	backoff_increase_factor = 1.0f)

ESPDEPRECATED("Use const char* or uint32_t overload instead. Removed in 2026.7.0", "2026.1.0") void set_timeout(const std voi	set_timeout )(const char *name, uint32_t timeout, std::function< void()> &&f)
	Set a timeout function with a unique name.

ESPDEPRECATED("Use const char* or uint32_t overload instead. Removed in 2026.7.0", "2026.1.0") bool cancel_timeout(const std boo	cancel_timeout )(const char *name)
	Cancel a timeout function.

ESPDEPRECATED("Use const char* overload instead. Removed in 2026.7.0", "2026.1.0") void defer(const std voi	defer )(const char *name, std::function< void()> &&f)
	Defer a callback to the next loop() call.

ESPDEPRECATED("Use const char* overload instead. Removed in 2026.7.0", "2026.1.0") bool cancel_defer(const std boo	cancel_defer )(const char *name)
	Cancel a defer callback using the specified name, name must not be empty.

const LogString *	component_source_ {nullptr}

uint16_t	warn_if_blocking_over_ {WARN_IF_BLOCKING_OVER_MS}
	Warn if blocked for this many ms (max 65.5s)

uint8_t	component_state_ {0x00}
	State of this component - each bit has a purpose: Bits 0-2: Component state (0x00=CONSTRUCTION, 0x01=SETUP, 0x02=LOOP, 0x03=FAILED, 0x04=LOOP_DONE) Bit 3: STATUS_LED_WARNING Bit 4: STATUS_LED_ERROR Bits 5-7: Unused - reserved for future expansion.

volatile bool	pending_enable_loop_ {false}
	ISR-safe flag for enable_loop_soon_any_context.

Detailed Description

MQTTComponent is the base class for all components that interact with MQTT to expose certain functionality or data from actuators or sensors to clients.

Although this class should work with all MQTT solutions, it has been specifically designed for use with Home Assistant. For example, this class supports Home Assistant MQTT discovery out of the box.

In order to implement automatic Home Assistant discovery, all sub-classes should:

Implement send_discovery that creates a Home Assistant discovery payload.
Override component_type() to return the appropriate component type such as "light" or "sensor".
Subscribe to command topics using subscribe() or subscribe_json() during setup().

In order to best separate the front- and back-end of ESPHome, all sub-classes should only parse/send MQTT messages and interact with back-end components via callbacks to ensure a clean separation.

Definition at line 91 of file mqtt_component.h.

Constructor & Destructor Documentation

◆ MQTTComponent()

esphome::mqtt::MQTTComponent::MQTTComponent ( )

explicitdefault

Constructs a MQTTComponent.

Member Function Documentation

◆ call_dump_config()

void esphome::mqtt::MQTTComponent::call_dump_config ( )

overridevirtual

Reimplemented from esphome::Component.

Definition at line 408 of file mqtt_component.cpp.

◆ call_setup()

void esphome::mqtt::MQTTComponent::call_setup ( )

overridevirtual

Override setup_ so that we can call send_discovery() when needed.

Reimplemented from esphome::Component.

Definition at line 369 of file mqtt_component.cpp.

◆ component_type()

virtual const char * esphome::mqtt::MQTTComponent::component_type ( ) const

pure virtual

Override this method to return the component type (e.g. "light", "sensor", ...)

◆ compute_is_internal_()

bool esphome::mqtt::MQTTComponent::compute_is_internal_ ( )

protected

Compute is_internal status based on topics and entity state.

Called once during setup to cache the result.

Definition at line 424 of file mqtt_component.cpp.

◆ disable_availability()

void esphome::mqtt::MQTTComponent::disable_availability ( )

Definition at line 368 of file mqtt_component.cpp.

◆ disable_discovery()

void esphome::mqtt::MQTTComponent::disable_discovery ( )

Disable discovery. Sets friendly name to "".

Definition at line 358 of file mqtt_component.cpp.

◆ friendly_name_()

const StringRef & esphome::mqtt::MQTTComponent::friendly_name_ ( ) const

protected

Get the friendly name of this MQTT component.

Definition at line 418 of file mqtt_component.cpp.

◆ get_command_topic_()

std::string esphome::mqtt::MQTTComponent::get_command_topic_ ( ) const

protected

Get the MQTT topic for listening to commands (allocates std::string).

Definition at line 130 of file mqtt_component.cpp.

◆ get_command_topic_to_()

StringRef esphome::mqtt::MQTTComponent::get_command_topic_to_ ( std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN > buf ) const

protected

Get the MQTT command topic into a buffer (no heap allocation for non-lambda custom topics).

Parameters

buf	Buffer of exactly MQTT_DEFAULT_TOPIC_MAX_LEN bytes.

Returns: StringRef pointing to the topic in the buffer.

Definition at line 116 of file mqtt_component.cpp.

◆ get_default_object_id_to_()

StringRef esphome::mqtt::MQTTComponent::get_default_object_id_to_ ( std::span< char, OBJECT_ID_MAX_LEN > buf ) const

protected

Get the object ID for this MQTT component, writing to the provided buffer.

Definition at line 419 of file mqtt_component.cpp.

◆ get_default_topic_for_()

std::string esphome::mqtt::MQTTComponent::get_default_topic_for_ ( const std::string & suffix ) const

protected

Get this components state/command/... topic (allocates std::string).

Parameters

suffix The suffix/key such as "state" or "command".

Returns: The full topic.

Definition at line 102 of file mqtt_component.cpp.

◆ get_default_topic_for_to_()

StringRef esphome::mqtt::MQTTComponent::get_default_topic_for_to_	(	std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN >	buf,
		const char *	suffix,
		size_t	suffix_len ) const

protected

Get this components state/command/... topic into a buffer.

Parameters

buf	The buffer to write to (must be exactly MQTT_DEFAULT_TOPIC_MAX_LEN).
suffix	The suffix/key such as "state" or "command".

Returns: StringRef pointing to the buffer with the topic.

Definition at line 77 of file mqtt_component.cpp.

◆ get_discovery_topic_to_()

StringRef esphome::mqtt::MQTTComponent::get_discovery_topic_to_	(	std::span< char, MQTT_DISCOVERY_TOPIC_MAX_LEN >	buf,
		const MQTTDiscoveryInfo &	discovery_info ) const

protected

Helper method to get the discovery topic for this component into a buffer.

Definition at line 54 of file mqtt_component.cpp.

◆ get_entity()

virtual const EntityBase * esphome::mqtt::MQTTComponent::get_entity ( ) const

protectedpure virtual

Gets the Entity served by this MQTT component.

◆ get_icon_ref_()

StringRef esphome::mqtt::MQTTComponent::get_icon_ref_ ( ) const

protected

Get the icon field of this component as StringRef.

Definition at line 422 of file mqtt_component.cpp.

◆ get_qos()

uint8_t esphome::mqtt::MQTTComponent::get_qos ( ) const

Definition at line 339 of file mqtt_component.cpp.

◆ get_retain()

bool esphome::mqtt::MQTTComponent::get_retain ( ) const

Definition at line 341 of file mqtt_component.cpp.

◆ get_setup_priority()

float esphome::mqtt::MQTTComponent::get_setup_priority ( ) const

overridevirtual

MQTT_COMPONENT setup priority.

Reimplemented from esphome::Component.

Definition at line 357 of file mqtt_component.cpp.

◆ get_state_topic_()

std::string esphome::mqtt::MQTTComponent::get_state_topic_ ( ) const

protected

Get the MQTT topic that new states will be shared to (allocates std::string).

Definition at line 124 of file mqtt_component.cpp.

◆ get_state_topic_to_()

StringRef esphome::mqtt::MQTTComponent::get_state_topic_to_ ( std::span< char, MQTT_DEFAULT_TOPIC_MAX_LEN > buf ) const

protected

Get the MQTT state topic into a buffer (no heap allocation for non-lambda custom topics).

Parameters

buf	Buffer of exactly MQTT_DEFAULT_TOPIC_MAX_LEN bytes.

Returns: StringRef pointing to the topic in the buffer.

Definition at line 108 of file mqtt_component.cpp.

◆ is_connected_()

bool esphome::mqtt::MQTTComponent::is_connected_ ( ) const

protected

Definition at line 415 of file mqtt_component.cpp.

◆ is_disabled_by_default_()

bool esphome::mqtt::MQTTComponent::is_disabled_by_default_ ( ) const

protected

Get whether the underlying Entity is disabled by default.

Definition at line 423 of file mqtt_component.cpp.

◆ is_discovery_enabled()

bool esphome::mqtt::MQTTComponent::is_discovery_enabled ( ) const

Definition at line 343 of file mqtt_component.cpp.

◆ is_internal()

bool esphome::mqtt::MQTTComponent::is_internal ( ) const

inline

Returns cached is_internal result (computed once during setup).

Definition at line 109 of file mqtt_component.h.

◆ process_resend()

void esphome::mqtt::MQTTComponent::process_resend ( )

Process pending resend if needed (called by MQTTClientComponent)

Definition at line 392 of file mqtt_component.cpp.

◆ publish() [1/10]

bool esphome::mqtt::MQTTComponent::publish	(	const char *	topic,
		const char *	payload )

Send a MQTT message (no heap allocation for topic).

Parameters

topic	The topic as C string.
payload	The null-terminated payload.

Definition at line 150 of file mqtt_component.cpp.

◆ publish() [2/10]

bool esphome::mqtt::MQTTComponent::publish	(	const char *	topic,
		const char *	payload,
		size_t	payload_length )

Send a MQTT message (no heap allocation for topic).

Parameters

topic	The topic as C string.
payload	The payload buffer.
payload_length	The length of the payload.

Definition at line 144 of file mqtt_component.cpp.

◆ publish() [3/10]

bool esphome::mqtt::MQTTComponent::publish	(	const char *	topic,
		ProgmemStr	payload )

Send a MQTT message with a PROGMEM string payload (no heap allocation for topic).

Parameters

topic	The topic as C string.
payload	The payload (ProgmemStr - stored in flash on ESP8266).

Definition at line 159 of file mqtt_component.cpp.

◆ publish() [4/10]

bool esphome::mqtt::MQTTComponent::publish	(	const std::string &	topic,
		const char *	payload )

inline

Send a MQTT message.

Parameters

topic	The topic.
payload	The null-terminated payload.

Definition at line 175 of file mqtt_component.h.

◆ publish() [5/10]

bool esphome::mqtt::MQTTComponent::publish	(	const std::string &	topic,
		const char *	payload,
		size_t	payload_length )

Send a MQTT message.

Parameters

topic	The topic.
payload	The payload buffer.
payload_length	The length of the payload.

Definition at line 140 of file mqtt_component.cpp.

◆ publish() [6/10]

bool esphome::mqtt::MQTTComponent::publish	(	const std::string &	topic,
		const std::string &	payload )

Send a MQTT message.

Parameters

topic	The topic.
payload	The payload.

Definition at line 136 of file mqtt_component.cpp.

◆ publish() [7/10]

bool esphome::mqtt::MQTTComponent::publish	(	const std::string &	topic,
		ProgmemStr	payload )

Send a MQTT message with a PROGMEM string payload.

Parameters

topic	The topic.
payload	The payload (ProgmemStr - stored in flash on ESP8266).

Definition at line 155 of file mqtt_component.cpp.

◆ publish() [8/10]

bool esphome::mqtt::MQTTComponent::publish	(	StringRef	topic,
		const char *	payload )

inline

Send a MQTT message (no heap allocation for topic).

Parameters

topic	The topic as StringRef (for use with get_state_topic_to_()).
payload	The null-terminated payload.

Definition at line 209 of file mqtt_component.h.

◆ publish() [9/10]

bool esphome::mqtt::MQTTComponent::publish	(	StringRef	topic,
		const char *	payload,
		size_t	payload_length )

inline

Send a MQTT message (no heap allocation for topic).

Parameters

topic	The topic as StringRef (for use with get_state_topic_to_()).
payload	The payload buffer.
payload_length	The length of the payload.

Definition at line 193 of file mqtt_component.h.

◆ publish() [10/10]

bool esphome::mqtt::MQTTComponent::publish	(	StringRef	topic,
		ProgmemStr	payload )

inline

Send a MQTT message with a PROGMEM string payload (no heap allocation for topic).

Parameters

topic	The topic as StringRef (for use with get_state_topic_to_()).
payload	The payload (ProgmemStr - stored in flash on ESP8266).

Definition at line 231 of file mqtt_component.h.

◆ publish_json() [1/3]

bool esphome::mqtt::MQTTComponent::publish_json	(	const char *	topic,
		const json::json_build_t &	f )

Construct and send a JSON MQTT message (no heap allocation for topic).

Parameters

topic	The topic as C string.
f	The Json Message builder.

Definition at line 174 of file mqtt_component.cpp.

◆ publish_json() [2/3]

bool esphome::mqtt::MQTTComponent::publish_json	(	const std::string &	topic,
		const json::json_build_t &	f )

Construct and send a JSON MQTT message.

Parameters

topic	The topic.
f	The Json Message builder.

Definition at line 170 of file mqtt_component.cpp.

◆ publish_json() [3/3]

bool esphome::mqtt::MQTTComponent::publish_json	(	StringRef	topic,
		const json::json_build_t &	f )

inline

Construct and send a JSON MQTT message (no heap allocation for topic).

Parameters

topic	The topic as StringRef (for use with get_state_topic_to_()).
f	The Json Message builder.

Definition at line 253 of file mqtt_component.h.

◆ schedule_resend_state()

void esphome::mqtt::MQTTComponent::schedule_resend_state ( )

Internal method for the MQTT client base to schedule a resend of the state on reconnect.

Definition at line 414 of file mqtt_component.cpp.

◆ send_discovery()

virtual void esphome::mqtt::MQTTComponent::send_discovery	(	JsonObject	root,
		SendDiscoveryConfig &	config )

pure virtual

Send discovery info the Home Assistant, override this.

◆ send_discovery_()

bool esphome::mqtt::MQTTComponent::send_discovery_ ( )

protected

Internal method to start sending discovery info, this will call send_discovery().

Definition at line 180 of file mqtt_component.cpp.

◆ send_initial_state()

virtual bool esphome::mqtt::MQTTComponent::send_initial_state ( )

pure virtual

◆ set_availability()

void esphome::mqtt::MQTTComponent::set_availability	(	std::string	topic,
		std::string	payload_available,
		std::string	payload_not_available )

Set the Home Assistant availability data.

See See Home Assistant for more info.

Definition at line 361 of file mqtt_component.cpp.

◆ set_command_retain()

void esphome::mqtt::MQTTComponent::set_command_retain ( bool command_retain )

Set whether command message should be retained.

Definition at line 359 of file mqtt_component.cpp.

◆ set_custom_command_topic()

template<typename T >

void esphome::mqtt::MQTTComponent::set_custom_command_topic ( T && custom_command_topic )

inline

Definition at line 133 of file mqtt_component.h.

◆ set_custom_state_topic()

template<typename T >

void esphome::mqtt::MQTTComponent::set_custom_state_topic ( T && custom_state_topic )

inline

Set a custom state topic. Do not set for default behavior.

Definition at line 130 of file mqtt_component.h.

◆ set_qos()

void esphome::mqtt::MQTTComponent::set_qos ( uint8_t qos )

Set QOS for state messages.

Definition at line 48 of file mqtt_component.cpp.

◆ set_retain()

void esphome::mqtt::MQTTComponent::set_retain ( bool retain )

Set whether state message should be retained.

Definition at line 52 of file mqtt_component.cpp.

◆ set_subscribe_qos()

void esphome::mqtt::MQTTComponent::set_subscribe_qos ( uint8_t qos )

Set the QOS for subscribe messages (used in discovery).

Definition at line 50 of file mqtt_component.cpp.

◆ subscribe()

void esphome::mqtt::MQTTComponent::subscribe	(	const std::string &	topic,
		mqtt_callback_t	callback,
		uint8_t	qos = 0 )

Subscribe to a MQTT topic.

Parameters

topic	The topic. Wildcards are currently not supported.
callback	The callback that will be called when a message with matching topic is received.
qos	The MQTT quality of service. Defaults to 0.

Definition at line 347 of file mqtt_component.cpp.

◆ subscribe_json()

void esphome::mqtt::MQTTComponent::subscribe_json	(	const std::string &	topic,
		const mqtt_json_callback_t &	callback,
		uint8_t	qos = 0 )

Subscribe to a MQTT topic and automatically parse JSON payload.

If an invalid JSON payload is received, the callback will not be called.

Parameters

topic	The topic. Wildcards are currently not supported.
callback	The callback with a parsed JsonObject that will be called when a message with matching topic is received.
qos	The MQTT quality of service. Defaults to 0.

Definition at line 351 of file mqtt_component.cpp.

Field Documentation

◆ availability_

std::unique_ptr<Availability> esphome::mqtt::MQTTComponent::availability_

protected

Definition at line 338 of file mqtt_component.h.

◆ command_retain_

bool esphome::mqtt::MQTTComponent::command_retain_

protected

Definition at line 343 of file mqtt_component.h.

◆ custom_command_topic_

TemplatableValue<std::string> esphome::mqtt::MQTTComponent::custom_command_topic_ {}

protected

Definition at line 336 of file mqtt_component.h.

◆ custom_state_topic_

TemplatableValue<std::string> esphome::mqtt::MQTTComponent::custom_state_topic_ {}

protected

Definition at line 335 of file mqtt_component.h.

◆ discovery_enabled_

bool esphome::mqtt::MQTTComponent::discovery_enabled_

protected

Definition at line 345 of file mqtt_component.h.

◆ is_internal_

bool esphome::mqtt::MQTTComponent::is_internal_

protected

Cached result of compute_is_internal_(), set during setup.

Definition at line 347 of file mqtt_component.h.

◆ qos_

uint8_t esphome::mqtt::MQTTComponent::qos_

protected

Definition at line 341 of file mqtt_component.h.

◆ resend_state_

bool esphome::mqtt::MQTTComponent::resend_state_

protected

Definition at line 346 of file mqtt_component.h.

◆ retain_

bool esphome::mqtt::MQTTComponent::retain_

protected

Definition at line 344 of file mqtt_component.h.

◆ subscribe_qos_

uint8_t esphome::mqtt::MQTTComponent::subscribe_qos_

protected

Definition at line 342 of file mqtt_component.h.

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

esphome/components/mqtt/mqtt_component.h
esphome/components/mqtt/mqtt_component.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MQTTComponent()

Member Function Documentation

◆ call_dump_config()

◆ call_setup()

◆ component_type()

◆ compute_is_internal_()

◆ disable_availability()

◆ disable_discovery()

◆ friendly_name_()

◆ get_command_topic_()

◆ get_command_topic_to_()

◆ get_default_object_id_to_()

◆ get_default_topic_for_()

◆ get_default_topic_for_to_()

◆ get_discovery_topic_to_()

◆ get_entity()

◆ get_icon_ref_()

◆ get_qos()

◆ get_retain()

◆ get_setup_priority()

◆ get_state_topic_()

◆ get_state_topic_to_()

◆ is_connected_()

◆ is_disabled_by_default_()

◆ is_discovery_enabled()

◆ is_internal()

◆ process_resend()

◆ publish() [1/10]

◆ publish() [2/10]

◆ publish() [3/10]

◆ publish() [4/10]

◆ publish() [5/10]

◆ publish() [6/10]

◆ publish() [7/10]

◆ publish() [8/10]

◆ publish() [9/10]

◆ publish() [10/10]

◆ publish_json() [1/3]

◆ publish_json() [2/3]

◆ publish_json() [3/3]

◆ schedule_resend_state()

◆ send_discovery()

◆ send_discovery_()

◆ send_initial_state()

◆ set_availability()

◆ set_command_retain()

◆ set_custom_command_topic()

◆ set_custom_state_topic()

◆ set_qos()

◆ set_retain()

◆ set_subscribe_qos()

◆ subscribe()

◆ subscribe_json()

Field Documentation

◆ availability_

◆ command_retain_

◆ custom_command_topic_

◆ custom_state_topic_

◆ discovery_enabled_

◆ is_internal_

◆ qos_

◆ resend_state_

◆ retain_

◆ subscribe_qos_