ESPHome  2021.9.1
Public Member Functions
esphome::mqtt::CustomMQTTDevice Class Reference

This class is a helper class for custom components that communicate using MQTT. More...

#include <custom_mqtt_device.h>

Public Member Functions

template<typename T >
void subscribe (const std::string &topic, void(T::*callback)(const std::string &, const std::string &), uint8_t qos=0)
 Subscribe to an MQTT topic with the given Quality of Service. More...
 
template<typename T >
void subscribe (const std::string &topic, void(T::*callback)(const std::string &), uint8_t qos=0)
 
template<typename T >
void subscribe (const std::string &topic, void(T::*callback)(), uint8_t qos=0)
 
template<typename T >
void subscribe_json (const std::string &topic, void(T::*callback)(const std::string &, JsonObject &), uint8_t qos=0)
 Subscribe to an MQTT topic and call the callback if the payload can be decoded as JSON with the given Quality of Service. More...
 
template<typename T >
void subscribe_json (const std::string &topic, void(T::*callback)(JsonObject &), uint8_t qos=0)
 
bool publish (const std::string &topic, const std::string &payload, uint8_t qos=0, bool retain=false)
 Publish an MQTT message with the given payload and QoS and retain settings. More...
 
bool publish (const std::string &topic, float value, int8_t number_decimals=3)
 Publish an MQTT message with the given floating point number and number of decimals. More...
 
bool publish (const std::string &topic, int value)
 Publish an MQTT message with the given integer as payload. More...
 
bool publish_json (const std::string &topic, const json::json_build_t &f, uint8_t qos, bool retain)
 Publish a JSON-encoded MQTT message with the given Quality of Service and retain settings. More...
 
bool publish_json (const std::string &topic, const json::json_build_t &f)
 Publish a JSON-encoded MQTT message. More...
 
bool is_connected ()
 Check whether the MQTT client is currently connected and messages can be published. More...
 

Detailed Description

This class is a helper class for custom components that communicate using MQTT.

It has 5 helper functions that you can use (square brackets indicate optional):

Definition at line 18 of file custom_mqtt_device.h.

Member Function Documentation

◆ is_connected()

bool esphome::mqtt::CustomMQTTDevice::is_connected ( )

Check whether the MQTT client is currently connected and messages can be published.

Definition at line 27 of file custom_mqtt_device.cpp.

◆ publish() [1/3]

bool esphome::mqtt::CustomMQTTDevice::publish ( const std::string &  topic,
const std::string &  payload,
uint8_t  qos = 0,
bool  retain = false 
)

Publish an MQTT message with the given payload and QoS and retain settings.

Example:

void in_some_method() {
publish("the/topic", "The Payload", 0, true);
}
Parameters
topicThe topic to publish to.
payloadThe payload to publish.
qosThe Quality of Service to publish with. Defaults to 0
retainWhether to retain the message. Defaults to false.

Definition at line 9 of file custom_mqtt_device.cpp.

◆ publish() [2/3]

bool esphome::mqtt::CustomMQTTDevice::publish ( const std::string &  topic,
float  value,
int8_t  number_decimals = 3 
)

Publish an MQTT message with the given floating point number and number of decimals.

Example:

void in_some_method() {
publish("the/topic", 1.0);
// with two digits after the decimal point
publish("the/topic", 1.0, 2);
}
Parameters
topicThe topic to publish to.
payloadThe payload to publish.
number_decimalsThe number of digits after the decimal point to round to, defaults to 3 digits.

Definition at line 12 of file custom_mqtt_device.cpp.

◆ publish() [3/3]

bool esphome::mqtt::CustomMQTTDevice::publish ( const std::string &  topic,
int  value 
)

Publish an MQTT message with the given integer as payload.

Example:

void in_some_method() {
publish("the/topic", 42);
}
Parameters
topicThe topic to publish to.
payloadThe payload to publish.

Definition at line 16 of file custom_mqtt_device.cpp.

◆ publish_json() [1/2]

bool esphome::mqtt::CustomMQTTDevice::publish_json ( const std::string &  topic,
const json::json_build_t f,
uint8_t  qos,
bool  retain 
)

Publish a JSON-encoded MQTT message with the given Quality of Service and retain settings.

Example:

void in_some_method() {
publish("the/topic", [=](JsonObject &root) {
root["the_key"] = "Hello World!";
}, 0, false);
}
Parameters
topicThe topic to publish to.
payloadThe payload to publish.
qosThe Quality of Service to publish with.
retainWhether to retain the message.

Definition at line 21 of file custom_mqtt_device.cpp.

◆ publish_json() [2/2]

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

Publish a JSON-encoded MQTT message.

Example:

void in_some_method() {
publish("the/topic", [=](JsonObject &root) {
root["the_key"] = "Hello World!";
});
}
Parameters
topicThe topic to publish to.
payloadThe payload to publish.

Definition at line 24 of file custom_mqtt_device.cpp.

◆ subscribe() [1/3]

template<typename T >
void esphome::mqtt::CustomMQTTDevice::subscribe ( const std::string &  topic,
void(T::*)(const std::string &, const std::string &)  callback,
uint8_t  qos = 0 
)

Subscribe to an MQTT topic with the given Quality of Service.

Example:

class MyCustomMQTTDevice : public Component, public mqtt:CustomMQTTDevice {
public:
void setup() override {
subscribe("the/topic", &MyCustomMQTTDevice::on_message);
pinMode(5, OUTPUT);
}
// topic and payload parameters can be removed if not needed
// e.g: void on_message() {
void on_message(const std::string &topic, const std::string &payload) {
// do something with topic and payload
if (payload == "ON") {
digitalWrite(5, HIGH);
} else {
digitalWrite(5, LOW);
}
}
};
Template Parameters
TA C++ template argument for determining the type of the callback.
Parameters
topicThe topic to subscribe to. Re-subscription on re-connects is automatically handled.
callbackThe callback (must be a class member) to subscribe with.
qosThe Quality of Service to subscribe with. Defaults to 0.

Definition at line 190 of file custom_mqtt_device.h.

◆ subscribe() [2/3]

template<typename T >
void esphome::mqtt::CustomMQTTDevice::subscribe ( const std::string &  topic,
void(T::*)(const std::string &)  callback,
uint8_t  qos = 0 
)

Definition at line 196 of file custom_mqtt_device.h.

◆ subscribe() [3/3]

template<typename T >
void esphome::mqtt::CustomMQTTDevice::subscribe ( const std::string &  topic,
void(T::*)()  callback,
uint8_t  qos = 0 
)

Definition at line 200 of file custom_mqtt_device.h.

◆ subscribe_json() [1/2]

template<typename T >
void esphome::mqtt::CustomMQTTDevice::subscribe_json ( const std::string &  topic,
void(T::*)(const std::string &, JsonObject &)  callback,
uint8_t  qos = 0 
)

Subscribe to an MQTT topic and call the callback if the payload can be decoded as JSON with the given Quality of Service.

Example:

class MyCustomMQTTDevice : public Component, public mqtt:CustomMQTTDevice {
public:
void setup() override {
subscribe_json("the/topic", &MyCustomMQTTDevice::on_json_message);
pinMode(5, OUTPUT);
}
// topic parameter can be remove if not needed:
// e.g.: void on_json_message(JsonObject &payload) {
void on_json_message(const std::string &topic, JsonObject &payload) {
// do something with topic and payload
if (payload["number"] == 1) {
digitalWrite(5, HIGH);
} else {
digitalWrite(5, LOW);
}
}
};
Template Parameters
TA C++ template argument for determining the type of the callback.
Parameters
topicThe topic to subscribe to. Re-subscription on re-connects is automatically handled.
callbackThe callback (must be a class member) to subscribe with.
qosThe Quality of Service to subscribe with. Defaults to 0.

Definition at line 205 of file custom_mqtt_device.h.

◆ subscribe_json() [2/2]

template<typename T >
void esphome::mqtt::CustomMQTTDevice::subscribe_json ( const std::string &  topic,
void(T::*)(JsonObject &)  callback,
uint8_t  qos = 0 
)

Definition at line 211 of file custom_mqtt_device.h.


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