use flash strings for MQTT topics

src/devices/boiler.cpp

@@ -324,7 +324,7 @@ void Boiler::publish_values() {
 
     // if we have data, publish it
     if (!doc.isNull()) {
-        Mqtt::publish("boiler_data", doc);
+        Mqtt::publish(F("boiler_data"), doc);
     }
 }
 
@@ -476,8 +476,8 @@ void Boiler::check_active() {
         uint8_t latest_boilerState = (tap_water_active_ << 1) + heating_active_;
         if (latest_boilerState != last_boilerState) {
             last_boilerState = latest_boilerState;
-            Mqtt::publish("tapwater_active", tap_water_active_);
+            Mqtt::publish(F("tapwater_active"), tap_water_active_);
-            Mqtt::publish("heating_active", heating_active_);
+            Mqtt::publish(F("heating_active"), heating_active_);
         }
     }
 }

src/devices/solar.cpp

@@ -170,7 +170,7 @@ void Solar::publish_values() {
 
     // if we have data, publish it
     if (!doc.isNull()) {
-        Mqtt::publish("sm_data", doc);
+        Mqtt::publish(F("sm_data"), doc);
     }
 }
 

src/devices/thermostat.cpp

@@ -304,7 +304,7 @@ void Thermostat::publish_values() {
 
         // send this specific data using the thermostat_data topic
         if (mqtt_format_ != MQTT_format::NESTED) {
-            Mqtt::publish("thermostat_data", doc);
+            Mqtt::publish(F("thermostat_data"), doc);
             rootThermostat = doc.to<JsonObject>(); // clear object
         }
     }
@@ -446,7 +446,7 @@ void Thermostat::publish_values() {
 
     // if we're using nested json, send all in one go under one topic called thermostat_data
     if (mqtt_format_ == MQTT_format::NESTED) {
-        Mqtt::publish("thermostat_data", doc);
+        Mqtt::publish(F("thermostat_data"), doc);
     }
 }
 

src/emsesp.cpp

@@ -316,8 +316,10 @@ void EMSESP::publish_sensor_values(const bool force) {
     }
 }
 
+// MQTT publish a telegram as raw data
 void EMSESP::publish_response(std::shared_ptr<const Telegram> telegram) {
     StaticJsonDocument<EMSESP_MAX_JSON_SIZE_SMALL> doc;
+
     char buffer[100];
     doc["src"]    = Helpers::hextoa(buffer, telegram->src);
     doc["dest"]   = Helpers::hextoa(buffer, telegram->dest);
@@ -325,6 +327,7 @@ void EMSESP::publish_response(std::shared_ptr<const Telegram> telegram) {
     doc["offset"] = Helpers::hextoa(buffer, telegram->offset);
     strcpy(buffer, Helpers::data_to_hex(telegram->message_data, telegram->message_length).c_str());
     doc["data"] = buffer;
+
     if (telegram->message_length <= 4) {
         uint32_t value = 0;
         for (uint8_t i = 0; i < telegram->message_length; i++) {
@@ -332,7 +335,8 @@ void EMSESP::publish_response(std::shared_ptr<const Telegram> telegram) {
         }
         doc["value"] = value;
     }
-    Mqtt::publish("response", doc);
+
+    Mqtt::publish(F("response"), doc);
 }
 
 // search for recognized device_ids : Me, All, otherwise print hex value

src/mqtt.cpp

@@ -479,9 +479,9 @@ void Mqtt::on_connect() {
 #ifndef EMSESP_STANDALONE
     doc["ip"] = WiFi.localIP().toString();
 #endif
-    publish("info", doc, false); // send with retain off
+    publish(F("info"), doc, false); // send with retain off
 
-    publish("status", "online", true); // say we're alive to the Last Will topic, with retain on
+    publish(F("status"), "online", true); // say we're alive to the Last Will topic, with retain on
 
     reset_publish_fails(); // reset fail count to 0
 
@@ -538,6 +538,15 @@ void Mqtt::publish(const std::string & topic, const std::string & payload, bool
     queue_publish_message(topic, payload, retain);
 }
 
+// MQTT Publish, using a specific retain flag, topic is a flash string
+void Mqtt::publish(const __FlashStringHelper * topic, const std::string & payload, bool retain) {
+    queue_publish_message(uuid::read_flash_string(topic), payload, retain);
+}
+
+void Mqtt::publish(const __FlashStringHelper * topic, const JsonDocument & payload, bool retain) {
+    publish(uuid::read_flash_string(topic), payload, retain);
+}
+
 void Mqtt::publish(const std::string & topic, const JsonDocument & payload, bool retain) {
     std::string payload_text;
     serializeJson(payload, payload_text); // convert json to string
@@ -548,6 +557,9 @@ void Mqtt::publish(const std::string & topic, const JsonDocument & payload, bool
 void Mqtt::publish(const std::string & topic, const bool value) {
     queue_publish_message(topic, value ? "1" : "0", false);
 }
+void Mqtt::publish(const __FlashStringHelper * topic, const bool value) {
+    queue_publish_message(uuid::read_flash_string(topic), value ? "1" : "0", false);
+}
 
 // no payload
 void Mqtt::publish(const std::string & topic) {

src/mqtt.h

@@ -88,7 +88,10 @@ class Mqtt {
 
     static void publish(const std::string & topic, const std::string & payload, bool retain = false);
     static void publish(const std::string & topic, const JsonDocument & payload, bool retain = false);
+    static void publish(const __FlashStringHelper * topic, const JsonDocument & payload, bool retain = false);
+    static void publish(const __FlashStringHelper * topic, const std::string & payload, bool retain = false);
     static void publish(const std::string & topic, const bool value);
+    static void publish(const __FlashStringHelper * topi, const bool value);
     static void publish(const std::string & topic);
 
     static void show_topic_handlers(uuid::console::Shell & shell, const uint8_t device_type);

src/sensors.cpp

@@ -347,9 +347,9 @@ void Sensors::publish_values() {
     }
 
     if ((mqtt_format_ == MQTT_format::NESTED) || (mqtt_format_ == MQTT_format::CUSTOM)) {
-        Mqtt::publish("sensors", doc);
+        Mqtt::publish(F("sensors"), doc);
     } else if (mqtt_format_ == MQTT_format::HA) {
-        Mqtt::publish("homeassistant/sensor/ems-esp/state", doc);
+        Mqtt::publish(F("homeassistant/sensor/ems-esp/state"), doc);
     }
 }
 } // namespace emsesp

src/shower.cpp

@@ -53,7 +53,7 @@ void Shower::loop() {
                 // first check to see if hot water has been on long enough to be recognized as a Shower/Bath
                 if (!shower_on_ && (time_now - timer_start_) > SHOWER_MIN_DURATION) {
                     shower_on_ = true;
-                    Mqtt::publish("shower_active", (bool)true);
+                    Mqtt::publish(F("shower_active"), (bool)true);
                     LOG_DEBUG(F("[Shower] hot water still running, starting shower timer"));
                 }
                 // check if the shower has been on too long
@@ -74,7 +74,7 @@ void Shower::loop() {
                 if ((timer_pause_ - timer_start_) > SHOWER_OFFSET_TIME) {
                     duration_ = (timer_pause_ - timer_start_ - SHOWER_OFFSET_TIME);
                     if (duration_ > SHOWER_MIN_DURATION) {
-                        Mqtt::publish("shower_active", (bool)false);
+                        Mqtt::publish(F("shower_active"), (bool)false);
                         LOG_DEBUG(F("[Shower] finished with duration %d"), duration_);
                         publish_values();
                     }
@@ -129,7 +129,7 @@ void Shower::publish_values() {
         doc["duration"] = s;
     }
 
-    Mqtt::publish("shower_data", doc);
+    Mqtt::publish(F("shower_data"), doc);
 }
 
 } // namespace emsesp

src/system.cpp

@@ -237,7 +237,7 @@ void System::send_heartbeat() {
     doc["rxfails"]          = EMSESP::rxservice_.telegram_error_count();
     doc["adc"]              = analog_; //analogRead(A0);
 
-    Mqtt::publish("heartbeat", doc, false); // send to MQTT with retain off. This will add to MQTT queue.
+    Mqtt::publish(F("heartbeat"), doc, false); // send to MQTT with retain off. This will add to MQTT queue.
 }
 
 // measure and moving average adc