MQTT: add client code

include/secrets.h_template

@@ -5,3 +5,7 @@
 
 #define WIFI_SSID "Wifi_SSID"
 #define WIFI_PASSWORD "secretPassword"
+
+#define MQTT_SERVER "mqttserver.fritz.box"
+#define MQTT_USER "user"
+#define MQTT_PASSWORD "password"

platformio.ini

@@ -14,8 +14,9 @@ board = esp32dev
 framework = arduino
 monitor_speed = 115200
 lib_deps =
-    witnessmenow/UniversalTelegramBot @ ^1.3.0
-    adafruit/Adafruit GFX Library @ 1.12.3
+    witnessmenow/UniversalTelegramBot @ ~1.3.0
+    adafruit/Adafruit GFX Library @ ~1.12.3
+    knolleary/PubSubClient @ ~2.8
 build_flags=-DTELEGRAM_DEBUG
 ; OTA update path: hostname is flipdottelegram.fritz.box
 upload_protocol = espota

src/main.cpp

@@ -3,6 +3,8 @@
 #include <WiFiClientSecure.h>
 #include <ArduinoOTA.h>
 #include <time.h>
+#include <PubSubClient.h>
+#include <ArduinoJson.h>
 
 #include "Telegram.h"
 #include "FlipDotDrv.h"
@@ -12,6 +14,36 @@
 String Text = "";
 const char *const HOSTNAME = "flipdottelegram";
 
+/* ------------ MQTT variables -------------- */
+WiFiClient espClient;
+PubSubClient mqtt(espClient);
+#define FLIPDOT_AVAILABILITY_TOPIC "flipdotdisplay/available"
+#define FLIPDOT_SWITCH_TOPIC "flipdotdisplay/switch"
+#define FLIPDOT_TEXT_TOPIC "flipdotdisplay/text"
+void mqttCallback(char *topic, unsigned char *message, unsigned int length);
+
+void publishOpen()
+{
+  mqtt.publish(FLIPDOT_SWITCH_TOPIC "/state", "open");
+
+  JsonDocument doc;
+  doc["value"] = Text;
+  char output[256];
+  serializeJson(doc, output);
+  mqtt.publish(FLIPDOT_TEXT_TOPIC "/state", output);
+}
+
+void publishClose()
+{
+  mqtt.publish(FLIPDOT_SWITCH_TOPIC "/state", "close");
+
+  JsonDocument doc;
+  doc["value"] = Text;
+  char output[256];
+  serializeJson(doc, output);
+  mqtt.publish(FLIPDOT_TEXT_TOPIC "/state", output);
+}
+
 /* ------------ OTA section and variables -------------- */
 bool OTAStarted;
 void onOTAStart()
@@ -117,6 +149,10 @@ void setup()
   /* setup ArduinoOTA */
   ArduinoOTA.setHostname(HOSTNAME);
   ArduinoOTA.onStart(onOTAStart);
+
+  /* prepare MQTT client */
+  mqtt.setServer(MQTT_SERVER, 1883);
+  mqtt.setCallback(mqttCallback);
 }
 
 void loop()
@@ -165,6 +201,21 @@ void loop()
       lastTelegramRefresh = now;
       tele.cyclic(now);
     }
+
+    /* handle MQTT transmissions */
+    if (!mqtt.loop())
+    {
+      Serial.println("MQTT not connected");
+
+      // try to connect to MQTT broker again
+      if (mqtt.connect(HOSTNAME, MQTT_USER, MQTT_PASSWORD, FLIPDOT_AVAILABILITY_TOPIC, 2, true, "offline"))
+      {
+        // publish availability message
+        mqtt.subscribe(FLIPDOT_SWITCH_TOPIC);
+        mqtt.subscribe(FLIPDOT_TEXT_TOPIC);
+        mqtt.publish(FLIPDOT_AVAILABILITY_TOPIC, "available");
+      }
+    }
   }
   else
   {
@@ -178,6 +229,8 @@ void loop()
 
       ArduinoOTA.end();
 
+      mqtt.disconnect();
+
       oldWifiStatus = WiFi.status();
     }
   }
@@ -239,12 +292,12 @@ void loop()
 }
 
 /* function to write text onto the canvas
- * 
+ *
  * @param text       - C string to be printed
  * @param background - boolean switch if the background should be transparent (false) or black (true)
  * @param x          - position in X direction to write the Text, -1 centers the text
  * @param y          - position in Y direction to write the Text, -1 centers the text
- * 
+ *
  *  */
 void displayText(const char *text, bool background, int16_t x, int16_t y)
 {
@@ -291,6 +344,7 @@ void displayText(const char *text, bool background, int16_t x, int16_t y)
 String printOpen(String Args)
 {
   Text = "offen";
+  publishOpen();
 
   return Text;
 }
@@ -298,6 +352,7 @@ String printOpen(String Args)
 String printClose(String Args)
 {
   Text = "leider zu";
+  publishClose();
 
   return Text;
 }
@@ -308,6 +363,62 @@ String printText(String Args)
   Serial.print(Args);
   Serial.println("'");
   Text = Args;
+  publishClose();
 
   return Text;
 }
+
+void mqttCallback(char *topic, unsigned char *message, unsigned int length)
+{
+  String MessageString;
+
+  /* Convert all char* to Strings for simpler handling */
+  for (int i = 0; i < length; i++)
+  {
+    MessageString += message[i];
+  }
+  String ToppicString(topic);
+
+  /* if topic is the switch topic check for on, off, open, close */
+  if (ToppicString == FLIPDOT_SWITCH_TOPIC)
+  {
+    Serial.println("Switch topic received: " + MessageString);
+
+    if ((MessageString == "open") ||
+        (MessageString == "on"))
+    {
+      printOpen(MessageString);
+    }
+    else if ((MessageString == "close") ||
+             (MessageString == "off"))
+    {
+      printClose(MessageString);
+    }
+  }
+
+  /* if topic is the text topic try deserializing the json text */
+  if (ToppicString == FLIPDOT_TEXT_TOPIC)
+  {
+    Serial.println("Text topic received: " + MessageString);
+    JsonDocument doc;
+    if (deserializeJson(doc, (const char *)message, length) == DeserializationError::Ok)
+    {
+      MessageString = doc["value"] | String("none"); // the pipe operand tells the default value, if "value" is not existing
+
+      if ((MessageString != "none"))
+      {
+        printText(MessageString);
+      }
+      else
+      {
+        Serial.print(FLIPDOT_TEXT_TOPIC);
+        Serial.println(" has no [\"value\"]!");
+      }
+    }
+    else
+    {
+      Serial.print(FLIPDOT_TEXT_TOPIC);
+      Serial.println(" is no json!");
+    }
+  }
+}