First version of mqtt connection handling

include/Configuration.h

@@ -3,7 +3,7 @@
 #include <Arduino.h>
 
 #define CONFIG_FILENAME "/config.bin"
-#define CONFIG_VERSION 0x00010500 // 0.1.5 // make sure to clean all after change
+#define CONFIG_VERSION 0x00010600 // 0.1.6 // make sure to clean all after change
 
 #define WIFI_MAX_SSID_STRLEN 31
 #define WIFI_MAX_PASSWORD_STRLEN 31
@@ -42,6 +42,7 @@ struct CONFIG_T {
     char Mqtt_Username[MQTT_MAX_USERNAME_STRLEN + 1];
     char Mqtt_Password[MQTT_MAX_PASSWORD_STRLEN + 1];
     char Mqtt_Topic[MQTT_MAX_TOPIC_STRLEN + 1];
+    bool Mqtt_Retain;
 };
 
 class ConfigurationClass {

include/MqttSettings.h

@@ -1,15 +1,32 @@
 #pragma once
 
+#include <Arduino.h>
 #include <AsyncMqttClient.h>
+#include <Ticker.h>
+#include <WiFi.h>
 #include <memory>
 
 class MqttSettingsClass {
 public:
     MqttSettingsClass();
     void init();
+    void performReconnect();
+    bool getConnected();
+    void publish(String subtopic, String payload);
 
 private:
-    std::unique_ptr<AsyncMqttClient> mqttClient;
+    void WiFiEvent(WiFiEvent_t event);
+
+    void onMqttDisconnect(AsyncMqttClientDisconnectReason reason);
+    void onMqttConnect(bool sessionPresent);
+
+    void performConnect();
+    void performDisconnect();
+
+    AsyncMqttClient mqttClient;
+    String clientId;
+    String willTopic;
+    Ticker mqttReconnectTimer;
 };
 
 extern MqttSettingsClass MqttSettings;

src/Configuration.cpp

@@ -28,6 +28,7 @@ void ConfigurationClass::init()
     strlcpy(config.Mqtt_Username, MQTT_USER, sizeof(config.Mqtt_Username));
     strlcpy(config.Mqtt_Password, MQTT_PASSWORD, sizeof(config.Mqtt_Password));
     strlcpy(config.Mqtt_Topic, MQTT_TOPIC, sizeof(config.Mqtt_Topic));
+    config.Mqtt_Retain = true;
 }
 
 bool ConfigurationClass::write()
@@ -76,6 +77,10 @@ void ConfigurationClass::migrate()
         strlcpy(config.Mqtt_Topic, MQTT_TOPIC, sizeof(config.Mqtt_Topic));
     }
 
+    if (config.Cfg_Version < 0x00010600) {
+        config.Mqtt_Retain = true;
+    }
+
     config.Cfg_Version = CONFIG_VERSION;
     write();
 }

src/MqttSettings.cpp

@@ -1,12 +1,94 @@
 #include "MqttSettings.h"
+#include "Configuration.h"
+#include "WiFiSettings.h"
+#include <AsyncMqttClient.h>
+#include <Ticker.h>
+#include <WiFi.h>
 
 MqttSettingsClass::MqttSettingsClass()
     : mqttClient()
 {
 }
 
+void MqttSettingsClass::WiFiEvent(WiFiEvent_t event)
+{
+    switch (event) {
+    case SYSTEM_EVENT_STA_GOT_IP:
+        Serial.println(F("WiFi connected"));
+        performConnect();
+        break;
+    case SYSTEM_EVENT_STA_DISCONNECTED:
+        Serial.println(F("WiFi lost connection"));
+        mqttReconnectTimer.detach(); // ensure we don't reconnect to MQTT while reconnecting to Wi-Fi
+        break;
+    }
+}
+
+void MqttSettingsClass::onMqttConnect(bool sessionPresent)
+{
+    Serial.println(F("Connected to MQTT."));
+    mqttClient.publish(willTopic.c_str(), 2, Configuration.get().Mqtt_Retain, "online");
+}
+
+void MqttSettingsClass::onMqttDisconnect(AsyncMqttClientDisconnectReason reason)
+{
+    Serial.println(F("Disconnected from MQTT."));
+
+    mqttReconnectTimer.once(
+        2, +[](MqttSettingsClass* instance) { instance->performConnect(); }, this);
+}
+
+void MqttSettingsClass::performConnect()
+{
+    if (WiFi.isConnected() && Configuration.get().Mqtt_Enabled) {
+        Serial.println("Connecting to MQTT...");
+        CONFIG_T& config = Configuration.get();
+        mqttClient.setServer(config.Mqtt_Hostname, config.Mqtt_Port);
+        mqttClient.setCredentials(config.Mqtt_Username, config.Mqtt_Password);
+
+        willTopic = String(config.Mqtt_Topic) + "status";
+        mqttClient.setWill(willTopic.c_str(), 2, Configuration.get().Mqtt_Retain, "offline");
+
+        clientId = WiFiSettings.getApName();
+        mqttClient.setClientId(clientId.c_str());
+
+        mqttClient.connect();
+    }
+}
+
+void MqttSettingsClass::performDisconnect()
+{
+    mqttClient.publish(willTopic.c_str(), 2, Configuration.get().Mqtt_Retain, "offline");
+    mqttClient.disconnect();
+}
+
+void MqttSettingsClass::performReconnect()
+{
+    performDisconnect();
+
+    mqttReconnectTimer.once(
+        2, +[](MqttSettingsClass* instance) { instance->performConnect(); }, this);
+}
+
+bool MqttSettingsClass::getConnected()
+{
+    return mqttClient.connected();
+}
+
+void MqttSettingsClass::publish(String subtopic, String payload)
+{
+    String topic = Configuration.get().Mqtt_Topic;
+    topic += subtopic;
+    mqttClient.publish(topic.c_str(), 2, Configuration.get().Mqtt_Retain, payload.c_str());
+}
+
 void MqttSettingsClass::init()
 {
+    using namespace std::placeholders;
+    WiFi.onEvent(std::bind(&MqttSettingsClass::WiFiEvent, this, _1));
+
+    mqttClient.onConnect(std::bind(&MqttSettingsClass::onMqttConnect, this, _1));
+    mqttClient.onDisconnect(std::bind(&MqttSettingsClass::onMqttDisconnect, this, _1));
 }
 
 MqttSettingsClass MqttSettings;