MQTT at least talks to server, works in native and esp32

src/mqtt/MQTT.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "configuration.h"
+
+#include <PubSubClient.h>
+#include <WiFiClient.h>
+
+/**
+ * Our wrapper/singleton for sending/receiving MQTT "udp" packets.  This object isolates the MQTT protocol implementation from
+ * the two components that use it: MQTTPlugin and MQTTSimInterface.
+ */
+class MQTT
+{
+    /// Our globally unique node ID
+    String nodeId = "fixmemode";
+
+    // supposedly the current version is busted:
+    // http://www.iotsharing.com/2017/08/how-to-use-esp32-mqtts-with-mqtts-mosquitto-broker-tls-ssl.html
+    // WiFiClientSecure wifiClient;
+    WiFiClient mqttClient;
+    PubSubClient pubSub;
+
+  public:
+    MQTT();
+
+    /**
+     * Publish a packet on the glboal MQTT server.
+     * @param channelId must be a globally unique channel ID
+     */
+    void publish(const MeshPacket *mp, String channelId);
+
+  private:
+    const char *getTopic(String suffix, const char *direction = "dev");
+};
+
+void mqttInit();
+
+extern MQTT *mqtt;