Minor updates/cleanup

MQTTInterface.cpp

@@ -74,7 +74,7 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
         DIAG(F("MQTT Callback:[%s] [%s] [%d] on interface [%x]"), topic, (char *)payload, length, mqtt);
     switch (payload[0])
     {
-    case '<':
+    case '<':   // Recieved a DCC-EX Command
     {
         const char s[2] = "/"; // topic delimiter is /
         char *token;
@@ -120,8 +120,6 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
         // if we make it until here we dont even need to test the last "cmd" element from the topic as there is no
         // subscription for anything else
 
-        // DIAG(F("MQTT Message arrived on [%s]: [%d]"), buf, topicid);
-
         // Prepare the DCC-EX command
         csmsg_t tm; // topic message
 
@@ -146,16 +144,17 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
             DIAG(F("MQTT Message arrived [%s]: [%s]"), topic, tm.cmd);
         break;
     }
-    case 'm':
+    case 'm':   // Recieved an MQTT Connection management message
     {
         switch (payload[1])
         {
-        case 'i':
+        case 'i':   // Inital handshake message to create the tunnel
         {
             char buffer[MAXPAYLOAD];
             char *tmp = (char *)payload + 3;
             strlcpy(buffer, tmp, length);
             buffer[length - 4] = '\0';
+
             // DIAG(F("MQTT buffer %s - %s - %s - %d"), payload, tmp, buffer, length);
 
             auto distantid = strtol(buffer, NULL, 10);
@@ -170,15 +169,8 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
                 DIAG(F("MQTT Invalid Handshake ID"));
                 return;
             }
-            // ---------------------------
+
             // Create a new MQTT client
-            // ---------------------------
-
-            // check in the clients if the distantid has been set already somewhere
-            // if so we either have a new one with the same id then we have a collision -> publish a collision
-            // or its the same i.e; the message comming back as we are subscribed -> stop here
-
-            // All is ok so set up the channel; MQTT Ctrl command
 
             auto subscriberid = mqtt->obtainSubscriberID(); // to be used in the parsing process for the clientid in the ringbuffer
 
@@ -190,10 +182,8 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
 
             auto topicid = cantorEncode((long)subscriberid, (long)distantid);
             DIAG(F("MQTT Client connected : subscriber [%d] : distant [%d] : topic: [%d]"), subscriberid, (int)distantid, topicid);
-            // extract the number delivered from
-            // we need to check if the id we got from the client has been used allready and if yes reject and ask for a different one
 
-            // initalize the new mqtt client object
+            // extract the number delivered from & initalize the new mqtt client object
             clients[subscriberid] = {(int)distantid, subscriberid, topicid, false}; // set to true once the channels are available
 
             auto sq = mqtt->getSubscriptionQueue();
@@ -201,16 +191,15 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
 
             return;
         }
-        default:
+        default:    // Invalid message
         {
             // ignore
             return;
         }
         }
     }
-    default:
+    default:    // invalid command / message
     {   
-        // invalid command
         DIAG(F("MQTT Invalid DCC-EX command: %s"), (char *)payload);
         break;
     }
@@ -473,26 +462,33 @@ void checkSubscribers(Queue<int> &sq, csmqttclient_t *clients)
         if (Diag::MQTT)
             DIAG(F("MQTT new subscriber topic: %s %s"), tbuffer, ok ? "OK" : "NOK");
 
-        // send the topicid on which the CS will listen for commands to the MQTT client on the root topic
+        // send the topic on which the CS will listen for commands and the ones on which it will publish for the connecting
-        char buffer[30];
+        // client to pickup. Once the connecting client has setup other topic setup messages on the main channel shall be
-        memset(buffer, 0, 30);
+        // ignored
-        sprintf(buffer, "mc(%d,%ld)", (int)clients[s].distant, clients[s].topic);
+        // JSON message { init: <number> channels: {result: <string>, diag: <string> }}
+
+        char buffer[MAXPAYLOAD*2];
+        memset(buffer, 0, MAXPAYLOAD*2);
+
+        // sprintf(buffer, "mc(%d,%ld)", (int)clients[s].distant, clients[s].topic);
+
+        sprintf(buffer, "{ \"init\": %d, \"subscribeto\": {\"result\": \"%s/%ld/result\" , \"diag\": \"%s/%ld/diag\" }, \"publishto\": {\"cmd\": \"%s/%ld/cmd\" } }", 
+                        (int)clients[s].distant, 
+                        mqtt->getClientID(), 
+                        clients[s].topic, 
+                        mqtt->getClientID(), 
+                        clients[s].topic, 
+                        mqtt->getClientID(), 
+                        clients[s].topic
+                );
+
         if (Diag::MQTT)
-            DIAG(F("MQTT Publishing: [%s] to [%s]"), buffer, mqtt->getClientID());
+            DIAG(F("MQTT channel setup message: [%s]"), buffer);
+            
         mqtt->publish(mqtt->getClientID(), buffer);
 
         // on the cs side all is set and we declare that the cs is open for business
         clients[s].open = true;
-
-        // we now need to subscribe to the ../clientid/topicid/cmd topic as we shall recieve the cmds from there
-        // in the < case we should test that we got the command on the right topic ...
-        DIAG(F("MQTT CS is listening for commands on [%s]"), tbuffer);
-        memset(buffer, 0, 30);
-        sprintf(buffer, "%s/%ld/result", mqtt->getClientID(), clients[s].topic);
-        DIAG(F("MQTT CS is publishing return information to [%s]"), buffer);
-        memset(buffer, 0, 30);
-        sprintf(buffer, "%s/%ld/diag", mqtt->getClientID(), clients[s].topic);
-        DIAG(F("MQTT CS is publishing diagnostic information to [%s]"), buffer);
     }
 }