From 33e104b34cfbb015adca9a7adabc651375ddfb2a Mon Sep 17 00:00:00 2001
From: Nick Adams <4012017+Nick-Adams-AU@users.noreply.github.com>
Date: Tue, 26 Mar 2019 09:21:14 +1000
Subject: [PATCH] Add a keep-alive NOOP to the C-Gate connection

At times, the C-Gate connection may be interrupted due to connectivity issues (i.e. WiFi dropouts) or because the server crashed or was restarted. We won't find out about this until we attempt to write to the socket possibly hours after the connection was dropped.

Add a periodic NOOP command on the C-Gate connection to detect a failed connection sooner.
---
 index.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/index.js b/index.js
index 93f34ae..b6b4c92 100644
--- a/index.js
+++ b/index.js
@@ -40,6 +40,7 @@ var event = new net.Socket();
 var HOST = settings.cbusip;
 var COMPORT = 20023;
 var EVENTPORT = 20025;
+var KEEPALIVE = 30;
 
 var logging = settings.logging;
 
@@ -64,6 +65,11 @@ function started(){
         command.write('GET //'+settings.cbusname+'/'+settings.getallnetapp+'/* level\n');
       },settings.getallperiod*1000);
     }
+    // Send a NOOP to the Cgate server to keep the connection open and detect if the connection was closed
+    setInterval(function(){
+      console.log('NOOP');
+      command.write('NOOP\n');
+    },KEEPALIVE);
   }
 
 }