From f41bcd55d612e4062be1f1911c541637cabdb978 Mon Sep 17 00:00:00 2001
From: hodlbank <github@hodlbank.org>
Date: Mon, 8 Oct 2018 23:41:38 +0000
Subject: [PATCH] [f] Fix for #971 - "Fatal error when Ethereum node going
 offline". [a] Added .once() into Events.

---
 cmd/cmd_controller.js | 2 +-
 lib/core/events.js    | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/cmd/cmd_controller.js b/cmd/cmd_controller.js
index 8bd93dd23..5b0c1d657 100644
--- a/cmd/cmd_controller.js
+++ b/cmd/cmd_controller.js
@@ -286,7 +286,7 @@ class EmbarkController {
         engine.startService("namingSystem");
         engine.startService("console");
         engine.startService("pluginCommand");
-        engine.events.on('check:backOnline:Ethereum', () => callback());
+        engine.events.once('check:backOnline:Ethereum', () => callback());
       },
       function ipcConnect(callback) {
         // Do specific work in case we are connected to a socket:
diff --git a/lib/core/events.js b/lib/core/events.js
index 6b34c0b4c..5a3ab0a8f 100644
--- a/lib/core/events.js
+++ b/lib/core/events.js
@@ -19,6 +19,7 @@ function log(eventType, eventName) {
 
 EventEmitter.prototype._maxListeners = 350;
 const _on         = EventEmitter.prototype.on;
+const _once       = EventEmitter.prototype.once;
 const _setHandler = EventEmitter.prototype.setHandler;
 
 EventEmitter.prototype.on = function(requestName, cb) {
@@ -27,6 +28,12 @@ EventEmitter.prototype.on = function(requestName, cb) {
   return _on.call(this, requestName, cb);
 };
 
+EventEmitter.prototype.once = function(requestName, cb) {
+  log("listening to event (once): ", requestName);
+  warnIfLegacy(requestName);
+  return _once.call(this, requestName, cb);
+};
+
 EventEmitter.prototype.setHandler = function(requestName, cb) {
   log("setting handler for: ", requestName);
   warnIfLegacy(requestName);