handling pings from server

Author: SaranshBS

lib/config/constants.js

@@ -13,6 +13,8 @@ const {
 
 const kUpstreamClosed = Symbol('kUpstreamClosed');
 const kMessageReceived = Symbol('kMessageReceived');
+const kPingReceived = Symbol('kPingReceived');
+const kSendPing = Symbol('kSendPing');
 const kError = Symbol('kError');
 const kSendMessage = Symbol('kSendMessage');
 const kQueueMessage = Symbol('kQueueMessage');

lib/core/Context.js

@@ -8,6 +8,8 @@ const { createTarget } = require('../util/util');
 const {
   kUpstreamClosed,
   kMessageReceived,
+  kPingReceived,
+  kSendPing,
   kEnableIncomingQueue,
   kEnableOutgoingQueue,
   kError,
@@ -107,6 +109,10 @@ class Context extends EventEmitter {
       logger.debug(`${INCOMING} [${this.connectionId}] [MESSAGE] - ${msg}`);
     });
 
+    this.incomingSocket.on(kSendPing, () => {
+      this.incomingSocket.ping();
+    });
+
     this.incomingSocket.on(kDrainMessage, (msg) => {
       this.outgoingSocket.emit(kSendMessage, msg);
     });
@@ -165,6 +171,10 @@ class Context extends EventEmitter {
       this.emit(kAddNewContext, connectionId);
     });
 
+    this.outgoingSocket.on(kPingReceived, () => {
+      this.incomingSocket.emit(kSendPing);
+    });
+
     this.outgoingSocket.on(kMessageReceived, (msg) => {
       if (this.outgoingLock) {
         logger.debug(`${OUTGOING} [${this.connectionId}] [QUEUE] - ${msg}`);

lib/core/IncomingWebSocket.js

@@ -128,6 +128,13 @@ class IncomingWebSocket extends EventEmitter {
   send(msg) {
     this.socket.send(msg);
   }
+
+  /**
+   * Relays ping from upstream.
+   */
+   ping() {
+    this.socket.ping();
+  }
 }
 
 module.exports = IncomingWebSocket;

lib/core/OutgoingWebSocket.js

@@ -13,6 +13,7 @@ const {
   kAddNewContext,
   kReleaseTap,
   kMessageReceived,
+  kPingReceived,
   kError,
   kUpstreamRestart,
   kUpstreamClosed,
@@ -71,6 +72,7 @@ class OutgoingWebSocket extends EventEmitter {
     this.socket.on('message', this.messageHandler.bind(this));
     this.socket.on('close', this.closeHandler.bind(this));
     this.socket.on('error', this.errorHandler.bind(this));
+    this.socket.on('ping', this.pingHandler.bind(this));
   }
 
   /**
@@ -108,6 +110,10 @@ class OutgoingWebSocket extends EventEmitter {
     this.emit(kMessageReceived, msg);
   }
 
+  pingHandler() {
+    this.emit(kPingReceived);
+  }
+
   /**
    * Triggers when socket connection is closed.
    *