feat: increase the default value of pingTimeout

darrachequesne · darrachequesne · commit f55a79a28a5f · 2022-06-06T08:23:47.000+02:00
This value was updated from 60000 to 5000 in [1], included in `engine.io@3.2.0` (Feb 2018). The reasoning back then: Some users experienced long delays between disconnection on the server-side and on the client-side. The "disconnect" event would take a long time to fire in the browser, probably due to a timer being delayed. Hence the change. That being said, the current value (5s) now causes unexpected disconnections when a big payload is sent over a slow network, because it prevents the ping-pong packets from being exchanged between the client and the server. This can also happen when a synchronous task blocks the server for more than 5 seconds. The new value (20s) thus seems like a good balance between quick disconnection detection and tolerance to various delays. Note: pingInterval + pingTimeout is still below the threshold of React Native, which complains if a timer is set with a delay of more than 1 minute. [1]: 65b1ad1 Related: - socketio/socket.io#2770 - socketio/socket.io#2769 - socketio/socket.io#3054 - socketio/socket.io#3376 Backported from 5a7fa13
diff --git a/README.md b/README.md
@@ -221,7 +221,7 @@ to a single process.
       - `Object`: optional, options object
     - **Options**
       - `pingTimeout` (`Number`): how many ms without a pong packet to
-        consider the connection closed (`5000`)
+        consider the connection closed (`20000`)
       - `pingInterval` (`Number`): how many ms before sending a new ping
         packet (`25000`)
       - `upgradeTimeout` (`Number`): how many ms before an uncompleted transport upgrade is cancelled (`10000`)
diff --git a/lib/server.js b/lib/server.js
@@ -37,7 +37,7 @@ function Server (opts) {
   opts = opts || {};
 
   this.wsEngine = opts.wsEngine || process.env.EIO_WS_ENGINE || 'ws';
-  this.pingTimeout = opts.pingTimeout || 5000;
+  this.pingTimeout = opts.pingTimeout || 20000;
   this.pingInterval = opts.pingInterval || 25000;
   this.upgradeTimeout = opts.upgradeTimeout || 10000;
   this.maxHttpBufferSize = opts.maxHttpBufferSize || 1e6;
