[feature] Introduce the autoPong option

Add the ability to disable the automatic sending of pong responses to
pings.

Fixes #2186

doc/ws.md

@@ -72,6 +72,8 @@ This class represents a WebSocket server. It extends the `EventEmitter`.
 ### new WebSocketServer(options[, callback])
 
 - `options` {Object}
+  - `autoPong` {Boolean} Specifies whether or not to automatically send a pong
+    in response to a ping. Defaults to `true`.
   - `allowSynchronousEvents` {Boolean} Specifies whether any of the `'message'`,
     `'ping'`, and `'pong'` events can be emitted multiple times in the same
     tick. To improve compatibility with the WHATWG standard, the default value
@@ -296,6 +298,8 @@ This class represents a WebSocket. It extends the `EventEmitter`.
 - `address` {String|url.URL} The URL to which to connect.
 - `protocols` {String|Array} The list of subprotocols.
 - `options` {Object}
+  - `autoPong` {Boolean} Specifies whether or not to automatically send a pong
+    in response to a ping. Defaults to `true`.
   - `allowSynchronousEvents` {Boolean} Specifies whether any of the `'message'`,
     `'ping'`, and `'pong'` events can be emitted multiple times in the same
     tick. To improve compatibility with the WHATWG standard, the default value

lib/websocket-server.js

@@ -32,6 +32,8 @@ class WebSocketServer extends EventEmitter {
    * @param {Boolean} [options.allowSynchronousEvents=false] Specifies whether
    *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
    *     multiple times in the same tick
+   * @param {Boolean} [options.autoPong=true] Specifies whether or not to
+   *     automatically send a pong in response to a ping
    * @param {Number} [options.backlog=511] The maximum length of the queue of
    *     pending connections
    * @param {Boolean} [options.clientTracking=true] Specifies whether or not to
@@ -59,6 +61,7 @@ class WebSocketServer extends EventEmitter {
 
     options = {
       allowSynchronousEvents: false,
+      autoPong: true,
       maxPayload: 100 * 1024 * 1024,
       skipUTF8Validation: false,
       perMessageDeflate: false,
@@ -379,7 +382,7 @@ class WebSocketServer extends EventEmitter {
       `Sec-WebSocket-Accept: ${digest}`
     ];
 
-    const ws = new this.options.WebSocket(null);
+    const ws = new this.options.WebSocket(null, undefined, this.options);
 
     if (protocols.size) {
       //

lib/websocket.js

@@ -84,6 +84,7 @@ class WebSocket extends EventEmitter {
 
       initAsClient(this, address, protocols, options);
     } else {
+      this._autoPong = options.autoPong;
       this._isServer = true;
     }
   }
@@ -625,6 +626,8 @@ module.exports = WebSocket;
  * @param {Boolean} [options.allowSynchronousEvents=false] Specifies whether any
  *     of the `'message'`, `'ping'`, and `'pong'` events can be emitted multiple
  *     times in the same tick
+ * @param {Boolean} [options.autoPong=true] Specifies whether or not to
+ *     automatically send a pong in response to a ping
  * @param {Function} [options.finishRequest] A function which can be used to
  *     customize the headers of each http request before it is sent
  * @param {Boolean} [options.followRedirects=false] Whether or not to follow
@@ -650,6 +653,7 @@ module.exports = WebSocket;
 function initAsClient(websocket, address, protocols, options) {
   const opts = {
     allowSynchronousEvents: false,
+    autoPong: true,
     protocolVersion: protocolVersions[1],
     maxPayload: 100 * 1024 * 1024,
     skipUTF8Validation: false,
@@ -668,6 +672,8 @@ function initAsClient(websocket, address, protocols, options) {
     port: undefined
   };
 
+  websocket._autoPong = opts.autoPong;
+
   if (!protocolVersions.includes(opts.protocolVersion)) {
     throw new RangeError(
       `Unsupported protocol version: ${opts.protocolVersion} ` +
@@ -1212,7 +1218,7 @@ function receiverOnMessage(data, isBinary) {
 function receiverOnPing(data) {
   const websocket = this[kWebSocket];
 
-  websocket.pong(data, !websocket._isServer, NOOP);
+  if (websocket._autoPong) websocket.pong(data, !this._isServer, NOOP);
   websocket.emit('ping', data);
 }
 

test/websocket-server.test.js

@@ -116,6 +116,30 @@ describe('WebSocketServer', () => {
           wss.close(done);
         });
       });
+
+      it('honors the `autoPong` option', (done) => {
+        const wss = new WebSocket.Server({ autoPong: false, port: 0 }, () => {
+          const ws = new WebSocket(`ws://localhost:${wss.address().port}`);
+
+          ws.on('open', () => {
+            ws.ping();
+          });
+
+          ws.on('pong', () => {
+            done(new Error("Unexpected 'pong' event"));
+          });
+        });
+
+        wss.on('connection', (ws) => {
+          ws.on('ping', () => {
+            ws.close();
+          });
+
+          ws.on('close', () => {
+            wss.close(done);
+          });
+        });
+      });
     });
 
     it('emits an error if http server bind fails', (done) => {

test/websocket.test.js

@@ -197,6 +197,30 @@ describe('WebSocket', () => {
           });
         });
       });
+
+      it('honors the `autoPong` option', (done) => {
+        const wss = new WebSocket.Server({ port: 0 }, () => {
+          const ws = new WebSocket(`ws://localhost:${wss.address().port}`, {
+            autoPong: false
+          });
+
+          ws.on('ping', () => {
+            ws.close();
+          });
+
+          ws.on('close', () => {
+            wss.close(done);
+          });
+        });
+
+        wss.on('connection', (ws) => {
+          ws.on('pong', () => {
+            done(new Error("Unexpected 'pong' event"));
+          });
+
+          ws.ping();
+        });
+      });
     });
   });
 
@@ -2325,6 +2349,29 @@ describe('WebSocket', () => {
         ws.close();
       });
     });
+
+    it('is called automatically when a ping is received', (done) => {
+      const buf = Buffer.from('hi');
+      const wss = new WebSocket.Server({ port: 0 }, () => {
+        const ws = new WebSocket(`ws://localhost:${wss.address().port}`);
+
+        ws.on('open', () => {
+          ws.ping(buf);
+        });
+
+        ws.on('pong', (data) => {
+          assert.deepStrictEqual(data, buf);
+          wss.close(done);
+        });
+      });
+
+      wss.on('connection', (ws) => {
+        ws.on('ping', (data) => {
+          assert.deepStrictEqual(data, buf);
+          ws.close();
+        });
+      });
+    });
   });
 
   describe('#resume', () => {