[fix] Respond with the supported protocol versions (#2291)

Add the `Sec-WebSocket-Version` header, listing all supported versions, to the response if the client requested version is either invalid or unacceptable.

Author: samuel871211

lib/websocket-server.js

@@ -256,9 +256,11 @@ class WebSocketServer extends EventEmitter {
  return;
  }
 
- if (version !== 8 && version !== 13) {
+ if (version !== 13 && version !== 8) {
  const message = 'Missing or invalid Sec-WebSocket-Version header';
- abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+ abortHandshakeOrEmitwsClientError(this, req, socket, 400, message, {
+ 'Sec-WebSocket-Version': '13, 8'
+ });
  return;
  }
 
@@ -526,15 +528,23 @@ function abortHandshake(socket, code, message, headers) {
  * @param {Duplex} socket The socket of the upgrade request
  * @param {Number} code The HTTP response status code
  * @param {String} message The HTTP response body
+ * @param {Object} [headers] The HTTP response headers
  * @private
  */
-function abortHandshakeOrEmitwsClientError(server, req, socket, code, message) {
+function abortHandshakeOrEmitwsClientError(
+ server,
+ req,
+ socket,
+ code,
+ message,
+ headers
+) {
  if (server.listenerCount('wsClientError')) {
  const err = new Error(message);
  Error.captureStackTrace(err, abortHandshakeOrEmitwsClientError);
 
  server.emit('wsClientError', err, socket, req);
  } else {
- abortHandshake(socket, code, message);
+ abortHandshake(socket, code, message, headers);
  }
 }

test/websocket-server.test.js

@@ -813,6 +813,7 @@ describe('WebSocketServer', () => {
 
  req.on('response', (res) => {
  assert.strictEqual(res.statusCode, 400);
+ assert.strictEqual(res.headers['sec-websocket-version'], '13, 8');
 
  const chunks = [];
 
@@ -849,6 +850,7 @@ describe('WebSocketServer', () => {
 
  req.on('response', (res) => {
  assert.strictEqual(res.statusCode, 400);
+ assert.strictEqual(res.headers['sec-websocket-version'], '13, 8');
 
  const chunks = [];