[feat] Allow configuration of Access-Control-Allow-Origin value (#511)

It's now possible to specify an origins value (default value is '*') when initialising the engine. This value will be returned as the Access-Control-Allow-Origin value.

Related: #449

Author: flenter

README.md

@@ -228,6 +228,7 @@ to a single process.
       - `maxHttpBufferSize` (`Number`): how many bytes or characters a message
         can be, before closing the session (to avoid DoS). Default
         value is `10E7`.
+      - `origins` (`String`): the allowed origins (`*`)
       - `allowRequest` (`Function`): A function that receives a given handshake
         or upgrade request as its first parameter, and can decide whether to
         continue or not. The second argument is a function that needs to be

lib/server.js

@@ -45,6 +45,7 @@ function Server (opts) {
   this.allowUpgrades = false !== opts.allowUpgrades;
   this.allowRequest = opts.allowRequest;
   this.cookie = false !== opts.cookie ? (opts.cookie || 'io') : false;
+  this.origins = opts.origins || '*';
   this.cookiePath = false !== opts.cookiePath ? (opts.cookiePath || '/') : false;
   this.cookieHttpOnly = false !== opts.cookieHttpOnly;
   this.perMessageDeflate = false !== opts.perMessageDeflate ? (opts.perMessageDeflate || true) : false;
@@ -221,7 +222,7 @@ Server.prototype.handleRequest = function (req, res) {
   var self = this;
   this.verify(req, false, function (err, success) {
     if (!success) {
-      sendErrorMessage(req, res, err);
+      self.sendErrorMessage(req, res, err);
       return;
     }
 
@@ -242,7 +243,7 @@ Server.prototype.handleRequest = function (req, res) {
  * @api private
  */
 
-function sendErrorMessage (req, res, code) {
+Server.prototype.sendErrorMessage = function (req, res, code) {
   var headers = { 'Content-Type': 'application/json' };
 
   var isForbidden = !Server.errorMessages.hasOwnProperty(code);
@@ -254,20 +255,21 @@ function sendErrorMessage (req, res, code) {
     }));
     return;
   }
+
+  headers['Access-Control-Allow-Origin'] = this.origins;
+  headers['Vary'] = 'Origin';
   if (req.headers.origin) {
     headers['Access-Control-Allow-Credentials'] = 'true';
-    headers['Access-Control-Allow-Origin'] = req.headers.origin;
-  } else {
-    headers['Access-Control-Allow-Origin'] = '*';
   }
+
   if (res !== undefined) {
     res.writeHead(400, headers);
     res.end(JSON.stringify({
       code: code,
       message: Server.errorMessages[code]
     }));
   }
-}
+};
 
 /**
  * generate a socket id.
@@ -293,9 +295,12 @@ Server.prototype.handshake = function (transportName, req) {
   var id = this.generateId(req);
 
   debug('handshaking client "%s"', id);
+  var opts = {
+    origins: this.origins
+  };
 
   try {
-    var transport = new transports[transportName](req);
+    var transport = new transports[transportName](req, opts);
     if ('polling' === transportName) {
       transport.maxHttpBufferSize = this.maxHttpBufferSize;
       transport.httpCompression = this.httpCompression;
@@ -309,7 +314,7 @@ Server.prototype.handshake = function (transportName, req) {
       transport.supportsBinary = true;
     }
   } catch (e) {
-    sendErrorMessage(req, req.res, Server.errors.BAD_REQUEST);
+    this.sendErrorMessage(req, req.res, Server.errors.BAD_REQUEST);
     return;
   }
   var socket = new Socket(id, this, transport, req);
@@ -404,7 +409,10 @@ Server.prototype.onWebSocket = function (req, socket) {
       // transport error handling takes over
       socket.removeListener('error', onUpgradeError);
 
-      var transport = new transports[req._query.transport](req);
+      var opts = {
+        origins: this.origins
+      };
+      var transport = new transports[req._query.transport](req, opts);
       if (req._query && req._query.b64) {
         transport.supportsBinary = false;
       } else {

lib/transport.js

@@ -26,12 +26,14 @@ function noop () {}
  * Transport constructor.
  *
  * @param {http.IncomingMessage} request
+ * @param {Object} opts allows the origins option to be passed along
  * @api public
  */
 
-function Transport (req) {
+function Transport (req, opts) {
   this.readyState = 'open';
   this.discarded = false;
+  this.origins = opts.origins;
 }
 
 /**

lib/transports/index.js

@@ -27,10 +27,10 @@ exports.polling.upgradesTo = ['websocket'];
  * @api private
  */
 
-function polling (req) {
+function polling (req, opts) {
   if ('string' === typeof req._query.j) {
-    return new JSONP(req);
+    return new JSONP(req, opts);
   } else {
-    return new XHR(req);
+    return new XHR(req, opts);
   }
 }

lib/transports/polling-jsonp.js

@@ -21,8 +21,8 @@ module.exports = JSONP;
  * @api public
  */
 
-function JSONP (req) {
-  Polling.call(this, req);
+function JSONP (req, opts) {
+  Polling.call(this, req, opts);
 
   this.head = '___eio[' + (req._query.j || '').replace(/[^0-9]/g, '') + '](';
   this.foot = ');';

lib/transports/polling-xhr.js

@@ -18,8 +18,8 @@ module.exports = XHR;
  * @api public
  */
 
-function XHR (req) {
-  Polling.call(this, req);
+function XHR (req, opts) {
+  Polling.call(this, req, opts);
 }
 
 /**
@@ -58,11 +58,10 @@ XHR.prototype.onRequest = function (req) {
 XHR.prototype.headers = function (req, headers) {
   headers = headers || {};
 
+  headers['Access-Control-Allow-Origin'] = this.origins;
+  headers['Vary'] = 'Origin';
   if (req.headers.origin) {
     headers['Access-Control-Allow-Credentials'] = 'true';
-    headers['Access-Control-Allow-Origin'] = req.headers.origin;
-  } else {
-    headers['Access-Control-Allow-Origin'] = '*';
   }
 
   return Polling.prototype.headers.call(this, req, headers);

lib/transports/polling.js

@@ -27,8 +27,8 @@ module.exports = Polling;
  * @api public.
  */
 
-function Polling (req) {
-  Transport.call(this, req);
+function Polling (req, opts) {
+  Transport.call(this, req, opts);
 
   this.closeTimeout = 30 * 1000;
   this.maxHttpBufferSize = null;

lib/transports/websocket.js

@@ -21,8 +21,8 @@ module.exports = WebSocket;
  * @api public
  */
 
-function WebSocket (req) {
-  Transport.call(this, req);
+function WebSocket (req, opts) {
+  Transport.call(this, req, opts);
   var self = this;
   this.socket = req.websocket;
   this.socket.on('message', this.onData.bind(this));

test/server.js

@@ -58,7 +58,7 @@ describe('server', function () {
             expect(res.body.code).to.be(0);
             expect(res.body.message).to.be('Transport unknown');
             expect(res.header['access-control-allow-credentials']).to.be('true');
-            expect(res.header['access-control-allow-origin']).to.be('http://engine.io');
+            expect(res.header['access-control-allow-origin']).to.be('*');
             done();
           });
       });
@@ -75,7 +75,7 @@ describe('server', function () {
             expect(res.body.code).to.be(1);
             expect(res.body.message).to.be('Session ID unknown');
             expect(res.header['access-control-allow-credentials']).to.be('true');
-            expect(res.header['access-control-allow-origin']).to.be('http://engine.io');
+            expect(res.header['access-control-allow-origin']).to.be('*');
             done();
           });
       });
@@ -416,7 +416,7 @@ describe('server', function () {
             expect(res.body.code).to.be(3);
             expect(res.body.message).to.be('Bad request');
             expect(res.header['access-control-allow-credentials']).to.be('true');
-            expect(res.header['access-control-allow-origin']).to.be('http://engine.io');
+            expect(res.header['access-control-allow-origin']).to.be('*');
             done();
           });
       });
@@ -932,7 +932,7 @@ describe('server', function () {
     it('should trigger transport close before open for ws', function (done) {
       var opts = { transports: ['websocket'] };
       listen(opts, function (port) {
-        var url = 'ws://%s:%d'.s('0.0.0.50', port);
+        var url = 'ws://%s:%d'.s('0.0.0.0', port);
         var socket = new eioc.Socket(url);
         socket.on('open', function () {
           done(new Error('Test invalidation'));
@@ -2589,7 +2589,7 @@ describe('server', function () {
 
   describe('cors', function () {
     it('should handle OPTIONS requests', function (done) {
-      listen({handlePreflightRequest: true}, function (port) {
+      listen({handlePreflightRequest: true, origins: 'engine.io:*'}, function (port) {
         request.options('http://localhost:%d/engine.io/default/'.s(port))
           .set('Origin', 'http://engine.io')
           .query({ transport: 'polling' })
@@ -2599,7 +2599,7 @@ describe('server', function () {
             expect(res.body.code).to.be(2);
             expect(res.body.message).to.be('Bad handshake method');
             expect(res.header['access-control-allow-credentials']).to.be('true');
-            expect(res.header['access-control-allow-origin']).to.be('http://engine.io');
+            expect(res.header['access-control-allow-origin']).to.be('engine.io:*');
             done();
           });
       });
@@ -2624,7 +2624,7 @@ describe('server', function () {
         var headers = {};
         if (req.headers.origin) {
           headers['Access-Control-Allow-Credentials'] = 'true';
-          headers['Access-Control-Allow-Origin'] = req.headers.origin;
+          headers['Access-Control-Allow-Origin'] = '*';
         } else {
           headers['Access-Control-Allow-Origin'] = '*';
         }
@@ -2642,7 +2642,7 @@ describe('server', function () {
             expect(res.status).to.be(200);
             expect(res.body).to.be.empty();
             expect(res.header['access-control-allow-credentials']).to.be('true');
-            expect(res.header['access-control-allow-origin']).to.be('http://engine.io');
+            expect(res.header['access-control-allow-origin']).to.be('*');
             expect(res.header['access-control-allow-methods']).to.be('GET,HEAD,PUT,PATCH,POST,DELETE');
             expect(res.header['access-control-allow-headers']).to.be('origin, content-type, accept');
             done();