How to enable CORS on express.js 4.x on all files?

Question

I keep receiving

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://example.com:2013/socket.io/?EIO=3&transport=polling&t=1433950808025-0. (Reason: CORS request failed).

while I try to access my node.js. This doesn't work for me:

app.use(function(req, res, next) {   res.header("Access-Control-Allow-Origin", "*");   res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");   next(); }); 

@edit: here is the updated full code:

var express = require('express'); var http = require('http'); var expressvar = express();  expressvar.use(function (req, res, next) {     res.setHeader('Access-Control-Allow-Headers', 'accept, authorization, content-type, x-requested-with');     res.setHeader('Access-Control-Allow-Methods', 'GET,HEAD,PUT,PATCH,POST,DELETE');     res.setHeader('Access-Control-Allow-Origin', req.header('origin'));     next(); }); expressvar.use(express.static('../')); expressvar.use("/socket.io", express.static('../socket.io')); var app = http.createServer(expressvar); var io = require('socket.io').listen(app); app.listen(2013); 

Answer 1

Try this solution (edited to include full working code)

var app = require('express')(); var server = require('http').Server(app); var io = require('socket.io')(server);  io.set('origins', '*:*');  app.use(function(req, res, next) {   res.header('Access-Control-Allow-Origin', req.get('Origin') || '*');   res.header('Access-Control-Allow-Credentials', 'true');   res.header('Access-Control-Allow-Methods', 'GET,HEAD,PUT,PATCH,POST,DELETE');   res.header('Access-Control-Expose-Headers', 'Content-Length');   res.header('Access-Control-Allow-Headers', 'Accept, Authorization, Content-Type, X-Requested-With, Range');   if (req.method === 'OPTIONS') {     return res.send(200);   } else {     return next();   } });  server.listen(80);  app.get('/', function (req, res) {   res.send('OK'); });  io.on('connection', function (socket) {   socket.emit('news', { hello: 'world' });   socket.on('my other event', function (data) {     console.log(data);   }); }); 

Answer 2

cors package does this

// npm install --save cors var express = require('express'); var cors = require('cors'); var app = express(); app.use(cors()); app.use(express.static()); app.get('*', function(){}); require('http').createServer(app).listen(3000)