How do I enable CORS in Socket.IO?

How do I enable CORS in Socket.IO?

To enable CORS in Socket.IO, you can set the cors option when initializing the server. For example: const io = require('socket.io')(server, { cors: { origin: '*', methods: ['GET', 'POST'] } }); This allows requests from any origin.

What does the origin option do?

The origin option specifies which domains are allowed to access your Socket.IO server. Using '*' allows all domains, but you can specify a specific domain for better security.

Can I restrict it to multiple origins?

Yes, you can restrict it to multiple origins by using a function for the origin option. For example: origin: (origin, callback) => { if (['http://example.com', 'http://another.com'].includes(origin)) { callback(null, true); } else { callback(new Error('Not allowed by CORS')); } }.

What about credentials?

To allow credentials, you need to set credentials: true in the CORS options. This allows cookies and HTTP authentication to be sent with requests.