Why is my socket.io using long polling instead of the websocket?

Question

So I set up socket.io with a NodeJS + ExpressJS server and everything is working well. The only problem is I just realized that my emit() calls are using the f

Answer 1

Since Socket.IO 1.x, the fallback algorithm changed from a downgrade approach to an upgrade approach.

Long polling pretty much works everywhere, so that is used at first so you can get a "connection" right away. Then in the background, an attempt is made to upgrade the long polling connection to a websocket connection. If the upgrade is successful, the long polling stops and the session switches to the websocket connection. If it's not successful, the long polling "connection" stays open and continues to be used.