s-fabian/websocket-issue

Websocket issue

Scenario one: yarn without-next

1. Visit http://localhost:3000/ws/html
2. The browser tries to connect to the websocket server
3. The server receives the request, logs "Websocket trying to connect!"
4. The server handles the request (in this case returns a 501)
5. The error or connect event of the websocket is triggered

Scenario two: yarn with-next

1. Visit http://localhost:3000/
2. Close the tab
3. Visit http://localhost:3000/ws/html
4. The browser tries to connect to the websocket server
5. The server doesn't receive the request, doesn't log "Websocket trying to connect!"
6. No event is triggered on the websocket

Solution: yarn with-next-fix

How? Well, the problem is caused by app?.getRequestHandler()().

This function adds a listener onto the server matching the upgrade event.

This can be prevented by overriding the function that's used to add an event listener into caching the function for the event handler into a local variable.

Now you can call this variable if the url matches /_next/webpack-hmr, otherwise you can use your own websocket logic.