Added WebSocket arg to allow manually setting port

[ijjk]

Saw a reply on the original pull request that the WebSocket using a random port broke their set up so I added a --websocket or -w argument similar to the -p argument to allow manually setting this port also.

[timneutkens]

Could someone that ran into this explain exactly why this wouldn't work? We're using Node.js defaults by listening on port 0. So it seems like the correct default / the user shouldn't need to worry about this 🤔

[timneutkens]

Potentially because of a docker-compose type environment I guess?

[ijjk]

Yeah, I would think using a random port would work for most setups using Next. Although being able to manually map it could be good in case anyone keeps their environment's firewall locked down on a port basis or they are using a docker-compose environment as you said.

@glenarama could you explain a little more your use case for manually mapping the WebSocket port?

[ghost]

I'm using a Chromebook, it has a Linux container which I use for Dev.
In order to do local in browser testing/dev I need to open up specific ports. Currently the page reloads every few seconds because the port is blocked.

[timneutkens]

I think this should only be a next.config.js option. I'm not sure about the name though 🤔 devWebsocketPort 🤔

[ijjk]

The devWebSocketPort name seems to make sense, I just pushed up that change.

[timneutkens]

@ijjk could you add a section to the readme explaining that by default there is no need to configure this, but if you do you can do it by setting devWebSocketPort

[timneutkens]

Could you also add a test for this if possible. There's a test suite for config options in test/integration/config

[ijjk]

I added a note in the README under "Configuring the onDemandEntries" let me know if that's not the right place for it. I also added a test in the suite you mentioned. I had to dynamically write to the next.config.js for that test suite since there is the possibility of the port I define in the config being unavailable.

[timneutkens]

Let's always read from devWebsocketPort and add 0 as a default in packages/next-server/server/config.js` Then we have a single source of truth 👍

[ijjk]

Good idea, I updated it

[timneutkens]

I just realized we have a onDemandEntries key, totally forgot about it 🤦‍♂️ Can you move devWebSocketPort under onDemandEntries and call it websocketPort 🕵️

[timneutkens]

Then I'll merge 💯

[timneutkens]

As per my updated comment, sorry for changing it yet again 😅

[ijjk]

It's all good, that seems like a better place for it. I also moved the onDemandEntries config to the defaultConfig to keep that as the source of truth.

[ghost]

Thanks guys, really appreciate it!!

[timneutkens]

Awesome thanks so much 🙏 Happy new year!

[ijjk]

Happy New Year to you too!