I have a small app deployed at temporaryhack.com for playing around with Elixir/Phoenix/LiveView etc.
The main page I converted to a LiveView - though it doesn’t do anything “LiveView-specific” just yet.
When deployed on fly.io, websockets are broken:
WebSocket connection to 'wss://temporaryhack.com/live/websocket?_csrf_token=Jms9AAQSPR4YbUsAOSN5JzUsYlUSRAwOn-N8BJpL_5sKtp-sPXW2KsvQ&_track_static%5B0%5D=https%3A%2F%2Ftemporaryhack.com%2Fassets%2Fapp-f1ac6921074f4d4f0db4ec733775c544.css%3Fvsn%3Dd&_track_static%5B1%5D=https%3A%2F%2Ftemporaryhack.com%2Fassets%2Fapp-4fe838d26a3620637ab66dd64d0c15a2.js%3Fvsn%3Dd&_mounts=0&vsn=2.0.0' failed:
This only happens when deployed to fly.io, I am unable to reproduce this issue locally.
I’m new to LiveView, and surely just missing something straightforward.
Thanks for the help!
What is the value if your check_origin config in config/runtime.exs. By default, we ensure the websocket connections match the URL host of the endpoint. For recent phoenix projects this is usually set to the PHX_HOST environment variable which is configured in your fly.toml. My guess is this value is the original fly.dev domain, but needs to be changed to your temporaryhack.com domain.
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Sure enough, that did it.
Thanks!
Errr actually you were proposing something slightly different, let me do that.
Great! For posterity for you and others, you can also do check_origin: :conn, which will allow any x-forwarded-for host. This is convenient if you have multiple domains that you don’t want to list explicitly, but can only be used if you are behind a proxy such that you can trust x-forwarded wasn’t set by the client. Fly sets this header so check_origin: :conn is a good option, but you’ll still want to configure your endpoint’t :url (which is based on PHX_HOST by default) for link/url generation.
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