WebSocket has fewer instances than Raw

[3noch]

I don't understand the internals yet but it's clear that the WebSocket type is lacking some instances that Raw has. When trying to wrap servant-auth's Auth combinator around Raw, things work fine. But if I wrap it around WebSocket I get a No instance for (HasServer (AddSetCookieApi (AddSetCookieApi WebSocket)) '[CookieSettings, JWTSettings]).

[moesenle]

Thanks for the report! I'm also still pretty inexperienced with the internals of servant. This library was more like an early experiment. But I'll look into it as soon as I have time.

[3noch]

Actually I might be wrong about this. It may be that servant-auth has specific handling of Raw. I'll need to see if it is extensible!

[SamProtas]

So I ran into this issue as well (servant-auth authenticated Websockets not type-checking) and here's what I came up with:

type instance AddSetCookieApi WebSocket = WebSocket

instance AddSetCookies ('S n) (m ()) (m ()) where
  addSetCookies _ a = a

I'm currently using:

servant-auth 0.3.1.0
servant-auth-server 0.3.2.0
servant-websockets 1.1.0

At this point I think this needs to stay an orphan as I doubt either servant-auth or servant-websockets will aquire the other as a dependency.

Assuming I'm understanding the problem (and solution) correctly, it may be beneficial to change the associated types for HasServer Websocket m etc. to something like Connection -> m WebsocketNoResponse instead of Connection -> m (). This way, the orphan instance above won't clobber someone actually trying to return () somewhere. In general, I don't think the endpoint really "returns" anything, so a custom datatype might let other combinators work better with this library by making it easier to handle edge cases like this without clobbering another use case.

[dnikolovv]

Any solution to this?

I tried @SamProtas's suggestion, but I get • Overlapping instances for Servant.Auth.Server.Internal.AddSetCookie.AddSetCookies.

[Gab0]

Hello, I can use Servant.Auth with Raw. But when I have a server with Servant.Auth and a Servant.WebSockets endpoint I get the same error as @dnikolovv. Does anyone manage to solve this or have an idea on how to start?