Handle websocket authentication via initial payload

[alexandra-c]

Component(s)

router

Is your feature request related to a problem? Please describe.

The Cosmo router's built-in authentication currently looks for the JWT token only in the request header. For websocket requests made from a browser, headers cannot be altered, so the token can only be sent via URL Query, Cookie, or initial payload.

Currently, if the router configuration is set to authorization >> require_authentication: true, websocket requests will receive an Unauthorized response, causing Subscriptions to fail.

Describe the solution you'd like

The Cosmo router's websocket authentication behavior needs to be updated to allow the JWT token to be acquired from the initial payload as well as the header.

@jensneuse suggested the following implementation steps on Discord:

Add a configuration option to modify WebSocket authentication behavior to allow authentication via the initial payload.
Allow configuration of the initial payload field where the auth token is located.
Modify websocket.go to consider this configuration.

Describe alternatives you've considered

No response

Additional context

I have started working on a version of authentication that also looks for the token in the initial payload. I created this feature request to further discuss the implementation steps in more detail.

Thank you! :)

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[jensneuse]

Hey, thanks for opening this issue.
Can you describe how you'd like to solve this issue?
Ideally, you could start outlining the solution and create a PR that updates the Router config so that we can discuss how to implement this.

[alexandra-c]

Here's a draft of my implementation #918
I added a new configuration section for websocket that handles authentication, I was thinking in the future maybe other authentication methods may be implemented...
It looks something like this:

websocket:
  ...
  authentication:
    from_initial_payload:
      enabled: true
      secret_key: "authorization"

Then I separated the initialPayload authentication from the header one, so I defined a new authenticator websocketInitialPayloadAuthenticator and renamed the existing one in httpHeaderAuthenticator since it was only handling authentication via header.
Also extracted the JWT decoding part in a separate interface called jwksTokenDecoder in order to reuse it in both authenticators.

Now the problem is that in handleUpgradeRequest method from websocket.go file, we are checking access control before upgrading the connection, which for the auth via initial payload that's too soon, we won't have the initial payload. For ws auth via initial payload, the checking must be done later on, after handler.Initialize() is called, hence the new WebSocketAuthenticationConfiguration section, and then set tehn initialPayload to the request context so we can use it the authenticator. This probably can be made in a better way...I'm open to suggestions.

Can you take a look at the PR draft and share your thoughts regarding my implementation idea?

Thanks!

[StarpTech]

Fixed with #918