**Backport:** https://codeberg.org/forgejo/forgejo/pulls/12231#12202 began a refactor of Forgejo's authentication implementations by providing structured data on an authentication success. However, error cases were maintained as-is in that refactor, leaving a complex situation: what does returning an error from an authentication method mean?; does it mean that the authentication failed, or that a server error occurred? Can another authentication still be tried?
This PR changes authentication methods so that they can return one of four things:
- `AuthenticationSuccess` with an authentication result.
- `AuthenticationNotAttempted` which indicates that no credentials relevant for this authentication method were presented. If every method returned `AuthenticationNotAttempted`, then you would have an unauthenticated access.
- `AuthenticationAttemptedIncorrectCredential` which indicates that credentials were present and failed validation -- a situation indicating a `401 Unauthorized`.
- `AuthenticationError` which indicates that an internal server error occurred and failed authentication -- indicating a `500 Internal Server Error`.
This paves the way for one more refactor coming next: `basic.go` and `oauth2.go` perform 3-4 different authentications each (access tokens, oauth JWTs, actions tokens, actions JWTs, and username/password). With the capability to return these more precise responses, these authentication methods can be split up into separate logic that isn't intertwined together.
Co-authored-by: Mathieu Fenniak <mathieu@fenniak.net>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12468
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
**Backport:** https://codeberg.org/forgejo/forgejo/pulls/12202
Currently authentication methods return information in two forms: they return who was authenticated as a `*user_model.User`, and then they insert key-values into `ctx.Data` which has critical impact on how the authenticated request is treated. This PR changes the authentication methods to return structured data in the form of an `AuthenticationResult`, with all the key-value information in `ctx.Data` being moved into methods on the `AuthenticationResult` interface.
Authentication workflows in Forgejo are a real mess. This is the first step in trying to clean it up and make the code predictable and reasonable, and is both follow-up work that was identified from the repo-specific access tokens (where the `"ApiTokenReducer"` key-value was added), and is pre-requisite work to future JWT enhancements that are [being discussed](https://codeberg.org/forgejo/forgejo/issues/3571#issuecomment-13268004).
Co-authored-by: Mathieu Fenniak <mathieu@fenniak.net>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12462
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
