Rescue specific exceptions in Authenticable

[aldesantis]

Currently, Knock::Authenticable rescues all exceptions when trying to decode the JWT and find the user. This is an anti-pattern: if, for whatever reason, either .from_token_payload or any other piece of the code in the rescue block fails for an unexpected reason, authentication will silently fail.

In the best-case scenario, this means that the developer is left to debug a confusing issue without the required context.

In the worst-case scenario, authentication fails and the developer does not know about it (it should be caught by tests, but not all applications are tested properly, as we all know).

This PR changes Knock::Authenticable#define_current_entity_getter to only rescue ActiveRecord::RecordNotFound and JWT::DecodeError, the two errors which should be handled. All other errors will crash the application, as one would expect.

I have run the existing test suite against the PR and it passes.

[aldesantis]

@nsarno have you had a chance to review this? :)

[nsarno]

@alessandro1997 I haven't. I'm way behind on reviewing PR's at the moment. Sorry about that.

[aldesantis]

No problem! Thank you for all the work you did with Knock so far.

[nsarno]

Ideally we don't want to force the dependency on ActiveRecord, so you could replace:

ActiveRecord::RecordNotFound with Knock.not_found_exception_class

see: https://github.com/nsarno/knock/blob/master/lib/knock.rb#L20

[aldesantis]

@nsarno fixed! :)

[nsarno]

Thank you @alessandro1997 👍