This displays more useful messages for the most common issues we see:
- CSRF (when the user switches browser)
- Invalid IAT (when the server clock is wrong)
- OAuth::Unauthorized for OAuth1 providers, when the credentials are incorrect
This commit also stops earlier for disabled authenticators. Now we stop at the request phase, rather than the callback phase.
Previously the 'reconnect' process was a bit magic - IF you were already logged into discourse, and followed the auth flow, your account would be reconnected and you would be 'logged in again'.
Now, we explicitly check for a reconnect=true parameter when the flow is started, store it in the session, and then only follow the reconnect logic if that variable is present. Setting this parameter also skips the 'logged in again' step, which means reconnect now works with 2fa enabled.
Also added some helpful functionality for plugin developers:
- Raises RuntimeException if the auth provider has been registered too late
- Logs use of deprecated parameters
