In the past we would build the stack of Omniauth providers at boot, which meant that plugins had to register any authenticators in the root of their plugin.rb (i.e. not in an `after_initialize` block). This could be frustrating because many features are not available that early in boot (e.g. Zeitwerk autoloading).
Now that we build the omniauth strategy stack 'just in time', it is safe for plugins to register their auth methods in an `after_initialize` block. This commit relaxes the old restrictions so that plugin authors have the option to move things around.
Previously, we would build the stack of omniauth authenticators once on boot. That meant that all strategies had to be included, even if they were disabled. We then used the `before_request_phase` to ensure disabled strategies could not be used. This works well, but it means that omniauth is often doing unnecessary work running logic in disabled strategies.
This commit refactors things so that we build the stack of strategies on each request. That means we only need to include the enabled strategies in the stack - disabled strategies are totally ignored. Building the stack on-demand like this does add some overhead to auth requests, but on the majority of sites that will be significantly outweighed by the fact we're now skipping logic for disabled authenticators.
As well as the slight performance improvement, this new approach means that:
- Broken (i.e. exception-raising) strategies cannot cause issues on a site if they're disabled
- `other_phase` of disabled strategies will never appear in the backtrace of other authentication errors
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
