FR: notification/documentation on oidc_login_disable_registration

[r2evans]

Up front, my thanks an accolades for this working plugin!

Related to #14 and my recent comment.

I know that the oidc_login_disable_registration behavior is mentioned in the readme. I believe that the mistake I made (and @buekera) is easy to make: the authentication appears to go well, but it does not gain entry into nextcloud. The issue is the concept/ramifications of "registration". I wholly agree that the default behavior is reasonable and the smart thing to do.

I have two suggestions (requests):

1. Improve the documentation to include some ramifications:

   -    // Disable creation of new users from OIDC login
   +    // Disable creation of users new to Nextcloud from OIDC login.
   +    // A user may be known to the IdP but not (yet) known to Nextcloud.
   +    // This setting controls what to do in this case.
   +    // - 'true' (default): if the user authenticates to the IdP but is not known to Nextcloud,
   +    //     then they will be returned to the login screen and not allowed entry;
   +    // - 'false': if the user authenticates but is not yet known to Nextcloud,
   +    //     then the user will be automatically created; note that with this setting,
   +    //     you will be allowing (or relying on) a third-party (the IdP) to create new users
        'oidc_login_disable_registration' => true,
   

2. Is there a way to mention this either in the logs or in the interface? Perhaps something referencing either "user creation", "registration", or something to indicate that this configuration stopped the user experience.

[pulsejet]

Sorry for being unresponsive.

We are actually throwing a relevant error, so it should show up when the user does not exist in NC db. Did this error not show up for you? That may be worth investigation. https://github.com/pulsejet/nextcloud-oidc-login/blob/fbedcd4ed18d73493e9265c96e4b4e7323010cfd/lib/Controller/LoginController.php#L201

But I agree this can be a bit confusing. Can you make a PR with the README change mentioned above?