Varied fixes and additions

[mjauvin]

Related to wintercms/winter#1133

• Add access_token to the user metadata
• Add LinkedIn OpenID provider (supported by socialite)
• Add Providers controller and model
• Add events to extend the plugin
• Move providers button generation into a view
• Extra scopes added to the provider config are now passed to the provider.
• Handle callback exception by flashing the error and redirecting back to signin page
• Signin Page is retrieved from the session, so it can be changed by other plugins with different signin page

[mjauvin]

@LukeTowers what did you have in mind exactly with the prevent_native_auth config?

[mjauvin]

@LukeTowers in Handle::callback() you wrote this @TODO comment:

        // Check if the user is allowed to keep a persistent session
        if (is_null($remember = Config::get('cms.backendForceRemember', false))) {
            $remember = false;
            // @TODO: Get this from the request
            // $remember = (bool) post('remember');
        }

But it won't work since callback is a GET request coming from the provider (post values from the signin form are not available here, unless they get saved in some other way?)

[mjauvin]

But it won't work since callback is a GET request coming from the provider (post values from the signin form are not available here, unless they get saved in some other way?)

@mjauvin In order to support that we'd probably need to store a value in the session before redirecting them away and retrieve it when they come back.

So we'd need an ajax handler for the remember checkbox that sets this in the session ?

[mjauvin]

@LukeTowers For the event I named winter.sso.register, I guess we would add {before/after}Register methods to the AuthManager and call this from the winter.sso plugin ? And the external events (*.user.beforeRegister / *.user.register) would be triggered from those methods ?

Should I submit a PR to add these methods to the backend AuthManager and to another for the Winter.User to add to its AuthManager ?

[mjauvin]

@LukeTowers see latest commit for the new event methods. Is that what you envisioned or similar?

Maybe the {after/before}Register event methods should be called within the AuthManager's register() method itself ?