SilverStripe\SAML\Control\SAMLController::acs
Assertion Consumer Service
The user gets sent back here after authenticating with the IdP, off-site. The earlier redirection to the IdP can be found in the SAMLAuthenticator::authenticate. After this handler completes, we end up with a rudimentary Member record (which will be created on-the-fly if not existent), with the user already logged in. Login triggers memberLoggedIn hooks, which allows LDAP side of this module to finish off loading Member data.
Signature
public function acs()