<p><strong>Fields: AuthId, LdapSearchAttributes, LdapSearchValue</strong></p>
<p>You may specify an authentication-source-id which will be used to authenticate the user.
    The AuthId must match one of the authentication-sources, definded in the identity providers configuration.
    (For simplesamlphp look at config/authsources.php) If it does not match, the identity provider will throw an error.
    You can use this field, to switch over to a LDAP for example.
    If the field is empty, the authentication will be against the user-data in the webservice.</p>
<p>If your AuthId links to a LDAP-configuration, you may use the fields LdapSearchAttributes,
    to set the search-attributes, LDAP should use, to find the user.
    The value can be a simple string or a comma separated list of values.</p>
<p>Within the LdapSearchValue you can set an alternative username, the LDAP should use as the search-value.
    If you leave it empty, the username-value from the login-form will be used.</p>