WellKnownEndpoints know how to create an endpoint specific MessageExtension for retrieving the WellKnownAttributes Usefull for use in combination with the beforeAuth callback on OpenIDConsumer. The following example shows a method that can be passed to beforeAuth to add an extension that fetches the Email, FullName, FirstName & LastName attributes from the selected endpoint.

  def ext(di:DiscoveryInformation, authReq: AuthRequest): Unit = {
   import WellKnownAttributes._
   WellKnownEndpoints.findEndpoint(di) map {ep 
     => ep.makeAttributeExtension(List(Email, FullName, FirstName, LastName)) foreach {ex => authReq.addExtension(ex)}}
 }
 

See MetaOpenIDProtoUser for an example of how to extract the returned attribute values