Share 'Securely verifying the viewer is who he claims to be'

I read the NingApi pdf section 2.2 on authentication, I am using the php classes from github. However I seem to authenticate that I am I (a developer with access rights to a ning network) but i can't authenticate that the viewer is the user he claims to be Similar to this users post I want to get the current users email when he's viewing an external PHP file. With the api I seem to be able to get…