how to get login credentials by openId?

Question

Is is possible to get login credentials such as name/id if user does login by openId

Answer 1

You will not get their actual username (or password), but you will get their OpenID wich is unique.

Answer 2

There are two accepted methods for retrieving these kind of things by OpenID: SReg and Attribute Exchange (AX). Both of these are extensions to the standard OpenID specification; SReg is the older of the two and specifies a set of fields that can be requested and sent with authentication, whereas AX allows requesting of any attribute.

Both of the specification documents are pretty concise on how they work, although it's difficult to guage what the standard "names" are for attributes to be requested from AX. Usually, servers tend to implement the SReg names.

OpenID Simple Registration Extension Specification 1.0

OpenID Attribute Exchange Specification 1.0 Final