I'm implementing an XMPP client for Google Talk that is using the relatively new X-OAUTH2 mechanism. I had the idea that I shouldn't need to store either username or password for the authentication to the service. However, Google's documentation for the X-OAUTH2 authentication states this is the initial <auth>
request to make:
<auth xmlns="urn:ietf:params:xml:ns:xmpp-sasl"
mechanism="X-OAUTH2"
auth:service="oauth2"
xmlns:auth="http://www.google.com/talk/protocol/auth">
base64("\0" + user_name + "\0" + oauth_token)
</auth>
Note that it requires the "user_name" to be sent along with the token. Is there something I'm missing here? Or do I really have to have my application prompt for the username? (Note that the user would already have logged in via OAuth2 to receive the access token)
I don't know of any other service that uses OAuth that requires the client to provide a username. For instance, this same app can connect to Facebook Chat via XMPP and OAuth2 without needing the username to be provided in XMPP.