c# - OpenID: Trying to Get Email Address from Google OP

Question

I’m using dotnetopenauth 3.2 to implement Openid and can’t figure out how to get Google to pass the email address in the Claims Response. I know that Google doesn’t support simple registration, but I can’t determine what they do support.

Caveat to this question is that I just started learning OpenID and I know I don’t have a solid grasp on the specification which I think is leading to my confusion.

Any help would be appreciated!

Answer 1

Ok figured it out. I posted a question on Goolge's Federated Log API group and was told to use Attribute exchange.

Below is the code for DotNetOpenAuth.

Please don't use this code in production. This is for illustration purposes only!

The Request:

using (OpenIdRelyingParty openid = new OpenIdRelyingParty())
{
    IAuthenticationRequest request = openid.CreateRequest(openidurl);

    var fetch = new FetchRequest();
    fetch.Attributes.AddRequired(WellKnownAttributes.Contact.Email);
    request.AddExtension(fetch);

    // Send your visitor to their Provider for authentication.
    request.RedirectToProvider();
}

The Response:

OpenIdRelyingParty openid = new OpenIdRelyingParty();
var response = openid.GetResponse();
if (response != null)
{
    switch (response.Status)
    {
        case AuthenticationStatus.Authenticated:
        {
            var fetch = response.GetExtension<FetchResponse>();
            string email = string.Empty();
            if (fetch != null)
            {
                email =  fetch.GetAttributeValue(
                    WellKnownAttributes.Contact.Email);
            }

            FormsAuthentication.RedirectFromLoginPage(
                response.ClaimedIdentifier, false);
            break;
        }
        ...
    }
}