Question

I am trying to use DotNetOpenAuthto authenticated user which I am able to do. But I am not able to figure out a way to get additional parameters like email, firstname, lastname etc which are provided by the google.

The code snippet which I am using is:

<%@ Register Assembly="DotNetOpenAuth" Namespace="DotNetOpenAuth.OpenId.RelyingParty" TagPrefix="rp" %>

………………………….

<rp:OpenIdButton runat="server" ID="OpenIdTextButton1"
    OnLoggedIn="OpenIdTextBox1_LoggedIn"
    Text="aaaa"
    Identifier="https://www.google.com/accounts/o8/id" 
    />

Answer 1

Several hints in my blog post How to pretty much guarantee that you might get an email address with OpenID.

In short, you need to activate the AXFetchAsSregTransform behavior:

<configuration>
   <configSections>
      <section name="dotNetOpenAuth" type="DotNetOpenAuth.Configuration.DotNetOpenAuthSection" requirePermission="false" allowLocation="true"/>
   </configSections>
   <dotNetOpenAuth>
      <openid>
         <relyingParty>
            <behaviors>
               <!-- The following OPTIONAL behavior allows RPs to use SREG only, but be compatible
                    with OPs that use Attribute Exchange (in various formats). -->
               <add type="DotNetOpenAuth.OpenId.Behaviors.AXFetchAsSregTransform, DotNetOpenAuth" />
            </behaviors>
         </relyingParty>
      </openid>
   </dotNetOpenAuth>
</configuration>

And then you need to tell the Provider that you require the user’s email address. Ideally this would be done like this:

<rp:OpenIdButton runat="server"
    Text="Log in with Google"
    Identifier="https://www.google.com/accounts/o8/id">
    <Extensions>
        <sreg:ClaimsRequest Email="Require" />
    </Extensions>
</rp:OpenIdButton>

However there is a bug in DotNetOpenAuth (v3.4.7 fixes this) that keeps the <Extensions> tag from working on OpenIdButton. So instead, you must add the attribute request in your code-behind. So your tag looks like:

<rp:OpenIdButton runat="server"
    Text="Log in with Google"
    OnLoggingIn="OpenId_LoggingIn" 
    Identifier="https://www.google.com/accounts/o8/id" />

And your code-behind has this method:

protected void OpenId_LoggingIn(object sender, OpenIdEventArgs e) {
    e.Request.AddExtension(new ClaimsRequest() { Email = DemandLevel.Require });
}