Facebook login using external bearer token (MVC4 Web Api)

Question

I'm trying to implement facebook login using external bearer token. I created new project in VS 2013 and selected individual user account authentication like in this tulorial http://www.asp.net/web-api/overview/security/external-authentication-services.

I configured facebook authentication:

app.UseFacebookAuthentication(
            appId: "123[...]",
            appSecret: "123[...]");

And all work fine.

My test method:

[OverrideAuthentication]
[HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)]
[Route("ExternalLogin2", Name = "ExternalLogin2")]
public async Task<IHttpActionResult> GetExternalLogin2()
{
    ExternalLoginData externalLogin = ExternalLoginData.FromIdentity(User.Identity as ClaimsIdentity);
    return Ok();
}

I don't understand how [HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)] works.

I invoke GET request in fiddler:

GET http://localhost:17353/api/Account/ExternalLogin2 HTTP/1.1
Authorization: Bearer [my facebook token]
Content-Length: 28
Host: localhost:17353

But I receive 401 result.

What I must do for authenticating by external bearer token?

Answer 1

I haven't found solution for this problem. But I solved task by another way. I added HTTP header X-Facebook-Token and passed it there. In overrided method GrantResourceOwnerCredentials(context) of OAuthAuthorizationServerProvider I caught the token from context.Request.Headers["X-Facebook-Token"].

string facebookToken = context.Request.Headers["X-Facebook-Token"];
if (facebookToken == null)
{
    context.SetError("invalid_grant", "Facebook token was not found in X-Facebook-Token header.");
    return;
}

dynamic facebookUser;
if (!FacebookUtil.TryGetUser(facebookToken, out facebookUser))
{
    context.SetError("invalid_grant", "Facebook token is incorrect.");
    return;
}

In FacebookUtil.TryGetUser() I used Facebook library http://www.nuget.org/packages/facebook

public static bool TryGetUser(string facebookToken, out dynamic user)
{
    var facebookClient = new FacebookClient(facebookToken)
    {
        AppId = AppSettings.FacebookAppId,
        AppSecret = AppSettings.FacebookAppSecret
    };

    try
    {
        user = facebookClient.Get("me");
        return true;
    }
    catch (Exception)
    {
        user = null;
        return false;
    }
}