Get IPrincipal from OAuth Bearer Token in OWIN

Question

I have successfully added OAuth to my WebAPI 2 project using OWIN. I receive tokens and can use them in the HTTP Header to access resources.

Now I want to use those tokens also on other channels for authentication that are not the standard HTTP requests that the OWIN template is made for. For example, I am using WebSockets where the client has to send the OAuth Bearer Token to authenticate.

On the server side, I receive the token through the WebSocket. But how can I now put this token into the OWIN pipeline to extract the IPrincipal and ClientIdentifier from it? In the WebApi 2 template, all this is abstracted for me, so there is nothing I have to do to make it work.

So, basically, I have the token as a string and want to use OWIN to access the user information encoded in that token.

Thank you in advance for the help.

Answer 1

I found a part of the solution in this blog post: http://leastprivilege.com/2013/10/31/retrieving-bearer-tokens-from-alternative-locations-in-katanaowin/

So I created my own Provider as follows:

public class QueryStringOAuthBearerProvider : OAuthBearerAuthenticationProvider
{
    public override Task RequestToken(OAuthRequestTokenContext context)
    {
        var value = context.Request.Query.Get("access_token");

        if (!string.IsNullOrEmpty(value))
        {
            context.Token = value;
        }

        return Task.FromResult<object>(null);
    }
}

Then I needed to add it to my App in Startup.Auth.cs like this:

OAuthBearerOptions = new OAuthBearerAuthenticationOptions()
{
   Provider = new QueryStringOAuthBearerProvider(),
   AccessTokenProvider = new AuthenticationTokenProvider()
   {
       OnCreate = create,
       OnReceive = receive
   },
};

app.UseOAuthBearerAuthentication(OAuthBearerOptions);

With a custom AuthenticationTokenProvider, I can retrieve all other values from the token early in the pipeline:

public static Action<AuthenticationTokenCreateContext> create = new Action<AuthenticationTokenCreateContext>(c =>
{
    c.SetToken(c.SerializeTicket());
});

public static Action<AuthenticationTokenReceiveContext> receive = new Action<AuthenticationTokenReceiveContext>(c =>
{
    c.DeserializeTicket(c.Token);
    c.OwinContext.Environment["Properties"] = c.Ticket.Properties;
});

And now, for example in my WebSocket Hander, I can retrieve ClientId and others like this:

IOwinContext owinContext = context.GetOwinContext();
if (owinContext.Environment.ContainsKey("Properties"))
{
    AuthenticationProperties properties = owinContext.Environment["Properties"] as AuthenticationProperties;
    string clientId = properties.Dictionary["clientId"];
...
 }