context.Request.User is null in OWIN OAuthAuthorizationServerProvider

Question

I'm trying to implement OAuth using OWIN for a Web API v2 endpoint on my local intranet. The API is hosted in IIS using built-in Windows Authentication. In short, this is what I want to happen.

When I ask for my Token at /token

Pull the WindowsPrincipal out of the OWIN context
Use the SID from the WindowsPrincipal to look up some roles for this user in a SQL table.
Create a new ClaimsIdentity that stores the username and roles
Turn that into a Json Web Token (JWT) that I sent bak

When I request a resource from my API using my token

Convert the JWT Bearer token back to the ClaimsIdentity
Use that ClaimsIdentity for authorizing requests to the resource by role
This way I don't have to do a database lookup for user roles on each request. It's just baked into the JWT.

I think I'm setting everything up correctly. My Startup.Configuration method looks like this.

public void Configuration(IAppBuilder app)
{

    // token generation
    // This is what drives the action when a client connects to the /token route
    app.UseOAuthAuthorizationServer(new OAuthAuthorizationServerOptions
    {
        // for demo purposes
        AllowInsecureHttp = true,

        TokenEndpointPath = new PathString("/token"),
        AccessTokenExpireTimeSpan = TimeSpan.FromHours(8),
        AccessTokenFormat = GetMyJwtTokenFormat(),
        Provider = new MyAuthorizationServerProvider()
    });



    //// token consumption
    app.UseOAuthBearerAuthentication(
        new OAuthBearerAuthenticationOptions()
        {
            Realm = "http://www.ccl.org",
            Provider = new OAuthBearerAuthenticationProvider(),
            AccessTokenFormat = GetMyJwtTokenFormat()
        }
    );


    app.UseWebApi(WebApiConfig.Register());

}

MyAuthorizationServerProvider looks like this...

    public class MyAuthorizationServerProvider : OAuthAuthorizationServerProvider
    {

        public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {

            // Since I'm hosting in IIS with Windows Auth enabled
            // I'm expecting my WindowsPrincipal to be here, but it's null  :(
            var windowsPrincipal = context.OwinContext.Request.User.Identity;

            // windowsPrincipal is null here.  Why?

            // Call SQL to get roles for this user

            // create the identity with the roles
            var id = new ClaimsIdentity(stuff, more stuff);

            context.Validated(id);
        }
    }

My problem is that context.Request.User is null here. I can't get to my WindowsPrincipal. If I create some other dummy middleware, I can get to the WindowsPrincipal without issue. Why is it null in this context? Am I doing something wrong?

Tratcher Tratcher · Accepted Answer · 2014-07-30T19:17:40

Swap the order of UseOAuthAuthorizationServer and UseOAuthBearerAuthentication. UseOAuthBearerAuthentication calls UseStageMarker(PipelineStage.Authenticate); to make it (and everything before it) run earlier in the ASP.NET pipeline. User is null when you run during the Authenticate stage.

context.Request.User is null in OWIN OAuthAuthorizationServerProvider

1 Answers