How to verify userCredentials inside WebApi using OAuth and twitter external provider?



I have created WebApi and enable TwitterAuthentication code.

On HomeController.cs used [Authorize] attribute.

Now how can I verify credentials and give access to Authorize Controller without open login box ?

 public void ConfigureAuth(IAppBuilder app)
            // Configure the db context and user manager to use a single instance per request

            // Enable the application to use a cookie to store information for the signed in user
            // and to use a cookie to temporarily store information about a user logging in with a third party login provider
            app.UseCookieAuthentication(new CookieAuthenticationOptions());

            // Configure the application for OAuth based flow
            PublicClientId = "self";
            OAuthOptions = new OAuthAuthorizationServerOptions
                TokenEndpointPath = new PathString("/Token"),
                Provider = new ApplicationOAuthProvider(PublicClientId),
                AuthorizeEndpointPath = new PathString("/api/Account/ExternalLogin"),
                AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
                // In production mode set AllowInsecureHttp = false
                AllowInsecureHttp = true

            // Enable the application to use bearer tokens to authenticate users

            // Uncomment the following lines to enable logging in with third party login providers
            //    clientId: "",
            //    clientSecret: "");

                consumerKey: "mykey",
                consumerSecret: "mysecret");

I have added one application into twitter app - get the consumer key. and consumer secret.

I do not want a twitter login popup to be opened for login credentials while authorizing webapi.