We need to add support to login using windows live into the windows store application. The backend web service authenticates the user identity using one of the well known providers – google, facebook and now windows live.

WebAuthenticationBroker comes handy to get authentication code in the windows store app. authentication code is passed to the backend web service. sample code below:

Windows.Security.Authentication.Web.WebAuthenticationBroker.authenticateAsync(
    Windows.Security.Authentication.Web.WebAuthenticationOptions.none,
    // redirect_uri parameter is encodeUriCcomponent('https://login.live.com/oauth20_desktop.srf')
    //  scope can be wl.basic others. refer other scope values here
    // client id is created by adding your application here
    new Windows.Foundation.Uri('https://login.live.com/oauth20_authorize.srf?client_id=&redirect_uri=https%3A%2F%2Flogin.live.com%2Foauth20_desktop.srf&response_type=code&scope=wl.emails'),
    new Windows.Foundation.Uri('https://login.live.com/oauth20_desktop.srf')).then(
       function (result)
       {
           if (result.responseStatus === Windows.Security.Authentication.Web.WebAuthenticationStatus.success)
           {
               var uri = new Windows.Foundation.Uri(result.responseData);
               var code = uri.queryParsed.getFirstValueByName('code');
           }
       }).then(null, function onerror(innerError)
       {
           // handle error
       });

Important notes:

1. http://login.live.com/oauth20_token.srf api to get token from authentication code fails with 500 internal server error if HTTP POST is used as per documentation. HTTP GET has to be used instead. documentation is out of date. Refer this thread at msdn.