Samantha J Samantha J - 2 months ago 22
AngularJS Question

Example of an SPA with a login screen that uses AngularJS and connects to ASP.NET Web API 2?

I would like to create a new AngularJS, Web API Single page application. Does anyone have any examples that show how I can set up a user login screen that connects to a WEB API controller for a simple login (no need for google/facebook login etc) that uses ASP.NET Identity and without the need for user registration.

Also how can I handle showing a new view once the login has been completed. What I would like is to have a solution that does not show routing in the browser URL. So for example I would like to be able to switch from the login view and a couple of other different views without the url changing from

www.abc.com
.

In other words I would like to avoid showing
www.abc.com/login
,
www.abc.com/screen1
,
www.abc.com/screen2


Any advice would be much appreciated.

Answer

So, instead of trying to find an example, I created one instead (link at the bottom). To explain how the functionality works, I want to go over a few things:

  • The new ASP.NET Identity system provides an OAuth 2.0 Bearer token implementation which can be used with clients that consume a Web API resource over HTTP. Since the authentication is not stored in a session cookie, the server is not responsible for maintaining the authentication state. The side-effect is that the consumer has to manage authenticating the server and managing the returned token. This is the system that Microsoft uses in the SPA template that it provides with VS 2013.

  • AngularJS makes no assumptions about authentication, so it's up to you how to authenticate.

  • AngularJS provides the $http service for querying remote HTTP-based services as well as $resource which is built on top of $http. Using Authorization headers with the Bearer token implementation above, you can combine both to provide authenticated access to server resources over HTTP. AngularJS allows you to set a 'default' Authorization header which it will use in every subsequent HTTP transaction.

With that in mind, the way I accomplished this is by creating a User service that handles all of the authentication details, including setting the HTTP Authorization header, between the Web API server and the SPA. Based on the authentication status of the user, you can hide certain UI elements in order to prevent navigation. However, if you also define the state as requiring authentication as a property of the resolve object for the state, a watcher set on the $stateChangeError event will capture the error and redirect the user to the login form. Upon proper authentication, it will then redirect the user to the state they were trying to navigate to.

In order to prevent authentication from being lost between browser sessions (since the client is responsible for maintaining the authentication token, and that token is maintained in memory), I also added the ability for the user to persist the authentication to a cookie. All of this is transparent to the user. For them, it is practically identical to traditional form-and-session based authentication.

I'm not sure why you want to prevent the user from seeing the routes, but I have coded it as such. I am in debt to Sedushi's Plunker example of how to use AngularUI Router to navigate in a stateful manner without using URLs. Still, I'm not sure I can personally recommend this for any application I would write on my own.

The full solution (both the WebAPI and the WebUI) is available with step-by-step instructions here.

Let me know about any specific part that is unclear, and I will try to make it more clear in the answer.