title: AngularJS with .NET Web API: Authentication with AD
body: <p>I have a .NET Web API with a bunch of end points/methods that an Angular App calls.  I want to now implement the login system against our active directory, and wondering what my options are. </p>
  
  <p>Back in the days, it was simple: windows or forms authentication, and then just some simple configuration in the web.config, and may be a custom provider. But now it seems like there are a lot more options with OWIN, OAuth, token based authentication, etc.  </p>
  
  <p>Where do I start? I have a form with username, password, and a login button on the Angular app, and I have the active directory in the backend. What should happen after the user hits the login button? Any direction would help.</p>
  
  <p>Thanks.</p>