title: Authenticating with Web API
body: <p>I am using ASP.NET WebAPI for a web service that I am building. He web service will use the Identity service to authenticate users.</p>
  
  <p>I am a bit stuck as to how to authenticate users externally. Our current system is very basic- we send a username and password in the XML request as a separate field and it is all done in 1 request.</p>
  
  <p>From what I can see from looking on Google, the best way is to request a token from the Ali and then pass this token in subsequent requests. Is there a way where I can do it all in 1 request (that is, send to the API my request for data as well as the username/password or perhaps an API key in a single request?)</p>