title: asp.net mvc learn from what host the resource has been requested
body: <p>How to learn from what host the resource, for example js a file has been requested?</p>
  
  <p>Example</p>
  
  <p><strong>site.com -> request from mySite.com/api.js</strong></p>
  
  <p>I so understand, I should use RouteConstraint?</p>