title: C# Read file info from URL
body: <p>In my ASP.NET MVC application I'm reading an external file from URL and saving it into a directory on my server. I do this in a loop for every few seconds to have actual data if the file was modified. </p>
  
  <p>What I need is to recognize that the <code>LastWrittenTime</code> of the file accessed via the URL is different from file already downloaded to the server. I cannot use <code>FileInfo</code> class because "URI formats are not supported".</p>
  
  <p>So how do I get the last written time of the file from the URL without needing to download the full file for every loop?</p>