title: Considerations when turning on RouteExistingFiles
body: <p>I am looking to generate <em>some</em> CSS files dynamically in my Content folder.</p>
  
  <p>At the moment, this folder has an ignore route (<code>routes.IgnoreRoute("Content/{*wildcard}");</code>) and, I'd like that to remain, as I don't need/want most of my content folders to go into the MVC request lifecycle.</p>
  
  <p><strong>Example:</strong></p>
  
  <pre><code> routes.MapRoute(
    "DynamicCSS",
    "Content/Css/Dynamic/{guid}.css",
    new { controller = "Site", action = "GenerateCSS" },
    new { guid = @"^([0-9a-fA-F]){8}([0-9a-fA-F]){4}([0-9a-fA-F]){4}([0-9a-fA-F]){4}([0-9a-fA-F]){12}$" }
  );
  
  //If the file has already been generated, IIS should just return the file, saving a request in MVC.
  routes.RouteExistingFiles = true; //was formerly false
  
  //Ignore routes
  routes.IgnoreRoute("Content/{*wildcard}");
  </code></pre>
  
  <p>I have a couple questions/concerns about this setup:</p>
  
  <ul>
  <li>Will this work? Routes in ASP.NET MVC are lazy, but I don't know if the ignore routes are checked first. There's no documentation (I've Googled!) on this form of usage.</li>
  <li>Are there any security implications to consider when switching on <code>RouteExistingFiles</code>? I don't want IIS to pick up any of my Model/Views folders by directly referencing them.</li>
  </ul>
  
  <p>Many thanks for any suggestions.</p>
  
  <p><strong>Edit:</strong></p>
  
  <p>After further research, I have found an <a href="http://stevesmithblog.com/blog/ignoreroute-in-asp-net-routing-is-order-dependent/" rel="nofollow noreferrer">article</a> on my first issue.</p>