IIS Asset cache fingerprinting.

Fingerprint.cs

//source-reference http://madskristensen.net/post/cache-busting-in-aspnet

using System; 
using System.IO; 
using System.Web; 
using System.Web.Caching; 
using System.Web.Hosting;
public class Fingerprint 
{ 
  public static string Tag(string rootRelativePath) 
  { 
    if (HttpRuntime.Cache[rootRelativePath] == null) 
    { 
      string absolute = HostingEnvironment.MapPath("~" + rootRelativePath);
      DateTime date = File.GetLastWriteTime(absolute); 
      int index = rootRelativePath.LastIndexOf('/');
      string result = rootRelativePath.Insert(index, "/v-" + date.Ticks); 
      HttpRuntime.Cache.Insert(rootRelativePath, result, new CacheDependency(absolute)); 
    }
      return HttpRuntime.Cache[rootRelativePath] as string; 
  } 
}