A version of http://madskristensen.net/post/cache-busting-in-aspnet for when you can't easily mess with URL rewriting

Fingerprint

using System.IO;
using System.Web;
using System.Web.Hosting;
using System.Web.Caching;

namespace Hughesdon.Cache {
  public static class Fingerprint
  {
    public static string Tag(string path)
    {
      if(HttpRuntime.Cache[path] == null)
      {
        string absolute = HostingEnvironment.MapPath("~" + path);
        
        var lastModifiedDate = File.GetLastWriteTime(absolute);
        
        string result = path + "?v=" + lastModifiedDate.Ticks;
        
        HttpRuntime.Cache.Insert(path, result, new CacheDependency(absolute));
      }
      return HttpRuntime.Cache[path] as string;
    }
  }
}