JavascriptHandler.cs

public class JavascriptHandler : IHttpHandler
{
  private readonly static bool enabledAutoMinified = ConfigurationManager.AppSettings["enableAutoMinified"] == "true";
  private readonly static Minifier minifier = new Minifier();
  private readonly static CodeSettings minifierSettings = new CodeSettings()
  {
    /* Minifier code settings here */
  };

  bool IHttpHandler.IsReusable
  {
    get { return false; }
  }

  void IHttpHandler.ProcessRequest(HttpContext context)
  {
    /*
     * logic for getting folder name and file info here
     *
     */

    // if the user sent us a "if-modified-since" header, compare the date to the cache date
    DateTime modifiedSince;
    var header = context.Request.Headers["If-Modified-Since"];
    if (header != null && DateTime.TryParse(header, out modifiedSince) && webInfo.DateTime == modifiedSince)
    {
      // send a 304 and exit out
      context.Response.StatusCode = 304;
      context.ApplicationInstance.CompleteRequest();
    }
    else
    {
      // set the cache headers
      var cacheHeader = context.Response.Cache;
      cacheHeader.SetValidUntilExpires(true); // cache this server-side
      cacheHeader.SetCacheability(HttpCacheability.Public); //tell the client to cache this file
      //cache for a long time, we are 100% dependant on the JS control
      // to give us a unique name everytime the underlying files change
      cacheHeader.SetExpires(DateTime.Today.AddDays(365));
      cacheHeader.SetMaxAge(TimeSpan.FromDays(365)); //cache for a long time
      cacheHeader.SetLastModified(webInfo.DateTime); //inform the client of what we know to be the lastmodified date

      // IIS won't gzip the request if the return content type isn't the following:
      context.Response.ContentType = "application/x-javascript";
      //get the folder/file that correspond to this request
      var javascriptFolder = context.Server.MapPath(folderPath);
      var javascriptFile = javascriptFolder + ".js";

      string[] files = new string[] { };
      if (Directory.Exists(javascriptFolder))
      {
        files = Directory.GetFiles(javascriptFolder);
      }
      else if (File.Exists(javascriptFile))
      {
        files = new[] { javascriptFile };
      }
      //run through all the files in the folder minify them and concate them
      foreach (var fileName in files)
      {
        var js = File.ReadAllText(fileName);
        if (enabledAutoMinified)
        {
          var minifiedJs = minifier.MinifyJavaScript(js, minifierSettings);
          // write the minified js directly into the output stream
          context.Response.Output.Write(minifiedJs);
          // Microsoft Ajax Minifier removes the last semi-colon
          //  since we are concatenating then we should put it back
          //  line break so that we can deciminate the different files
          context.Response.Output.WriteLine(";");
          foreach (var error in minifier.ErrorList)
          {
            // write any errors into the trace so we can debug later
            context.Trace.Warn("minifier", error.ToString());
          }
        }
        else
        {
          // if we aren't minifying then just concatenate all the js files
          context.Response.Output.Write(js);
        }
      }
    }
  }
}