The Tor Browser / file revision

 // Parse the query string, and give us the value for a certain key, or false if

 // it does not exist.

 function parseQuery(request, key) {

   var params = request.queryString.split('?')[0].split('&');

   for (var j = 0; j < params.length; ++j) {

     var p = params[j];

     if (p == key)

       return true;

     if (p.indexOf(key + "=") == 0)

       return p.substring(key.length + 1);

     if (p.indexOf("=") < 0 && key == "")

       return p;

   }

   return false;

 }

 function handleRequest(request, response) {

   try {

     // Get the filename to send back.

     var filename = parseQuery(request, "file");

     const CC = Components.Constructor;

     const BinaryOutputStream = CC("@mozilla.org/binaryoutputstream;1",

                                   "nsIBinaryOutputStream",

                                   "setOutputStream");

     var file = Components.classes["@mozilla.org/file/directory_service;1"].

       getService(Components.interfaces.nsIProperties).

       get("CurWorkD", Components.interfaces.nsILocalFile);

     var fis  = Components.classes['@mozilla.org/network/file-input-stream;1'].

       createInstance(Components.interfaces.nsIFileInputStream);

     var bis  = Components.classes["@mozilla.org/binaryinputstream;1"].

       createInstance(Components.interfaces.nsIBinaryInputStream);

     var paths = "tests/content/media/test/" + filename;

     dump(paths + '\n');

     var split = paths.split("/");

     for(var i = 0; i < split.length; ++i) {

       file.append(split[i]);

     }

     fis.init(file, -1, -1, false);

     // handle range requests

     var partialstart = 0,

         partialend = file.fileSize - 1;

     if (request.hasHeader("Range")) {

       var range = request.getHeader("Range");

       var parts = range.replace(/bytes=/, "").split("-");

       var partialstart = parts[0];

       var partialend = parts[1];

       if (!partialend.length) {

         partialend = file.fileSize - 1;

       }

       response.setStatusLine(request.httpVersion, 206, "Partial Content");

       var contentRange = "bytes " + partialstart + "-" + partialend + "/" + file.fileSize;

       response.setHeader("Content-Range", contentRange);

     }

     fis.seek(Components.interfaces.nsISeekableStream.NS_SEEK_SET, partialstart);

     bis.setInputStream(fis);

     var sendContentType = parseQuery(request, "nomime");

     if (sendContentType == false) {

       var contentType = parseQuery(request, "type");

       if (contentType == false) {

         // This should not happen.

         dump("No type specified without having \'nomime\' in parameters.");

         return;

       }

       response.setHeader("Content-Type", contentType, false);

     }

     response.setHeader("Content-Length", ""+bis.available(), false);

     var bytes = bis.readBytes(bis.available());

     response.write(bytes, bytes.length);

   } catch (e) {

     dump ("ERROR : " + e + "\n");

   }

 }