The Tor Browser / file revision

 const CC = Components.Constructor;

 const BinaryInputStream = CC("@mozilla.org/binaryinputstream;1",

                              "nsIBinaryInputStream",

                              "setInputStream");

 function handleRequest(request, response)

 {

   if (request.hasHeader("Content-Type"))

     response.setHeader("Result-Content-Type",

                        request.getHeader("Content-Type"));

   response.setHeader("Content-Type", "text/plain; charset=ISO-8859-1");

   var body = new BinaryInputStream(request.bodyInputStream);

   var avail;

   var bytes = [];

   while ((avail = body.available()) > 0)

     Array.prototype.push.apply(bytes, body.readByteArray(avail));

   var data = String.fromCharCode.apply(null, bytes);

   response.setHeader("Result-Content-Length", "" + data.length);

   if (data.indexOf("TEST_REDIRECT_STR") >= 0) {

     var newURL = "http://" + data.split("&url=")[1];

     response.setStatusLine(null, 307, "redirect");

     response.setHeader("Location", newURL, false);

   }

   else {

     response.write(data);

   }

 }