The Tor Browser / file revision

 const CC = Components.Constructor;

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

                              "nsIBinaryInputStream",

                              "setInputStream");

 function handleRequest(request, response)

 {

   response.setHeader("Content-Type", "text/plain", false);

   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.bodyOutputStream.write(data, data.length);

 }