function handleRequest(request, response) { var file = Components.classes["@mozilla.org/file/directory_service;1"] .getService(Components.interfaces.nsIProperties) .get("CurWorkD", Components.interfaces.nsIFile); file.append("tests"); file.append("image"); file.append("test"); file.append("mochitest"); if (request.getHeader("Accept") == "*/*") { file.append('blue.png'); } else { file.append('red.png'); } response.setStatusLine(request.httpVersion, 200, "OK"); response.setHeader("Content-Type", "image/png", false); response.setHeader("Cache-Control", "no-cache", false); var fileStream = Components.classes['@mozilla.org/network/file-input-stream;1'] .createInstance(Components.interfaces.nsIFileInputStream); fileStream.init(file, 1, 0, false); var binaryStream = Components.classes['@mozilla.org/binaryinputstream;1'] .createInstance(Components.interfaces.nsIBinaryInputStream); binaryStream.setInputStream(fileStream); response.bodyOutputStream.writeFrom(binaryStream, binaryStream.available()); binaryStream.close(); fileStream.close(); }