var fs = require('fs'); require('http').createServer(function (req, res) { res.end(); if (req.headers['x-write-call']) { res.writeHead(200, {'Content-Type': 'text/plain'}).write('blah'); } Promise.resolve().then(() => { req.on('data', (data) => { fs.appendFile(data.toString(), '', function() {}); }); }); }).listen(7080);