var gz_urls = /\.gz$/ middleware = function(req, res, next) { if ('GET' != req.method && 'HEAD' != req.method) { return next(); } if (gz_urls.test(req.url)) { console.log('GZIP detected for url: ' + req.url); res.setHeader('Content-Encoding', 'gzip'); } return next(); } console.log(middleware); module.exports = function(bs) { return { "server": { "baseDir": "", "routes": { "/node_modules": "node_modules", "/assets": "assets" } }, middleware: [ middleware ] } }