Request logger middleware example using winston logger

requestLogger.js

// To use:
// server.use(requestLogger);

function requestLogger(req, res, next) {
  req._startTime = new Date();
  var logRequest = function() {
    res.removeListener('finish', logRequest);
    res.removeListener('close', logRequest);
    var status = res.headersSent && res.statusCode || null;
    var userAgent = req.headers['user-agent'];
    var contentLength = req.connection.bytesWritten || null;
    var respTime = parseInt(Date.now() - req._startTime.getTime());
    return winLogger.info(req.method + ' ' + req.url + ' ' + (status || '-') + ' ' + (contentLength || '-') + ' - ' + respTime + ' ms', {
      request: {
        userAgent: userAgent,
        url: req.url,
        method: req.method
      },
      response: {
        status: status,
        contentLength: contentLength,
        respTime: respTime
      }
    });
  };
  res.on('finish', logRequest);
  res.on('close', logRequest);
  return next();
}