simple tool for profiling node.js web apps

profile.js

var config = require('config')
var profilingEnabled = config.profile === undefined ? true : config.profile

var callback = function(name, callback) {
  if (!profilingEnabled) return callback
  var start = new Date()
  var step = 0
  return function end() {
    console.log(name,'profile:',((new Date()) - start),'ms',step++)
    callback.apply(this, arguments)
  }
}

var middleware = function(name, middleware) {
  if (!profilingEnabled) return middleware
  return function (req, res, next) {
    var start = new Date()
    middleware(req, res, function() {
      console.log(name,'profile:',((new Date()) - start),'ms')
      next()
    })
  }
}

var response = function(req, res, next) {
  if (!profilingEnabled) return next()
  var oldEnd = res.end
  var start = new Date()
  res.end = function() {
    console.log('request',req.url,'profile:',((new Date()) - start),'ms')
    oldEnd.apply(res, arguments)
  }
  res.on('close', function() {
    console.log('request-close',req.url,'profile:',((new Date()) - start),'ms')
  })
  next()
}

module.exports = {
  callback: callback,
  middleware: middleware,
  response: response
}

// use cases
// time db call
db.tags.findOne({name: this.category}, profile.callback('get-category', function(err, tag) {
  // do something with category
}))

// time middleware
app.use(profile.middleware('cookieparser',express.cookieParser()))

// time response using middleware
app.use(profiler.response)