wechat emoticons dl

dl.js

var https = require('https')
var http = require('http')
var fs = require('fs')
var path = require('path')
var list = require('./emoticons.json')

var threads = 5
var chunck = Math.ceil(list.length / threads)

for (var i = 0; i < threads; ++i) {
  download(list.slice(i * chunck, (i + 1) * chunck))
}

function loopAsync(turns, work, callback) {
  var currentTurn = 0
  var isDone = false
  var hasNext = false

  function done() {
    isDone = true
    callback.apply(this, arguments)
  }

  function next() {
    if (isDone) return
    hasNext = true

    while (!isDone && currentTurn < turns && hasNext) {
      hasNext = false
      work.call(this, currentTurn++, next, done)
    }

    if (currentTurn >= turns && hasNext) {
      isDone = true
      callback()
    }
  }

  next()
}

function download(emoticons) {
  loopAsync(emoticons.length, function (index, next, done) {
    var emoticon = emoticons[index]
    
    http.get(emoticon.url, function(res) {
      var name = path.join(__dirname, emoticon.md5 + '.gif')
      res.pipe(fs.createWriteStream(name))
      res.on('end', next)
    })
  }, function() {
    console.log('finished')
  })
}