app.js

var cheerio = require('cheerio')
  , superagent = require('superagent')
  , express = require('express')
  , async = require('async')
  , url = require('url');
var cnodeUrl = 'http://cnodejs.org/';

function analyze(page) {
  var $ = cheerio.load(page);
        return ({
          title: $('.topic_full_title').text().trim(),
          comment1: $('.reply_content').eq(0).text().trim(),
        });
}

function fetchUrl(url, callback) {
  superagent.get(url)
    .end(function (err, res) {
      var page = res.text;

      var postTime = analyze(page);

      callback(null, postTime);
    });
}


// start
var app = express();

app.get('/', function (req, res, next) {
superagent.get(cnodeUrl)
  .end(function(err,sres){
    if(err){
      return console.error(err);
    }
    var topicUrls = [];
    var $ = cheerio.load(sres.text);
    $('#topic_list .topic_title').each(function(idx,element){
      var $element = $(element);
      var href = url.resolve(cnodeUrl,$element.attr('href'));
      topicUrls.push(href);
    })

  async.mapLimit(topicUrls, 5, function(url, callback) {
    fetchUrl(url, callback);
  }, function (err, result) {
    res.send(result);
  });
});
});

// listen
app.listen(3000, function () {
  console.log('app is listening at port 3000');
});