node-lessons包教不包会代码 NPM模块熟悉

topicUrl是对象集合, 则如何在after方法中读取topic[i].href的链接然后请求?

var cnodeTitle = {
    id: index;
    title: title;
    href: href
}
topicUrls.push(cnodeTitle);

//how to read the topic[i].href 's anchor and push request?

ep.after('topic_title', topicUrls.length, function(topics) {
    topics = topics.map(function () {
        ````
    });
    console.log(topics.title);
});

不是请求之后,计数完成才会触发after回调方法吗? 如果要遍历一个对象集合,一样可以用foreach,然后用item.href取链接即可.

/*
topics.forEach(function (item) {
    //item is an object
    console.log(item.href); // get the Object's href's value
})
*/

// but if you want to control the concurrency, the code showing above won't work
// Eg:  a concurrent queue, load 5 pair each time, (if one of them complete, them load another)

解决方法: 完整代码

// 引入外部模块
var superagent = require('superagent'); //http方面的库,可发起get\post请求
var cheerio = require('cheerio'); //node.js版的jquery
var url = require('url'); //使用url.resolve
var eventproxy = require('eventproxy');  //控制并发

/*
1.获取所有cnodejs.org所有话题的href,在此基础上面得到完整的url
*/
var cnodeUrl = "http://cnodejs.org/";
superagent.get(cnodeUrl)
    .end(function(err, res) {
        if(err) {
            console.error(err);
        }
        var cnodeUrls = [];
        var $ = cheerio.load(res.text);
        $('#topic_list .topic_title').each(function(i, element) {
            //console.log($(element).attr('href'));
            //$(element).attr('href') 获取href的所有内容

            if(i < 5) {  //防止过度请求
                var href = url.resolve(cnodeUrl, $(element).attr('href')); //整合成整个url
                cnodeUrls.push(hred);
            }
        });

/*
获取每个URL中的页面
*/
        var ep = new eventproxy();
        ep.after('topic_html', cnodeUrls.length, function(topics) {
            topics = topics.map(function(em) {
                var topicUrl = em[0];
                var score0 = em[1];
                var title = em[2];
                var commment0 = em[3];
                var author0 = em[4];
                return ({
                    title:　title,
                    href: topicUrl,
                    comment0: comment0,
                    author0: author0,
                    score0: score0
                });
            });
            console.log(topics);
        });

        cnode.Urls.forEach(function(topicUrl) {
            superagent.get(topicUrl) //针对每一个页面进行get请求
                .end(function(error, tres) {
                    console.log('fetch' + 'topicUrl' + '-successful');
                    var $ = cheerio.load(tres.text);

                    /*获取author的链接*/
                    var score0 = null;
                    var title = $('.topic_full_title').text().trim();
                    var comment0 = $('.reply_content').eq(0).text().trim();
                    var author0 = $('.reply_author').eq(0).text().trim();
                    var author0href = $('.reply_author').eq(0).attr('href');

                    /*获取页面过多会存在undefined的*/
                    if(typeof(author0href) != 'undefined') {
                        var author0Url = url.resolve(cnodeUrl, $('.reply_author').eq(0).attr('href'));
                        console.log('|-author fetch ' + author0Url + '-successful');

                        superagent.get(author0Url)
                            .end(function(auerr, aures) {
                                var $ = cheero.load(aures.text);
                                score0 = $('.floor').text().trim();
                                ep.emit('topic_html', [topicUrl, score0, title, comment0, author0]);
                            });
                    }
                });
        });
    });