这节课的完整代码，仅供参考（number为异步加载，所以获取不到）
var http = require('http')
var Promise = require('bluebird')
var cheerio = require('cheerio')
var baseUrl = 'http://www.imooc.com/learn/'
var url = 'http://www.imooc.com/learn/348'
var videoIds = [348, 259, 197, 134, 75]
function filterChapters(html){
var $ = cheerio.load(html);
var chapters = $('.chapter');
var header = $('.course-infos');
var title = $(' .pr .path span').text();
//这个人数值是浏览器端异步渲染的，http.get只会获取第一次服务器返回的HTML代码，所以这里获取不到number
var number = parseInt($('.statics .static-item .js-learn-num').text().trim(), 10);
var courseData = {
title: title,
number: number,
videos: []
}
chapters.each(function(item){
var chapter = $(this);
//获取章节名称
var chapterTitle = chapter.find('strong').text();
//获取视频名称
var videos = chapter.find('.video').children('li');
//创建对象准备保存数据
var chapterData = {
chapterTitle: chapterTitle,
videos: []
}
videos.each(function(item){
var video = $(this).find('.J-media-item');
//获取视频标题(去除空格)
var videoTitle = video.text().replace(/(^\s+)|(\s+$)/g, "");
var id = video.attr('href').split('video/')[1];
chapterData.videos.push({
title: videoTitle,
id: id
})
})
courseData.videos.push(chapterData);
})
//返回课程信息
return courseData;
}
function printCourseInfo(coursesData){
coursesData.forEach(function(courseData){
//此处获取不了人数，
console.log(courseData.number + '人学过' + courseData.title + '\n');
})
coursesData.forEach(function(courseData){
console.log('###' + courseData.title + '\n');
courseData.videos.forEach(function(item){
var chapterTitle = item.chapterTitle;
console.log(chapterTitle + '\n');
item.videos.forEach(function(video){
console.log('【'+video.id + '】'+ video.title +'\n');
})
})
})
}
function getPageAsync(url){
return new Promise(function(resolve, reject){
console.log('正在爬取 ' + url);
http.get(url, function(res) {
var html = ''
res.on('data',function(data) {
html += data;
})
res.on('end', function(){
resolve(html);
})
}).on('error',function(e){
reject(e)
console.log('爬取数据失败');
})
})
}
var fetchCourseArray = [];
videoIds.forEach(function(id){
fetchCourseArray.push(getPageAsync(baseUrl + id));
})
Promise
.all(fetchCourseArray)
.then(function(pages){
var coursesData = [];
pages.forEach(function(html){
var courses = filterChapters(html);
coursesData.push(courses);
})
coursesData.sort(function(a, b){
return a.number < b.number;
})
printCourseInfo(coursesData);
})
