cherrio模块
安装
cnpm install cherrio
使用方法
const cheerio = require('cheerio')
const $ = cheerio.load('<h2 class="title">Hello world</h2>')
$('h2.title').text('Hello there!')
$('h2').addClass('welcome')
$.html()
//=> <html><head></head><body><h2 class="title welcome">Hello there!</h2></body></html>
request模块
var request = require('request');
request('http://www.google.com', function (error, response, body) {
console.log('error:', error); // Print the error if one occurred
console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received
console.log('body:', body); // Print the HTML for the Google homepage.
});
爬虫系统 request cheerio
- 爬取一个网站的内容信息
- 分析内容
- 储存数据 下载图片
简单的爬虫
//发起服务端请求 请求一个网页
const request = require('request')
const fs= require('fs')
const path= require('path')
const cheerio = require('cheerio')
//以百度为例
let url ='https://www.baidu.com/'
request(url,(err,response,body)=>{
console.log(err)
//把爬取到的body 写入新文件中
fs.writeFile(path.join(__dirname,'./baidu.html'),body,(err)=>{
if(err){
console.log('爬取失败')
}else{
console.log('爬取成功')
}
})
//根据一个网址 下载对应的网页文件
const $ = cheerio.load(body)
let imgs = []
// 用正则判断数组中的路径是否存在https
var Reg = /(http[s]?|ftp)/;
$('img').each((index, ele) => { // 遍历所有
var src = $(e).attr('src');
if (!Reg.test(src)) {
src = src.replace(//{2}/, 'https://') //正则判断
}
imgs.push(src)
})
// 下载数组里的图片
for (let index = 0; index < imgs.length; index++) {
if (imgs[index].indexOf('png') !== -1) {
request(imgs[index]).pipe(fs.createWriteStream(`./img/${index}.png`)) //用下标命名，要建好img文件夹
};
}
})