node.js 爬虫案例 | 易学教程

本案例是爬的一部小说，爬取并存在本地

使用了动态浏览器头部信息，和动态ip代理, 这2个方式可以有效的伪装自己，不至于被反爬，然后拉黑，之前已有记录，浏览器头部信息，也记录的有，

app.js

import request from 'request';
import userAgents from './common/userAgent.js';
import Promise from 'bluebird';
import cheerio from 'cheerio';//类似jquery写法
import fs from 'fs';
const  Iconv = require('iconv').Iconv;

const iconv = new Iconv('GBK', 'UTF-8');

const URL = 'http://www.qb5200.org/xiaoshuo/62/62493/';
let pageUrl = `${URL}6161384.html`; //章节存放变量，初始化是第一章地址
//这里只做测试，所以用变量存，而实际应用中，应该使用数据缓存
const expiryTime = 5 * 60 * 1000;// 过期间隔时间，毫秒
let ips = null; //代理ip
let time = null;// 存储代理IP的时间，判断是否过期，如果过期重新请求
let pageNumber = 1; //页码
//let info = '';//爬取到的内容存放变量
/**
 * 请求免费代理，可做缓存，这里就存在变量中，只做测试
 */
const getProxyList = () => {
    return new Promise((resolve, reject) => {
            const nowDate = Date.now();
            if( nowDate - time <  expiryTime ){
                resolve(ips);
                return;
            }
            const apiURL = 'http://www.66ip.cn/mo.php?sxb=&tqsl=100&port=&export=&ktip=&sxa=&submit=%CC%E1++%C8%A1&textarea=http%3A%2F%2Fwww.66ip.cn%2F%3Fsxb%3D%26tqsl%3D100%26ports%255B%255D2%3D%26ktip%3D%26sxa%3D%26radio%3Dradio%26submit%3D%25CC%25E1%2B%2B%25C8%25A1';
        const options = { method: 'GET', url: apiURL, gzip: true, encoding: null,
            headers: {
                'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
                'Accept-Encoding': 'gzip, deflate',
                'Accept-Language': 'zh-CN,zh;q=0.8,en;q=0.6,zh-TW;q=0.4',
                'User-Agent': 'Mozilla/8.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36',
                'referer': 'http://www.66ip.cn/'
            },
        };
        request(options, (error, response, body)=>{
            try {
                     if(Buffer.isBuffer(body)){
                         const ret = body.toString().match(/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:\d{1,4}/g);
                         ips = ret;
                         time = Date.now();
                         resolve(ret);
                     }
            } catch (e) {
                  console.log(e);
            }
        });
    })
}
//爬取小说
async function getPageIndex(ipList,url){
    return new Promise((resolve, reject) => {
        let userAgent = userAgents[parseInt(Math.random() * userAgents.length)];
        let ip = ipList[parseInt(Math.random() * ips.length)];
        let useIp = `http://${ip}`;const options = { method: 'GET', url: url, gzip: true, encoding: null,
            headers: {
                'User-Agent': userAgent, //动态设置浏览器头部信息
            },
            proxy: useIp, //动态设置代理ip
            timeout: 8000
        };
        request( options , (error, response, body)=>{
                //429 Too Many Requests 这个问题貌似是服务器问题
             if (error || body.toString().indexOf('429 Too Many Requests') >= 0 ) {
                console.log(`爬取页面失败，${error}，正在重新寻找代理ip... ×`);
                resolve(undefined);
                return;
              }else{
                 console.log('爬取页面成功，  √');
            }
            resolve(body)
        })
    })    
}
//获取内容
async function getChapter(body){
    return new Promise((resolve, reject) => {
        let result = iconv.convert(new Buffer(body, 'binary')).toString();
        let $ = cheerio.load(result);
        let title = $('#title').text();
        title = `第${pageNumber}章 ${title}`;
        let content = $('#content').text();
        let list = $('#footlink>a');
        console.log(title);
        //这里是因为有时候拿不到下一页的按钮，就自己退出了，所以做下处理
        if(list.length === 0){
            resolve(undefined);
            return;
        }
        list.each(function(i,item){
            let $this = $(this);
            if($this.text() === '下一页'){
                let path = $this.attr('href');
                if( path.indexOf('http') >= 0 ){
                    path = null;
                }else{
                    path = URL + path ;
                }
                resolve({
                    content: `${title}\n ${content}\n\n\n\n`,
                    path: path
                });
            }
        })
        
    })
}
//写入到本地
async function Write(info){
    return new Promise((resolve, reject) => {
        const decodedText = new Buffer(info);
        fs.readFile('九天剑道.txt',function(err,_buffer){
            if(err){//读取失败，则直接创建
                fs.writeFile('九天剑道.txt',decodedText,function(err){
                    if(err){
                        console.log(err);
                    }else{
                        console.log('写入成功---!');
                        resolve(true);
                    }
                })
            }
            if(Buffer.isBuffer(_buffer)){//判断是否是Buffer对象
                fs.writeFile('九天剑道.txt',new Buffer(_buffer.toString() + info),function(err){
                    if(err){
                        console.log(err);
                    }else{
                        console.log('写入成功!');
                        resolve(true);
                    }
                })
            }
        })
        
    });
}
//启动方法
async function startFun(){
    const ipList = await getProxyList();//获取代理ip
    const body = await getPageIndex( ipList, pageUrl );//爬取主页面
    if(!body){
        startFun();
        return;
    }
    const item = await getChapter(body);//获取爬到的内容
    if(!item){
        startFun();
        return;
    }
    const info = item.content;
    //判断是否有下一页，全部爬完之后写入到本地，生产文件
    //如果章节过多，应该加上一点处理方式，这里不赘述，我想应该是这样的
    if(item.path){
//        if(pageNumber%2===0){
        const isWrite =  await Write(info);
//            info = '';
//        }
        pageNumber++;
        pageUrl = item.path;
        startFun();
    }
}
//启动方法
startFun();

package.json

{
  "name": "reptile",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    "start": "babel-node app.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "bluebird": "^3.5.1",
    "cheerio": "^1.0.0-rc.2",
    "fs": "^0.0.1-security",
    "iconv": "^2.3.0",
    "request": "^2.87.0"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-stage-2": "^6.24.1"
  }
}