爬个资料吧

var superagent = require(‘superagent‘);
var fs = require("fs");

var i = 0;//文件名
function test(imgs){//下载图片
	var _img = ‘7o@o7xcocmkL_slKMQRJ7BmfZy6MmpTR2LRhppJrt@1YmiPLbwQiPSyNJDH6cy0dKYx_OqO5XxA=‘//第一张图片的部分地址
	if(imgs){
		_img = imgs
	}
	var saveImg = ‘https://view57.book118.com/img/?img=‘+_img//需要下载的图片地址
        superagent
        .get(saveImg)
        .send({
        	img:_img
        })
        .end((err,res)=>{
        	console.log(‘img===‘+res.body)
        	res.setEncoding("binary")
        	i++;
        	var tmp = "./aa/"+ i +".png"
        	fs.writeFile(tmp, res.body, "binary", function (err) {
		        if (err) {
		          return console.error(err);
		        }else{
		        	 console.log("保存成功");
		        	 setTimeout(function(){//做人低调
		        	 	 getUrl(_img);
		        	 },1500)
		        }
		       
	        });
        })
	
}


function getUrl(_img){//获取图片地址参数
	superagent
    .get(‘https://view57.book118.com/pdf/GetNextPage/?f=RjpcT2ZmaWNlV2ViMzY1XE9mZmljZVdlYlxjYWNoZVxQREZcMTE2MTIyNDE0MDMyMzEzMjUwMjEwMTQ1NDVfMTgxMjQ4XDIxMTM0MzUtNTg1ZTBmYWI0Njk4Yi5kb2MudGVtcA%3D%3D&img=7o%40o7xcocmkL_slKMQRJ7BmfZy6MmpTR2LRhppJrt%401YmiPLbwQiPfCa5XE1j4YCnc1NXftPWUs%3D&isMobile=false&isNet=True&readLimit=m05GD%40CZT1P0GOn8Lv_JjQ%3D%3D&furl=o4j9ZG7fK96K7ALNwHnKKQSGvsVp16t3OGQ8hCU%40qfk6tlpWD7Ja6aejeMBHDc30Bl0SYXklcX15I0vqB0%40iSi0tdf2506q8tknYr5_l2nM%3D‘)
    .set(‘Accept‘,‘application/json, text/javascript, */*; q=0.01‘)
    .set(‘Content-Type‘,‘application/json; charset=utf-8‘)
    .set(‘Connection‘,‘keep-alive‘)
    .set(‘Cookie‘,‘__cfduid=d36900c15ce242f30af1efa4ffa36dae31522302561; CLIENT_SYS_UN_ID=3rvhcVv2CTUEqq/kHfvAAg==; Hm_lvt_5d91dc9c92e499ab00ba867fc2294136=1542852289,1542852292,1542855730; Hm_lpvt_5d91dc9c92e499ab00ba867fc2294136=1542855772‘)
    .set(‘Host‘,‘view57.book118.com‘)
    .set(‘Referer‘,‘https://view57.book118.com/pdf/dXAxNS5ib29rMTE4LmNvbS44MFwyMTEzNDM1LTU4NWUwZmFiNDY5OGIuZG9j?readpage=m05GD%40CZT1P0GOn8Lv_JjQ%3D%3D&furl=o4j9ZG7fK96K7ALNwHnKKQSGvsVp16t3OGQ8hCU%40qfk6tlpWD7Ja6aejeMBHDc30Bl0SYXklcX15I0vqB0%40iSi0tdf2506q8tknYr5_l2nM%3D&token=PDWfni5ovTsVBbpwUGR6QPhtBOXaydS6‘)
    .set(‘User-Agent‘,‘Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36‘)
    .set(‘X-Requested-With‘,‘XMLHttpRequest‘)
    .send({
    	img:_img
    })
    .end((err,response)=>{
    	var res = JSON.parse(response.text)
        console.log(res.NextPage);//拿到下个接口需要的参数
        
        
    	test(res.NextPage)
      
        
    })
}
test();