Nodejs request async problem for loop not work - node.js

Question

I'm a beginner of nodejs, async bothers me.
I want my code run sequencely or it will breaks.
I have a for loop, and it simply doesn't work...
Here are all the codes:
const util = require('util');
const request = require('request');
const cheerio = require('cheerio');
var host = "http://www.nicotv.me";
var url = "http://www.nicotv.me/video/play/57838-1-%s.html";
var len = 99;
var tab = /-(\d)-/.exec(url);
tab = tab[1] // '1' not '-1-'
function getLen(url) {
//you can ignore this function, it gives len=2
request(url, function (err, response, html) {
if (err) {
console.log('url:', url);
console.log('error:', err);
console.log('statusCode:', response && response.statusCode);
}
else{
var $ = cheerio.load(html);
var cls = '.ff-playurl-dropdown-%s';
$(util.format(cls, tab)).filter(function (){
var data = $(this);
len = data.html().match(/<a href=/g).length;
console.log("episode:", len);
});
getLink(len, function(){
});
}
});
}
getLen(util.format(url, 1)); //len = 2
var getLink = function(lengths, callback){
for (let i = 1; i <= lengths; i++) {
var tmp = util.format(url, i);
try {
request(tmp, function (err, res, html){
console.log('url:', tmp);
if(err){
console.log("error:", err);
console.log("statusCode:", res && res.statusCode);
}else{
var reg = /src="(\/player.php?.{1,})"/;
var result = reg.exec(html);
console.log(result[1]);
}
});
callback();
} catch (error) {
console.log(error);
break;
}
}
}
here is my output:
episode: 2
url: http://www.nicotv.me/video/play/57838-1-2.html
/player.php?u=aHR0cDovL3R5angyLmtpbmdzbnVnLmNuLzM2MHl1bi0xNS5waHA/dmlkPTE1NzkxMzU2MzEyNDAwNTQ5&p=360biaofan&c=0&j=aHR0cDovL2ppZXhpLmtpbmdzbnVnLmNuLzM2MGJpYW9mYW4ucGhwP3VybD0=&x=10&y=&z=
url: http://www.nicotv.me/video/play/57838-1-2.html
/player.php?u=aHR0cDovL3R5angyLmtpbmdzbnVnLmNuLzM2MHl1bi0xNS5waHA/dmlkPTE1Nzg1MDQyMDYyNDAwNTgx&p=360biaofan&c=0&j=aHR0cDovL2ppZXhpLmtpbmdzbnVnLmNuLzM2MGJpYW9mYW4ucGhwP3VybD0=&x=10&y=&z=aHR0cDovL3R5angyLmtpbmdzbnVnLmNuLzM2MHl1bi0xNS5waHA/dmlkPTE1NzkxMzU2MzEyNDAwNTQ5
First problem is these two /player*** link are from 57838-1-1.html
And one of them are not complete.
Second problem is the url output shows 57838-1-2.html twice.
Thanks for your kindly help.

Answer 1

Yesterday had the same problem, so I solved with:
Using request-promise
Replace the loop method arrTitles.Each with for (const jt of arrTitles)
Here a sample:
const request = require('request-promise');
const cheerio = require('cheerio');
var getUrlData =
async function (url) {
console.log(url);
try {
return await request.get(url);
}
catch (err) {
console.error(`${err}: ${url}`);
}
return;
};
var run =
async function (pageUrl) {
var arrData =
await fn.getUrlData(pageUrl)
.then(response => readTable(response));
console.log(arrData);
};
var readTable =
function (document) {
var $;
let arrData = [];
try {
$ = cheerio.load(document);
$('table tr')
.each(
function (trN) {
$(this)
.children('td')
.each(
function (tdN) {
arrData.push($(this).text().trim());
}
)
});
}
catch { }
return arrData;
};
run();