How to parse images via a NodeJs GET request?

Question

JavaScript

I've been sitting for more than 9 hours, help me figure it out.

So everything works great, the problem is that I want to check if there is an image at this url or not? And it overwrites and I can't do it.

var request = require('request'),
    cheerio = require('cheerio'),
    sys = require('sys'),
    http = require('http'),
    token = require('token'),
    crypto = require('crypto'),
    net = require('net'),
    get = require('get'),
    Iconv  = require('iconv').Iconv;

for (var i = 0; i < 5; i++) { // неудачная попытка сделать цикл, хотя работает но request.get перезаписивает 
// переменную и происходит такая ситуация что реально проверяется только одна ссылка на картинку
    var token = crypto.randomBytes(16).toString('hex');  // генерация мд5 на угад парсить думаю
    var url = 'https://wu.wsiz.rzeszow.pl/wunet/photos/s' + token + '.jpg';
request.get({uri: url, method: 'GET', encoding: 'binary' }, function (err, res, body) {

    console.time(url);
    body = new Buffer(body, 'binary');
    var iconv = new Iconv('latin1', 'utf8//IGNORE');
    body = iconv.convert(body).toString();

    var $ = cheerio.load(body);


    var tmp = $('h1').html();
// Если есть h1 значит попало на ошибку и изображения тут нету, проверка ниже
    if (tmp==null)
        console.log('ok='+url+'##############################################');
       // Если заголовка нету, значит есть изображения
    else {
        console.log('fuck %)'+ token);
    }
    console.timeEnd(url);

});}

Normal image - https://wu.wsiz.rzeszow.pl/wunet/photos/se9191809b...
e9191809bf90e68444f1200592ee4c06 - a unique code of 32 characters. s is the salt, .jpg is the extension of the picture

How to make it so that it doesn't overwrite. I want to do this for myself. I wonder if nodejs can pull this off. Thanks for answers.

Answer 1

Or read what a closure is or this code won't work. Or you can't declare functions inside a loop, or you can't write var inside a loop. Or you learn JavaScript here: learn.javascript.ru or node here: learn.javascript.ru/nodejs-screencast and then labs here: nodeschool.io

var request = require('request'),
    crypto = require('crypto');

var token, url;
for (var i = 0; i < 5; i++) {
  token = crypto.randomBytes(16).toString('hex');
  url = 'https://wu.wsiz.rzeszow.pl/wunet/photos/s' + token + '.jpg';
  doRequest(url);
}

function doRequest(url) {
    request.get(
    	{ uri:url, method:'GET', encoding:'binary' },
    	function (err, res, body) {
            console.time(url);
            body = new Buffer(body, 'binary');
            console.timeEnd(url);
        }
    );
}

Answer 2

It looks like you just run the loop to the end and the process ends. The node is asynchronous, control on request.get is not blocked. Read about async and promises.

Answer 3

Thank you very much! Tell me, how can the memory be freed, because with a large cycle - it gives an error that there is not enough memory ... Can I use this module?
https://github.com/nodejitsu/forever