old-kivi/crawler/specific/olx.js

'use strict'

let fetch = require('node-fetch');
let cheerio = require('cheerio');
let fs = require('fs');
import {AD_TYPE_SALE, IGNORED_USERNAMES} from '../enums';

export default class OlxCrawler {

  constructor(fromPage = 0, toPage = 10, maxResults = 1000) {
    this.fromPage = fromPage;
    this.toPage = toPage;
    this.maxResults = maxResults;
  }

  async indexSingle(url) {
    try {
      const res = await fetch(url);
      const body = await res.text();
      const $ = cheerio.load(body);

      const username = $('#lg > div.desno2.profil > div:nth-child(2) > div.vrsta1.vrsta_desno > a > div.username > span').text();

      if (IGNORED_USERNAMES.includes((username || '').toLowerCase())) {
        return null;
      }

      const title = $('#naslovartikla').text();
      const price = $('#pc > p:nth-child(2)').text();
      const size = $('#dodatnapolja1 > div:nth-child(1) > div.df2').text();
      const rooms = $('#dodatnapolja1 > div:nth-child(2) > div.df2').text();
      const address = $('#dodatnapolja1 > div:nth-child(5) > div.df2').text();
      const location = $('#artikal_glavni_div > div.artikal_lijevo > div.op.pop.mobile-lokacija').attr('data-content');

      const adType = $('#artikal_glavni_div > div.artikal_lijevo > div:nth-child(15) > div:nth-child(2) > div.df2').text();
      const time = $('time').attr('datetime');
      const olxId = $('#artikal_glavni_div > div.artikal_lijevo > div:nth-child(15) > div:nth-child(4) > div.df2').text();

      const descriptions = $('.artikal_detaljniopis_tekst');
      const floor = $('#dodatnapolja1').find(':contains(Sprat)').last().nextAll().text();
      const latLngRe = /LatLng\(([0-9]+\.[0-9]+)\,\s+([0-9]+\.[0-9]+)\)/g;
      const imgRe = /href":("[^"]*")/g;
      const matches = latLngRe.exec(body);
      let lng = '',
        lat = '';

      const images = [];
      const imgMatches = body.match(imgRe);

      const parseRooms = (rooms) => parseInt([...rooms].filter(c => !isNaN(c)).filter(c => c.trim()).join())
      const parsePrice = (price) => parseFloat(price.replace(".", ""))


      for (let i = 0; imgMatches && i < imgMatches.length; i++) {
        let img = imgMatches[i].replace("href\":", "")
        img = img.replace("\"", "");
        img = img.replace("\"", "");
        images.push(img);
      }

      if (matches && matches.length >= 3) {
        lat = matches[1];
        lng = matches[2];
      }

      const parsedPrice = parsePrice(price);

      const data = {
        url,
        title,
        price: isNaN(parsedPrice) || price,
        size: parseFloat(size),
        rooms: parseRooms(rooms),
        floor: parseInt(floor),
        address,
        location,
        adType: AD_TYPE_SALE,
        time,
        shortDescription: descriptions.first().text(),
        longDescription: descriptions.last().text(),
        lat,
        lng,
        loc: [parseFloat(lat), parseFloat(lng)],
        images
      };

      return data;
    } catch (e) {
      console.error('Exception caught: ' + e);
    }

    return null;
  }

  async indexPage(pageNr, maxResults = 1000) {
    try {
      console.log('Starting to index page: ' + pageNr);
      const url = `http://www.olx.ba/pretraga?vrsta=samoprodaja&sort_order=desc&kategorija=23&sort_po=datum&kanton=9&stranica=${pageNr}`;

      const res     = await fetch(url);
      const body    = await res.text();
      const $       = cheerio.load(body);
      const hrefs   = [];
      const results = {};

      $('#rezultatipretrage').find('.listitem').each((i, elem) => {
        const href = $(elem).find('a').first().attr('href');
        hrefs.push(href);
      });

      let actualNoOfResults = (hrefs.length <= maxResults) ? hrefs.length : maxResults;

      for (let i = 0; i < hrefs.length; i++) {
        console.log(`indexing: ${hrefs[i]}`);

        const singleData = await this.indexSingle(hrefs[i]);

        if (singleData) {
          results[hrefs[i]] = singleData;
        }
        await this.sleep(500);
      }

      return results;
    } catch (e) {
      console.error('Exception caught:' + e);
    }
  }

  async sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }

  async indexPages(start, end, maxResults = 1000) {
    let results = {};
    for (let i = start; i <= end; i++) {
      let result = await this.indexPage(i, maxResults);
      Object.assign(results, result)
      await this.sleep(5000);
    }
    return results;
  }

  async crawl() {
    let results = await this.indexPages(this.fromPage, this.toPage, this.maxResults);
    return results;
  }
}