353 lines
12 KiB
JavaScript
353 lines
12 KiB
JavaScript
const fetch = require('node-fetch');
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const cheerio = require('cheerio');
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const { allRERequest, findPointInsideBoundingBox } = require('../db/dbHelper');
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const { getRealEstateTypeEnum } = require('../enums');
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const { getRegion, getMunicipality } = require('../codes')
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const Promise = require("bluebird");
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module.exports = class OlxCrawler {
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//TODO figure best way to handle paging
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constructor(fromPage = 0, toPage = 10, maxResults = 1000) {
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this.fromPage = fromPage;
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this.toPage = toPage;
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this.maxResults = maxResults;
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}
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async indexPages(urls) {
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const indexers = [];
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urls.forEach(url => {
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indexers.push(new Indexer(url));
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});
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return Promise.map(indexers, function (indexer) {
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return indexer.indexWithPagination();
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}).then(async (results) => {
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return results
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})
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}
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async crawl() {
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console.log("OLX CRAWLER: start crawl");
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const filteredResults = [];
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const realestateRequests = await allRERequest();
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console.log("OLX CRAWLER: found " + realestateRequests.length + "subscribed RealEstateRequests");
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const urls = this.createRequestUrls(realestateRequests);
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let results = await this.indexPages(urls, this.fromPage, this.toPage, this.maxResults);
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console.log("Final crawler results");
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console.log(results[0].length);
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for (const finalResult of results[0]) {
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if (null !== finalResult) {
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if (finalResult.lat !== undefined && finalResult.lat !== null && finalResult.lat !== "") {
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const pointInsideBoundingBox = await findPointInsideBoundingBox([finalResult.lng, finalResult.lat], finalResult.email);
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if (pointInsideBoundingBox[0].length !== 0) {
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filteredResults.push(finalResult);
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}
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}
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}
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}
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console.log("OLX CRAWLER: number of olx crawler results, after geo location filtering: " + filteredResults.length);
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return filteredResults;
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}
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createRequestUrls(realestateRequests) {
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const urls = []
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for (const request of realestateRequests) {
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const realsestateType = "kategorija=" + getRealEstateTypeEnum(request.realEstateType).olxCategory;
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const region = "kanton=" + getRegion(request.region).olxid;
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const municipality = "grad%5B%5D=" + getMunicipality(request.region, request.municipality).olxid;
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const sizeMin = "kvadrata_min=" + request.sizeMin;
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const sizeMax = "kvadrata_max=" + request.sizeMax;
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const priceMin = "od=" + request.priceMin;
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const priceMax = "do=" + request.priceMax;
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const olxUrl = {
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url: `https://www.olx.ba/pretraga?${realsestateType}&id=2&stanje=0&vrstapregleda=tabela&sort_order=desc&${region}&${municipality}&${priceMin}&${priceMax}&vrsta=samoprodaja&${sizeMin}&${sizeMax}&stranica=`,
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email: request.email,
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uuid: request.uniqueId
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}
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console.log(olxUrl.url);
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urls.push(olxUrl);
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}
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return urls;
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}
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};
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class Indexer {
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/**
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*
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* @param {String|Array} olxUrl single or array of objects containing url email and uuid
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* @param {Array} hrefResutls array contaning urls from crawler results
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*/
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constructor(olxUrl, hrefResutls) {
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this.olxUrl = olxUrl;
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this.hrefResutls = hrefResutls;
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}
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async indexWithPagination(pageNumber = 1) {
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console.log("This is olxUrl:" + this.olxUrl.url);
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const pageNr = this.olxUrl.url.match(/\d+$/);
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const indexers = this.prepareIndexers(pageNumber ? [pageNumber] : pageNr);
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try {
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return Promise.map(indexers.indexers, function (indexer) {
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return indexer.indexPage(pageNumber);
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}).then(async (results) => {
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let hasResults = false;
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results.forEach(result => {
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if (!hasResults) {
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console.log("No results detected")
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hasResults = result.hasResults
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}
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});
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if (!hasResults) {
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console.log("HAS NO MORE RESULTS, stop the paging, there are some results and they should contain only HREFS");
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console.log(results.length);
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const singlePageIndexers = this.prepareHrefIndexers(results);
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if (singlePageIndexers.length === 0) {
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console.log("THERE IS NOT EVEN SINGLE RESULT");
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return []
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}
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return Promise.map(singlePageIndexers, function (indexer) {
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return indexer.indexSingle();
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}).then(async (results) => {
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console.log("SinglePageMethod in HAS NO RESULTS, MarketAralms");
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console.log(results.length);
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return results;
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});
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} else {
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console.log("HAS MORE RESULTS, should only contain HREFS");
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console.log(results.length);
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const newResults = await this.indexWithPagination(results[0].pageNumber + 5);
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const singlePageIndexers = this.prepareHrefIndexers(results);
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const newerResults = await Promise.map(singlePageIndexers, function (indexer) {
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return indexer.indexSingle();
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}).then(async (results) => {
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console.log("SinglePageMethod HAS RESULTS, should contain MarketAlerts only");
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console.log(results.length);
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return results;
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});
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Array.prototype.push.apply(newResults, newerResults);
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return newResults;
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}
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});
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} catch (e) {
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console.error("Error has accured", e);
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}
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}
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prepareIndexers(pageNr) {
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console.log("Entering prepareIndexers : page nr - " + pageNr);
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const indexers = [];
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let lastPageNumber;
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if (pageNr) {
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for (let index = Number(pageNr[0]); index <= Number(pageNr[0]) + 5; index++) {
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lastPageNumber = index;
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const newOlxUrl = {
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url: this.olxUrl.url.replace(/\d+$/, "") + index,
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email: this.olxUrl.email,
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uuid: this.olxUrl.uuid
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}
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indexers.push(new Indexer(newOlxUrl));
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}
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} else {
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for (let index = 1; index <= 5; index++) {
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lastPageNumber = index;
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const newOlxUrl = {
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url: this.olxUrl.url + index,
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email: this.olxUrl.email,
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uuid: this.olxUrl.uuid
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}
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indexers.push(new Indexer(newOlxUrl));
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}
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}
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return {
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indexers: indexers,
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lastPageNumber: lastPageNumber
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};
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}
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prepareHrefIndexers(results) {
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const indexers = []
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if (!Array.isArray(results)) {
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results.hrefs.forEach(href => {
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const newOlxUrl = {
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url: href,
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email: results.olxUrl.email,
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uuid: results.olxUrl.uuid
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}
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indexers.push(new Indexer(newOlxUrl));
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});
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} else {
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results.forEach(result => {
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if (result !== null && result.hasOwnProperty('hrefs')) {
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result.hrefs.forEach(href => {
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// console.log(href);
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const newOlxUrl = {
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url: href,
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email: result.olxUrl.email,
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uuid: result.olxUrl.uuid
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}
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indexers.push(new Indexer(newOlxUrl));
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})
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}
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});
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}
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return indexers;
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}
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async indexPage(pageNumber) {
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console.log("Page number in index page, max page number :")
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console.log(pageNumber);
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try {
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console.log("Indexing page: " + this.olxUrl.url);
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const res = await fetch(this.olxUrl.url);
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const body = await res.text();
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const $ = cheerio.load(body);
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const hrefs = [];
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let hasResults = false
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$('#rezultatipretrage').find('.listitem').each((i, elem) => {
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hasResults = true
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const href = $(elem).find('a').first().attr('href');
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hrefs.push(href);
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});
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console.log("this is hrefs for olxUrl" + this.olxUrl.url);
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console.log("NUMBER OF HREFS " + hrefs.length);
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return {
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hrefs: hrefs,
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hasResults: hasResults,
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pageNumber: pageNumber,
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olxUrl: this.olxUrl
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}
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} catch (e) {
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console.error('Exception caught:' + e);
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}
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}
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async indexSingle() {
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try {
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console.log("Index single");
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console.log(this.olxUrl.url);
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if (this.olxUrl.url === undefined) {
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return {}
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}
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const res = await fetch(this.olxUrl.url);
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const body = await res.text();
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const $ = cheerio.load(body);
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const title = $('#naslovartikla').text().trim();
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const realEstateType = $('#artikal_glavni_div > div.artikal_lijevo > div:nth-child(3) > div > span:nth-child(3) > a > span').text();
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const price = $('#pc > p:nth-child(2)').text();
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const size = $('#dodatnapolja1 > div:nth-child(1) > div.df2').text();
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const rooms = $('#dodatnapolja1 > div:nth-child(2) > div.df2').text();
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const address = $('#dodatnapolja1 > div:nth-child(5) > div.df2').text();
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const gardenSize = $('#dodatnapolja1 > div:nth-child(6) > div.df2').text();
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const location = $('#artikal_glavni_div > div.artikal_lijevo > div.op.pop.mobile-lokacija').attr('data-content');
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const time = $('time').attr('datetime');
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const olxId = $('#artikal_glavni_div > div.artikal_lijevo > div:nth-child(15) > div:nth-child(4) > div.df2').text();
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const descriptions = $('.artikal_detaljniopis_tekst');
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const latLngRe = /LatLng\(([0-9]+\.[0-9]+)\,\s+([0-9]+\.[0-9]+)\)/g;
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const imgRe = /href":("[^"]*")/g;
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const matches = latLngRe.exec(body);
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let lng = '',
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lat = '';
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const parsePrice = (price) => parseFloat(price.replace(".", ""))
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if (matches && matches.length >= 3) {
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lat = matches[1];
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lng = matches[2];
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}
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const parsedPrice = parsePrice(price);
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const locationArray = location.split(",");
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const region = locationArray[0];
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const municipality = locationArray[1];
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const data = {
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realEstateType: this.getCategoryId(realEstateType),
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email: this.olxUrl.email,
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uuid: this.olxUrl.uuid,
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olxId: olxId,
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url: this.olxUrl.url,
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title,
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price: isNaN(parsedPrice) ? 0 : parsedPrice,
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size: parseFloat(size),
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gardenSize: isNaN(parseFloat(gardenSize)) ? 0 : parseFloat(gardenSize),
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address,
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region,
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municipality,
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time,
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shortDescription: descriptions.first().text(),
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longDescription: descriptions.last().text(),
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lat,
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lng,
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loc: [parseFloat(lat), parseFloat(lng)],
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};
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return data;
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} catch (e) {
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console.error('Exception caught: ' + e.message);
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}
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return null;
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}
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getCategoryId(category) {
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switch (category) {
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case 'Stanovi':
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return 'stan';
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case 'Vikendice':
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return 'vikendica'
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case 'Kuće':
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return 'kuca';
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default:
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return '';
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}
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}
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}
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