Created non-concurrent request groups.

app/crawler/specificConfigs/olx.js

@@ -35,6 +35,5 @@ module.exports = {
   OLX_IGNORED_USERNAMES: olxIgnoredUsernames || [],
   OLX_DELAY_BETWEEN_PAGES:
     parseInt(process.env.OLX_DELAY_BETWEEN_PAGES) || 1000,
-  OLX_DELAY_BETWEEN_ADS: parseInt(process.env.OLX_DELAY_BETWEEN_ADS) || 1000,
   OLX_FORCE_CRAWL: !!parseInt(process.env.OLX_FORCE_CRAWL)
 };

app/crawler/specificCrawlers/olx.js

@@ -18,7 +18,9 @@ const {
 
 const {
   DEFAULT_TIMEZONE,
-  PRINT_CRAWLER_DEBUG
+  PRINT_CRAWLER_DEBUG,
+  NUMBER_OF_CONCURRENT_REQ_SCRAPER_API,
+  DELAY_BETWEEN_REQ_SCRAPER_API
 } = require("../../config/appConfig");
 
 const OLX_ENUMS = {
@@ -42,10 +44,7 @@ const OLX_ENUMS = {
   OLX_RENEWED_DATE_FORMAT: "DD.MM.YYYY. u HH:mm"
 };
 
-const {
-  OLX_FORCE_CRAWL,
-  OLX_DELAY_BETWEEN_ADS
-} = require("../specificConfigs/olx");
+const { OLX_FORCE_CRAWL } = require("../specificConfigs/olx");
 
 class OlxCrawler {
   constructor(
@@ -55,8 +54,7 @@ class OlxCrawler {
     maxPages = 1000,
     maxResultsPerPage = 100,
     ignoredUsernames = [],
-    delayBetweenPages = 1000,
-    delayBetweenAds = OLX_DELAY_BETWEEN_ADS
+    delayBetweenPages = 1000
   ) {
     this.savers = savers;
     this.baseUrl = "https://www.olx.ba/pretraga?sort_order=desc&sort_po=datum";
@@ -66,7 +64,6 @@ class OlxCrawler {
     this.maxResultsPerPage = maxResultsPerPage;
     this.ignoredUsernames = ignoredUsernames;
     this.delayBetweenPages = delayBetweenPages;
-    this.delayBetweenAds = delayBetweenAds;
   }
 
   async crawl() {
@@ -195,14 +192,26 @@ class OlxCrawler {
       let actualNoOfResults =
         hrefs.length <= maxResultsPerPage ? hrefs.length : maxResultsPerPage;
 
-      const asyncScraping = [];
-      for (let i = 0; i < actualNoOfResults; i++) {
-        asyncScraping.push(this.scrapeAd(hrefs[i]));
-        //Delaying next scrape ad request to avoid ScraperAPI server error
-        asyncScraping.push(this.sleep(this.delayBetweenAds));
+      const scrapedData = [];
+      for (
+        let i = 0;
+        i < actualNoOfResults;
+        i += NUMBER_OF_CONCURRENT_REQ_SCRAPER_API
+      ) {
+        const concurrentUrlsToScrape = hrefs.slice(
+          i,
+          NUMBER_OF_CONCURRENT_REQ_SCRAPER_API
+        );
+
+        const concurrentReqScraperApi = concurrentUrlsToScrape.map(url =>
+          this.scrapeAd(url)
+        );
+        const concurrentReqData = await Promise.all(concurrentReqScraperApi);
+        scrapedData.push(concurrentReqData);
+
+        this.sleep(DELAY_BETWEEN_REQ_SCRAPER_API);
       }
 
-      const scrapedData = await Promise.all(asyncScraping);
       const filteredScrapedData = scrapedData.filter(adData => !!adData);
       return filteredScrapedData;
     } catch (e) {
@@ -217,7 +226,7 @@ class OlxCrawler {
     //let numberOfParseErrors = 0;
     //   do {
     try {
-      await this.sleep(this.delayBetweenAds);
+      // await this.sleep(this.delayBetweenAds);
 
       const adPageSource = await fetch(url);
       const body = await adPageSource.text();
@@ -696,7 +705,7 @@ class OlxCrawler {
       console.error("Exception caught: " + e.message, "\r\nURL:", url);
     }
     //  } while (hasParseErrors && numberOfParseErrors <= 1);
-    await this.sleep(this.delayBetweenAds);
+    // await this.sleep(this.delayBetweenAds);
 
     return null;
   }
@@ -913,6 +922,28 @@ class OlxCrawler {
     console.log("sprat = NEPOZNATO [", floorText, "]");
     return null;
   }
+  /*
+  async consecutiveRequestSending(requestsToScraperApi) {
+    let dataFromAllRequests = [];
+
+    for (
+      const i = 0;
+      i <= requestsToScraperApi.length;
+      i + NUMBER_OF_CONCURRENT_REQ_SCRAPER_API
+    ) {
+      const concurrentRequestsToScraperApi = requestsToScraperApi.slice(
+        i,
+        NUMBER_OF_CONCURRENT_REQ_SCRAPER_API
+      );
+      const dataFromConcurrentRequest = await Promise.all(
+        concurrentRequestsToScraperApi
+      );
+      dataFromAllRequests.push(dataFromConcurrentRequest);
+      this.sleep(DELAY_BETWEEN_REQ_SCRAPER_API);
+    }
+
+    return dataFromAllRequests;
+  }*/
 
   async sleep(ms) {
     // console.log("Sleep for:", ms);