From 27e5ff37806019dd44fa8fbe58b5a290f85d7692 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?K=D0=B8=D1=80=D0=BE=2EK=D1=80=D0=B8=D0=BA=D0=B0?=
 <95271587+Goshko812@users.noreply.github.com>
Date: Wed, 14 Aug 2024 22:44:38 +0300
Subject: [PATCH] Updated the BFS scraper to now properly work

---
 BFS.js | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 BFS.js

diff --git a/BFS.js b/BFS.js
new file mode 100644
index 0000000..201b3bf
--- /dev/null
+++ b/BFS.js
@@ -0,0 +1,139 @@
+const { chromium } = require('playwright');
+const cheerio = require('cheerio');
+const fs = require('fs');
+const path = require('path');
+const crypto = require('crypto');  // For hashing filenames
+const url = require('url');
+
+const websiteUrl = 'https://www.tu-sofia.bg/';
+const outputDir = './output';
+const baseDomain = new URL(websiteUrl).hostname;  // Extract the base domain
+const ignoredDomainsRegex = /facebook\.com|linkedin\.com|youtube\.com|focus-news\.net|novini\.bg|sliveninfo\.bg|utroruse\.com|trafficnews\.bg|pressoffice\.tu-sofia\.bg|career\.tu-sofia\.bg|digilib\.nalis\.bg|proceedings\.tu-sofia\.bg|sopkoni\.tu-sofia\.bg|elara\.tu-sofia\.bg|design\.tu-sofia\.bg|otsk-nk\.tu-sofia\.bg|rcvt\.tu-sofia\.bg|e-university\.tu-sofia\.bg|ef-conference\.tu-sofia\.bg|infotech-bg\.com|bultrans\.org|metrology-bg\.org|konkursi-as\.tu-sofia\.bg|google\.com/i;
+
+(async () => {
+  const browser = await chromium.launch();
+  const page = await browser.newPage();
+
+  // Intercept network requests to handle file downloads
+  await page.route('**/*', async (route) => {
+    const request = route.request();
+    const fileUrl = request.url();
+
+    // Determine file type by extension
+    const fileExtensions = ['.pdf', '.avi', '.mp4', '.jpg', '.png', '.zip', '.rar', '.doc', '.docx', '.xls', '.xlsx'];
+    const extension = path.extname(fileUrl).toLowerCase();
+
+    if (fileExtensions.includes(extension)) {
+      console.log(`Downloading file from ${fileUrl}`);
+      let buffer;
+      const maxRetries = 3;
+      let retries = 0;
+
+      while (retries < maxRetries) {
+        try {
+          // Fetch the file content
+          const response = await page.request.fetch(request);
+          buffer = await response.body();
+          break; // Exit loop if successful
+        } catch (error) {
+          retries++;
+          console.log(`Failed to download ${fileUrl}. Retry ${retries}/${maxRetries}`);
+          if (retries === maxRetries) {
+            console.log(`Skipping ${fileUrl} after ${maxRetries} retries.`);
+            return route.abort(); // Abort the request after max retries
+          }
+        }
+      }
+
+      if (buffer) {
+        // Hash the file path to avoid long filenames
+        const hash = crypto.createHash('md5').update(fileUrl).digest('hex');
+        const urlObj = new URL(fileUrl);
+        const directory = path.join(outputDir, urlObj.hostname);
+        const filePath = path.join(directory, `${hash}${extension}`);
+
+        // Ensure directory exists
+        fs.mkdirSync(directory, { recursive: true });
+        fs.writeFileSync(filePath, buffer);
+      }
+
+      return route.abort(); // Abort the navigation
+    }
+
+    // Continue navigation for HTML pages
+    return route.continue();
+  });
+
+  const crawledPages = new Set();
+  const queue = [websiteUrl];
+
+  while (queue.length > 0) {
+    const currentPageUrl = queue.shift();
+    if (crawledPages.has(currentPageUrl)) continue;
+    crawledPages.add(currentPageUrl);
+
+    console.log(`Crawling ${currentPageUrl}`);
+
+    try {
+      const currentUrlObj = new URL(currentPageUrl);
+
+      // Check if the URL belongs to the base domain
+      if (currentUrlObj.hostname !== baseDomain) {
+        console.log(`Skipping ${currentPageUrl} - Outside of base domain`);
+        continue; // Skip URLs outside of the base domain
+      }
+
+      await page.goto(currentPageUrl, { timeout: 60000 });
+
+      // Wait for the page to be fully loaded
+      await page.waitForLoadState('networkidle');  // Ensures all network activity is finished
+
+      // Extract the content safely
+      let html;
+      try {
+        html = await page.content();
+      } catch (error) {
+        console.log(`Error retrieving content for ${currentPageUrl}: ${error.message}`);
+        continue; // Skip to the next URL
+      }
+
+      const $ = cheerio.load(html);
+
+      // Extract text content
+      const textContent = $('body').text().trim();
+      const urlObj = new URL(currentPageUrl);
+      const hostname = urlObj.hostname;
+
+      // Hash the file path to avoid long filenames
+      const hash = crypto.createHash('md5').update(urlObj.pathname).digest('hex');
+      const textFilePath = path.join(outputDir, hostname, hash, 'index.txt');
+
+      fs.mkdirSync(path.dirname(textFilePath), { recursive: true });
+      fs.writeFileSync(textFilePath, textContent);
+
+      // Find new links to crawl
+      const newLinks = [];
+      $('a').each((index, element) => {
+        let href = $(element).attr('href');
+        if (href) {
+          href = new URL(href, currentPageUrl).href;  // Convert to absolute URL
+          const linkUrlObj = new URL(href);
+          const linkHostname = linkUrlObj.hostname;
+
+          // Skip ignored domains and URLs outside the base domain
+          if (!ignoredDomainsRegex.test(linkHostname) && linkHostname === baseDomain) {
+            newLinks.push(href);
+          }
+        }
+      });
+
+      // Add new links to the queue for BFS
+      queue.push(...newLinks);
+    } catch (error) {
+      console.log(`Error loading or processing ${currentPageUrl}: ${error.message}`);
+      continue; // Skip to the next URL
+    }
+  }
+
+  await browser.close();
+})();