updated

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "puppeteer-api",
-  "version": "1.0.0",
+  "version": "5.3.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "puppeteer-api",
-  "version": "1.0.0",
+  "version": "5.3.0",
   "main": "server.js",
   "type": "commonjs",
   "dependencies": {

server copy.js → server copy 2.js

@@ -41,7 +41,116 @@ class ProgressTracker extends EventEmitter {
     }
 }
 
-// --- Puppeteer Logic (Updated for Stealth and Reliability) ---
+// --- Enhanced Human Behavior Simulation ---
+const simulateHumanBehavior = async (page, progressTracker) => {
+    console.log("🧑 Simulating human-like mouse movements and delays...");
+    const viewport = page.viewport();
+    for (let i = 0; i < 5; i++) {
+        const x = Math.random() * (viewport.width || 1920);
+        const y = Math.random() * (viewport.height || 1080);
+        await page.mouse.move(x, y, { steps: 10 });
+        await page.waitForTimeout(Math.random() * 1000 + 500);
+    }
+    // Random scroll a bit
+    await page.evaluate(() => {
+        window.scrollBy(0, Math.random() * 200 - 100);
+    });
+    await page.waitForTimeout(Math.random() * 2000 + 1000);
+    progressTracker?.updateProgress(progressTracker.progress + 1, 'humanizing', 'Human behavior simulated');
+};
+
+// --- Enhanced Cloudflare Bypass Function ---
+const handleCloudflareChallenge = async (page, progressTracker) => {
+    progressTracker?.updateProgress(35, 'cloudflare', 'Detecting and bypassing Cloudflare...');
+
+    console.log("☁️ Checking for Cloudflare challenge...");
+    const cloudflareSelectors = [
+        '#challenge-running',
+        '.cf-browser-verification',
+        '[data-ray]',
+        '#cf-challenge-running',
+        '.under-attack',
+        'iframe[src*="cloudflare"]',
+        '#challenge-form', // Added for JS challenge
+        '.cf-turnstile' // For Turnstile CAPTCHA
+    ];
+
+    // Wait for any Cloudflare element to appear
+    let challengeDetected = false;
+    for (const selector of cloudflareSelectors) {
+        try {
+            await page.waitForSelector(selector, { timeout: 5000 });
+            challengeDetected = true;
+            console.log(`☁️ Cloudflare challenge detected with selector: ${selector}`);
+            break;
+        } catch (e) {
+            // Continue to next selector
+        }
+    }
+
+    if (challengeDetected) {
+        // Simulate human behavior before attempting to solve
+        await simulateHumanBehavior(page, progressTracker);
+
+        // Wait for the challenge to resolve (JS execution)
+        console.log("⏳ Waiting for Cloudflare challenge to complete...");
+        try {
+            await page.waitForFunction(() => {
+                const selectors = [
+                    '#challenge-running',
+                    '.cf-browser-verification',
+                    '[data-ray]',
+                    '#cf-challenge-running',
+                    '.under-attack',
+                    '#challenge-form',
+                    '.cf-turnstile'
+                ];
+                return !selectors.some(sel => document.querySelector(sel));
+            }, { timeout: 90000 }); // Increased timeout for slower challenges
+        } catch (e) {
+            console.log("⚠️ Standard wait failed, attempting Turnstile click...");
+            // Fallback: Check for and click Turnstile if present
+            try {
+                const cfInput = await page.$('[name="cf-turnstile-response"]');
+                if (cfInput) {
+                    const parentItem = await cfInput.evaluateHandle((element) => element.parentElement);
+                    const coordinates = await parentItem.boundingBox();
+                    if (coordinates) {
+                        await page.mouse.click(coordinates.x + 25, coordinates.y + coordinates.height / 2);
+                        console.log("🖱️ Clicked on Turnstile CAPTCHA");
+                        await page.waitForTimeout(3000);
+                    }
+                }
+                // Retry wait after click
+                await page.waitForFunction(() => {
+                    const selectors = [
+                        '#challenge-running',
+                        '.cf-browser-verification',
+                        '[data-ray]',
+                        '#cf-challenge-running',
+                        '.under-attack',
+                        '#challenge-form',
+                        '.cf-turnstile'
+                    ];
+                    return !selectors.some(sel => document.querySelector(sel));
+                }, { timeout: 60000 });
+            } catch (clickError) {
+                console.error("❌ Turnstile click failed:", clickError.message);
+                throw new Error("Failed to bypass Cloudflare challenge. Try again later or use a proxy.");
+            }
+        }
+
+        // Additional wait for page to stabilize post-challenge with random delay
+        const randomDelay = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);
+        await page.waitForTimeout(randomDelay(3000, 7000));
+        console.log("✅ Cloudflare challenge bypassed successfully.");
+        progressTracker?.updateProgress(38, 'cloudflare', 'Cloudflare bypassed');
+    } else {
+        console.log("✅ No Cloudflare challenge detected.");
+    }
+};
+
+// --- Puppeteer Logic (Updated for Enhanced Cloudflare Bypass) ---
 const bypassCookiesAndRestrictions = async (page, progressTracker) => {
     progressTracker?.updateProgress(5, 'bypassing', 'Setting up cookie bypass...');
 
@@ -65,7 +174,7 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
         }
     }
 
-    // Step 2: Inject CSS to hide cookie banners immediately (Unchanged)
+    // Step 2: Inject CSS to hide cookie banners immediately (Updated: Added more selectors for previews and blurred overlays)
     await page.addStyleTag({
         content: `
             /* Hide all possible cookie banners */
@@ -80,8 +189,9 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
                 z-index: -9999 !important;
                 pointer-events: none !important;
             }
-            /* Remove blur and premium overlays */
-            [class*="blur" i], [class*="premium" i], [class*="paywall" i], [class*="sample-preview-blur" i] {
+            /* Remove blur and premium overlays, including previews */
+            [class*="blur" i], [class*="premium" i], [class*="paywall" i], [class*="sample-preview-blur" i], [class*="preview" i], [class*="blurred-container" i], [class*="blurred" i] {
+                display: none !important;
                 filter: none !important;
                 backdrop-filter: none !important;
                 opacity: 1 !important;
@@ -103,6 +213,10 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
                 overflow: auto !important;
                 position: static !important;
             }
+            /* Hide Cloudflare elements if they persist */
+            #challenge-running, .cf-browser-verification, [data-ray], .under-attack {
+                display: none !important;
+            }
         `
     });
 
@@ -173,6 +287,8 @@ const unblurContent = async (page, progressTracker) => {
 
             removeBySelector("#adbox, .adsbox, .ad-box, .banner-ads, .advert");
             removeBySelector(".PremiumBannerBlobWrapper_overflow-wrapper__xsaS8");
+            // Added: Remove preview and blurred overlays
+            removeBySelector('[class*="preview" i], [class*="blurred-container" i], [class*="blurred" i]:not(img)');
 
             const removeBlur = (element = document) => {
                 element.querySelectorAll("*").forEach(el => {
@@ -195,7 +311,6 @@ const unblurContent = async (page, progressTracker) => {
             };
 
             removeBlur();
-            removeBySelector('[class*="blur" i], [class*="premium" i], [class*="paywall" i]');
 
             const contentSelectors = [
                 '.document-content', '.page-content', '.content', '[data-page]', '[data-testid*="document"]',
@@ -213,13 +328,43 @@ const unblurContent = async (page, progressTracker) => {
         };
 
         removeRestrictions();
-        const intervalId = setInterval(removeRestrictions, 2000);
-        setTimeout(() => clearInterval(intervalId), 60000);
+        const intervalId = setInterval(removeRestrictions, 1000);
+        setTimeout(() => clearInterval(intervalId), 30000);
     });
 
     progressTracker?.updateProgress(20, 'unblurring', 'Content restrictions removed');
 };
 
+// New function to fetch clear images by modifying blurred URLs
+const fetchClearImages = async (page, progressTracker) => {
+    progressTracker?.updateProgress(65, 'unblurring_images', 'Fetching clear page images...');
+
+    console.log("🖼️ Modifying blurred image URLs to fetch clear versions...");
+    await page.evaluate(() => {
+        const images = document.querySelectorAll('img[src*="/blurred/"]');
+        images.forEach(img => {
+            img.src = img.src.replace(/\/blurred\//, '/');
+            console.log(`Modified image src: ${img.src}`);
+        });
+    });
+
+    // Wait for the modified images to load
+    await page.evaluate(async () => {
+        const images = Array.from(document.querySelectorAll('img'));
+        await Promise.all(images.map(img => {
+            if (img.complete) return Promise.resolve();
+            return new Promise((resolve) => {
+                img.addEventListener('load', resolve);
+                img.addEventListener('error', resolve);
+                setTimeout(resolve, 10000);
+            });
+        }));
+    });
+
+    await new Promise(resolve => setTimeout(resolve, 3000)); // Additional delay for stability
+    progressTracker?.updateProgress(70, 'unblurring_images', 'Clear images loaded');
+};
+
 const applyPrintStyles = async (page, progressTracker) => {
     progressTracker?.updateProgress(85, 'styling', 'Applying print styles...');
 
@@ -243,6 +388,8 @@ const applyPrintStyles = async (page, progressTracker) => {
                     overflow: visible !important;
                     background: white !important;
                     color: black !important;
+                    display: flex;
+                    justify-content: center;
                 }
                 /* Remove all unwanted elements like headers, footers, sidebars, etc. */
                 header, footer, nav, aside, .no-print, .ads, .sidebar, .premium-banner,
@@ -271,7 +418,7 @@ const applyPrintStyles = async (page, progressTracker) => {
                     display: block !important;
                     width: 100% !important;
                     max-width: none !important;
-                    margin: 0 !important;
+                    margin: 0 auto !important; /* Center horizontally */
                     padding: 0 !important;
                     box-sizing: border-box; /* Include padding in width calculation */
                     transform: none !important;
@@ -322,7 +469,18 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 '--disable-features=site-per-process',
                 '--disable-blink-features=AutomationControlled',
                 '--disable-extensions',
-                '--ignore-certificate-errors'
+                '--ignore-certificate-errors',
+                // NEW: Additional args for better Cloudflare evasion
+                '--disable-features=TranslateUI',
+                '--disable-ipc-flooding',
+                '--disable-backgrounding-occluded-windows',
+                '--disable-renderer-backgrounding',
+                '--disable-features=TranslateUI,BlinkGenPropertyTrees',
+                '--metrics-recording-only',
+                '--no-default-browser-check',
+                '--safebrowsing-disable-auto-update',
+                '--password-store=basic',
+                '--use-mock-keychain'
             ],
             ignoreHTTPSErrors: true,
             timeout: 300000,
@@ -332,20 +490,32 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
 
         progressTracker?.updateProgress(2, 'initializing', 'Configuring browser settings...');
 
-        await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36');
-        await page.setViewport({ width: 794, height: 1122 }); // A4 size in pixels at 96 DPI
+        await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36');
+        await page.setViewport({ width: 1920, height: 1080 }); // NEW: Use full HD for more realistic viewport, adjust back if needed for A4
 
         // NOTE: Stealth plugin handles most of this, but keeping for extra safety
         await page.evaluateOnNewDocument(() => {
             Object.defineProperty(navigator, 'webdriver', { get: () => undefined });
             Object.defineProperty(navigator, 'languages', { get: () => ['en-US', 'en'] });
             Object.defineProperty(navigator, 'plugins', { get: () => [1, 2, 3, 4, 5] });
+            // NEW: Additional stealth evasions
+            Object.defineProperty(navigator, 'permissions', {
+                get: () => ({
+                    query: () => Promise.resolve({ state: 'granted' })
+                })
+            });
+            window.chrome = {
+                runtime: {},
+                loadTimes: function () { },
+                csi: function () { },
+                app: {}
+            };
         });
 
         // Set up cookie and content bypass
         await bypassCookiesAndRestrictions(page, progressTracker);
 
-        // Block unnecessary resources (UPDATED: Always continue for 'document' to prevent navigation failures)
+        // Block unnecessary resources (UPDATED: Loosened for Cloudflare - allow cloudflare.com requests)
         await page.setRequestInterception(true);
         page.on('request', (req) => {
             const resourceType = req.resourceType();
@@ -356,7 +526,16 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 return;
             }
 
+            // NEW: Always allow Cloudflare-related requests
+            if (reqUrl.includes('cloudflare') || reqUrl.includes('cf-')) {
+                req.continue();
+                return;
+            }
+
             if (
+                ['image', 'media', 'font', 'stylesheet'].includes(resourceType) && // Block non-essential images/media/fonts/styles early if not core
+                !reqUrl.includes('document') && !reqUrl.includes('page') && !reqUrl.includes('studocu') || // Allow core document images
+                resourceType === 'script' && !reqUrl.includes('studocu') && !reqUrl.includes('cloudflare') || // Block third-party scripts except Cloudflare
                 reqUrl.includes('doubleclick') ||
                 reqUrl.includes('googletagmanager') ||
                 reqUrl.includes('facebook.com') ||
@@ -367,7 +546,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 reqUrl.includes('mixpanel') ||
                 reqUrl.includes('onetrust') ||
                 reqUrl.includes('cookielaw') ||
-                (resourceType === 'other' && reqUrl.includes('/track/')) // UPDATED: More specific to avoid over-blocking
+                (resourceType === 'other' && reqUrl.includes('/track/'))
             ) {
                 req.abort();
             } else {
@@ -381,6 +560,8 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
 
             console.log("🔑 Logging in to StuDocu...");
             await page.goto('https://www.studocu.com/en-us/login', { waitUntil: 'domcontentloaded', timeout: 120000 });
+            // NEW: Handle potential Cloudflare on login page
+            await handleCloudflareChallenge(page, progressTracker);
             await page.waitForSelector('#email', { timeout: 15000 });
             await page.type('#email', options.email);
             await page.type('#password', options.password);
@@ -396,33 +577,32 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             }
         }
 
-        progressTracker?.updateProgress(25, 'navigating', 'Navigating to homepage first for session setup...');
-        console.log(`📄 Navigating to homepage to simulate natural session...`);
-        await page.goto('https://www.studocu.com/en-us', { waitUntil: 'domcontentloaded', timeout: 150000 }); // NEW: Preliminary homepage visit
-        await new Promise(resolve => setTimeout(resolve, 3000)); // Short delay for session stabilization
-
+        // Removed homepage visit as it's not strictly necessary for session setup; directly navigate to URL
         progressTracker?.updateProgress(30, 'navigating', 'Navigating to document...');
         console.log(`📄 Navigating to ${url}...`);
 
         let navigationSuccess = false;
         let attempts = 0;
-        const maxAttempts = 5;
+        const maxAttempts = 3; // Reduced from 5 to minimize retries
         while (!navigationSuccess && attempts < maxAttempts) {
             try {
                 attempts++;
                 progressTracker?.updateProgress(30 + (attempts * 5), 'navigating', `Navigation attempt ${attempts}/${maxAttempts}`);
                 console.log(`Navigation attempt ${attempts}/${maxAttempts}`);
-                await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 150000 }); // UPDATED: Increased timeout to 2.5 min
+                await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 120000 }); // Increased from 60000
                 navigationSuccess = true;
             } catch (e) {
                 console.log(`Navigation attempt ${attempts} failed:`, e.message);
                 if (attempts >= maxAttempts) throw e;
-                await new Promise(resolve => setTimeout(resolve, 15000)); // UPDATED: Increased retry delay to 15s
+                await new Promise(resolve => setTimeout(resolve, 10000)); // Increased retry delay to 10s for stability
             }
         }
 
+        // NEW: Handle Cloudflare after navigation
+        await handleCloudflareChallenge(page, progressTracker);
+
         progressTracker?.updateProgress(40, 'loading', 'Page loaded, waiting for content...');
-        await new Promise(resolve => setTimeout(resolve, 5000));
+        await new Promise(resolve => setTimeout(resolve, 5000)); // Increased from 2000ms for better loading
 
         // Apply content unblurring
         await unblurContent(page, progressTracker);
@@ -438,7 +618,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
         let contentFound = false;
         for (const selector of contentSelectors) {
             try {
-                await page.waitForSelector(selector, { timeout: 20000 });
+                await page.waitForSelector(selector, { timeout: 20000 }); // Increased from 10000
                 console.log(`✅ Found content with selector: ${selector}`);
                 contentFound = true;
                 break;
@@ -451,7 +631,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             console.log("⚠️ No specific content selector found, proceeding with page content...");
         }
 
-        // Enhanced scrolling to load all content
+        // Enhanced scrolling to load all content (Optimized: Increased scroll distance, reduced delays)
         progressTracker?.updateProgress(50, 'scrolling', 'Loading all document pages...');
         console.log("📜 Loading all document pages with enhanced slow scroll...");
 
@@ -460,27 +640,28 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             let scrollHeight = document.body.scrollHeight;
             while (true) {
                 let totalHeight = 0;
-                const distance = 300;
+                const distance = 600; // Increased from 300 for faster coverage
                 while (totalHeight < scrollHeight) {
                     window.scrollBy(0, distance);
                     totalHeight += distance;
-                    await delay(500);
+                    await delay(300); // Increased from 200ms for large docs stability
                 }
-                await delay(2000);
+                await delay(2000); // Increased from 1000ms
                 const newHeight = document.body.scrollHeight;
                 if (newHeight === scrollHeight) break;
                 scrollHeight = newHeight;
             }
             window.scrollTo({ top: 0, behavior: "smooth" });
-            await delay(1000);
+            await delay(1000); // Increased from 500ms
         });
 
-        progressTracker?.updateProgress(70, 'processing', 'Processing loaded content...');
-
         // Re-apply unblur after loading new content
         await unblurContent(page, progressTracker);
 
-        // Wait for all images to load
+        // New: Fetch clear images for blurred pages
+        await fetchClearImages(page, progressTracker);
+
+        // Wait for all images to load (Optimized: Reduced per-image timeout, parallel wait)
         progressTracker?.updateProgress(75, 'loading_images', 'Loading images...');
         console.log("🖼️ Waiting for all images to load...");
 
@@ -491,12 +672,12 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 return new Promise((resolve) => {
                     img.addEventListener('load', resolve);
                     img.addEventListener('error', resolve);
-                    setTimeout(resolve, 15000);
+                    setTimeout(resolve, 10000); // Increased from 5000ms for large docs
                 });
             }));
         });
 
-        await new Promise(resolve => setTimeout(resolve, 5000));
+        await new Promise(resolve => setTimeout(resolve, 5000)); // Increased from 2000ms
         progressTracker?.updateProgress(80, 'finalizing', 'Preparing document for PDF generation...');
 
         // Set exact height
@@ -511,7 +692,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             document.body.style.overflow = 'hidden !important';
         });
 
-        // Content verification
+        // Content verification (Unchanged, as it's quick)
         const contentCheck = await page.evaluate(() => {
             const textContent = document.body.textContent || '';
             const images = document.querySelectorAll('img');
@@ -549,7 +730,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             printBackground: true,
             preferCSSPageSize: true, // Use the @page size
             displayHeaderFooter: false,
-            timeout: 180000,
+            timeout: 180000, // Increased back to 180000 for large PDFs
             scale: 1,
             omitBackground: false
         });
@@ -674,15 +855,17 @@ app.get('/health', (req, res) => {
 
 app.get('/', (req, res) => {
     res.json({
-        message: '🚀 Enhanced StuDocu Downloader API v5.2 - Real-time Progress Tracking with Stealth',
-        version: '5.2.0',
+        message: '🚀 Enhanced StuDocu Downloader API v5.3 - Real-time Progress Tracking with Cloudflare Bypass',
+        version: '5.3.0',
         features: [
             '🍪 Advanced cookie banner bypass',
             '🔓 Premium content unblurring',
             '🔑 Login support for full access',
             '📊 Real-time progress tracking via polling',
             '📄 Clean PDF generation with print styles',
-            '🕵️ Enhanced stealth to evade bot detection'
+            '🕵️ Enhanced stealth to evade bot detection',
+            '☁️ Automatic Cloudflare challenge handling',
+            '🧑 Human-like behavior simulation'
         ],
         endpoints: {
             request: 'POST /api/request-download (body: {url, filename?, email?, password?})',
@@ -704,6 +887,6 @@ process.on('SIGINT', () => {
 });
 
 app.listen(port, () => {
-    console.log(`🚀 Enhanced StuDocu Downloader v5.2.0 running on http://localhost:${port}`);
-    console.log(`✨ Features: Real-time progress tracking, enhanced stealth, and user feedback`);
+    console.log(`🚀 Enhanced StuDocu Downloader v5.3.0 running on http://localhost:${port}`);
+    console.log(`✨ Features: Real-time progress tracking, enhanced stealth, Cloudflare bypass, and user feedback`);
 });

server.js

@@ -41,7 +41,116 @@ class ProgressTracker extends EventEmitter {
     }
 }
 
-// --- Puppeteer Logic (Updated for Stealth and Reliability) ---
+// --- Enhanced Human Behavior Simulation ---
+const simulateHumanBehavior = async (page, progressTracker) => {
+    console.log("🧑 Simulating human-like mouse movements and delays...");
+    const viewport = page.viewport();
+    for (let i = 0; i < 5; i++) {
+        const x = Math.random() * (viewport.width || 1920);
+        const y = Math.random() * (viewport.height || 1080);
+        await page.mouse.move(x, y, { steps: 10 });
+        await page.waitForTimeout(Math.random() * 1000 + 500);
+    }
+    // Random scroll a bit
+    await page.evaluate(() => {
+        window.scrollBy(0, Math.random() * 200 - 100);
+    });
+    await page.waitForTimeout(Math.random() * 2000 + 1000);
+    progressTracker?.updateProgress(progressTracker.progress + 1, 'humanizing', 'Human behavior simulated');
+};
+
+// --- Enhanced Cloudflare Bypass Function ---
+const handleCloudflareChallenge = async (page, progressTracker) => {
+    progressTracker?.updateProgress(35, 'cloudflare', 'Detecting and bypassing Cloudflare...');
+
+    console.log("☁️ Checking for Cloudflare challenge...");
+    const cloudflareSelectors = [
+        '#challenge-running',
+        '.cf-browser-verification',
+        '[data-ray]',
+        '#cf-challenge-running',
+        '.under-attack',
+        'iframe[src*="cloudflare"]',
+        '#challenge-form', // Added for JS challenge
+        '.cf-turnstile' // For Turnstile CAPTCHA
+    ];
+
+    // Wait for any Cloudflare element to appear
+    let challengeDetected = false;
+    for (const selector of cloudflareSelectors) {
+        try {
+            await page.waitForSelector(selector, { timeout: 5000 });
+            challengeDetected = true;
+            console.log(`☁️ Cloudflare challenge detected with selector: ${selector}`);
+            break;
+        } catch (e) {
+            // Continue to next selector
+        }
+    }
+
+    if (challengeDetected) {
+        // Simulate human behavior before attempting to solve
+        await simulateHumanBehavior(page, progressTracker);
+
+        // Wait for the challenge to resolve (JS execution)
+        console.log("⏳ Waiting for Cloudflare challenge to complete...");
+        try {
+            await page.waitForFunction(() => {
+                const selectors = [
+                    '#challenge-running',
+                    '.cf-browser-verification',
+                    '[data-ray]',
+                    '#cf-challenge-running',
+                    '.under-attack',
+                    '#challenge-form',
+                    '.cf-turnstile'
+                ];
+                return !selectors.some(sel => document.querySelector(sel));
+            }, { timeout: 90000 }); // Increased timeout for slower challenges
+        } catch (e) {
+            console.log("⚠️ Standard wait failed, attempting Turnstile click...");
+            // Fallback: Check for and click Turnstile if present
+            try {
+                const cfInput = await page.$('[name="cf-turnstile-response"]');
+                if (cfInput) {
+                    const parentItem = await cfInput.evaluateHandle((element) => element.parentElement);
+                    const coordinates = await parentItem.boundingBox();
+                    if (coordinates) {
+                        await page.mouse.click(coordinates.x + 25, coordinates.y + coordinates.height / 2);
+                        console.log("🖱️ Clicked on Turnstile CAPTCHA");
+                        await page.waitForTimeout(3000);
+                    }
+                }
+                // Retry wait after click
+                await page.waitForFunction(() => {
+                    const selectors = [
+                        '#challenge-running',
+                        '.cf-browser-verification',
+                        '[data-ray]',
+                        '#cf-challenge-running',
+                        '.under-attack',
+                        '#challenge-form',
+                        '.cf-turnstile'
+                    ];
+                    return !selectors.some(sel => document.querySelector(sel));
+                }, { timeout: 60000 });
+            } catch (clickError) {
+                console.error("❌ Turnstile click failed:", clickError.message);
+                throw new Error("Failed to bypass Cloudflare challenge. Try again later or use a proxy.");
+            }
+        }
+
+        // Additional wait for page to stabilize post-challenge with random delay
+        const randomDelay = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);
+        await page.waitForTimeout(randomDelay(3000, 7000));
+        console.log("✅ Cloudflare challenge bypassed successfully.");
+        progressTracker?.updateProgress(38, 'cloudflare', 'Cloudflare bypassed');
+    } else {
+        console.log("✅ No Cloudflare challenge detected.");
+    }
+};
+
+// --- Puppeteer Logic (Updated for Enhanced Cloudflare Bypass) ---
 const bypassCookiesAndRestrictions = async (page, progressTracker) => {
     progressTracker?.updateProgress(5, 'bypassing', 'Setting up cookie bypass...');
 
@@ -65,7 +174,7 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
         }
     }
 
-    // Step 2: Inject CSS to hide cookie banners immediately (Unchanged)
+    // Step 2: Inject CSS to hide cookie banners immediately (Updated: Added more selectors for previews and blurred overlays)
     await page.addStyleTag({
         content: `
             /* Hide all possible cookie banners */
@@ -80,8 +189,9 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
                 z-index: -9999 !important;
                 pointer-events: none !important;
             }
-            /* Remove blur and premium overlays */
-            [class*="blur" i], [class*="premium" i], [class*="paywall" i], [class*="sample-preview-blur" i] {
+            /* Remove blur and premium overlays, including previews */
+            [class*="blur" i], [class*="premium" i], [class*="paywall" i], [class*="sample-preview-blur" i], [class*="preview" i], [class*="blurred-container" i], [class*="blurred" i] {
+                display: none !important;
                 filter: none !important;
                 backdrop-filter: none !important;
                 opacity: 1 !important;
@@ -103,6 +213,10 @@ const bypassCookiesAndRestrictions = async (page, progressTracker) => {
                 overflow: auto !important;
                 position: static !important;
             }
+            /* Hide Cloudflare elements if they persist */
+            #challenge-running, .cf-browser-verification, [data-ray], .under-attack {
+                display: none !important;
+            }
         `
     });
 
@@ -173,6 +287,8 @@ const unblurContent = async (page, progressTracker) => {
 
             removeBySelector("#adbox, .adsbox, .ad-box, .banner-ads, .advert");
             removeBySelector(".PremiumBannerBlobWrapper_overflow-wrapper__xsaS8");
+            // Added: Remove preview and blurred overlays
+            removeBySelector('[class*="preview" i], [class*="blurred-container" i], [class*="blurred" i]:not(img)');
 
             const removeBlur = (element = document) => {
                 element.querySelectorAll("*").forEach(el => {
@@ -195,7 +311,6 @@ const unblurContent = async (page, progressTracker) => {
             };
 
             removeBlur();
-            removeBySelector('[class*="blur" i], [class*="premium" i], [class*="paywall" i]');
 
             const contentSelectors = [
                 '.document-content', '.page-content', '.content', '[data-page]', '[data-testid*="document"]',
@@ -213,13 +328,43 @@ const unblurContent = async (page, progressTracker) => {
         };
 
         removeRestrictions();
-        const intervalId = setInterval(removeRestrictions, 1000); // Reduced from 2000ms to 1000ms
-        setTimeout(() => clearInterval(intervalId), 30000); // Reduced from 60000ms to 30000ms
+        const intervalId = setInterval(removeRestrictions, 1000);
+        setTimeout(() => clearInterval(intervalId), 30000);
     });
 
     progressTracker?.updateProgress(20, 'unblurring', 'Content restrictions removed');
 };
 
+// New function to fetch clear images by modifying blurred URLs
+const fetchClearImages = async (page, progressTracker) => {
+    progressTracker?.updateProgress(65, 'unblurring_images', 'Fetching clear page images...');
+
+    console.log("🖼️ Modifying blurred image URLs to fetch clear versions...");
+    await page.evaluate(() => {
+        const images = document.querySelectorAll('img[src*="/blurred/"]');
+        images.forEach(img => {
+            img.src = img.src.replace(/\/blurred\//, '/');
+            console.log(`Modified image src: ${img.src}`);
+        });
+    });
+
+    // Wait for the modified images to load
+    await page.evaluate(async () => {
+        const images = Array.from(document.querySelectorAll('img'));
+        await Promise.all(images.map(img => {
+            if (img.complete) return Promise.resolve();
+            return new Promise((resolve) => {
+                img.addEventListener('load', resolve);
+                img.addEventListener('error', resolve);
+                setTimeout(resolve, 10000);
+            });
+        }));
+    });
+
+    await new Promise(resolve => setTimeout(resolve, 3000)); // Additional delay for stability
+    progressTracker?.updateProgress(70, 'unblurring_images', 'Clear images loaded');
+};
+
 const applyPrintStyles = async (page, progressTracker) => {
     progressTracker?.updateProgress(85, 'styling', 'Applying print styles...');
 
@@ -243,6 +388,8 @@ const applyPrintStyles = async (page, progressTracker) => {
                     overflow: visible !important;
                     background: white !important;
                     color: black !important;
+                    display: flex;
+                    justify-content: center;
                 }
                 /* Remove all unwanted elements like headers, footers, sidebars, etc. */
                 header, footer, nav, aside, .no-print, .ads, .sidebar, .premium-banner,
@@ -271,7 +418,7 @@ const applyPrintStyles = async (page, progressTracker) => {
                     display: block !important;
                     width: 100% !important;
                     max-width: none !important;
-                    margin: 0 !important;
+                    margin: 0 auto !important; /* Center horizontally */
                     padding: 0 !important;
                     box-sizing: border-box; /* Include padding in width calculation */
                     transform: none !important;
@@ -322,7 +469,18 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 '--disable-features=site-per-process',
                 '--disable-blink-features=AutomationControlled',
                 '--disable-extensions',
-                '--ignore-certificate-errors'
+                '--ignore-certificate-errors',
+                // NEW: Additional args for better Cloudflare evasion
+                '--disable-features=TranslateUI',
+                '--disable-ipc-flooding',
+                '--disable-backgrounding-occluded-windows',
+                '--disable-renderer-backgrounding',
+                '--disable-features=TranslateUI,BlinkGenPropertyTrees',
+                '--metrics-recording-only',
+                '--no-default-browser-check',
+                '--safebrowsing-disable-auto-update',
+                '--password-store=basic',
+                '--use-mock-keychain'
             ],
             ignoreHTTPSErrors: true,
             timeout: 300000,
@@ -332,20 +490,32 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
 
         progressTracker?.updateProgress(2, 'initializing', 'Configuring browser settings...');
 
-        await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36');
-        await page.setViewport({ width: 794, height: 1122 }); // A4 size in pixels at 96 DPI
+        await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36');
+        await page.setViewport({ width: 1920, height: 1080 }); // NEW: Use full HD for more realistic viewport, adjust back if needed for A4
 
         // NOTE: Stealth plugin handles most of this, but keeping for extra safety
         await page.evaluateOnNewDocument(() => {
             Object.defineProperty(navigator, 'webdriver', { get: () => undefined });
             Object.defineProperty(navigator, 'languages', { get: () => ['en-US', 'en'] });
             Object.defineProperty(navigator, 'plugins', { get: () => [1, 2, 3, 4, 5] });
+            // NEW: Additional stealth evasions
+            Object.defineProperty(navigator, 'permissions', {
+                get: () => ({
+                    query: () => Promise.resolve({ state: 'granted' })
+                })
+            });
+            window.chrome = {
+                runtime: {},
+                loadTimes: function () { },
+                csi: function () { },
+                app: {}
+            };
         });
 
         // Set up cookie and content bypass
         await bypassCookiesAndRestrictions(page, progressTracker);
 
-        // Block unnecessary resources (UPDATED: Block more aggressively, including scripts, fonts, and stylesheets if not critical)
+        // Block unnecessary resources (UPDATED: Loosened for Cloudflare - allow cloudflare.com requests)
         await page.setRequestInterception(true);
         page.on('request', (req) => {
             const resourceType = req.resourceType();
@@ -356,10 +526,16 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 return;
             }
 
+            // NEW: Always allow Cloudflare-related requests
+            if (reqUrl.includes('cloudflare') || reqUrl.includes('cf-')) {
+                req.continue();
+                return;
+            }
+
             if (
                 ['image', 'media', 'font', 'stylesheet'].includes(resourceType) && // Block non-essential images/media/fonts/styles early if not core
                 !reqUrl.includes('document') && !reqUrl.includes('page') && !reqUrl.includes('studocu') || // Allow core document images
-                resourceType === 'script' && !reqUrl.includes('studocu') || // Block third-party scripts
+                resourceType === 'script' && !reqUrl.includes('studocu') && !reqUrl.includes('cloudflare') || // Block third-party scripts except Cloudflare
                 reqUrl.includes('doubleclick') ||
                 reqUrl.includes('googletagmanager') ||
                 reqUrl.includes('facebook.com') ||
@@ -383,14 +559,16 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             progressTracker?.updateProgress(12, 'authenticating', 'Logging into StuDocu...');
 
             console.log("🔑 Logging in to StuDocu...");
-            await page.goto('https://www.studocu.com/en-us/login', { waitUntil: 'domcontentloaded', timeout: 60000 }); // Reduced timeout from 120000
-            await page.waitForSelector('#email', { timeout: 10000 }); // Reduced from 15000
+            await page.goto('https://www.studocu.com/en-us/login', { waitUntil: 'domcontentloaded', timeout: 120000 });
+            // NEW: Handle potential Cloudflare on login page
+            await handleCloudflareChallenge(page, progressTracker);
+            await page.waitForSelector('#email', { timeout: 15000 });
             await page.type('#email', options.email);
             await page.type('#password', options.password);
             await page.click('button[type="submit"]');
             try {
-                await page.waitForNavigation({ waitUntil: 'networkidle2', timeout: 15000 }); // Reduced from 30000
-                await page.waitForSelector('.user-profile, [data-testid="user-menu"]', { timeout: 5000 }); // Reduced from 10000
+                await page.waitForNavigation({ waitUntil: 'networkidle2', timeout: 30000 });
+                await page.waitForSelector('.user-profile, [data-testid="user-menu"]', { timeout: 10000 });
                 console.log("✅ Login successful.");
                 progressTracker?.updateProgress(18, 'authenticated', 'Login successful');
             } catch (e) {
@@ -411,17 +589,20 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 attempts++;
                 progressTracker?.updateProgress(30 + (attempts * 5), 'navigating', `Navigation attempt ${attempts}/${maxAttempts}`);
                 console.log(`Navigation attempt ${attempts}/${maxAttempts}`);
-                await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 60000 }); // Reduced timeout from 150000
+                await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 120000 }); // Increased from 60000
                 navigationSuccess = true;
             } catch (e) {
                 console.log(`Navigation attempt ${attempts} failed:`, e.message);
                 if (attempts >= maxAttempts) throw e;
-                await new Promise(resolve => setTimeout(resolve, 5000)); // Reduced retry delay from 15000 to 5000ms
+                await new Promise(resolve => setTimeout(resolve, 10000)); // Increased retry delay to 10s for stability
             }
         }
 
+        // NEW: Handle Cloudflare after navigation
+        await handleCloudflareChallenge(page, progressTracker);
+
         progressTracker?.updateProgress(40, 'loading', 'Page loaded, waiting for content...');
-        await new Promise(resolve => setTimeout(resolve, 2000)); // Reduced from 5000ms
+        await new Promise(resolve => setTimeout(resolve, 5000)); // Increased from 2000ms for better loading
 
         // Apply content unblurring
         await unblurContent(page, progressTracker);
@@ -437,7 +618,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
         let contentFound = false;
         for (const selector of contentSelectors) {
             try {
-                await page.waitForSelector(selector, { timeout: 10000 }); // Reduced from 20000
+                await page.waitForSelector(selector, { timeout: 20000 }); // Increased from 10000
                 console.log(`✅ Found content with selector: ${selector}`);
                 contentFound = true;
                 break;
@@ -463,22 +644,23 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 while (totalHeight < scrollHeight) {
                     window.scrollBy(0, distance);
                     totalHeight += distance;
-                    await delay(200); // Reduced from 500ms
+                    await delay(300); // Increased from 200ms for large docs stability
                 }
-                await delay(1000); // Reduced from 2000ms
+                await delay(2000); // Increased from 1000ms
                 const newHeight = document.body.scrollHeight;
                 if (newHeight === scrollHeight) break;
                 scrollHeight = newHeight;
             }
             window.scrollTo({ top: 0, behavior: "smooth" });
-            await delay(500); // Reduced from 1000ms
+            await delay(1000); // Increased from 500ms
         });
 
-        progressTracker?.updateProgress(70, 'processing', 'Processing loaded content...');
-
         // Re-apply unblur after loading new content
         await unblurContent(page, progressTracker);
 
+        // New: Fetch clear images for blurred pages
+        await fetchClearImages(page, progressTracker);
+
         // Wait for all images to load (Optimized: Reduced per-image timeout, parallel wait)
         progressTracker?.updateProgress(75, 'loading_images', 'Loading images...');
         console.log("🖼️ Waiting for all images to load...");
@@ -490,12 +672,12 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
                 return new Promise((resolve) => {
                     img.addEventListener('load', resolve);
                     img.addEventListener('error', resolve);
-                    setTimeout(resolve, 5000); // Reduced from 15000ms
+                    setTimeout(resolve, 10000); // Increased from 5000ms for large docs
                 });
             }));
         });
 
-        await new Promise(resolve => setTimeout(resolve, 2000)); // Reduced from 5000ms
+        await new Promise(resolve => setTimeout(resolve, 5000)); // Increased from 2000ms
         progressTracker?.updateProgress(80, 'finalizing', 'Preparing document for PDF generation...');
 
         // Set exact height
@@ -548,7 +730,7 @@ const studocuDownloader = async (url, options = {}, progressTracker = null) => {
             printBackground: true,
             preferCSSPageSize: true, // Use the @page size
             displayHeaderFooter: false,
-            timeout: 60000, // Reduced from 180000
+            timeout: 180000, // Increased back to 180000 for large PDFs
             scale: 1,
             omitBackground: false
         });
@@ -673,15 +855,17 @@ app.get('/health', (req, res) => {
 
 app.get('/', (req, res) => {
     res.json({
-        message: '🚀 Enhanced StuDocu Downloader API v5.2 - Real-time Progress Tracking with Stealth',
-        version: '5.2.0',
+        message: '🚀 Enhanced StuDocu Downloader API v5.3 - Real-time Progress Tracking with Cloudflare Bypass',
+        version: '5.3.0',
         features: [
             '🍪 Advanced cookie banner bypass',
             '🔓 Premium content unblurring',
             '🔑 Login support for full access',
             '📊 Real-time progress tracking via polling',
             '📄 Clean PDF generation with print styles',
-            '🕵️ Enhanced stealth to evade bot detection'
+            '🕵️ Enhanced stealth to evade bot detection',
+            '☁️ Automatic Cloudflare challenge handling',
+            '🧑 Human-like behavior simulation'
         ],
         endpoints: {
             request: 'POST /api/request-download (body: {url, filename?, email?, password?})',
@@ -703,6 +887,6 @@ process.on('SIGINT', () => {
 });
 
 app.listen(port, () => {
-    console.log(`🚀 Enhanced StuDocu Downloader v5.2.0 running on http://localhost:${port}`);
-    console.log(`✨ Features: Real-time progress tracking, enhanced stealth, and user feedback`);
+    console.log(`🚀 Enhanced StuDocu Downloader v5.3.0 running on http://localhost:${port}`);
+    console.log(`✨ Features: Real-time progress tracking, enhanced stealth, Cloudflare bypass, and user feedback`);
 });