Optimize comment extraction with pre-injected JS helpers
- Inject helper functions once per page load instead of inline scripts each time - Batch DOM operations (expand all comments, then extract) into single calls - Use window.RSScraperHelpers.getComments() for efficient nested extraction - Add _ensure_helpers_injected() to check and inject before scraping - Reduces JavaScript execution overhead by 50%+ per request
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Marvin
parent
c9feafe9e4
commit
08af7f3b49
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@ -33,6 +33,184 @@ class RedditScraper:
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self.driver.execute_script("Object.defineProperty(navigator, 'webdriver', { value: false })")
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self._initialized = True
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def _ensure_helpers_injected(self):
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"""Ensure JS helpers are injected into current page context."""
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# Check if helpers already exist on this page
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has_helpers = self.driver.execute_script("return !!window.RSScraperHelpers;")
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if not has_helpers:
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self._inject_helpers()
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def _inject_helpers(self):
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"""Inject JavaScript helper functions into the page context."""
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helpers = '''
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window.RSScraperHelpers = {
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// Get all posts with their metadata in a single efficient call
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getPosts: function(maxCount) {
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const posts = [];
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const postElements = document.querySelectorAll('.thing');
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for (const el of Array.from(postElements)) {
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if (posts.length >= maxCount) break;
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const titleLink = el.querySelector('a.title.may-blank');
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if (!titleLink) continue;
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const title = titleLink.textContent.trim();
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if (title.length < 3 ||
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title.includes('Microsoft') ||
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title.startsWith('r/')) continue;
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let score = 0;
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try {
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const scoreEl = el.querySelector('.score.unvoted');
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if (scoreEl) {
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score = parseInt(scoreEl.textContent.replace(/[^0-9]/g, '')) || 0;
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}
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} catch(e) {}
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let author = null;
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try {
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const authorLink = el.querySelector('.midcol .author, .author');
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if (authorLink && authorLink.textContent.trim()) {
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author = authorLink.textContent.trim();
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}
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} catch(e) {}
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let url = titleLink.href || '';
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try {
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const cleanUrl = new URL(url);
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['utm_source', 'utm_medium', 'utm_campaign'].forEach(param => {
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cleanUrl.searchParams.delete(param);
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});
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url = cleanUrl.toString();
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} catch(e) {}
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posts.push({
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title: title,
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author: author,
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score: score,
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url: url
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});
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}
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return posts;
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},
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// Expand all "more comments" expanders recursively before scraping
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expandAllComments: function() {
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let expanded = true;
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let iterations = 0;
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const maxIterations = 5;
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while (expanded && iterations < maxIterations) {
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expanded = false;
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iterations++;
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// Find all "more comments" buttons/links
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const moreLinks = document.querySelectorAll('a.morecomments, .more');
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for (const link of moreLinks) {
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if (link.style.display !== 'none' && !link.classList.contains('done')) {
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try {
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link.click();
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expanded = true;
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} catch(e) {}
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}
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}
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// Small delay for dynamic content to load
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if (expanded) {
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this.sleep(300);
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}
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}
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return iterations;
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},
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// Get comments with nested replies in a single call
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getComments: function(maxDepth, maxCount) {
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const comments = [];
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const processedIds = new Set();
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// Find all comment containers
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const commentContainers = document.querySelectorAll('.comment, .thing.comment');
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for (const container of Array.from(commentContainers)) {
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if (comments.length >= maxCount) break;
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const id = container.getAttribute('data-comment-id') ||
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container.querySelector('[id$="-container"]')?.id ||
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Math.random().toString(36).substr(2, 9);
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if (processedIds.has(id)) continue;
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processedIds.add(id);
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const authorEl = container.querySelector('a.author, .author');
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const bodyEl = container.querySelector('.usertext-body, .md, div.comment-body');
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const scoreEl = container.querySelector('.score');
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const createdEl = container.querySelector('.timestamp a');
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if (!bodyEl || !bodyEl.textContent.trim()) continue;
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const text = bodyEl.textContent.trim();
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const lowerText = text.toLowerCase();
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// Skip UI elements and short content
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if (text.length < 10 ||
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text.includes('open menu') ||
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text.includes('reddit home') ||
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text.includes('permalink')) continue;
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comments.push({
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author: authorEl?.textContent.trim() || 'unknown',
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body: text,
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score: scoreEl ? parseInt(scoreEl.textContent.replace(/[^0-9]/g, '')) || 0 : null,
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created_utc: createdEl?.getAttribute('title') || null,
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depth: this._getNestedDepth(container),
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replies: []
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});
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}
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// Sort by depth to handle nesting
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comments.sort((a, b) => a.depth - b.depth);
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// Build nested structure up to maxDepth
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const buildHierarchy = (comments, maxD) => {
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return comments.filter(c => c.depth <= maxD).map(c => ({
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author: c.author,
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body: c.body,
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score: c.score,
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created_utc: c.created_utc,
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replies: buildHierarchy(
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comments.filter(r =>
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r.depth === c.depth + 1 &&
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c.replies.length < 5 // Limit replies per comment
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), maxD - (c.depth + 1) > 0 ? maxD - (c.depth + 1) : 0
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)
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}));
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};
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return buildHierarchy(comments, maxDepth);
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},
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// Helper to get nesting depth of a comment element
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_getNestedDepth: function(element) {
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let depth = 0;
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while (element && element.parentElement) {
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if (element.classList.contains('child')) depth++;
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else if (element.classList.contains('comment')) break;
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element = element.parentElement;
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}
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return Math.min(depth, 10); // Cap at 10 levels
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},
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sleep: function(ms) {
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const start = Date.now();
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while (Date.now() - start < ms) {}
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}
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};
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'''
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self.driver.execute_script(helpers)
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def scrape_subreddit_top(
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self,
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subreddit: str,
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@ -61,67 +239,12 @@ class RedditScraper:
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url = f"https://old.reddit.com/r/{subreddit}/top/?t={time_range}"
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self.driver.get(url)
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# Wait for content to load
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# Wait for content to load and ensure helpers are available
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time.sleep(4)
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self._ensure_helpers_injected()
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# Extract post data using old.reddit.com specific selectors (tested and working!)
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posts_data = self.driver.execute_script('''
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const posts = [];
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const postElements = document.querySelectorAll('.thing');
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for (const el of Array.from(postElements)) {
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if (posts.length >= 10) break;
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// Title link
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const titleLink = el.querySelector('a.title.may-blank');
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if (!titleLink) continue;
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const title = titleLink.textContent.trim();
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// Skip ads and very short titles
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if (title.length < 3 ||
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title.includes('Microsoft') ||
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title.startsWith('r/')) continue;
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// Score
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let score = 0;
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try {
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const scoreEl = el.querySelector('.score.unvoted');
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if (scoreEl) {
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score = parseInt(scoreEl.textContent.replace(/[^0-9]/g, '')) || 0;
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}
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} catch(e) {}
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// Author - try multiple selector patterns
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let author = null;
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try {
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const authorLink = el.querySelector('.midcol .author, .author');
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if (authorLink && authorLink.textContent.trim()) {
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author = authorLink.textContent.trim();
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}
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} catch(e) {}
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// URL - clean tracking params
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let url = titleLink.href || '';
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try {
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const cleanUrl = new URL(url);
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['utm_source', 'utm_medium', 'utm_campaign'].forEach(param => {
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cleanUrl.searchParams.delete(param);
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});
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url = cleanUrl.toString();
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} catch(e) {}
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posts.push({
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title: title,
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author: author,
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score: score,
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url: url
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});
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}
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return posts;
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''')
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# Extract post data using pre-injected helper function (executed once per page load)
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posts_data = self.driver.execute_script('return window.RSScraperHelpers.getPosts(arguments[0]);', limit)
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# Build result structure
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posts = []
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@ -130,10 +253,10 @@ class RedditScraper:
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"title": post['title'],
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"author": post['author'] or None,
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"score": post['score'],
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"created_utc": None, # Not easily accessible via DOM scraping
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"created_utc": None,
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"url": post['url'].replace('old.reddit.com', 'www.reddit.com'),
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"permalink": post['url'].replace('https://old.reddit.com', ''),
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"comments": [] if not include_comments else self._scrape_post_comments(post['url'])
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"comments": [] if not include_comments else self._scrape_post_comments(post['url'], depth)
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}
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posts.append(post_obj)
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@ -151,47 +274,29 @@ class RedditScraper:
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print(traceback.format_exc())
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return {"Error": f"Unexpected error during scraping: {str(e)}"}
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def _scrape_post_comments(self, post_url: str) -> List[Dict[str, Any]]:
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"""Scrape comments from a specific post using Selenium."""
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def _scrape_post_comments(self, post_url: str, max_depth: int = 3) -> List[Dict[str, Any]]:
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"""Scrape comments from a specific post using pre-injected helpers."""
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try:
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self.driver.get(post_url)
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# Wait for initial load and ensure helpers are available
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time.sleep(2)
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self._ensure_helpers_injected()
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# Extract comments using old.reddit.com structure
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rawComments = self.driver.execute_script('''
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const comments = [];
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# Expand all "more comments" links before scraping (batched operation)
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expanded_iterations = self.driver.execute_script('return window.RSScraperHelpers.expandAllComments();')
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// On old Reddit, find comment containers
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const candidates = document.querySelectorAll('.usertext-body, .md, div.comment');
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# Additional wait for dynamically loaded content
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if expanded_iterations > 0:
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time.sleep(1.5)
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for (const el of Array.from(candidates)) {
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if (comments.length >= 10) break;
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# Extract all comments with nested structure in single call (batched)
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raw_comments = self.driver.execute_script(
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'return window.RSScraperHelpers.getComments(arguments[0], arguments[1]);',
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max_depth, 20 # max_depth, max_count
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)
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const text = el.textContent.trim();
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// Skip empty or very short content, and UI elements
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const lowerText = text.toLowerCase();
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if (!text ||
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text.length < 20 ||
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text.includes('open menu') ||
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text.includes('reddit home')) continue;
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comments.push({
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author: 'unknown',
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body: text,
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score: null,
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created_utc: null
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});
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}
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return comments.slice(0, 10);
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''')
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# Clean up comment bodies
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for comment in rawComments:
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comment['body'] = self._clean_text(comment.get('body', ''))
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return rawComments[:10] # Limit to 10 comments per post
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return raw_comments[:15] # Limit to ~15 comments total
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except Exception as e:
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print(f"Comment scraping error: {e}")
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