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Munich-news/docs/EXTRACTION_STRATEGIES.md
2025-11-11 14:09:21 +01:00

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Content Extraction Strategies

The crawler uses multiple strategies to dynamically extract article metadata from any website.

🎯 What Gets Extracted

  1. Title - Article headline
  2. Author - Article writer/journalist
  3. Published Date - When article was published
  4. Content - Main article text
  5. Description - Meta description/summary

📋 Extraction Strategies

1. Title Extraction

Tries multiple methods in order of reliability:

Strategy 1: H1 Tag

<h1>Article Title Here</h1>

Most reliable - usually the main headline

Strategy 2: Open Graph Meta Tag

<meta property="og:title" content="Article Title Here" />

Used by Facebook, very reliable

Strategy 3: Twitter Card Meta Tag

<meta name="twitter:title" content="Article Title Here" />

Used by Twitter, reliable

Strategy 4: Title Tag (Fallback)

<title>Article Title | Site Name</title>

⚠️ Often includes site name, needs cleaning

Cleaning:

  • Removes " | Site Name"
  • Removes " - Site Name"

2. Author Extraction

Tries multiple methods:

Strategy 1: Meta Author Tag

<meta name="author" content="John Doe" />

Standard HTML meta tag

<a rel="author" href="/author/john-doe">John Doe</a>

Semantic HTML

Strategy 3: Common Class Names

<div class="author-name">John Doe</div>
<span class="byline">By John Doe</span>
<p class="writer">John Doe</p>

Searches for: author-name, author, byline, writer

Strategy 4: Schema.org Markup

<span itemprop="author">John Doe</span>

Structured data

Strategy 5: JSON-LD Structured Data

<script type="application/ld+json">
{
  "@type": "NewsArticle",
  "author": {
    "@type": "Person",
    "name": "John Doe"
  }
}
</script>

Most structured, very reliable

Cleaning:

  • Removes "By " prefix
  • Validates length (< 100 chars)

3. Date Extraction

Tries multiple methods:

Strategy 1: Time Tag with Datetime

<time datetime="2024-11-10T10:00:00Z">November 10, 2024</time>

Most reliable - ISO format

Strategy 2: Article Published Time Meta

<meta property="article:published_time" content="2024-11-10T10:00:00Z" />

Open Graph standard

Strategy 3: OG Published Time

<meta property="og:published_time" content="2024-11-10T10:00:00Z" />

Facebook standard

Strategy 4: Common Class Names

<span class="publish-date">November 10, 2024</span>
<time class="published">2024-11-10</time>
<div class="timestamp">10:00 AM, Nov 10</div>

Searches for: publish-date, published, date, timestamp

Strategy 5: Schema.org Markup

<meta itemprop="datePublished" content="2024-11-10T10:00:00Z" />

Structured data

Strategy 6: JSON-LD Structured Data

<script type="application/ld+json">
{
  "@type": "NewsArticle",
  "datePublished": "2024-11-10T10:00:00Z"
}
</script>

Most structured


4. Content Extraction

Tries multiple methods:

Strategy 1: Semantic HTML Tags

<article>
  <p>Article content here...</p>
</article>

Best practice HTML5

Strategy 2: Common Class Names

<div class="article-content">...</div>
<div class="article-body">...</div>
<div class="post-content">...</div>
<div class="entry-content">...</div>
<div class="story-body">...</div>

Searches for common patterns

Strategy 3: Schema.org Markup

<div itemprop="articleBody">
  <p>Content here...</p>
</div>

Structured data

Strategy 4: Main Tag

<main>
  <p>Content here...</p>
</main>

Semantic HTML5

Strategy 5: Body Tag (Fallback)

<body>
  <p>Content here...</p>
</body>

⚠️ Last resort, may include navigation

Content Filtering:

  • Removes <script>, <style>, <nav>, <footer>, <header>, <aside>
  • Filters out short paragraphs (< 50 chars) - likely ads/navigation
  • Keeps only substantial paragraphs
  • No length limit - stores full article content

🔍 How It Works

Example: Crawling a News Article

# 1. Fetch HTML
response = requests.get(article_url)
soup = BeautifulSoup(response.content, 'html.parser')

# 2. Extract title (tries 4 strategies)
title = extract_title(soup)
# Result: "New U-Bahn Line Opens in Munich"

# 3. Extract author (tries 5 strategies)
author = extract_author(soup)
# Result: "Max Mustermann"

# 4. Extract date (tries 6 strategies)
published_date = extract_date(soup)
# Result: "2024-11-10T10:00:00Z"

# 5. Extract content (tries 5 strategies)
content = extract_main_content(soup)
# Result: "The new U-Bahn line connecting..."

# 6. Save to database
article_doc = {
    'title': title,
    'author': author,
    'published_at': published_date,
    'full_content': content,
    'word_count': len(content.split())
}

📊 Success Rates by Strategy

Based on common news sites:

Strategy Success Rate Notes
H1 for title 95% Almost universal
OG meta tags 90% Most modern sites
Time tag for date 85% HTML5 sites
JSON-LD 70% Growing adoption
Class name patterns 60% Varies by site
Schema.org 50% Not widely adopted

🎨 Real-World Examples

Example 1: Süddeutsche Zeitung

<article>
  <h1>New U-Bahn Line Opens</h1>
  <span class="author">Max Mustermann</span>
  <time datetime="2024-11-10T10:00:00Z">10. November 2024</time>
  <div class="article-body">
    <p>The new U-Bahn line...</p>
  </div>
</article>

Extracts: Title (H1), Author (class), Date (time), Content (article-body)

Example 2: Medium Blog

<article>
  <h1>How to Build a News Crawler</h1>
  <meta property="og:title" content="How to Build a News Crawler" />
  <meta property="article:published_time" content="2024-11-10T10:00:00Z" />
  <a rel="author" href="/author">Jane Smith</a>
  <section>
    <p>In this article...</p>
  </section>
</article>

Extracts: Title (OG meta), Author (rel), Date (article meta), Content (section)

Example 3: WordPress Blog

<div class="post">
  <h1 class="entry-title">My Blog Post</h1>
  <span class="byline">By John Doe</span>
  <time class="published">November 10, 2024</time>
  <div class="entry-content">
    <p>Blog content here...</p>
  </div>
</div>

Extracts: Title (H1), Author (byline), Date (published), Content (entry-content)


⚠️ Edge Cases Handled

  1. Missing Fields: Returns None instead of crashing
  2. Multiple Authors: Takes first one found
  3. Relative Dates: Stores as-is ("2 hours ago")
  4. Paywalls: Extracts what's available
  5. JavaScript-rendered: Only gets server-side HTML
  6. Ads/Navigation: Filtered out by paragraph length
  7. Site Name in Title: Cleaned automatically

🚀 Future Improvements

Potential enhancements:

  • JavaScript rendering (Selenium/Playwright)
  • Paywall bypass (where legal)
  • Image extraction
  • Video detection
  • Related articles
  • Tags/categories
  • Reading time estimation
  • Language detection
  • Sentiment analysis

🧪 Testing

Test the extraction on a specific URL:

from crawler_service import extract_article_content

url = "https://www.sueddeutsche.de/muenchen/article-123"
data = extract_article_content(url)

print(f"Title: {data['title']}")
print(f"Author: {data['author']}")
print(f"Date: {data['published_date']}")
print(f"Content length: {len(data['content'])} chars")
print(f"Word count: {data['word_count']}")

📚 Standards Supported

  • HTML5 semantic tags
  • Open Graph Protocol
  • Twitter Cards
  • Schema.org microdata
  • JSON-LD structured data
  • Dublin Core metadata
  • Common CSS class patterns