A Coding Implementation of Crawl4AI for Web Crawling, Markdown Generation, JavaScript Execution, and LLM-Based Structured Extraction

print(“📦 Installing system dependencies…”)
subprocess.run([‘apt-get’, ‘update’, ‘-qq’], capture_output=True)
subprocess.run([‘apt-get’, ‘install’, ‘-y’, ‘-qq’,
‘libnss3’, ‘libnspr4’, ‘libatk1.0-0’, ‘libatk-bridge2.0-0’,
‘libcups2’, ‘libdrm2’, ‘libxkbcommon0’, ‘libxcomposite1’,
‘libxdamage1’, ‘libxfixes3’, ‘libxrandr2’, ‘libgbm1’,
‘libasound2’, ‘libpango-1.0-0’, ‘libcairo2’], capture_output=True)
print(“✅ System dependencies installed!”)

print(“\n📦 Installing Python packages…”)
subprocess.run([sys.executable, ‘-m’, ‘pip’, ‘install’, ‘-U’, ‘crawl4ai’, ‘nest_asyncio’, ‘pydantic’, ‘-q’])
print(“✅ Python packages installed!”)

print(“\n📦 Installing Playwright browsers (this may take a minute)…”)
subprocess.run([sys.executable, ‘-m’, ‘playwright’, ‘install’, ‘chromium’], capture_output=True)
subprocess.run([sys.executable, ‘-m’, ‘playwright’, ‘install-deps’, ‘chromium’], capture_output=True)
print(“✅ Playwright browsers installed!”)

import nest_asyncio
nest_asyncio.apply()

import asyncio
import json
from typing import List, Optional
from pydantic import BaseModel, Field

print(“\n” + “=”*60)
print(“✅ INSTALLATION COMPLETE! Ready to crawl!”)
print(“=”*60)

print(“\n” + “=”*60)
print(“📖 PART 2: BASIC CRAWLING”)
print(“=”*60)

from crawl4ai import AsyncWebCrawler, BrowserConfig, CrawlerRunConfig, CacheMode

async def basic_crawl():
“””The simplest possible crawl – fetch a webpage and get markdown.”””
print(“\n🔍 Running basic crawl on example.com…”)

async with AsyncWebCrawler() as crawler:
result = await crawler.arun(url=”https://example.com”)

print(f”\n✅ Crawl successful: {result.success}”)
print(f”📄 Title: {result.metadata.get(‘title’, ‘N/A’)}”)
print(f”📝 Markdown length: {len(result.markdown.raw_markdown)} characters”)
print(f”\n— First 500 chars of markdown —“)
print(result.markdown.raw_markdown[:500])

return result

result = asyncio.run(basic_crawl())

print(“\n” + “=”*60)
print(“⚙️ PART 3: CONFIGURED CRAWLING”)
print(“=”*60)

async def configured_crawl():
“””Crawling with custom browser and crawler configurations.”””
print(“\n🔧 Running configured crawl with custom settings…”)

browser_config = BrowserConfig(
headless=True,
verbose=True,
viewport_width=1920,
viewport_height=1080,
user_agent=”Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36″
)

run_config = CrawlerRunConfig(
cache_mode=CacheMode.BYPASS,
word_count_threshold=10,
page_timeout=30000,
wait_until=”networkidle”,
verbose=True
)

async with AsyncWebCrawler(config=browser_config) as crawler:
result = await crawler.arun(
url=”https://httpbin.org/html”,
config=run_config
)

print(f”\n✅ Success: {result.success}”)
print(f”📊 Status code: {result.status_code}”)
print(f”\n— Content Preview —“)
print(result.markdown.raw_markdown[:400])

return result

result = asyncio.run(configured_crawl())

print(“\n” + “=”*60)
print(“📝 PART 4: MARKDOWN GENERATION”)
print(“=”*60)

from crawl4ai.content_filter_strategy import PruningContentFilter, BM25ContentFilter
from crawl4ai.markdown_generation_strategy import DefaultMarkdownGenerator

async def markdown_generation_demo():
“””Demonstrates raw vs fit markdown with content filtering.”””
print(“\n🎯 Demonstrating markdown generation strategies…”)

browser_config = BrowserConfig(headless=True, verbose=False)

run_config = CrawlerRunConfig(
cache_mode=CacheMode.BYPASS,
markdown_generator=DefaultMarkdownGenerator(
content_filter=PruningContentFilter(
threshold=0.4,
threshold_type=”fixed”,
min_word_threshold=20
)
)
)

async with AsyncWebCrawler(config=browser_config) as crawler:
result = await crawler.arun(
url=”https://en.wikipedia.org/wiki/Web_scraping”,
config=run_config
)

raw_len = len(result.markdown.raw_markdown)
fit_len = len(result.markdown.fit_markdown) if result.markdown.fit_markdown else 0

print(f”\n📊 Markdown Comparison:”)
print(f” Raw Markdown: {raw_len:,} characters”)
print(f” Fit Markdown: {fit_len:,} characters”)
print(f” Reduction: {((raw_len – fit_len) / raw_len * 100):.1f}%”)

print(f”\n— Fit Markdown Preview (first 600 chars) —“)
print(result.markdown.fit_markdown[:600] if result.markdown.fit_markdown else “N/A”)

return result

result = asyncio.run(markdown_generation_demo())