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docs/md_v2/basic/quickstart.md
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docs/md_v2/basic/quickstart.md
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# Quick Start Guide 🚀
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Welcome to the Crawl4AI Quickstart Guide! In this tutorial, we'll walk you through the basic usage of Crawl4AI with a friendly and humorous tone. We'll cover everything from basic usage to advanced features like chunking and extraction strategies, all with the power of asynchronous programming. Let's dive in! 🌟
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## Getting Started 🛠️
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First, let's import the necessary modules and create an instance of `AsyncWebCrawler`. We'll use an async context manager, which handles the setup and teardown of the crawler for us.
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```python
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import asyncio
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from crawl4ai import AsyncWebCrawler
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async def main():
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async with AsyncWebCrawler(verbose=True) as crawler:
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# We'll add our crawling code here
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pass
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if __name__ == "__main__":
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asyncio.run(main())
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```
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### Basic Usage
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Simply provide a URL and let Crawl4AI do the magic!
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```python
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async def main():
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async with AsyncWebCrawler(verbose=True) as crawler:
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result = await crawler.arun(url="https://www.nbcnews.com/business")
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print(f"Basic crawl result: {result.markdown[:500]}") # Print first 500 characters
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asyncio.run(main())
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```
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### Taking Screenshots 📸
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Capture screenshots of web pages easily:
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```python
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async def capture_and_save_screenshot(url: str, output_path: str):
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async with AsyncWebCrawler(verbose=True) as crawler:
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result = await crawler.arun(
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url=url,
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screenshot=True,
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bypass_cache=True
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)
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if result.success and result.screenshot:
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import base64
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screenshot_data = base64.b64decode(result.screenshot)
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with open(output_path, 'wb') as f:
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f.write(screenshot_data)
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print(f"Screenshot saved successfully to {output_path}")
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else:
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print("Failed to capture screenshot")
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```
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### Browser Selection 🌐
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Crawl4AI supports multiple browser engines. Here's how to use different browsers:
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```python
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# Use Firefox
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async with AsyncWebCrawler(browser_type="firefox", verbose=True, headless=True) as crawler:
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result = await crawler.arun(url="https://www.example.com", bypass_cache=True)
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# Use WebKit
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async with AsyncWebCrawler(browser_type="webkit", verbose=True, headless=True) as crawler:
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result = await crawler.arun(url="https://www.example.com", bypass_cache=True)
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# Use Chromium (default)
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async with AsyncWebCrawler(verbose=True, headless=True) as crawler:
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result = await crawler.arun(url="https://www.example.com", bypass_cache=True)
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```
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### User Simulation 🎭
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Simulate real user behavior to avoid detection:
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```python
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async with AsyncWebCrawler(verbose=True, headless=True) as crawler:
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result = await crawler.arun(
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url="YOUR-URL-HERE",
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bypass_cache=True,
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simulate_user=True, # Causes random mouse movements and clicks
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override_navigator=True # Makes the browser appear more like a real user
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)
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```
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### Understanding Parameters 🧠
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By default, Crawl4AI caches the results of your crawls. This means that subsequent crawls of the same URL will be much faster! Let's see this in action.
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```python
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async def main():
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async with AsyncWebCrawler(verbose=True) as crawler:
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# First crawl (caches the result)
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result1 = await crawler.arun(url="https://www.nbcnews.com/business")
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print(f"First crawl result: {result1.markdown[:100]}...")
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# Force to crawl again
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result2 = await crawler.arun(url="https://www.nbcnews.com/business", bypass_cache=True)
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print(f"Second crawl result: {result2.markdown[:100]}...")
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asyncio.run(main())
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```
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### Adding a Chunking Strategy 🧩
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Let's add a chunking strategy: `RegexChunking`! This strategy splits the text based on a given regex pattern.
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```python
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from crawl4ai.chunking_strategy import RegexChunking
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async def main():
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async with AsyncWebCrawler(verbose=True) as crawler:
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result = await crawler.arun(
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url="https://www.nbcnews.com/business",
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chunking_strategy=RegexChunking(patterns=["\n\n"])
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)
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print(f"RegexChunking result: {result.extracted_content[:200]}...")
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asyncio.run(main())
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```
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### Using LLMExtractionStrategy with Different Providers 🤖
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Crawl4AI supports multiple LLM providers for extraction:
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```python
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from crawl4ai.extraction_strategy import LLMExtractionStrategy
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from pydantic import BaseModel, Field
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class OpenAIModelFee(BaseModel):
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model_name: str = Field(..., description="Name of the OpenAI model.")
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input_fee: str = Field(..., description="Fee for input token for the OpenAI model.")
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output_fee: str = Field(..., description="Fee for output token for the OpenAI model.")
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# OpenAI
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await extract_structured_data_using_llm("openai/gpt-4o", os.getenv("OPENAI_API_KEY"))
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# Hugging Face
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await extract_structured_data_using_llm(
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"huggingface/meta-llama/Meta-Llama-3.1-8B-Instruct",
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os.getenv("HUGGINGFACE_API_KEY")
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)
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# Ollama
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await extract_structured_data_using_llm("ollama/llama3.2")
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# With custom headers
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custom_headers = {
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"Authorization": "Bearer your-custom-token",
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"X-Custom-Header": "Some-Value"
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}
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await extract_structured_data_using_llm(extra_headers=custom_headers)
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```
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### Knowledge Graph Generation 🕸️
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Generate knowledge graphs from web content:
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```python
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from pydantic import BaseModel
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from typing import List
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class Entity(BaseModel):
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name: str
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description: str
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class Relationship(BaseModel):
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entity1: Entity
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entity2: Entity
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description: str
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relation_type: str
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class KnowledgeGraph(BaseModel):
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entities: List[Entity]
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relationships: List[Relationship]
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extraction_strategy = LLMExtractionStrategy(
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provider='openai/gpt-4o-mini',
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api_token=os.getenv('OPENAI_API_KEY'),
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schema=KnowledgeGraph.model_json_schema(),
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extraction_type="schema",
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instruction="Extract entities and relationships from the given text."
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)
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async with AsyncWebCrawler() as crawler:
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result = await crawler.arun(
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url="https://paulgraham.com/love.html",
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bypass_cache=True,
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extraction_strategy=extraction_strategy
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)
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```
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### Advanced Session-Based Crawling with Dynamic Content 🔄
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For modern web applications with dynamic content loading, here's how to handle pagination and content updates:
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```python
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async def crawl_dynamic_content():
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async with AsyncWebCrawler(verbose=True) as crawler:
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url = "https://github.com/microsoft/TypeScript/commits/main"
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session_id = "typescript_commits_session"
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js_next_page = """
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const button = document.querySelector('a[data-testid="pagination-next-button"]');
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if (button) button.click();
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"""
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wait_for = """() => {
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const commits = document.querySelectorAll('li.Box-sc-g0xbh4-0 h4');
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if (commits.length === 0) return false;
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const firstCommit = commits[0].textContent.trim();
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return firstCommit !== window.firstCommit;
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}"""
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schema = {
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"name": "Commit Extractor",
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"baseSelector": "li.Box-sc-g0xbh4-0",
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"fields": [
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{
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"name": "title",
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"selector": "h4.markdown-title",
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"type": "text",
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"transform": "strip",
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},
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],
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}
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extraction_strategy = JsonCssExtractionStrategy(schema, verbose=True)
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for page in range(3): # Crawl 3 pages
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result = await crawler.arun(
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url=url,
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session_id=session_id,
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css_selector="li.Box-sc-g0xbh4-0",
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extraction_strategy=extraction_strategy,
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js_code=js_next_page if page > 0 else None,
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wait_for=wait_for if page > 0 else None,
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js_only=page > 0,
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bypass_cache=True,
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headless=False,
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)
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await crawler.crawler_strategy.kill_session(session_id)
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```
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### Handling Overlays and Fitting Content 📏
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Remove overlay elements and fit content appropriately:
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```python
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async with AsyncWebCrawler(headless=False) as crawler:
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result = await crawler.arun(
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url="your-url-here",
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bypass_cache=True,
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word_count_threshold=10,
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remove_overlay_elements=True,
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screenshot=True
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)
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```
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## Performance Comparison 🏎️
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Crawl4AI offers impressive performance compared to other solutions:
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```python
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# Firecrawl comparison
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from firecrawl import FirecrawlApp
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app = FirecrawlApp(api_key=os.environ['FIRECRAWL_API_KEY'])
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start = time.time()
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scrape_status = app.scrape_url(
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'https://www.nbcnews.com/business',
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params={'formats': ['markdown', 'html']}
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)
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end = time.time()
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# Crawl4AI comparison
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async with AsyncWebCrawler() as crawler:
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start = time.time()
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result = await crawler.arun(
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url="https://www.nbcnews.com/business",
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word_count_threshold=0,
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bypass_cache=True,
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verbose=False,
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)
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end = time.time()
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```
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Note: Performance comparisons should be conducted in environments with stable and fast internet connections for accurate results.
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## Congratulations! 🎉
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You've made it through the updated Crawl4AI Quickstart Guide! Now you're equipped with even more powerful features to crawl the web asynchronously like a pro! 🕸️
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Happy crawling! 🚀
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