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Enhance Crawl4AI with new features and documentation

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- Fix crawler text mode for improved performance; cover missing `srcset` and `data_srcset` attributes in image tags.
  - Introduced Managed Browsers for enhanced crawling experience.
  - Updated documentation for clearer navigation on configuration.
  - Changed 'text_only' to 'text_mode' in configuration and methods.
  - Improved performance and relevance in content filtering strategies.
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# Hooks & Auth for AsyncWebCrawler
Crawl4AI's AsyncWebCrawler allows you to customize the behavior of the web crawler using hooks. Hooks are asynchronous functions that are called at specific points in the crawling process, allowing you to modify the crawler's behavior or perform additional actions. This example demonstrates how to use various hooks to customize the asynchronous crawling process.
Crawl4AI's `AsyncWebCrawler` allows you to customize the behavior of the web crawler using hooks. Hooks are asynchronous functions called at specific points in the crawling process, allowing you to modify the crawler's behavior or perform additional actions. This updated documentation demonstrates how to use hooks, including the new `on_page_context_created` hook, and ensures compatibility with `BrowserConfig` and `CrawlerRunConfig`.
## Example: Using Crawler Hooks with AsyncWebCrawler
Let's see how we can customize the AsyncWebCrawler using hooks! In this example, we'll:
In this example, we'll:
1. Configure the browser when it's created.
2. Add custom headers before navigating to the URL.
3. Log the current URL after navigation.
4. Perform actions after JavaScript execution.
5. Log the length of the HTML before returning it.
1. Configure the browser and set up authentication when it's created.
2. Apply custom routing and initial actions when the page context is created.
3. Add custom headers before navigating to the URL.
4. Log the current URL after navigation.
5. Perform actions after JavaScript execution.
6. Log the length of the HTML before returning it.
### Hook Definitions
```python
import asyncio
from crawl4ai import AsyncWebCrawler
from crawl4ai.async_crawler_strategy import AsyncPlaywrightCrawlerStrategy
from crawl4ai.async_configs import BrowserConfig, CrawlerRunConfig
from playwright.async_api import Page, Browser, BrowserContext
async def on_browser_created(browser: Browser):
def log_routing(route):
# Example: block loading images
if route.request.resource_type == "image":
print(f"[HOOK] Blocking image request: {route.request.url}")
asyncio.create_task(route.abort())
else:
asyncio.create_task(route.continue_())
async def on_browser_created(browser: Browser, **kwargs):
print("[HOOK] on_browser_created")
# Example customization: set browser viewport size
context = await browser.new_context(viewport={'width': 1920, 'height': 1080})
# Example: Set browser viewport size and log in
context = await browser.new_context(viewport={"width": 1920, "height": 1080})
page = await context.new_page()
# Example customization: logging in to a hypothetical website
await page.goto('https://example.com/login')
await page.fill('input[name="username"]', 'testuser')
await page.fill('input[name="password"]', 'password123')
await page.click('button[type="submit"]')
await page.wait_for_selector('#welcome')
# Add a custom cookie
await context.add_cookies([{'name': 'test_cookie', 'value': 'cookie_value', 'url': 'https://example.com'}])
await page.goto("https://example.com/login")
await page.fill("input[name='username']", "testuser")
await page.fill("input[name='password']", "password123")
await page.click("button[type='submit']")
await page.wait_for_selector("#welcome")
await context.add_cookies([{"name": "auth_token", "value": "abc123", "url": "https://example.com"}])
await page.close()
await context.close()
async def before_goto(page: Page):
print("[HOOK] before_goto")
# Example customization: add custom headers
await page.set_extra_http_headers({'X-Test-Header': 'test'})
async def on_page_context_created(context: BrowserContext, page: Page, **kwargs):
print("[HOOK] on_page_context_created")
await context.route("**", log_routing)
async def after_goto(page: Page):
async def before_goto(page: Page, context: BrowserContext, **kwargs):
print("[HOOK] before_goto")
await page.set_extra_http_headers({"X-Test-Header": "test"})
async def after_goto(page: Page, context: BrowserContext, **kwargs):
print("[HOOK] after_goto")
# Example customization: log the URL
print(f"Current URL: {page.url}")
async def on_execution_started(page: Page):
async def on_execution_started(page: Page, context: BrowserContext, **kwargs):
print("[HOOK] on_execution_started")
# Example customization: perform actions after JS execution
await page.evaluate("console.log('Custom JS executed')")
async def before_return_html(page: Page, html: str):
async def before_return_html(page: Page, context: BrowserContext, html: str, **kwargs):
print("[HOOK] before_return_html")
# Example customization: log the HTML length
print(f"HTML length: {len(html)}")
return page
```
### Using the Hooks with the AsyncWebCrawler
### Using the Hooks with AsyncWebCrawler
```python
import asyncio
from crawl4ai import AsyncWebCrawler
from crawl4ai.async_crawler_strategy import AsyncPlaywrightCrawlerStrategy
async def main():
print("\n🔗 Using Crawler Hooks: Let's see how we can customize the AsyncWebCrawler using hooks!")
initial_cookies = [
{"name": "sessionId", "value": "abc123", "domain": ".example.com"},
{"name": "userId", "value": "12345", "domain": ".example.com"}
]
crawler_strategy = AsyncPlaywrightCrawlerStrategy(verbose=True, cookies=initial_cookies)
crawler_strategy.set_hook('on_browser_created', on_browser_created)
crawler_strategy.set_hook('before_goto', before_goto)
crawler_strategy.set_hook('after_goto', after_goto)
crawler_strategy.set_hook('on_execution_started', on_execution_started)
crawler_strategy.set_hook('before_return_html', before_return_html)
async with AsyncWebCrawler(verbose=True, crawler_strategy=crawler_strategy) as crawler:
result = await crawler.arun(
url="https://example.com",
js_code="window.scrollTo(0, document.body.scrollHeight);",
wait_for="footer"
)
print("\n🔗 Using Crawler Hooks: Customize AsyncWebCrawler with hooks!")
print("📦 Crawler Hooks result:")
# Configure browser and crawler settings
browser_config = BrowserConfig(
headless=True,
viewport_width=1920,
viewport_height=1080
)
crawler_run_config = CrawlerRunConfig(
js_code="window.scrollTo(0, document.body.scrollHeight);",
wait_for="footer"
)
# Initialize crawler
async with AsyncWebCrawler(browser_config=browser_config) as crawler:
crawler.crawler_strategy.set_hook("on_browser_created", on_browser_created)
crawler.crawler_strategy.set_hook("on_page_context_created", on_page_context_created)
crawler.crawler_strategy.set_hook("before_goto", before_goto)
crawler.crawler_strategy.set_hook("after_goto", after_goto)
crawler.crawler_strategy.set_hook("on_execution_started", on_execution_started)
crawler.crawler_strategy.set_hook("before_return_html", before_return_html)
# Run the crawler
result = await crawler.arun(url="https://example.com", config=crawler_run_config)
print("\n📦 Crawler Hooks Result:")
print(result)
asyncio.run(main())
```
### Explanation
### Explanation of Hooks
- `on_browser_created`: This hook is called when the Playwright browser is created. It sets up the browser context, logs in to a website, and adds a custom cookie.
- `before_goto`: This hook is called right before Playwright navigates to the URL. It adds custom HTTP headers.
- `after_goto`: This hook is called after Playwright navigates to the URL. It logs the current URL.
- `on_execution_started`: This hook is called after any custom JavaScript is executed. It performs additional JavaScript actions.
- `before_return_html`: This hook is called before returning the HTML content. It logs the length of the HTML content.
- **`on_browser_created`**: Called when the browser is created. Use this to configure the browser or handle authentication (e.g., logging in and setting cookies).
- **`on_page_context_created`**: Called when a new page context is created. Use this to apply routing, block resources, or inject custom logic before navigating to the URL.
- **`before_goto`**: Called before navigating to the URL. Use this to add custom headers or perform other pre-navigation actions.
- **`after_goto`**: Called after navigation. Use this to verify content or log the URL.
- **`on_execution_started`**: Called after executing custom JavaScript. Use this to perform additional actions.
- **`before_return_html`**: Called before returning the HTML content. Use this to log details or preprocess the content.
### Additional Ideas
### Additional Customizations
- **Handling authentication**: Use the `on_browser_created` hook to handle login processes or set authentication tokens.
- **Dynamic header modification**: Modify headers based on the target URL or other conditions in the `before_goto` hook.
- **Content verification**: Use the `after_goto` hook to verify that the expected content is present on the page.
- **Custom JavaScript injection**: Inject and execute custom JavaScript using the `on_execution_started` hook.
- **Content preprocessing**: Modify or analyze the HTML content in the `before_return_html` hook before it's returned.
- **Resource Management**: Use `on_page_context_created` to block or modify requests (e.g., block images, fonts, or third-party scripts).
- **Dynamic Headers**: Use `before_goto` to add or modify headers dynamically based on the URL.
- **Authentication**: Use `on_browser_created` to handle login processes and set authentication cookies or tokens.
- **Content Analysis**: Use `before_return_html` to analyze or modify the extracted HTML content.
These hooks provide powerful customization options for tailoring the crawling process to your needs.
By using these hooks, you can customize the behavior of the AsyncWebCrawler to suit your specific needs, including handling authentication, modifying requests, and preprocessing content.