Merge branch 'vr0.4.3b3'

crawl4ai/__init__.py

@@ -16,7 +16,7 @@ from .extraction_strategy import (
 )
 from .chunking_strategy import ChunkingStrategy, RegexChunking
 from .markdown_generation_strategy import DefaultMarkdownGenerator
-from .content_filter_strategy import PruningContentFilter, BM25ContentFilter, LLMContentFilter
+from .content_filter_strategy import PruningContentFilter, BM25ContentFilter, LLMContentFilter, RelevantContentFilter
 from .models import CrawlResult, MarkdownGenerationResult
 from .async_dispatcher import (
     MemoryAdaptiveDispatcher,
@@ -44,6 +44,7 @@ __all__ = [
     "ChunkingStrategy",
     "RegexChunking",
     "DefaultMarkdownGenerator",
+    "RelevantContentFilter",
     "PruningContentFilter",
     "BM25ContentFilter",
     "LLMContentFilter",

crawl4ai/__version__.py

@@ -1,2 +1,2 @@
 # crawl4ai/_version.py
-__version__ = "0.4.3b2"
+__version__ = "0.4.3b3"

crawl4ai/async_configs.py

@@ -6,12 +6,15 @@ from .config import (
     IMAGE_SCORE_THRESHOLD,
     SOCIAL_MEDIA_DOMAINS,
 )
-from .user_agent_generator import UserAgentGenerator
+
+from .user_agent_generator import UserAgentGenerator, UAGen, ValidUAGenerator, OnlineUAGenerator
 from .extraction_strategy import ExtractionStrategy
 from .chunking_strategy import ChunkingStrategy, RegexChunking
 from .markdown_generation_strategy import MarkdownGenerationStrategy
+from .content_filter_strategy import RelevantContentFilter, BM25ContentFilter, LLMContentFilter, PruningContentFilter
 from .content_scraping_strategy import ContentScrapingStrategy, WebScrapingStrategy
 from typing import Optional, Union, List
+from .cache_context import CacheMode
 
 
 class BrowserConfig:
@@ -29,6 +32,7 @@ class BrowserConfig:
                          Default: True.
         use_managed_browser (bool): Launch the browser using a managed approach (e.g., via CDP), allowing
                                     advanced manipulation. Default: False.
+        cdp_url (str): URL for the Chrome DevTools Protocol (CDP) endpoint. Default: "ws://localhost:9222/devtools/browser/".
         debugging_port (int): Port for the browser debugging protocol. Default: 9222.
         use_persistent_context (bool): Use a persistent browser context (like a persistent profile).
                                        Automatically sets use_managed_browser=True. Default: False.
@@ -77,17 +81,18 @@ class BrowserConfig:
         browser_type: str = "chromium",
         headless: bool = True,
         use_managed_browser: bool = False,
+        cdp_url: str = None,
         use_persistent_context: bool = False,
         user_data_dir: str = None,
         chrome_channel: str = "chromium",
         channel: str = "chromium",
-        proxy: Optional[str] = None,
+        proxy: str = None,
         proxy_config: dict = None,
         viewport_width: int = 1080,
         viewport_height: int = 600,
         accept_downloads: bool = False,
         downloads_path: str = None,
-        storage_state=None,
+        storage_state : Union[str, dict, None]=None,
         ignore_https_errors: bool = True,
         java_script_enabled: bool = True,
         sleep_on_close: bool = False,
@@ -95,19 +100,23 @@ class BrowserConfig:
         cookies: list = None,
         headers: dict = None,
         user_agent: str = (
-            "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) AppleWebKit/537.36 "
+            # "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) AppleWebKit/537.36 "
-            "(KHTML, like Gecko) Chrome/116.0.5845.187 Safari/604.1 Edg/117.0.2045.47"
+            # "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
+            # "(KHTML, like Gecko) Chrome/116.0.5845.187 Safari/604.1 Edg/117.0.2045.47"
+            "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/116.0.0.0 Safari/537.36"
         ),
-        user_agent_mode: str = None,
+        user_agent_mode: str = "",
-        user_agent_generator_config: dict = None,
+        user_agent_generator_config: dict = {},
         text_mode: bool = False,
         light_mode: bool = False,
         extra_args: list = None,
         debugging_port: int = 9222,
+        host: str = "localhost",
     ):
         self.browser_type = browser_type
         self.headless = headless
         self.use_managed_browser = use_managed_browser
+        self.cdp_url = cdp_url
         self.use_persistent_context = use_persistent_context
         self.user_data_dir = user_data_dir
         self.chrome_channel = chrome_channel or self.browser_type or "chromium"
@@ -136,17 +145,15 @@ class BrowserConfig:
         self.verbose = verbose
         self.debugging_port = debugging_port
 
-        user_agenr_generator = UserAgentGenerator()
+        fa_user_agenr_generator = ValidUAGenerator()
-        if self.user_agent_mode != "random" and self.user_agent_generator_config:
+        if self.user_agent_mode == "random":
-            self.user_agent = user_agenr_generator.generate(
+            self.user_agent = fa_user_agenr_generator.generate(
                 **(self.user_agent_generator_config or {})
             )
-        elif self.user_agent_mode == "random":
-            self.user_agent = user_agenr_generator.generate()
         else:
             pass
         
-        self.browser_hint = user_agenr_generator.generate_client_hints(self.user_agent)
+        self.browser_hint = UAGen.generate_client_hints(self.user_agent)
         self.headers.setdefault("sec-ch-ua", self.browser_hint)
 
         # If persistent context is requested, ensure managed browser is enabled
@@ -159,6 +166,7 @@ class BrowserConfig:
             browser_type=kwargs.get("browser_type", "chromium"),
             headless=kwargs.get("headless", True),
             use_managed_browser=kwargs.get("use_managed_browser", False),
+            cdp_url=kwargs.get("cdp_url"),
             use_persistent_context=kwargs.get("use_persistent_context", False),
             user_data_dir=kwargs.get("user_data_dir"),
             chrome_channel=kwargs.get("chrome_channel", "chromium"),
@@ -191,6 +199,7 @@ class BrowserConfig:
             "browser_type": self.browser_type,
             "headless": self.headless,
             "use_managed_browser": self.use_managed_browser,
+            "cdp_url": self.cdp_url,
             "use_persistent_context": self.use_persistent_context,
             "user_data_dir": self.user_data_dir,
             "chrome_channel": self.chrome_channel,
@@ -373,6 +382,11 @@ class CrawlerRunConfig:
         stream (bool): If True, stream the page content as it is being loaded.
         url: str = None  # This is not a compulsory parameter
         check_robots_txt (bool): Whether to check robots.txt rules before crawling. Default: False
+        user_agent (str): Custom User-Agent string to use. Default: None
+        user_agent_mode (str or None): Mode for generating the user agent (e.g., "random"). If None, use the provided
+                                       user_agent as-is. Default: None.
+        user_agent_generator_config (dict or None): Configuration for user agent generation if user_agent_mode is set.
+                                                    Default: None.
     """
 
     def __init__(
@@ -382,7 +396,7 @@ class CrawlerRunConfig:
         extraction_strategy: ExtractionStrategy = None,
         chunking_strategy: ChunkingStrategy = RegexChunking(),
         markdown_generator: MarkdownGenerationStrategy = None,
-        content_filter=None,
+        content_filter : RelevantContentFilter = None,
         only_text: bool = False,
         css_selector: str = None,
         excluded_tags: list = None,
@@ -396,7 +410,7 @@ class CrawlerRunConfig:
         # SSL Parameters
         fetch_ssl_certificate: bool = False,
         # Caching Parameters
-        cache_mode=None,
+        cache_mode: CacheMode =None,
         session_id: str = None,
         bypass_cache: bool = False,
         disable_cache: bool = False,
@@ -444,6 +458,9 @@ class CrawlerRunConfig:
         stream: bool = False,
         url: str = None,
         check_robots_txt: bool = False,
+        user_agent: str = None,
+        user_agent_mode: str = None,
+        user_agent_generator_config: dict = {},
     ):
         self.url = url
 
@@ -526,6 +543,11 @@ class CrawlerRunConfig:
         # Robots.txt Handling Parameters
         self.check_robots_txt = check_robots_txt
 
+        # User Agent Parameters
+        self.user_agent = user_agent
+        self.user_agent_mode = user_agent_mode
+        self.user_agent_generator_config = user_agent_generator_config
+
         # Validate type of extraction strategy and chunking strategy if they are provided
         if self.extraction_strategy is not None and not isinstance(
             self.extraction_strategy, ExtractionStrategy
@@ -623,6 +645,9 @@ class CrawlerRunConfig:
             stream=kwargs.get("stream", False),
             url=kwargs.get("url"),
             check_robots_txt=kwargs.get("check_robots_txt", False),
+            user_agent=kwargs.get("user_agent"),
+            user_agent_mode=kwargs.get("user_agent_mode"),
+            user_agent_generator_config=kwargs.get("user_agent_generator_config", {}),
         )
 
     # Create a funciton returns dict of the object
@@ -686,6 +711,9 @@ class CrawlerRunConfig:
             "stream": self.stream,
             "url": self.url,
             "check_robots_txt": self.check_robots_txt,
+            "user_agent": self.user_agent,
+            "user_agent_mode": self.user_agent_mode,
+            "user_agent_generator_config": self.user_agent_generator_config,
         }
 
     def clone(self, **kwargs):

crawl4ai/async_crawler_strategy.py

@@ -23,6 +23,7 @@ from .async_logger import AsyncLogger
 from playwright_stealth import StealthConfig
 from .ssl_certificate import SSLCertificate
 from .utils import get_home_folder, get_chromium_path
+from .user_agent_generator import ValidUAGenerator, OnlineUAGenerator
 
 stealth_config = StealthConfig(
     webdriver=True,
@@ -102,6 +103,7 @@ class ManagedBrowser:
         logger=None,
         host: str = "localhost",
         debugging_port: int = 9222,
+        cdp_url: Optional[str] = None, 
     ):
         """
         Initialize the ManagedBrowser instance.
@@ -116,6 +118,7 @@ class ManagedBrowser:
             logger (logging.Logger): Logger instance for logging messages. Default: None.
             host (str): Host for debugging the browser. Default: "localhost".
             debugging_port (int): Port for debugging the browser. Default: 9222.
+            cdp_url (str or None): CDP URL to connect to the browser. Default: None.
         """
         self.browser_type = browser_type
         self.user_data_dir = user_data_dir
@@ -126,12 +129,20 @@ class ManagedBrowser:
         self.host = host
         self.logger = logger
         self.shutting_down = False
+        self.cdp_url = cdp_url
 
     async def start(self) -> str:
         """
-        Starts the browser process and returns the CDP endpoint URL.
+        Starts the browser process or returns CDP endpoint URL.
-        If user_data_dir is not provided, creates a temporary directory.
+        If cdp_url is provided, returns it directly.
+        If user_data_dir is not provided for local browser, creates a temporary directory.
+        
+        Returns:
+            str: CDP endpoint URL
         """
+        # If CDP URL provided, just return it
+        if self.cdp_url:
+            return self.cdp_url
 
         # Create temp dir if needed
         if not self.user_data_dir:
@@ -1260,10 +1271,12 @@ class AsyncPlaywrightCrawlerStrategy(AsyncCrawlerStrategy):
         self._downloaded_files = []
 
         # Handle user agent with magic mode
-        user_agent = self.browser_config.user_agent
+        user_agent_to_override = config.user_agent
-        if config.magic and self.browser_config.user_agent_mode != "random":
+        if user_agent_to_override:
-            self.browser_config.user_agent = UserAgentGenerator().generate(
+            self.browser_config.user_agent = user_agent_to_override
-                **(self.browser_config.user_agent_generator_config or {})
+        elif config.magic or config.user_agent_mode == "random":
+            self.browser_config.user_agent = ValidUAGenerator().generate(
+                **(config.user_agent_generator_config or {})
             )
 
         # Get page for session

crawl4ai/user_agent_generator.py

@@ -2,8 +2,146 @@ import random
 from typing import Optional, Literal, List, Dict, Tuple
 import re
 
+from abc import ABC, abstractmethod
+import random
+from fake_useragent import UserAgent
+import requests
+from lxml import html
+import json
+from typing import Optional, List, Union, Dict
 
-class UserAgentGenerator:
+class UAGen(ABC):
+   @abstractmethod
+   def generate(self, 
+               browsers: Optional[List[str]] = None,
+               os: Optional[Union[str, List[str]]] = None,
+               min_version: float = 0.0,
+               platforms: Optional[Union[str, List[str]]] = None,
+               pct_threshold: Optional[float] = None,
+               fallback: str = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/116.0.0.0 Safari/537.36") -> Union[str, Dict]:
+       pass
+   
+   @staticmethod
+   def generate_client_hints( user_agent: str) -> str:
+        """Generate Sec-CH-UA header value based on user agent string"""
+        def _parse_user_agent(user_agent: str) -> Dict[str, str]:
+            """Parse a user agent string to extract browser and version information"""
+            browsers = {
+                "chrome": r"Chrome/(\d+)",
+                "edge": r"Edg/(\d+)",
+                "safari": r"Version/(\d+)",
+                "firefox": r"Firefox/(\d+)",
+            }
+
+            result = {}
+            for browser, pattern in browsers.items():
+                match = re.search(pattern, user_agent)
+                if match:
+                    result[browser] = match.group(1)
+
+            return result
+        browsers = _parse_user_agent(user_agent)
+
+        # Client hints components
+        hints = []
+
+        # Handle different browser combinations
+        if "chrome" in browsers:
+            hints.append(f'"Chromium";v="{browsers["chrome"]}"')
+            hints.append('"Not_A Brand";v="8"')
+
+            if "edge" in browsers:
+                hints.append(f'"Microsoft Edge";v="{browsers["edge"]}"')
+            else:
+                hints.append(f'"Google Chrome";v="{browsers["chrome"]}"')
+
+        elif "firefox" in browsers:
+            # Firefox doesn't typically send Sec-CH-UA
+            return '""'
+
+        elif "safari" in browsers:
+            # Safari's format for client hints
+            hints.append(f'"Safari";v="{browsers["safari"]}"')
+            hints.append('"Not_A Brand";v="8"')
+
+        return ", ".join(hints)
+
+class ValidUAGenerator(UAGen):
+   def __init__(self):
+       self.ua = UserAgent()
+       
+   def generate(self,
+               browsers: Optional[List[str]] = None,
+               os: Optional[Union[str, List[str]]] = None, 
+               min_version: float = 0.0,
+               platforms: Optional[Union[str, List[str]]] = None,
+               pct_threshold: Optional[float] = None,
+               fallback: str = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/116.0.0.0 Safari/537.36") -> str:
+       
+       self.ua = UserAgent(
+           browsers=browsers or ['Chrome', 'Firefox', 'Edge'],
+           os=os or ['Windows', 'Mac OS X'],
+           min_version=min_version,
+           platforms=platforms or ['desktop'],
+           fallback=fallback
+       )
+       return self.ua.random
+
+class OnlineUAGenerator(UAGen):
+   def __init__(self):
+       self.agents = []
+       self._fetch_agents()
+       
+   def _fetch_agents(self):
+       try:
+           response = requests.get(
+               'https://www.useragents.me/',
+               timeout=5,
+               headers={'Accept': 'text/html,application/xhtml+xml'}
+           )
+           response.raise_for_status()
+           
+           tree = html.fromstring(response.content)
+           json_text = tree.cssselect('#most-common-desktop-useragents-json-csv > div:nth-child(1) > textarea')[0].text
+           self.agents = json.loads(json_text)
+       except Exception as e:
+           print(f"Error fetching agents: {e}")
+           
+   def generate(self,
+               browsers: Optional[List[str]] = None,
+               os: Optional[Union[str, List[str]]] = None,
+               min_version: float = 0.0,
+               platforms: Optional[Union[str, List[str]]] = None, 
+               pct_threshold: Optional[float] = None,
+               fallback: str = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/116.0.0.0 Safari/537.36") -> Dict:
+       
+       if not self.agents:
+           self._fetch_agents()
+           
+       filtered_agents = self.agents
+       
+       if pct_threshold:
+           filtered_agents = [a for a in filtered_agents if a['pct'] >= pct_threshold]
+           
+       if browsers:
+           filtered_agents = [a for a in filtered_agents 
+                            if any(b.lower() in a['ua'].lower() for b in browsers)]
+           
+       if os:
+           os_list = [os] if isinstance(os, str) else os
+           filtered_agents = [a for a in filtered_agents 
+                            if any(o.lower() in a['ua'].lower() for o in os_list)]
+           
+       if platforms:
+           platform_list = [platforms] if isinstance(platforms, str) else platforms
+           filtered_agents = [a for a in filtered_agents 
+                            if any(p.lower() in a['ua'].lower() for p in platform_list)]
+           
+       return filtered_agents[0] if filtered_agents else {'ua': fallback, 'pct': 0}
+
+
+
+class UserAgentGenerator():
     """
     Generate random user agents with specified constraints.
 
@@ -187,9 +325,15 @@ class UserAgentGenerator:
         browser_stack = self.get_browser_stack(num_browsers)
 
         # Add appropriate legacy token based on browser stack
-        if "Firefox" in str(browser_stack):
+        if "Firefox" in str(browser_stack) or browser_type == "firefox":
             components.append(random.choice(self.rendering_engines["gecko"]))
-        elif "Chrome" in str(browser_stack) or "Safari" in str(browser_stack):
+        elif "Chrome" in str(browser_stack) or "Safari" in str(browser_stack) or browser_type == "chrome":
+            components.append(self.rendering_engines["chrome_webkit"])
+            components.append("(KHTML, like Gecko)")
+        elif "Edge" in str(browser_stack) or browser_type == "edge":
+            components.append(self.rendering_engines["safari_webkit"])
+            components.append("(KHTML, like Gecko)")
+        elif "Safari" in str(browser_stack) or browser_type == "safari":
             components.append(self.rendering_engines["chrome_webkit"])
             components.append("(KHTML, like Gecko)")
 
@@ -273,27 +417,13 @@ class UserAgentGenerator:
 
 # Example usage:
 if __name__ == "__main__":
-    generator = UserAgentGenerator()
-    print(generator.generate())
     
-    print("\nSingle browser (Chrome):")
+    # Usage example:
-    print(generator.generate(num_browsers=1, browser_type="chrome"))
+    generator = ValidUAGenerator()
+    ua = generator.generate()
+    print(ua)
     
-    print("\nTwo browsers (Gecko/Firefox):")
+    generator = OnlineUAGenerator()
-    print(generator.generate(num_browsers=2))
+    ua = generator.generate()
+    print(ua)
 
-    print("\nThree browsers (Chrome/Safari/Edge):")
-    print(generator.generate(num_browsers=3))
-
-    print("\nFirefox on Linux:")
-    print(
-        generator.generate(
-            device_type="desktop",
-            os_type="linux",
-            browser_type="firefox",
-            num_browsers=2,
-        )
-    )
-
-    print("\nChrome/Safari/Edge on Windows:")
-    print(generator.generate(device_type="desktop", os_type="windows", num_browsers=3))

docs/examples/v0_4_3b2_features_demo.py

@@ -299,7 +299,6 @@ async def demo_proxy_rotation():
             print(f"Error loading proxy: {e}")
             return None    
     
-    
     # Create 10 test requests to httpbin
     urls = ["https://httpbin.org/ip"] * 2
     
@@ -314,7 +313,7 @@ async def demo_proxy_rotation():
                 continue
                 
             # Create new config with proxy
-            current_config = run_config.clone(proxy_config=proxy)
+            current_config = run_config.clone(proxy_config=proxy, user_agent="")
             result = await crawler.arun(url=url, config=current_config)
             
             if result.success:

docs/md_v2/advanced/multi-url-crawling.md

@@ -5,16 +5,20 @@
 ## 1. Introduction
 
 When crawling many URLs:
+
 - **Basic**: Use `arun()` in a loop (simple but less efficient)
 - **Better**: Use `arun_many()`, which efficiently handles multiple URLs with proper concurrency control
 - **Best**: Customize dispatcher behavior for your specific needs (memory management, rate limits, etc.)
 
 **Why Dispatchers?**  
+
 - **Adaptive**: Memory-based dispatchers can pause or slow down based on system resources
 - **Rate-limiting**: Built-in rate limiting with exponential backoff for 429/503 responses
 - **Real-time Monitoring**: Live dashboard of ongoing tasks, memory usage, and performance
 - **Flexibility**: Choose between memory-adaptive or semaphore-based concurrency
 
+---
+
 ## 2. Core Components
 
 ### 2.1 Rate Limiter
@@ -22,34 +26,116 @@ When crawling many URLs:
 ```python
 class RateLimiter:
     def __init__(
-        base_delay: Tuple[float, float] = (1.0, 3.0),  # Random delay range between requests
+        # Random delay range between requests
-        max_delay: float = 60.0,                        # Maximum backoff delay
+        base_delay: Tuple[float, float] = (1.0, 3.0),  
-        max_retries: int = 3,                          # Retries before giving up
+        
-        rate_limit_codes: List[int] = [429, 503]       # Status codes triggering backoff
+        # Maximum backoff delay
+        max_delay: float = 60.0,                        
+        
+        # Retries before giving up
+        max_retries: int = 3,                          
+        
+        # Status codes triggering backoff
+        rate_limit_codes: List[int] = [429, 503]        
     )
 ```
 
-The RateLimiter provides:
+Here’s the revised and simplified explanation of the **RateLimiter**, focusing on constructor parameters and adhering to your markdown style and mkDocs guidelines.
-- Random delays between requests
+
-- Exponential backoff on rate limit responses
+#### RateLimiter Constructor Parameters
-- Domain-specific rate limiting
+
-- Automatic retry handling
+The **RateLimiter** is a utility that helps manage the pace of requests to avoid overloading servers or getting blocked due to rate limits. It operates internally to delay requests and handle retries but can be configured using its constructor parameters.
+
+**Parameters of the `RateLimiter` constructor:**
+
+1. **`base_delay`** (`Tuple[float, float]`, default: `(1.0, 3.0)`)  
+  The range for a random delay (in seconds) between consecutive requests to the same domain.
+
+- A random delay is chosen between `base_delay[0]` and `base_delay[1]` for each request.  
+- This prevents sending requests at a predictable frequency, reducing the chances of triggering rate limits.
+
+**Example:**  
+If `base_delay = (2.0, 5.0)`, delays could be randomly chosen as `2.3s`, `4.1s`, etc.
+
+---
+
+2. **`max_delay`** (`float`, default: `60.0`)  
+  The maximum allowable delay when rate-limiting errors occur.
+
+- When servers return rate-limit responses (e.g., 429 or 503), the delay increases exponentially with jitter.  
+- The `max_delay` ensures the delay doesn’t grow unreasonably high, capping it at this value.
+
+**Example:**  
+For a `max_delay = 30.0`, even if backoff calculations suggest a delay of `45s`, it will cap at `30s`.
+
+---
+
+3. **`max_retries`** (`int`, default: `3`)  
+  The maximum number of retries for a request if rate-limiting errors occur.
+
+- After encountering a rate-limit response, the `RateLimiter` retries the request up to this number of times.  
+- If all retries fail, the request is marked as failed, and the process continues.
+
+**Example:**  
+If `max_retries = 3`, the system retries a failed request three times before giving up.
+
+---
+
+4. **`rate_limit_codes`** (`List[int]`, default: `[429, 503]`)  
+  A list of HTTP status codes that trigger the rate-limiting logic.
+
+- These status codes indicate the server is overwhelmed or actively limiting requests.  
+- You can customize this list to include other codes based on specific server behavior.
+
+**Example:**  
+If `rate_limit_codes = [429, 503, 504]`, the crawler will back off on these three error codes.
+
+---
+
+**How to Use the `RateLimiter`:**
+
+Here’s an example of initializing and using a `RateLimiter` in your project:
+
+```python
+from crawl4ai import RateLimiter
+
+# Create a RateLimiter with custom settings
+rate_limiter = RateLimiter(
+    base_delay=(2.0, 4.0),  # Random delay between 2-4 seconds
+    max_delay=30.0,         # Cap delay at 30 seconds
+    max_retries=5,          # Retry up to 5 times on rate-limiting errors
+    rate_limit_codes=[429, 503]  # Handle these HTTP status codes
+)
+
+# RateLimiter will handle delays and retries internally
+# No additional setup is required for its operation
+```
+
+The `RateLimiter` integrates seamlessly with dispatchers like `MemoryAdaptiveDispatcher` and `SemaphoreDispatcher`, ensuring requests are paced correctly without user intervention. Its internal mechanisms manage delays and retries to avoid overwhelming servers while maximizing efficiency.
+
 
 ### 2.2 Crawler Monitor
 
 The CrawlerMonitor provides real-time visibility into crawling operations:
 
 ```python
+from crawl4ai import CrawlerMonitor, DisplayMode
 monitor = CrawlerMonitor(
-    max_visible_rows=15,           # Maximum rows in live display
+    # Maximum rows in live display
-    display_mode=DisplayMode.DETAILED  # DETAILED or AGGREGATED view
+    max_visible_rows=15,          
+
+    # DETAILED or AGGREGATED view
+    display_mode=DisplayMode.DETAILED  
 )
 ```
 
 **Display Modes**:
+
 1. **DETAILED**: Shows individual task status, memory usage, and timing
 2. **AGGREGATED**: Displays summary statistics and overall progress
 
+---
+
 ## 3. Available Dispatchers
 
 ### 3.1 MemoryAdaptiveDispatcher (Default)
@@ -57,6 +143,8 @@ monitor = CrawlerMonitor(
 Automatically manages concurrency based on system memory usage:
 
 ```python
+from crawl4ai.async_dispatcher import MemoryAdaptiveDispatcher
+
 dispatcher = MemoryAdaptiveDispatcher(
     memory_threshold_percent=90.0,  # Pause if memory exceeds this
     check_interval=1.0,             # How often to check memory
@@ -73,13 +161,37 @@ dispatcher = MemoryAdaptiveDispatcher(
 )
 ```
 
+**Constructor Parameters:**
+
+1. **`memory_threshold_percent`** (`float`, default: `90.0`)  
+  Specifies the memory usage threshold (as a percentage). If system memory usage exceeds this value, the dispatcher pauses crawling to prevent system overload.
+
+2. **`check_interval`** (`float`, default: `1.0`)  
+  The interval (in seconds) at which the dispatcher checks system memory usage.
+
+3. **`max_session_permit`** (`int`, default: `10`)  
+  The maximum number of concurrent crawling tasks allowed. This ensures resource limits are respected while maintaining concurrency.
+
+4. **`memory_wait_timeout`** (`float`, default: `300.0`)  
+  Optional timeout (in seconds). If memory usage exceeds `memory_threshold_percent` for longer than this duration, a `MemoryError` is raised.
+
+5. **`rate_limiter`** (`RateLimiter`, default: `None`)  
+  Optional rate-limiting logic to avoid server-side blocking (e.g., for handling 429 or 503 errors). See **RateLimiter** for details.
+
+6. **`monitor`** (`CrawlerMonitor`, default: `None`)  
+  Optional monitoring for real-time task tracking and performance insights. See **CrawlerMonitor** for details.
+
+---
+
 ### 3.2 SemaphoreDispatcher
 
 Provides simple concurrency control with a fixed limit:
 
 ```python
+from crawl4ai.async_dispatcher import SemaphoreDispatcher
+
 dispatcher = SemaphoreDispatcher(
-    max_session_permit=5,             # Fixed concurrent tasks
+    max_session_permit=20,         # Maximum concurrent tasks
     rate_limiter=RateLimiter(      # Optional rate limiting
         base_delay=(0.5, 1.0),
         max_delay=10.0
@@ -91,6 +203,19 @@ dispatcher = SemaphoreDispatcher(
 )
 ```
 
+**Constructor Parameters:**
+
+1. **`max_session_permit`** (`int`, default: `20`)  
+  The maximum number of concurrent crawling tasks allowed, irrespective of semaphore slots.
+
+2. **`rate_limiter`** (`RateLimiter`, default: `None`)  
+  Optional rate-limiting logic to avoid overwhelming servers. See **RateLimiter** for details.
+
+3. **`monitor`** (`CrawlerMonitor`, default: `None`)  
+  Optional monitoring for tracking task progress and resource usage. See **CrawlerMonitor** for details.
+
+---
+
 ## 4. Usage Examples
 
 ### 4.1 Batch Processing (Default)
@@ -128,6 +253,14 @@ async def crawl_batch():
                 print(f"Failed to crawl {result.url}: {result.error_message}")
 ```
 
+**Review:**  
+- **Purpose:** Executes a batch crawl with all URLs processed together after crawling is complete.  
+- **Dispatcher:** Uses `MemoryAdaptiveDispatcher` to manage concurrency and system memory.  
+- **Stream:** Disabled (`stream=False`), so all results are collected at once for post-processing.  
+- **Best Use Case:** When you need to analyze results in bulk rather than individually during the crawl.
+
+---
+
 ### 4.2 Streaming Mode
 
 ```python
@@ -161,6 +294,14 @@ async def crawl_streaming():
                 print(f"Failed to crawl {result.url}: {result.error_message}")
 ```
 
+**Review:**  
+- **Purpose:** Enables streaming to process results as soon as they’re available.  
+- **Dispatcher:** Uses `MemoryAdaptiveDispatcher` for concurrency and memory management.  
+- **Stream:** Enabled (`stream=True`), allowing real-time processing during crawling.  
+- **Best Use Case:** When you need to act on results immediately, such as for real-time analytics or progressive data storage.
+
+---
+
 ### 4.3 Semaphore-based Crawling
 
 ```python
@@ -189,6 +330,14 @@ async def crawl_with_semaphore(urls):
         return results
 ```
 
+**Review:**  
+- **Purpose:** Uses `SemaphoreDispatcher` to limit concurrency with a fixed number of slots.  
+- **Dispatcher:** Configured with a semaphore to control parallel crawling tasks.  
+- **Rate Limiter:** Prevents servers from being overwhelmed by pacing requests.  
+- **Best Use Case:** When you want precise control over the number of concurrent requests, independent of system memory.
+
+---
+
 ### 4.4 Robots.txt Consideration
 
 ```python
@@ -221,11 +370,13 @@ if __name__ == "__main__":
     asyncio.run(main())
 ```
 
-**Key Points**:
+**Review:**  
-- When `check_robots_txt=True`, each URL's robots.txt is checked before crawling
+- **Purpose:** Ensures compliance with `robots.txt` rules for ethical and legal web crawling.  
-- Robots.txt files are cached for efficiency
+- **Configuration:** Set `check_robots_txt=True` to validate each URL against `robots.txt` before crawling.  
-- Failed robots.txt checks return 403 status code
+- **Dispatcher:** Handles requests with concurrency limits (`semaphore_count=3`).  
-- Dispatcher handles robots.txt checks automatically for each URL
+- **Best Use Case:** When crawling websites that strictly enforce robots.txt policies or for responsible crawling practices.
+
+---
 
 ## 5. Dispatch Results
 
@@ -255,20 +406,24 @@ for result in results:
 
 ## 6. Summary
 
-1. **Two Dispatcher Types**:
+1. **Two Dispatcher Types**:
+
    - MemoryAdaptiveDispatcher (default): Dynamic concurrency based on memory
    - SemaphoreDispatcher: Fixed concurrency limit
 
-2. **Optional Components**:
+2. **Optional Components**:
+
    - RateLimiter: Smart request pacing and backoff
    - CrawlerMonitor: Real-time progress visualization
 
-3. **Key Benefits**:
+3. **Key Benefits**:
+
    - Automatic memory management
    - Built-in rate limiting
    - Live progress monitoring
    - Flexible concurrency control
 
 Choose the dispatcher that best fits your needs:
+
 - **MemoryAdaptiveDispatcher**: For large crawls or limited resources
 - **SemaphoreDispatcher**: For simple, fixed-concurrency scenarios

docs/md_v2/assets/styles.css

@@ -95,6 +95,10 @@ strong {
     
 }
 
+div.highlight {
+ margin-bottom: 2em;   
+}
+
 .terminal-card > header {
     color: var(--font-color);
     text-align: center;
@@ -231,6 +235,16 @@ pre {
     font-size: 2em;
 }
 
+.terminal h2 {
+    font-size: 1.5em;
+    margin-bottom: 0.8em;
+}
+
+.terminal h3 {
+    font-size: 1.3em;
+    margin-bottom: 0.8em;
+}
+
 .terminal h1, .terminal h2, .terminal h3, .terminal h4, .terminal h5, .terminal h6 {
     text-shadow: 0 0 0px var(--font-color), 0 0 0px var(--font-color), 0 0 0px var(--font-color);
 }

mkdocs.yml

@@ -1,4 +1,4 @@
-site_name: Crawl4AI Documentation
+site_name: Crawl4AI Documentation (v0.4.3b2)
 site_description:  🚀🤖 Crawl4AI, Open-source LLM-Friendly Web Crawler & Scraper
 site_url: https://docs.crawl4ai.com
 repo_url: https://github.com/unclecode/crawl4ai
@@ -52,6 +52,11 @@ nav:
 theme:
   name: 'terminal'
   palette: 'dark'
+  icon:
+    repo: fontawesome/brands/github
+
+plugins:
+  - search
 
 markdown_extensions:
   - pymdownx.highlight:
@@ -64,6 +69,9 @@ markdown_extensions:
   - attr_list
   - tables
 
+extra:
+  version: !ENV [CRAWL4AI_VERSION, 'development']
+
 extra_css:
   - assets/styles.css
   - assets/highlight.css
@@ -72,3 +80,4 @@ extra_css:
 extra_javascript:
   - assets/highlight.min.js
   - assets/highlight_init.js
+  - https://buttons.github.io/buttons.js

pyproject.toml

@@ -37,6 +37,7 @@ dependencies = [
     "rich>=13.9.4",
     "cssselect>=1.2.0",
     "httpx==0.27.2",
+    "fake-useragent>=2.0.3"
 ]
 classifiers = [
     "Development Status :: 4 - Beta",