Source code for langchain_community.document_loaders.recursive_url_loader
from__future__importannotationsimportasyncioimportinspectimportloggingimportrefromtypingimport(Callable,Iterator,List,Optional,Sequence,Set,Union,cast,)importaiohttpimportrequestsfromlangchain_core.documentsimportDocumentfromlangchain_core.utils.htmlimportextract_sub_linksfromlangchain_community.document_loaders.baseimportBaseLoaderlogger=logging.getLogger(__name__)def_metadata_extractor(raw_html:str,url:str,response:Union[requests.Response,aiohttp.ClientResponse])->dict:"""Extract metadata from raw html using BeautifulSoup."""content_type=getattr(response,"headers").get("Content-Type","")metadata={"source":url,"content_type":content_type}try:frombs4importBeautifulSoupexceptImportError:logger.warning("The bs4 package is required for default metadata extraction. ""Please install it with `pip install -U beautifulsoup4`.")returnmetadatasoup=BeautifulSoup(raw_html,"html.parser")iftitle:=soup.find("title"):metadata["title"]=title.get_text()ifdescription:=soup.find("meta",attrs={"name":"description"}):metadata["description"]=description.get("content",None)ifhtml:=soup.find("html"):metadata["language"]=html.get("lang",None)returnmetadata
[docs]classRecursiveUrlLoader(BaseLoader):"""Recursively load all child links from a root URL. **Security Note**: This loader is a crawler that will start crawling at a given URL and then expand to crawl child links recursively. Web crawlers should generally NOT be deployed with network access to any internal servers. Control access to who can submit crawling requests and what network access the crawler has. While crawling, the crawler may encounter malicious URLs that would lead to a server-side request forgery (SSRF) attack. To mitigate risks, the crawler by default will only load URLs from the same domain as the start URL (controlled via prevent_outside named argument). This will mitigate the risk of SSRF attacks, but will not eliminate it. For example, if crawling a host which hosts several sites: https://some_host/alice_site/ https://some_host/bob_site/ A malicious URL on Alice's site could cause the crawler to make a malicious GET request to an endpoint on Bob's site. Both sites are hosted on the same host, so such a request would not be prevented by default. See https://python.langchain.com/docs/security/ Setup: This class has no required additional dependencies. You can optionally install ``beautifulsoup4`` for richer default metadata extraction: .. code-block:: bash pip install -U beautifulsoup4 Instantiate: .. code-block:: python from langchain_community.document_loaders import RecursiveUrlLoader loader = RecursiveUrlLoader( "https://docs.python.org/3.9/", # max_depth=2, # use_async=False, # extractor=None, # metadata_extractor=None, # exclude_dirs=(), # timeout=10, # check_response_status=True, # continue_on_failure=True, # prevent_outside=True, # base_url=None, # ... ) Lazy load: .. code-block:: python docs = [] docs_lazy = loader.lazy_load() # async variant: # docs_lazy = await loader.alazy_load() for doc in docs_lazy: docs.append(doc) print(docs[0].page_content[:100]) print(docs[0].metadata) .. code-block:: python <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" />< {'source': 'https://docs.python.org/3.9/', 'content_type': 'text/html', 'title': '3.9.19 Documentation', 'language': None} Async load: .. code-block:: python docs = await loader.aload() print(docs[0].page_content[:100]) print(docs[0].metadata) .. code-block:: python <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" />< {'source': 'https://docs.python.org/3.9/', 'content_type': 'text/html', 'title': '3.9.19 Documentation', 'language': None} Content parsing / extraction: By default the loader sets the raw HTML from each link as the Document page content. To parse this HTML into a more human/LLM-friendly format you can pass in a custom ``extractor`` method: .. code-block:: python # This example uses `beautifulsoup4` and `lxml` import re from bs4 import BeautifulSoup def bs4_extractor(html: str) -> str: soup = BeautifulSoup(html, "lxml") return re.sub(r"\\n\\n+", "\\n\\n", soup.text).strip() loader = RecursiveUrlLoader( "https://docs.python.org/3.9/", extractor=bs4_extractor, ) print(loader.load()[0].page_content[:200]) .. code-block:: python 3.9.19 Documentation Download Download these documents Docs by version Python 3.13 (in development) Python 3.12 (stable) Python 3.11 (security-fixes) Python 3.10 (security-fixes) Python 3.9 (securit Metadata extraction: Similarly to content extraction, you can specify a metadata extraction function to customize how Document metadata is extracted from the HTTP response. .. code-block:: python import aiohttp import requests from typing import Union def simple_metadata_extractor( raw_html: str, url: str, response: Union[requests.Response, aiohttp.ClientResponse] ) -> dict: content_type = getattr(response, "headers").get("Content-Type", "") return {"source": url, "content_type": content_type} loader = RecursiveUrlLoader( "https://docs.python.org/3.9/", metadata_extractor=simple_metadata_extractor, ) loader.load()[0].metadata .. code-block:: python {'source': 'https://docs.python.org/3.9/', 'content_type': 'text/html'} Filtering URLs: You may not always want to pull every URL from a website. There are four parameters that allow us to control what URLs we pull recursively. First, we can set the ``prevent_outside`` parameter to prevent URLs outside of the ``base_url`` from being pulled. Note that the ``base_url`` does not need to be the same as the URL we pass in, as shown below. We can also use ``link_regex`` and ``exclude_dirs`` to be more specific with the URLs that we select. In this example, we only pull websites from the python docs, which contain the string "index" somewhere and are not located in the FAQ section of the website. .. code-block:: python loader = RecursiveUrlLoader( "https://docs.python.org/3.9/", prevent_outside=True, base_url="https://docs.python.org", link_regex=r'<a\\s+(?:[^>]*?\\s+)?href="([^"]*(?=index)[^"]*)"', exclude_dirs=['https://docs.python.org/3.9/faq'] ) docs = loader.load() .. code-block:: python ['https://docs.python.org/3.9/', 'https://docs.python.org/3.9/py-modindex.html', 'https://docs.python.org/3.9/genindex.html', 'https://docs.python.org/3.9/tutorial/index.html', 'https://docs.python.org/3.9/using/index.html', 'https://docs.python.org/3.9/extending/index.html', 'https://docs.python.org/3.9/installing/index.html', 'https://docs.python.org/3.9/library/index.html', 'https://docs.python.org/3.9/c-api/index.html', 'https://docs.python.org/3.9/howto/index.html', 'https://docs.python.org/3.9/distributing/index.html', 'https://docs.python.org/3.9/reference/index.html', 'https://docs.python.org/3.9/whatsnew/index.html'] """# noqa: E501
[docs]def__init__(self,url:str,max_depth:Optional[int]=2,use_async:Optional[bool]=None,extractor:Optional[Callable[[str],str]]=None,metadata_extractor:Optional[_MetadataExtractorType]=None,exclude_dirs:Optional[Sequence[str]]=(),timeout:Optional[int]=10,prevent_outside:bool=True,link_regex:Union[str,re.Pattern,None]=None,headers:Optional[dict]=None,check_response_status:bool=False,continue_on_failure:bool=True,*,base_url:Optional[str]=None,autoset_encoding:bool=True,encoding:Optional[str]=None,proxies:Optional[dict]=None,)->None:"""Initialize with URL to crawl and any subdirectories to exclude. Args: url: The URL to crawl. max_depth: The max depth of the recursive loading. use_async: Whether to use asynchronous loading. If True, lazy_load function will not be lazy, but it will still work in the expected way, just not lazy. extractor: A function to extract document contents from raw HTML. When extract function returns an empty string, the document is ignored. Default returns the raw HTML. metadata_extractor: A function to extract metadata from args: raw HTML, the source url, and the requests.Response/aiohttp.ClientResponse object (args in that order). Default extractor will attempt to use BeautifulSoup4 to extract the title, description and language of the page. ..code-block:: python import requests import aiohttp def simple_metadata_extractor( raw_html: str, url: str, response: Union[requests.Response, aiohttp.ClientResponse] ) -> dict: content_type = getattr(response, "headers").get("Content-Type", "") return {"source": url, "content_type": content_type} exclude_dirs: A list of subdirectories to exclude. timeout: The timeout for the requests, in the unit of seconds. If None then connection will not timeout. prevent_outside: If True, prevent loading from urls which are not children of the root url. link_regex: Regex for extracting sub-links from the raw html of a web page. headers: Default request headers to use for all requests. check_response_status: If True, check HTTP response status and skip URLs with error responses (400-599). continue_on_failure: If True, continue if getting or parsing a link raises an exception. Otherwise, raise the exception. base_url: The base url to check for outside links against. autoset_encoding: Whether to automatically set the encoding of the response. If True, the encoding of the response will be set to the apparent encoding, unless the `encoding` argument has already been explicitly set. encoding: The encoding of the response. If manually set, the encoding will be set to given value, regardless of the `autoset_encoding` argument. proxies: A dictionary mapping protocol names to the proxy URLs to be used for requests. This allows the crawler to route its requests through specified proxy servers. If None, no proxies will be used and requests will go directly to the target URL. Example usage: ..code-block:: python proxies = { "http": "http://10.10.1.10:3128", "https": "https://10.10.1.10:1080", } """# noqa: E501self.url=urlself.max_depth=max_depthifmax_depthisnotNoneelse2self.use_async=use_asyncifuse_asyncisnotNoneelseFalseself.extractor=extractorifextractorisnotNoneelselambdax:xmetadata_extractor=(metadata_extractorifmetadata_extractorisnotNoneelse_metadata_extractor)self.autoset_encoding=autoset_encodingself.encoding=encodingself.metadata_extractor=_wrap_metadata_extractor(metadata_extractor)self.exclude_dirs=exclude_dirsifexclude_dirsisnotNoneelse()ifany(url.startswith(exclude_dir)forexclude_dirinself.exclude_dirs):raiseValueError(f"Base url is included in exclude_dirs. Received base_url: {url} and "f"exclude_dirs: {self.exclude_dirs}")self.timeout=timeoutself.prevent_outside=prevent_outsideifprevent_outsideisnotNoneelseTrueself.link_regex=link_regexself.headers=headersself.check_response_status=check_response_statusself.continue_on_failure=continue_on_failureself.base_url=base_urlifbase_urlisnotNoneelseurlself.proxies=proxies
def_get_child_links_recursive(self,url:str,visited:Set[str],*,depth:int=0)->Iterator[Document]:"""Recursively get all child links starting with the path of the input URL. Args: url: The URL to crawl. visited: A set of visited URLs. depth: Current depth of recursion. Stop when depth >= max_depth. """ifdepth>=self.max_depth:return# Get all links that can be accessed from the current URLvisited.add(url)try:response=requests.get(url,timeout=self.timeout,headers=self.headers,proxies=self.proxies)ifself.encodingisnotNone:response.encoding=self.encodingelifself.autoset_encoding:response.encoding=response.apparent_encodingifself.check_response_statusand400<=response.status_code<=599:raiseValueError(f"Received HTTP status {response.status_code}")exceptExceptionase:ifself.continue_on_failure:logger.warning(f"Unable to load from {url}. Received error {e} of type "f"{e.__class__.__name__}")returnelse:raiseecontent=self.extractor(response.text)ifcontent:yieldDocument(page_content=content,metadata=self.metadata_extractor(response.text,url,response),)# Store the visited links and recursively visit the childrensub_links=extract_sub_links(response.text,url,base_url=self.base_url,pattern=self.link_regex,prevent_outside=self.prevent_outside,exclude_prefixes=self.exclude_dirs,continue_on_failure=self.continue_on_failure,)forlinkinsub_links:# Check all unvisited linksiflinknotinvisited:yield fromself._get_child_links_recursive(link,visited,depth=depth+1)asyncdef_async_get_child_links_recursive(self,url:str,visited:Set[str],*,session:Optional[aiohttp.ClientSession]=None,depth:int=0,)->List[Document]:"""Recursively get all child links starting with the path of the input URL. Args: url: The URL to crawl. visited: A set of visited URLs. depth: To reach the current url, how many pages have been visited. """ifnotself.use_async:raiseValueError("Async functions forbidden when not initialized with `use_async`")ifdepth>=self.max_depth:return[]# Disable SSL verification because websites may have invalid SSL certificates,# but won't cause any security issues for us.close_session=sessionisNonesession=(sessionifsessionisnotNoneelseaiohttp.ClientSession(connector=aiohttp.TCPConnector(ssl=False),timeout=aiohttp.ClientTimeout(total=self.timeout),headers=self.headers,))visited.add(url)try:asyncwithsession.get(url)asresponse:text=awaitresponse.text()ifself.check_response_statusand400<=response.status<=599:raiseValueError(f"Received HTTP status {response.status}")except(aiohttp.client_exceptions.InvalidURL,Exception)ase:ifclose_session:awaitsession.close()ifself.continue_on_failure:logger.warning(f"Unable to load {url}. Received error {e} of type "f"{e.__class__.__name__}")return[]else:raiseeresults=[]content=self.extractor(text)ifcontent:results.append(Document(page_content=content,metadata=self.metadata_extractor(text,url,response),))ifdepth<self.max_depth-1:sub_links=extract_sub_links(text,url,base_url=self.base_url,pattern=self.link_regex,prevent_outside=self.prevent_outside,exclude_prefixes=self.exclude_dirs,continue_on_failure=self.continue_on_failure,)# Recursively call the function to get the children of the childrensub_tasks=[]to_visit=set(sub_links).difference(visited)forlinkinto_visit:sub_tasks.append(self._async_get_child_links_recursive(link,visited,session=session,depth=depth+1))next_results=awaitasyncio.gather(*sub_tasks)forsub_resultinnext_results:ifisinstance(sub_result,Exception)orsub_resultisNone:# We don't want to stop the whole process, so just ignore it# Not standard html format or invalid url or 404 may cause this.continue# locking not fully working, temporary hack to ensure deduplicationresults+=[rforrinsub_resultifrnotinresults]ifclose_session:awaitsession.close()returnresults
[docs]deflazy_load(self)->Iterator[Document]:"""Lazy load web pages. When use_async is True, this function will not be lazy, but it will still work in the expected way, just not lazy."""visited:Set[str]=set()ifself.use_async:results=asyncio.run(self._async_get_child_links_recursive(self.url,visited))returniter(resultsor[])else:returnself._get_child_links_recursive(self.url,visited)
