> ## Documentation Index
> Fetch the complete documentation index at: https://cndoc-langchain.site/llms.txt
> Use this file to discover all available pages before exploring further.
# 递归URL集成
> 使用LangChain Python集成递归URL文档加载器。
`RecursiveUrlLoader` 允许您从根URL递归抓取所有子链接，并将其解析为文档。
## 概述
### 集成详情
| 类 | 包 | 本地 | 可序列化 | [JS支持](https://js.langchain.com/docs/integrations/document_loaders/web_loaders/recursive_url_loader/) |
| :------------------------------------------------------------------------------------------------------------------------------------------ | :---------------------------------------------------------------------------------- | :-: | :--: | :---------------------------------------------------------------------------------------------------: |
| [`RecursiveUrlLoader`](https://reference.langchain.com/python/langchain-community/document_loaders/recursive_url_loader/RecursiveUrlLoader) | [`langchain-community`](https://reference.langchain.com/python/langchain-community) | ✅ | ❌ | ✅ |
### 加载器特性
| 来源 | 文档惰性加载 | 原生异步支持 |
| :------------------: | :----: | :----: |
| `RecursiveUrlLoader` | ✅ | ❌ |
## 设置
### 凭证
使用 `RecursiveUrlLoader` 不需要任何凭证。
### 安装
`RecursiveUrlLoader` 位于 `langchain-community` 包中。没有其他必需的包，不过如果您也安装了 `beautifulsoup4`，您将获得更丰富的默认文档元数据。
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
pip install -qU langchain-community beautifulsoup4 lxml
```
## 实例化
现在我们可以实例化文档加载器对象并加载文档：
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
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,
# ...
)
```
## 加载
使用 `.load()` 同步将所有文档加载到内存中，每个访问的URL对应一个文档。从初始URL开始，我们递归遍历所有链接的URL，直到达到指定的 max\_depth。
让我们通过一个基本示例来了解如何在 [Python 3.9 文档](https://docs.python.org/3.9/) 上使用 `RecursiveUrlLoader`。
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
docs = loader.load()
docs[0].metadata
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
/Users/bagatur/.pyenv/versions/3.9.1/lib/python3.9/html/parser.py:170: XMLParsedAsHTMLWarning: It looks like you're parsing an XML document using an HTML parser. If this really is an HTML document (maybe it's XHTML?), you can ignore or filter this warning. If it's XML, you should know that using an XML parser will be more reliable. To parse this document as XML, make sure you have the lxml package installed, and pass the keyword argument `features="xml"` into the BeautifulSoup constructor.
k = self.parse_starttag(i)
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
{'source': 'https://docs.python.org/3.9/',
'content_type': 'text/html',
'title': '3.9.19 Documentation',
'language': None}
```
很好！第一个文档看起来就是我们开始的根页面。让我们看看下一个文档的元数据
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
docs[1].metadata
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
{'source': 'https://docs.python.org/3.9/using/index.html',
'content_type': 'text/html',
'title': 'Python Setup and Usage — Python 3.9.19 documentation',
'language': None}
```
这个URL看起来是我们根页面的子页面，这很棒！现在让我们从元数据转向查看其中一个文档的内容
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
print(docs[0].page_content[:300])
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
3.9.19 Documentation
= 10:
# 执行一些分页操作，例如
# index.upsert(page)
pages = []
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
/var/folders/4j/2rz3865x6qg07tx43146py8h0000gn/T/ipykernel_73962/2110507528.py:6: XMLParsedAsHTMLWarning: It looks like you're parsing an XML document using an HTML parser. If this really is an HTML document (maybe it's XHTML?), you can ignore or filter this warning. If it's XML, you should know that using an XML parser will be more reliable. To parse this document as XML, make sure you have the lxml package installed, and pass the keyword argument `features="xml"` into the BeautifulSoup constructor.
soup = BeautifulSoup(html, "lxml")
```
在这个示例中，我们一次加载到内存中的文档从未超过10个。
## 添加提取器
默认情况下，加载器将每个链接的原始HTML设置为文档页面内容。要将此HTML解析为更易于人类/LLM理解的格式，您可以传入一个自定义的 `extractor` 方法：
```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
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)
docs = loader.load()
print(docs[0].page_content[:200])
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
/var/folders/td/vzm913rx77x21csd90g63_7c0000gn/T/ipykernel_10935/1083427287.py:6: XMLParsedAsHTMLWarning: It looks like you're parsing an XML document using an HTML parser. If this really is an HTML document (maybe it's XHTML?), you can ignore or filter this warning. If it's XML, you should know that using an XML parser will be more reliable. To parse this document as XML, make sure you have the lxml package installed, and pass the keyword argument `features="xml"` into the BeautifulSoup constructor.
soup = BeautifulSoup(html, "lxml")
/Users/isaachershenson/.pyenv/versions/3.11.9/lib/python3.11/html/parser.py:170: XMLParsedAsHTMLWarning: It looks like you're parsing an XML document using an HTML parser. If this really is an HTML document (maybe it's XHTML?), you can ignore or filter this warning. If it's XML, you should know that using an XML parser will be more reliable. To parse this document as XML, make sure you have the lxml package installed, and pass the keyword argument `features="xml"` into the BeautifulSoup constructor.
k = self.parse_starttag(i)
```
```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
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
```
这看起来好多了！
您同样可以传入一个 `metadata_extractor` 来自定义如何从HTTP响应中提取文档元数据。有关更多信息，请参阅 [API参考](https://reference.langchain.com/python/langchain-community/document_loaders/recursive_url_loader/RecursiveUrlLoader)。
***
## API参考
这些示例仅展示了修改默认 `RecursiveUrlLoader` 的几种方式，但还有更多修改可以进行，以最好地适应您的用例。使用参数 `link_regex` 和 `exclude_dirs` 可以帮助您过滤掉不需要的URL，`aload()` 和 `alazy_load()` 可用于异步加载，等等。
有关配置和调用 `RecursiveUrlLoader` 的详细信息，请参阅 [API参考](https://reference.langchain.com/python/langchain-community/document_loaders/recursive_url_loader/RecursiveUrlLoader)。
***