WebBaseLoader 集成

使用 LangChain Python 集成 WebBaseLoader 文档加载器。

本文介绍如何使用 WebBaseLoader 将 HTML 网页中的所有文本加载到可用于下游处理的文档格式中。如需更自定义的网页加载逻辑，可参考一些子类示例，例如 IMSDbLoader、AZLyricsLoader 和 CollegeConfidentialLoader。

如果您不想处理网站爬取、绕过 JS 拦截站点以及数据清洗等问题，可考虑使用 FireCrawlLoader 或更快的选项 SpiderLoader。

概述

集成详情

• TODO: 填写表格功能。
• TODO: 若不相关则移除 JS 支持链接，否则确保链接正确。
• TODO: 确保 API 参考链接正确。

类	包	本地	可序列化	JS 支持
WebBaseLoader	langchain-community	✅	❌	❌

加载器特性

来源	文档惰性加载	原生异步支持
WebBaseLoader	✅	✅

设置

凭证

WebBaseLoader 不需要任何凭证。

安装

要使用 WebBaseLoader，首先需要安装 langchain-community Python 包。

pip install -qU langchain-community beautifulsoup4

初始化

现在我们可以实例化模型对象并加载文档：

from langchain_community.document_loaders import WebBaseLoader

loader = WebBaseLoader("https://www.example.com/")

要绕过获取过程中的 SSL 验证错误，可以设置 “verify” 选项：

loader.requests_kwargs = {'verify':False}

初始化多个页面

您也可以传入要加载的页面列表。

loader_multiple_pages = WebBaseLoader(
    ["https://www.example.com/", "https://google.com"]
)

加载

docs = loader.load()

docs[0]

Document(metadata={'source': 'https://www.example.com/', 'title': 'Example Domain', 'language': 'No language found.'}, page_content='\n\n\nExample Domain\n\n\n\n\n\n\n\nExample Domain\nThis domain is for use in illustrative examples in documents. You may use this\n    domain in literature without prior coordination or asking for permission.\nMore information...\n\n\n\n')

print(docs[0].metadata)

{'source': 'https://www.example.com/', 'title': 'Example Domain', 'language': 'No language found.'}

并发加载多个 URL

您可以通过并发抓取和解析多个 URL 来加速爬取过程。

并发请求有合理的限制，默认为每秒 2 个。如果您不担心成为良好网络公民，或者您控制着要抓取的服务器且不关心负载，可以更改 requests_per_second 参数以增加最大并发请求数。请注意，虽然这会加快爬取过程，但可能导致服务器屏蔽您。请谨慎操作！

pip install -qU  nest_asyncio

# 修复 asyncio 与 jupyter 的 bug
import nest_asyncio

nest_asyncio.apply()

loader = WebBaseLoader(["https://www.example.com/", "https://google.com"])
loader.requests_per_second = 1
docs = loader.aload()
docs

Fetching pages: 100%|###########################################################################| 2/2 [00:00<00:00,  8.28it/s]

[Document(metadata={'source': 'https://www.example.com/', 'title': 'Example Domain', 'language': 'No language found.'}, page_content='\n\n\nExample Domain\n\n\n\n\n\n\n\nExample Domain\nThis domain is for use in illustrative examples in documents. You may use this\n    domain in literature without prior coordination or asking for permission.\nMore information...\n\n\n\n'),
 Document(metadata={'source': 'https://google.com', 'title': 'Google', 'description': "Search the world's information, including webpages, images, videos and more. Google has many special features to help you find exactly what you're looking for.", 'language': 'en'}, page_content='GoogleSearch Images Maps Play YouTube News Gmail Drive More »Web History | Settings | Sign in\xa0Advanced search5 ways Gemini can help during the HolidaysAdvertisingBusiness SolutionsAbout Google© 2024 - Privacy - Terms  ')]

加载 XML 文件或使用不同的 BeautifulSoup 解析器

您也可以参考 SitemapLoader 作为使用此功能的示例，了解如何加载站点地图文件。

loader = WebBaseLoader(
    "https://www.govinfo.gov/content/pkg/CFR-2018-title10-vol3/xml/CFR-2018-title10-vol3-sec431-86.xml"
)
loader.default_parser = "xml"
docs = loader.load()
docs

[Document(metadata={'source': 'https://www.govinfo.gov/content/pkg/CFR-2018-title10-vol3/xml/CFR-2018-title10-vol3-sec431-86.xml'}, page_content='\n\n10\nEnergy\n3\n2018-01-01\n2018-01-01\nfalse\nUniform test method for the measurement of energy efficiency of commercial packaged boilers.\n§ 431.86\nSection § 431.86\n\nEnergy\nDEPARTMENT OF ENERGY\nENERGY CONSERVATION\nENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT\nCommercial Packaged Boilers\nTest Procedures\n\n\n\n\n§\u2009431.86\nUniform test method for the measurement of energy efficiency of commercial packaged boilers.\n(a) Scope. This section provides test procedures, pursuant to the Energy Policy and Conservation Act (EPCA), as amended, which must be followed for measuring the combustion efficiency and/or thermal efficiency of a gas- or oil-fired commercial packaged boiler.\n(b) Testing and Calculations. Determine the thermal efficiency or combustion efficiency of commercial packaged boilers by conducting the appropriate test procedure(s) indicated in Table 1 of this section.\n\nTable 1—Test Requirements for Commercial Packaged Boiler Equipment Classes\n\nEquipment category\nSubcategory\nCertified rated inputBtu/h\n\nStandards efficiency metric(§\u2009431.87)\n\nTest procedure(corresponding to\nstandards efficiency\nmetric required\nby §\u2009431.87)\n\n\n\nHot Water\nGas-fired\n≥300,000 and ≤2,500,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\nHot Water\nGas-fired\n>2,500,000\nCombustion Efficiency\nAppendix A, Section 3.\n\n\nHot Water\nOil-fired\n≥300,000 and ≤2,500,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\nHot Water\nOil-fired\n>2,500,000\nCombustion Efficiency\nAppendix A, Section 3.\n\n\nSteam\nGas-fired (all*)\n≥300,000 and ≤2,500,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\nSteam\nGas-fired (all*)\n>2,500,000 and ≤5,000,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\n\u2003\n\n>5,000,000\nThermal Efficiency\nAppendix A, Section 2.OR\nAppendix A, Section 3 with Section 2.4.3.2.\n\n\n\nSteam\nOil-fired\n≥300,000 and ≤2,500,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\nSteam\nOil-fired\n>2,500,000 and ≤5,000,000\nThermal Efficiency\nAppendix A, Section 2.\n\n\n\u2003\n\n>5,000,000\nThermal Efficiency\nAppendix A, Section 2.OR\nAppendix A, Section 3. with Section 2.4.3.2.\n\n\n\n*\u2009Equipment classes for commercial packaged boilers as of July 22, 2009 (74 FR 36355) distinguish between gas-fired natural draft and all other gas-fired (except natural draft).\n(c) Field Tests. The field test provisions of appendix A may be used only to test a unit of commercial packaged boiler with rated input greater than 5,000,000 Btu/h.\n[81 FR 89305, Dec. 9, 2016]\n\n\nEnergy Efficiency Standards\n\n')]

惰性加载

您可以使用惰性加载功能，一次仅加载一个页面，以最小化内存需求。

pages = []
for doc in loader.lazy_load():
    pages.append(doc)

print(pages[0].page_content[:100])
print(pages[0].metadata)

10
Energy
3
2018-01-01
2018-01-01
false
Uniform test method for the measurement of energy efficien
{'source': 'https://www.govinfo.gov/content/pkg/CFR-2018-title10-vol3/xml/CFR-2018-title10-vol3-sec431-86.xml'}

异步

pages = []
async for doc in loader.alazy_load():
    pages.append(doc)

print(pages[0].page_content[:100])
print(pages[0].metadata)

Fetching pages: 100%|###########################################################################| 1/1 [00:00<00:00, 10.51it/s]

10
Energy
3
2018-01-01
2018-01-01
false
Uniform test method for the measurement of energy efficien
{'source': 'https://www.govinfo.gov/content/pkg/CFR-2018-title10-vol3/xml/CFR-2018-title10-vol3-sec431-86.xml'}

使用代理

有时您可能需要使用代理来绕过 IP 封锁。您可以向加载器（以及底层的 requests）传入代理字典来使用它们。

loader = WebBaseLoader(
        "https://www.walmart.com/search?q=parrots",
        proxies={
        "http": "http://{username}:{password}:@proxy.service.com:6666/",
        "https": "https://{username}:{password}:@proxy.service.com:6666/",
    },
)
docs = loader.load()

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API 参考

有关 WebBaseLoader 所有功能和配置的详细文档，请参阅 API 参考

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