> ## 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.

# Cheerio 集成

> 使用 LangChain JavaScript 与 Cheerio 文档加载器集成。

本笔记本提供了快速入门 `CheerioWebBaseLoader` [文档加载器](/oss/javascript/integrations/document_loaders/) 的概览。有关所有 `CheerioWebBaseLoader` 功能和配置的详细文档，请参阅 [API 参考](https://reference.langchain.com/javascript/langchain-community/document_loaders/web/cheerio/CheerioWebBaseLoader)。

## 概述

### 集成详情

本示例介绍如何使用 Cheerio 从网页加载数据。每个网页将创建一个文档。

Cheerio 是一个快速、轻量级的库，允许你使用类似 jQuery 的语法来解析和遍历 HTML 文档。你可以使用 Cheerio 从网页中提取数据，而无需在浏览器中渲染它们。

但是，Cheerio 不模拟网页浏览器，因此无法执行页面上的 JavaScript 代码。这意味着它无法从需要 JavaScript 渲染的动态网页中提取数据。为此，你可以改用 [`PlaywrightWebBaseLoader`](/oss/javascript/integrations/document_loaders/web_loaders/web_playwright) 或 [`PuppeteerWebBaseLoader`](/oss/javascript/integrations/document_loaders/web_loaders/web_puppeteer)。

| 类                                                                                                                                          | 包                    |  本地 | 可序列化 | Python 支持 |
| :----------------------------------------------------------------------------------------------------------------------------------------- | :------------------- | :-: | :--: | :-------: |
| [`CheerioWebBaseLoader`](https://reference.langchain.com/javascript/langchain-community/document_loaders/web/cheerio/CheerioWebBaseLoader) | @langchain/community |  ✅  |   ✅  |     ❌     |

### 加载器特性

|           来源           | Web 支持 | Node 支持 |
| :--------------------: | :----: | :-----: |
| `CheerioWebBaseLoader` |    ✅   |    ✅    |

## 设置

要访问 `CheerioWebBaseLoader` 文档加载器，你需要安装 `@langchain/community` 集成包以及 `cheerio` 对等依赖项。

### 凭证

如果你想获得模型调用的自动跟踪，也可以取消注释以下内容来设置你的 [LangSmith](/langsmith/home) API 密钥：

```bash theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
# export LANGSMITH_TRACING="true"
# export LANGSMITH_API_KEY="your-api-key"
```

### 安装

LangChain CheerioWebBaseLoader 集成位于 `@langchain/community` 包中：

<CodeGroup>
  ```bash npm theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  npm install @langchain/community @langchain/core cheerio
  ```

  ```bash yarn theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  yarn add @langchain/community @langchain/core cheerio
  ```

  ```bash pnpm theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  pnpm add @langchain/community @langchain/core cheerio
  ```
</CodeGroup>

## 实例化

现在我们可以实例化模型对象并加载文档：

```typescript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import { CheerioWebBaseLoader } from "@langchain/community/document_loaders/web/cheerio"

const loader = new CheerioWebBaseLoader("https://news.ycombinator.com/item?id=34817881", {
  // 可选参数：...
})
```

## 加载

```typescript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
const docs = await loader.load()
docs[0]
```

```javascript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Document {
  pageContent: '\n' +
    '        \n' +
    '                  Hacker News\n' +
    '                            new | past | comments | ask | show | jobs | submit            \n' +
    '                              login\n' +
    '                          \n' +
    '              \n' +
    '\n' +
    '        \n' +
    '            What Lights the Universe’s Standard Candles? (quantamagazine.org)\n' +
    '          75 points by Amorymeltzer on Feb 17, 2023  | hide | past | favorite | 6 comments        \n' +
    '              \n' +
    '        \n' +
    '                  \n' +
    '          \n' +
    '          delta_p_delta_x on Feb 17, 2023           \n' +
    '             | next [–]          \n' +
    '                  \n' +
    "                  Astrophysical and cosmological simulations are often insightful. They're also very cross-disciplinary; besides the obvious astrophysics, there's networking and sysadmin, parallel computing and algorithm theory (so that the simulation programs are actually fast but still accurate), systems design, and even a bit of graphic design for the visualisations.Some of my favourite simulation projects:- IllustrisTNG: https://www.tng-project.org/- SWIFT: https://swift.dur.ac.uk/- CO5BOLD: https://www.astro.uu.se/~bf/co5bold_main.html (which produced these animations of a red-giant star: https://www.astro.uu.se/~bf/movie/AGBmovie.html)- AbacusSummit: https://abacussummit.readthedocs.io/en/latest/And I can add the simulations in the article, too.\n" +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                      \n' +
    '          \n' +
    '          froeb on Feb 18, 2023           \n' +
    '             | parent | next [–]          \n' +
    '                  \n' +
    "                  Supernova simulations are especially interesting too. I have heard them described as the only time in physics when all 4 of the fundamental forces are important. The explosion can be quite finicky too. If I remember right, you can't get supernova to explode properly in 1D simulations, only in higher dimensions. This was a mystery until the realization that turbulence is necessary for supernova to trigger--there is no turbulent flow in 1D.\n" +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                        \n' +
    '          \n' +
    '          andrewflnr on Feb 17, 2023           \n' +
    '             | prev | next [–]          \n' +
    '                  \n' +
    "                  Whoa. I didn't know the accretion theory of Ia supernovae was dead, much less that it had been since 2011.\n" +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                  \n' +
    '          \n' +
    '          andreareina on Feb 17, 2023           \n' +
    '             | prev | next [–]          \n' +
    '                  \n' +
    '                  This seems  to be the paper https://academic.oup.com/mnras/article/517/4/5260/6779709\n' +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                  \n' +
    '          \n' +
    '          andreareina on Feb 17, 2023           \n' +
    '             | prev [–]          \n' +
    '                  \n' +
    "                  Wouldn't double detonation show up as variance in the brightness?\n" +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                      \n' +
    '          \n' +
    '          yencabulator on Feb 18, 2023           \n' +
    '             | parent [–]          \n' +
    '                  \n' +
    '                  Or widening of the peak. If one type Ia supernova goes 1,2,3,2,1, the sum of two could go    1+0=1\n' +
    '    2+1=3\n' +
    '    3+2=5\n' +
    '    2+3=5\n' +
    '    1+2=3\n' +
    '    0+1=1\n' +
    '                      \n' +
    '                  \n' +
    '      \n' +
    '        \n' +
    '                  \n' +
    '  \n' +
    '\n' +
    '\n' +
    'Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact\n' +
    'Search:       \n' +
    '      \n' +
    '  \n',
  metadata: { source: 'https://news.ycombinator.com/item?id=34817881' },
  id: undefined
}
```

```typescript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
console.log(docs[0].metadata)
```

```javascript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
{ source: 'https://news.ycombinator.com/item?id=34817881' }
```

## 附加配置

`CheerioWebBaseLoader` 在实例化加载器时支持附加配置。以下是使用 `selector` 字段的示例，使其仅从提供的 HTML 类名加载内容：

```typescript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import { CheerioWebBaseLoader } from "@langchain/community/document_loaders/web/cheerio"

const loaderWithSelector = new CheerioWebBaseLoader("https://news.ycombinator.com/item?id=34817881", {
  selector: "p",
});

const docsWithSelector = await loaderWithSelector.load();
docsWithSelector[0].pageContent;
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Some of my favourite simulation projects:- IllustrisTNG: https://www.tng-project.org/- SWIFT: https://swift.dur.ac.uk/- CO5BOLD: https://www.astro.uu.se/~bf/co5bold_main.html (which produced these animations of a red-giant star: https://www.astro.uu.se/~bf/movie/AGBmovie.html)- AbacusSummit: https://abacussummit.readthedocs.io/en/latest/And I can add the simulations in the article, too.
```

***

## API 参考

有关所有 `CheerioWebBaseLoader` 功能和配置的详细文档，请参阅 [API 参考](https://reference.langchain.com/javascript/langchain-community/document_loaders/web/cheerio/CheerioWebBaseLoader)。

***

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