> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-zh.cn/llms.txt
> Use this file to discover all available pages before exploring further.

# WebPDFLoader 集成

> 使用 LangChain JavaScript 集成 WebPDFLoader 文档加载器。

本笔记本提供了快速入门 `WebPDFLoader` [文档加载器](/oss/javascript/integrations/document_loaders/) 的概述。有关 `WebPDFLoader` 所有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/pdf/WebPDFLoader)。

## 概述

### 集成详情

| 类                                                                                                                      | 包                                                                            |  本地 | 可序列化 | Python 支持 |
| :--------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------------------------- | :-: | :--: | :-------: |
| [`WebPDFLoader`](https://reference.langchain.com/javascript/langchain-community/document_loaders/web/pdf/WebPDFLoader) | [`@langchain/community`](https://www.npmjs.com/package/@langchain/community) |  ✅  | beta |     ❌     |

### 加载器特性

|       来源       | Web 加载器 | 仅 Node 环境 |
| :------------: | :-----: | :-------: |
| `WebPDFLoader` |    ✅    |     ❌     |

您可以在 Web 环境中使用此版本的流行 PDFLoader。
默认情况下，PDF 文件中的每一页都会创建一个文档，您可以通过将 `splitPages` 选项设置为 `false` 来更改此行为。

## 设置

要访问 `WebPDFLoader` 文档加载器，您需要安装 `@langchain/community` 集成包以及 `pdf-parse` 包：

### 凭证

如果您希望获得模型调用的自动追踪，您还可以通过取消注释以下内容来设置您的 [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 WebPDFLoader 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 pdf-parse
  ```

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

  ```bash pnpm theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  pnpm add @langchain/community @langchain/core pdf-parse
  ```
</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 fs from "fs/promises";
import { WebPDFLoader } from "@langchain/community/document_loaders/web/pdf"

const nike10kPDFPath = "../../../../data/nke-10k-2023.pdf";

// 将文件读取为缓冲区
const buffer = await fs.readFile(nike10kPDFPath);

// 从缓冲区创建 Blob
const nike10kPDFBlob = new Blob([buffer], { type: 'application/pdf' });

const loader = new WebPDFLoader(nike10kPDFBlob, {
  // 必需参数 = ...
  // 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: 'Table of Contents\n' +
    'UNITED STATES\n' +
    'SECURITIES AND EXCHANGE COMMISSION\n' +
    'Washington, D.C. 20549\n' +
    'FORM 10-K\n' +
    '(Mark One)\n' +
    '☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934\n' +
    'FOR THE FISCAL YEAR ENDED MAY 31, 2023\n' +
    'OR\n' +
    '☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934\n' +
    'FOR THE TRANSITION PERIOD FROM                         TO                         .\n' +
    'Commission File No. 1-10635\n' +
    'NIKE, Inc.\n' +
    '(Exact name of Registrant as specified in its charter)\n' +
    'Oregon93-0584541\n' +
    '(State or other jurisdiction of incorporation)(IRS Employer Identification No.)\n' +
    'One Bowerman Drive, Beaverton, Oregon 97005-6453\n' +
    '(Address of principal executive offices and zip code)\n' +
    '(503) 671-6453\n' +
    "(Registrant's telephone number, including area code)\n" +
    'SECURITIES REGISTERED PURSUANT TO SECTION 12(B) OF THE ACT:\n' +
    'Class B Common StockNKENew York Stock Exchange\n' +
    '(Title of each class)(Trading symbol)(Name of each exchange on which registered)\n' +
    'SECURITIES REGISTERED PURSUANT TO SECTION 12(G) OF THE ACT:\n' +
    'NONE\n' +
    'Indicate by check mark:YESNO\n' +
    '•if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.þ ̈\n' +
    '•if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. ̈þ\n' +
    '•whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding\n' +
    '12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the\n' +
    'past 90 days.\n' +
    'þ ̈\n' +
    '•whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T\n' +
    '(§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).\n' +
    'þ ̈\n' +
    '•whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,”\n' +
    '“accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.\n' +
    'Large accelerated filerþAccelerated filer☐Non-accelerated filer☐Smaller reporting company☐Emerging growth company☐\n' +
    '•if an emerging growth company, if the registrant has elected not to use the extended transition period for complying with any new or revised financial\n' +
    'accounting standards provided pursuant to Section 13(a) of the Exchange Act.\n' +
    ' ̈\n' +
    "•whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial\n" +
    'reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit\n' +
    'report.\n' +
    'þ\n' +
    '•if securities are registered pursuant to Section 12(b) of the Act, whether the financial statements of the registrant included in the filing reflect the\n' +
    'correction of an error to previously issued financial statements.\n' +
    ' ̈\n' +
    '•whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the\n' +
    "registrant's executive officers during the relevant recovery period pursuant to § 240.10D-1(b).\n" +
    ' ̈\n' +
    '•\n' +
    'whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).☐þ\n' +
    "As of November 30, 2022, the aggregate market values of the Registrant's Common Stock held by non-affiliates were:\n" +
    'Class A$7,831,564,572 \n' +
    'Class B136,467,702,472 \n' +
    '$144,299,267,044 ',
  metadata: {
    pdf: {
      version: '1.10.100',
      info: [Object],
      metadata: null,
      totalPages: 107
    },
    loc: { pageNumber: 1 }
  },
  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"}}
{
  pdf: {
    version: '1.10.100',
    info: {
      PDFFormatVersion: '1.4',
      IsAcroFormPresent: false,
      IsXFAPresent: false,
      Title: '0000320187-23-000039',
      Author: 'EDGAR Online, a division of Donnelley Financial Solutions',
      Subject: 'Form 10-K filed on 2023-07-20 for the period ending 2023-05-31',
      Keywords: '0000320187-23-000039; ; 10-K',
      Creator: 'EDGAR Filing HTML Converter',
      Producer: 'EDGRpdf Service w/ EO.Pdf 22.0.40.0',
      CreationDate: "D:20230720162200-04'00'",
      ModDate: "D:20230720162208-04'00'"
    },
    metadata: null,
    totalPages: 107
  },
  loc: { pageNumber: 1 }
}
```

## 用法，自定义 `pdfjs` 构建

默认情况下，我们使用 `pdf-parse` 捆绑的 `pdfjs` 构建，它与大多数环境兼容，包括 Node.js 和现代浏览器。如果您想使用更新版本的 `pdfjs-dist`，或者想使用自定义构建的 `pdfjs-dist`，可以通过提供一个自定义的 `pdfjs` 函数来实现，该函数返回一个解析为 `PDFJS` 对象的 Promise。

在以下示例中，我们使用 `pdfjs-dist` 的“传统”构建（参见 [pdfjs 文档](https://github.com/mozilla/pdf.js/wiki/Frequently-Asked-Questions#which-browsersenvironments-are-supported)），其中包含默认构建中未包含的多个 polyfill。

<CodeGroup>
  ```bash npm theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  npm install pdfjs-dist
  ```

  ```bash yarn theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  yarn add pdfjs-dist
  ```

  ```bash pnpm theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  pnpm add pdfjs-dist
  ```
</CodeGroup>

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

const blob = new Blob(); // 例如来自文件输入

const customBuildLoader = new WebPDFLoader(blob, {
  // 您可能需要在导入语句末尾添加 `.then(m => m.default)`
  // @lc-ts-ignore
  pdfjs: () => import("pdfjs-dist/legacy/build/pdf.js"),
});
```

## 消除多余空格

PDF 文件种类繁多，这使得读取它们具有挑战性。加载器默认解析单个文本元素并用空格将它们连接起来，但如果您看到过多的空格，这可能不是期望的行为。在这种情况下，您可以像这样用空字符串覆盖分隔符：

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

// new Blob(); 例如来自文件输入
const eliminatingExtraSpacesLoader = new WebPDFLoader(new Blob(), {
  parsedItemSeparator: "",
});
```

***

## API 参考

有关 `WebPDFLoader` 所有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/pdf/WebPDFLoader)。

***

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