Page.exposeFunction() 方法

🌐 Page.exposeFunction() method

该方法在页面的 window 对象上添加了一个名为 name 的函数。调用该函数时，会在 node.js 中执行 puppeteerFunction，并返回一个 Promise，该 Promise 解析为 puppeteerFunction 的返回值。

🌐 The method adds a function called name on the page's window object. When called, the function executes puppeteerFunction in node.js and returns a Promise which resolves to the return value of puppeteerFunction.

如果 puppeteerFunction 返回一个 Promise，它将被等待。

🌐 If the puppeteerFunction returns a Promise, it will be awaited.

note

通过 page.exposeFunction 安装的函数在导航过程中能够保留。

🌐 Functions installed via page.exposeFunction survive navigations.

语法

🌐 Signature

class Page {
  abstract exposeFunction(
    name: string,
    pptrFunction:
      | Function
      | {
          default: Function;
        },
  ): Promise<void>;
}

参数

🌐 Parameters

范围 🌐 Parameter	类型 🌐 Type	描述 🌐 Description
name	string	窗口对象上的函数名称 🌐 Name of the function on the window object
pptrFunction	Function | { default: Function; }	将在 Puppeteer 上下文中调用的回调函数。 🌐 Callback function which will be called in Puppeteer's context.

返回:

Promise<void>

示例 1

🌐 Example 1

在页面中添加 md5 函数的示例：

🌐 An example of adding an md5 function into the page:

import puppeteer from 'puppeteer';
import crypto from 'crypto';

const browser = await puppeteer.launch();
const page = await browser.newPage();
page.on('console', msg => console.log(msg.text()));
await page.exposeFunction('md5', text =>
  crypto.createHash('md5').update(text).digest('hex'),
);
await page.evaluate(async () => {
  // use window.md5 to compute hashes
  const myString = 'PUPPETEER';
  const myHash = await window.md5(myString);
  console.log(`md5 of ${myString} is ${myHash}`);
});
await browser.close();

示例 2

🌐 Example 2

在页面中添加 window.readfile 函数的示例：

🌐 An example of adding a window.readfile function into the page:

import puppeteer from 'puppeteer';
import fs from 'node:fs';

const browser = await puppeteer.launch();
const page = await browser.newPage();
page.on('console', msg => console.log(msg.text()));
await page.exposeFunction('readfile', async filePath => {
  return new Promise((resolve, reject) => {
    fs.readFile(filePath, 'utf8', (err, text) => {
      if (err) reject(err);
      else resolve(text);
    });
  });
});
await page.evaluate(async () => {
  // use window.readfile to read contents of a file
  const content = await window.readfile('/etc/hosts');
  console.log(content);
});
await browser.close();