Page.exposeFunction() 方法

¥Page.exposeFunction() method

该方法在页面的 window 对象上添加一个名为 name 的函数。调用时，该函数会执行 node.js 中的 puppeteerFunction 并返回 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 Promise，则将等待它。

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

注意

通过 page.exposeFunction 安装的功能在导航中仍然存在。

¥Functions installed via page.exposeFunction survive navigations.

签名

¥Signature

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

参数

¥Parameters

范围	类型	描述
name	string	窗口对象上的函数名称
pptrFunction	Function | { default: Function; }	将在 Puppeteer 上下文中调用的回调函数。

Returns:

Promise<void>

示例 1

¥Example 1

在页面中添加 md5 功能的示例：

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

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

(async () => {
  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 功能的示例：

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

import puppeteer from 'puppeteer';
import fs from 'fs';

(async () => {
  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();
})();