如何在 Puppeteer 中监听 postMessage 消息？

Question

https://github.com/GoogleChrome/puppeteer/blob/master/examples/custom-event.js展示了如何定义自己的事件，但没有展示如何将事件数据传输回 Puppeteer 外部的代码。

例如，如果我想postMessage使用 Puppeteer 读取代码中页面的事件数据来启动页面，您会如何做？

相关： https: //github.com/GoogleChrome/puppeteer/issues/2366

Answer 1

我刚刚遇到了同样的问题，下面是对我有用的东西。

使用Puppeteer库中的相同示例并进行一些修改。

'use strict';

const puppeteer = require('puppeteer');

(async() => {
    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    let msgCollection = [];

    // Define a window.onMessageReceivedEvent function on the page.
    await page.exposeFunction('onMessageReceivedEvent', e => {
        console.log(`${e.type} fired`, e.data || '');
        msgCollection.push(e.data);
    });

    /**
     * Attach an event listener to page to capture a custom event on page load/navigation.
     * @param {string} type Event name.
     * @return {!Promise}
     */
    function listenFor(type) {
        return page.evaluateOnNewDocument(type => {
            window.addEventListener(type, e => {
                window.onMessageReceivedEvent({type, data: e.data});
            });
        }, type);
    }

    await listenFor("message"); // Listen for "message" custom event on page load.

    await page.goto('https://jsfiddle.net/sa1nd0w5/', {waitUntil: 'networkidle0'});

    await browser.close();

    // Do something with the collected data
    console.log(msgCollection);

})();