javascript - puppeteer 师 : how check if browser is still open and working

Question

我试图在单个浏览器实例中打开多个选项卡，完成后我关闭选项卡，然后每隔 x 秒重新打开这些选项卡......但我想保持浏览器本身打开，所以我不必登录每个循环上的每个选项卡

所以浏览器保持打开，标签打开和关闭

这是我的简化代码，请忽略语法错误

var  global_browser = false ;
async function init_puppeteer( settings ) {



    if(global_browser === false )
        global_browser = await puppeteer.launch({headless: false  , args:['--no-sandbox']});

    for(var i = 0  ; i < settings.length ; i++ )
    {
        var setting = settings[i];
        open_tab($setting);
    }
}



 async function open_tab( setting ){
    const page    = await global_browser.newPage();
    // do stuff 
    page.close();   
}

setInterval(function (){
    init_puppeteer(settings)
}, 50000 );

这就是问题所在，有时浏览器会崩溃或出于任何原因关闭，但 global_browser仍然是 puppeteer 的对象/实例......当我尝试使用该实例打开选项卡时它不会工作，我得到类似的东西

(node:5720) UnhandledPromiseRejectionWarning: Error: WebSocket is not open: readyState 3 (CLOSED)

这是我的问题，我如何检查并确保我在 global_browser 中有一个工作/打开的 puppeteer 实例?所以我可以创建一个新实例并在前一个实例关闭时替换它

Answer 1

使用browser.on('disconnected') .
您可以使用 browser.on('disconnected') 监听浏览器何时关闭或崩溃，或者 browser.disconnect() 方法被调用。
然后，您可以自动重新启动浏览器，并继续您的程序。
以下类将启动浏览器，并在 'disconnected' 时自动重新启动浏览器。事件被触发:

class BrowserHandler {
  constructor() {
    const launch_browser = async () => {
      this.browser = false;
      this.browser = await puppeteer.launch();
      this.browser.on('disconnected', launch_browser);
    };
    
    (async () => {
      await launch_browser();
    })();
  }
}

BrowserHandler.browser将返回 false断开连接时。
此外，以下功能将使您能够强制程序等待浏览器完成启动，然后再继续:

const wait_for_browser = browser_handler => new Promise((resolve, reject) => {
  const browser_check = setInterval(() => {
    if (browser_handler.browser !== false) {
      clearInterval(browser_check);
      resolve(true);
    }
  }, 100);
});

完整示例:

'use strict';

const puppeteer = require('puppeteer');

/**
 * Class: BrowserHandler
 *     Relaunch Browser when Closed
 *     Return false when Browser is Disconnected
 */

class BrowserHandler {
  constructor() {
    const launch_browser = async () => {
      this.browser = false;
      this.browser = await puppeteer.launch();
      this.browser.on('disconnected', launch_browser);
    };
    
    (async () => {
      await launch_browser();
    })();
  }
}

/**
 * Function: wait_for_browser
 *     Wait for Browser to Finish Launching
 */

const wait_for_browser = browser_handler => new Promise((resolve, reject) => {
  const browser_check = setInterval(() => {
    if (browser_handler.browser !== false) {
      clearInterval(browser_check);
      resolve(true);
    }
  }, 100 );
});

// Main Program

(async () => {
  // Open Browser
  
  const browser_handler = new BrowserHandler;
  
  await wait_for_browser(browser_handler);
  
  // Open New Page
  
  let page = await browser_handler.browser.newPage();
  
  await page.goto('https://www.example.com/');
  
  // Disconnect and Automatically Reconnect Browser
  
  browser_handler.browser.disconnect();
  
  if (browser_handler.browser === false) {
    console.log('The browser has been disconnected.');
    
    await wait_for_browser(browser_handler);
  }
  
  console.log('The browser has been reconnected.');
  
  // Close and Automatically Reopen Browser
  
  await browser_handler.browser.close();
  
  if (browser_handler.browser === false) {
    console.log('The browser has been closed.');
    
    await wait_for_browser(browser_handler);
  }
  
  console.log('The browser has been reopened.');
  
  // Force Close Puppeteer
  
  process.exit();
})();

结果:

The browser has been disconnected.

The browser has been reconnected.

The browser has been closed.

The browser has been reopened.