javascript - 停止 puppeteer 进程，直到全局 var 值从 false 变为某个字符串

Question

我在我的 nodejs 服务器中运行 puppeteer ...想法是打开一个页面，通过 socket.io 读取验证码并将其发送给用户，当从用户接收到输入的值验证码以继续使用 puppeteer ...这里被简化了我的代码版本

   var captcha = false ;

    io.on('connection' , function(socket){

        socket.on('start_puppeteer' , function (data) {
            io.emit('push_msg' , {text : 'starting puppeteer  ....  '  });
            run(io);
        })

        socket.on('get_captcha_from_client' , function (data) {

            captcha = data.text ;
            console.log( 'capthca set : ' + captcha);
        })

    });

    function get_captcha() {
        return new Promise(function(resolve , reject ) {
            if(captcha === false )
                reject(captcha );
            else
                resolve(captcha);
        });
    }


async function run(io) {
    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    await page.goto('http://localhost');

    console.log( ' sending captcha to client ' );

    io.emit('send_captcha_to_client' , {text : 'captcha text'  });

    var captcha = await get_captcha();

    console.log( ' captcha confirm -> ' + captcha );

    browser.close();
}

问题是即使设置了验证码，代码也不会移动，我也没有在控制台中得到 captcha confirm

$ node pop.js
 sending captcha to client
(node:9356) UnhandledPromiseRejectionWarning: false
(node:9356) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch().
 (rejection id: 3)
(node:9356) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
capthca set : 1234

Answer 1

page.waitForFunction 计算一个函数 in browser context ，即您可以检查某个 DOM 节点是否存在或输入的值，但您只能访问该函数内部的页面对象。

现在，如果您只想等待验证码被解决，让您的 get_captcha 返回 Promise 并为它的结果 await :

function get_captcha() {
    return new Promise(resolve => {

        // ...Do something lengthy here...

        resolve(captcha);
    });
}

async function run(io) {
    // ....

    await page.goto('http://localhost');
    io.emit('send_captcha_to_client' , {text : 'captcha text'  });
    var captcha = await get_captcha();

    // ....
}