检查签证预约的Javascript机器人不起作用，我不知道如何修复它

Question

我正在尝试制作一个机器人，它可以获取我的凭据并检查我所在城市的美国领事馆签证面试预约的可用性，但这是我的第一个 Javascript 应用程序，我像无头鸡一样到处乱跑。

首先，FBI 特工的免责声明如下：此应用程序不可扩展，不会损害服务器，因为它使用我的帐户来检查预约日期。

现在来说说这个问题。这是前面提到的功能：

let checkAvailability = () => {
  (async () => {
    gSpinner.stop();
    console.log(chalk.gray('Opening Chrome headless...'));
    let browser = await puppeteer.launch();
    let page = await browser.newPage();

    let spinner = new CLI.Spinner('Signing in...');
    spinner.start();

    await page.goto('https://ais.usvisa-info.com/en-ca/niv/users/sign_in');
    await page.type('#user_email', config.username);
    await page.type('#user_password', config.password);
    await page.$eval('#policy_confirmed', check => check.checked = true);
    await page.waitForTimeout(3000);
    await Promise.all([
      page.waitForNavigation(), page.click('input[type=submit]')
    ]).catch(() => { console.error("Error Occurred.") });
    spinner.stop();
    console.log(chalk.green('Signed in!'));
    console.log(chalk.yellow(`Checking at: ${Date().toLocaleString()}`));

    let response = await page.goto(`https://ais.usvisa-info.com/en-ca/niv/schedule/${config.schedule_id}/appointment/days/${locationId}.json?appointments[expedite]=false`);
    let json = await response.json();
    console.log(json.slice(0, 5));
    if (json.length == 0) {
      console.log(chalk.red('No appointments!'));
    } else if(Date.parse(json[0].date) < alertBefore){
      console.log(chalk.green('Early appointment available!!!'));
      console.log(chalk.white(json[0].date));
      beepbeep(5)
    } else {
      console.log(chalk.red('No early appointments!'));
    }
    console.log(chalk.gray('Closing Chrome headless...'));
    await browser.close();

    let next = new Date();
    next.setTime(next.getTime() + interval);
    console.log(chalk.gray(`Next checking at: ${next.toLocaleString()}`));
    gSpinner.start();
    setTimeout(checkAvailability, interval);
  })();
}

checkAvailability();

对我来说，这应该可行，但目前我收到错误消息，表明该网站未在“await response.json();”处返回有效的 json 数据。这是错误代码：

undefined:1


SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at HTTPResponse.json (file:///C:/usvisa-appointment-checker/node_modules/puppeteer/lib/esm/puppeteer/common/HTTPResponse.js:164:21)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async file:///C:/usvisa-appointment-checker/check-appointment.js:73:16

我不知道 puppeteer 库是如何工作的，也不知道如何处理未定义的返回值或如何检查站点实际返回的值类型。有什么想法吗？

以下是完整代码供参考：

#!/usr/bin/env node

import chalk from 'chalk';
import figlet from 'figlet';
import clear from 'clear';
import CLI from 'clui';
import puppeteer from 'puppeteer';
import fs from 'fs';
import beepbeep from 'beepbeep';
import * as path from 'path';
import {fileURLToPath} from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const config = JSON.parse(fs.readFileSync(`${__dirname}/.config.json`));

let locationId = '';

switch(config.location) {
  case 'vancouver':
    locationId = '95';
    break;
  case 'calgary':
    locationId = '89';
    break;
  case 'ottawa':
    locationId = '92';
    break;
  case 'toronto':
    locationId = '94';
  case 'montreal':
    locationId = '91';
}

clear();

console.log(
  chalk.yellow(
    figlet.textSync('VISA Appointment')
  )
);

const interval = 600000;

const alertBefore = new Date(config.alert_for_appointment_before);

let gSpinner = new CLI.Spinner('Waiting for the next run...');

let checkAvailability = () => {
  (async () => {
    gSpinner.stop();
    console.log(chalk.gray('Opening Chrome headless...'));
    let browser = await puppeteer.launch();
    let page = await browser.newPage();

    let spinner = new CLI.Spinner('Signing in...');
    spinner.start();

    await page.goto('https://ais.usvisa-info.com/en-ca/niv/users/sign_in');
    await page.type('#user_email', config.username);
    await page.type('#user_password', config.password);
    await page.$eval('#policy_confirmed', check => check.checked = true);
    await page.waitForTimeout(3000);
    await Promise.all([
      page.waitForNavigation(), page.click('input[type=submit]')
    ]).catch(() => { console.error("Error Occurred.") });
    spinner.stop();
    console.log(chalk.green('Signed in!'));
    console.log(chalk.yellow(`Checking at: ${Date().toLocaleString()}`));

    let response = await page.goto(`https://ais.usvisa-info.com/en-ca/niv/schedule/${config.schedule_id}/appointment/days/${locationId}.json?appointments[expedite]=false`);
    let json = await response.json();
    console.log(json.slice(0, 5));
    if (json.length == 0) {
      console.log(chalk.red('No appointments!'));
    } else if(Date.parse(json[0].date) < alertBefore){
      console.log(chalk.green('Early appointment available!!!'));
      console.log(chalk.white(json[0].date));
      beepbeep(5)
    } else {
      console.log(chalk.red('No early appointments!'));
    }
    console.log(chalk.gray('Closing Chrome headless...'));
    await browser.close();

    let next = new Date();
    next.setTime(next.getTime() + interval);
    console.log(chalk.gray(`Next checking at: ${next.toLocaleString()}`));
    gSpinner.start();
    setTimeout(checkAvailability, interval);
  })();
}

checkAvailability();

仓库 git：https://github.com/patrickyin/usvisa-appointment-checker

尝试了一些基本的错误处理，但再次不知道我在做什么。使用 try 和 catch 只是给了我另一个类似的错误代码，因为我不知道网站返回什么类型的数据。

Answer 1

我知道这不能回答你的问题。但只是想提一下，有几个存储库可用于相同目的。 你可以检查一下：

https://github.com/Ali-Flt/us_visa_rescheduler
https://github.com/uxDaniel/visa_rescheduler
https://github.com/Soroosh-N/us_visa_scheduler
https://github.com/shcheglovnd/us_visa_scheduler_telegram
https://github.com/dvalbuena1/visa_rescheduler_aws
https://github.com/daydos/us-visa-appointment