Javascript机器人检查签证预约不起作用,我不知道如何解决

我正在尝试制作一个机器人,它可以获取我的证件,并检查我所在城市美国领事馆的签证面试预约是否可用,但这是我的第一个Javascript应用程序,我像一只无头鸡一样到处乱跑。

首先,联邦调查局特工的免责声明如下:该应用程序是不可扩展的,不会损害服务器,因为它使用我的帐户来检查约会日期。

现在,针对这个问题。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,这应该是完全合理的,但目前我收到错误消息,即网站在“wait-response.json();”处没有返回有效的json数据。以下是错误代码:

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,或者如何检查网站实际返回的类型o值。有什么想法吗?

以下是完整的代码供参考:

#!/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();

回购金额: 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-and-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的是什么类型的数据。