Puppeteer: A way to reduce the amount of repetitive work

[mylamour]

In recent days, I faced a problem that our team have to mange lot of tickets with ServiceNow. also ServiceNow was provided a cli tools but anyway i didn't get that from service-now store. finally I write a automation scripts with puppeteer and show my little experience within this tutorial.

0x01 Intro

Puppeteer is a Node library which provides a high-level API to control headless Chrome or Chromium over the DevTools Protocol. It can also be configured to use full (non-headless) Chrome or Chromium. and It was useful to do automation, eg. form submission, UI testing, keyboard input, etc.

Puppeteer Basics

we can just install it with npm install -i puppeteer , and i list some basics options here.

• take a screenshot

  
  const puppeteer = require('puppeteer');

(async () => { const browser = await puppeteer.launch(); const page = await browser.newPage(); await page.goto('https://example.com'); await page.screenshot({ path: 'example.png' });

await browser.close(); })();

* save a pdf
```js
  await page.pdf({ path: 'hn.pdf', format: 'a4' });

• Keyboard input

  await page.keyboard.press("Tab");
  await page.keyboard.type('this is funny')

• Click

  await page.waitForSelector('#header_attachment')
  await page.click('#header_attachment')

  I suggested to use waitForSelector before click due to the page has different response time.

• emulate a mobile device

  const iPhone = puppeteer.devices['iPhone 6'];
  await page.emulate(iPhone);

  Also you can setting Nexus 10 and Pixel 2 etc. The full device lists was here

• cookie Operation

  const cookies = await page.cookies()
  fs.writeFile('cookie.json', JSON.stringify(cookies, null, 2), function(err) {
  if (err) throw err;
  console.log('completed write of cookies');
  });

  even we use the cookie, it may not able to reuse the same session. And we can use the userDataDir option to store the data

Puppeteer Advanced

• Load extension

  chrome_extension='extension/path'
  browser = await launch({
      'headless': False,
      'args': [
          '--no-sandbox',
          '--load-extension={}'.format(chrome_extension),
          '--disable-extensions-except={}'.format(chrome_extension),
      ]
  })

• Executing JavaScript in the page context

  await page.evaluate(() => {
    // var aTags = document.getElementsByTagName("td");
    // var searchText = "\(empty\)";
    // var found;
  
    // for (var i = 0; i < aTags.length; i++) {
    //   if (aTags[i].textContent == searchText) {
    //     found = aTags[i];
    //     found.click();
    //     break;
    //   }
    }
  });

• Parallel

  const { Cluster } = require('puppeteer-cluster');
  (async () => {
  const cluster = await Cluster.launch({
  concurrency: Cluster.CONCURRENCY_CONTEXT,
  maxConcurrency: 2,
  });
  await cluster.task(async ({ page, data: url }) => {
  await page.goto(url);
  const screen = await page.screenshot();
  });
  cluster.queue('http://www.google.com/');
  cluster.queue('http://www.wikipedia.org/');
  await cluster.idle();
  await cluster.close();
  })();

• Anti-Detection (This is can't be describe in shortly)

0x02 Scenario

There was two main operations from my side, The fist one is to assign ticket to each person, and the second one is to close tickets. i will show you how to use puppeteer to implement an automation tools. and this is part code of tools.

const puppeteer = require('puppeteer-debug')
const fs = require('fs');
// const iPhone = puppeteer.devices['iPhone 6'];

; (async function () {

  const browser = await puppeteer.launch({
    // devtools: true,
    headless: false,
    userDataDir: './userdata'
  })

  const page = await browser.newPage()
  // await page.emulate(iPhone);
  await page.goto('https://paypal.service-now.com/sc_task_list.do?xxxxxxxxx&yyyyyyyy')
  await page.waitForTimeout(50000)

  var array = fs.readFileSync('owners').toString().split("\n");

  for (m in array) {

    console.log("Assign ticket to " + array[m])

    await page.evaluate(() => {
      var aTags = document.getElementsByTagName("td");
      var searchText = "\(empty\)";
      var found;

      for (var i = 0; i < aTags.length; i++) {
        if (aTags[i].textContent == searchText) {
          found = aTags[i];
          found.click();
          break;
        }
      }
    });

    for (let i = 0; i < 20; i++) {
      await page.keyboard.press('Enter')
      await page.waitForTimeout('2000')
      await page.keyboard.type(array[m])
      await page.waitForTimeout('2000')
      await page.keyboard.press('ArrowDown')
      await page.waitForTimeout('2000')
      await page.keyboard.press('Enter')
      await page.waitForTimeout('3000')
      if (i != 19) {
        await page.keyboard.press('ArrowDown')
      }
    }

    await page.evaluate(() => {
      document.getElementsByTagName("button")[4].click();
    });

    await page.waitForTimeout(5000)

  }

  await puppeteer.debug() // go to REPL
  await browser.close()

})()

The code was not difficult, and here is some trick what i learned from that.

• mobile site is more friendly for automation
• If you can't get an element with dynamic selector , you can just use js code to find that in the page context or you can use keyboard operations if it was allowed in the page.
• we should wait a selector before what we want do for that due to the response time was different even the same page.
• if you need to login with accounts each time, try to save user data with the main site but search site.

Here is the final results:

https://user-images.githubusercontent.com/12653147/122204653-f2af6600-ced1-11eb-8eac-6adbc8f13140.mp4

0x03 Conclusion

In last year, we are under fastest growing and there was lot of works need to do. After period of testing , i have to say —— it's necessary to make something automation. especially In daily basis.

Resources

• Puppeteer Homepage
• Mobile Devices Lists
• Load multiple extensions
• Puppeteer Cluster