Using a command line tool for a headless browser

I’m searching for a command line tool that can retrieve a webpage and run the related JavaScript code. My intention is to invoke a headless browser through the command line. I cannot use wget because it doesn’t execute JavaScript. Here’s an example of my current attempt:

wget --load-cookies cookies.txt -O /dev/null https://example.com/update?run=1

The scenario involves web pages that interact with Elasticsearch indexes, perform data processing, and update those indexes. We want to automate this task on an hourly schedule through a cron job. There’s no need for capturing images or HTML; we just want to load the page and execute its JavaScript functions via a cron job, ideally resembling something like run-headless https://example.com/update. I’m operating on CentOS 7. I’ve also searched on forums but couldn’t find a satisfactory solution. Tools like Selenium seem excessive for this purpose.

For executing JavaScript on web pages using a command-line tool, Puppeteer and Headless Chromium are excellent choices. These tools allow you to automate the browser in a headless mode, executing JavaScript as if in a real browser environment.

Here's how you can use Puppeteer with Node.js for your task:

  1. First, ensure you have Node.js and npm installed on your CentOS system. You can verify their installation with:

    node -v
    npm -v
  2. Create a new Node.js project or navigate to your existing project directory and install Puppeteer:

    npm install puppeteer
  3. Create a JavaScript file (e.g., run-headless.js) and use Puppeteer to open a browser and load your page:

    const puppeteer = require('puppeteer');
    

    (async () => {
    const browser = await puppeteer.launch({ headless: true });
    const page = await browser.newPage();
    await page.goto(‘https://example.com/update’);

    // You can further interact with the page here, if needed.

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

  4. You can now run this script from the command line:

    node run-headless.js

To automate this operation with cron, you can schedule it to run at your desired intervals by adding a new cron job. Here's an example of how you might add it to your crontab, assuming you want it to run hourly:

0 * * * * /usr/bin/node /path/to/your/project/run-headless.js

This approach is lightweight compared to Selenium and should efficiently execute the JavaScript on the page as needed. Puppeteer also offers extensive control and can be expanded for more complex interactions in the future.

You might also consider using PhantomJS as an alternative for this task. It's a headless WebKit scriptable with a JavaScript API, which can execute JavaScript on web pages.

Here’s a quick guide to get you started:

  1. First, you need to install PhantomJS. You can download it from the official site and follow their guidance for installation on CentOS 7.

  2. Create a simple script (e.g., run-script.js) to load the webpage:

    var page = require('webpage').create();
    page.open('https://example.com/update', function(status) {
      console.log("Status: " + status);
      phantom.exit();
    });
  3. Execute this script from the command line:

    phantomjs run-script.js

For cron automation, schedule this script with:

0 * * * * /path/to/phantomjs /path/to/run-script.js

PhantomJS is a lightweight solution fitting your requirement of executing JavaScript without Selenium’s overhead.

To efficiently execute JavaScript on webpages through the command line, without the overhead of tools like Selenium, you can utilize Puppeteer with Node.js. It's a practical choice due to its lightweight nature and compatibility with JavaScript rendering.

Follow these steps to set up Puppeteer for your task:

  1. Start by ensuring Node.js is installed. Confirm installation with:

    node -v
    npm -v
  2. Install Puppeteer in your project or create a new project directory:

    npm install puppeteer
  3. Create a JavaScript file, run-headless.js, to automate the browser action:

    const puppeteer = require('puppeteer');
    

    (async () => {
    const browser = await puppeteer.launch({ headless: true });
    const page = await browser.newPage();
    await page.goto(‘https://example.com/update’);
    await browser.close();
    })();

  4. Execute your script via the command line:

    node run-headless.js

To schedule this script to run on an hourly basis, use a cron job:

0 * * * * /usr/bin/node /path/to/your/project/run-headless.js

This approach allows you to execute JavaScript efficiently and automates the task without unnecessary complexity. Puppeteer offers further capabilities if you require more advanced interactions later on.