How can I execute Puppeteer code in Google Chrome Headless mode?

Other Questions Puppeteer
1

I am attempting to utilize Puppeteer to capture a screenshot after a specified delay, but I’m facing some basic issues. I installed the necessary packages successfully with the commands:

sudo apt-get install npm
sudo apt-get install node
npm install puppeteer

The documentation notes that device interaction involves creating a Browser instance and managing pages with Puppeteer’s API. However, I’m not acquainted with other browser testing frameworks, which makes it unclear what ‘create an instance of Browser’ entails.

I discovered an example script in examples/screenshot.js that looks like this:

'use strict';

const puppeteer = require('puppeteer');

(async() => {
    const browserInstance = await puppeteer.launch();
    const webpage = await browserInstance.newPage();
    await webpage.goto('http://example.com');
    await webpage.screenshot({path: 'example.png'});

    await browserInstance.close();
})();

However, I’m unsure how to execute this code. I attempted to run it using node examples/screenshot.js, but the terminal provides no output, and the screenshot is not found in the specified location. I’ve verified that permissions are correct. Additionally, I tried executing node install.js, running the script inline, and even testing it in a browser, but those methods were unsuccessful. How can I properly run my Puppeteer code?

2

To execute your Puppeteer code in Google Chrome Headless mode, you need to ensure your setup is correctly configured and that you're running the script with the right commands. Let's go through this step by step:

  1. Ensure Node.js is installed: Verify that node and npm are properly set up by running node -v and npm -v to check their versions. If installed correctly, these commands should return version numbers.
  2. Install Puppeteer: Since it seems you've already installed Puppeteer with npm install puppeteer, ensure it's in the node_modules directory within your project folder.
  3. Save your script: Place the provided code snippet in a file named screenshot.js. Ensure there's no node_modules folder permission issues by checking ls -l node_modules if needed.
  4. Run the script: Use the following command to execute the script:
    5. node screenshot.js

    This should launch a headless instance of Chrome, navigate to the URL, take a screenshot, and save it as example.png in the same directory.

  5. Check for errors: If the screenshot does not appear, look for any errors in your terminal output. Also, ensure that the file path is correctly written and you have write permissions in your current directory.
  6. Modify options if needed: If issues persist, you can launch Chrome in a non-headless mode by modifying the launch options:
    7. const browserInstance = await puppeteer.launch({headless: false});

    This helps visually debug any issues during page loading or screenshot capturing.

By following these steps, you should be able to execute your Puppeteer code successfully and capture the desired screenshot.

3

Executing Puppeteer code in Google Chrome Headless mode can seem tricky at first, but let's refine what's already been covered with a slightly different perspective and some additional insights:

  1. Project Setup: Ensure that both node and npm are installed by checking their versions with node -v and npm -v. You should see version numbers as output. This verifies your Node.js setup is correct.
  2. Script Verification: Make sure your examples/screenshot.js file is saved with the correct code snippet you shared:
    3. 'use strict';

    const puppeteer = require(‘puppeteer’);
    

    (async() => {
    
const browserInstance = await puppeteer.launch();
    
const webpage = await browserInstance.newPage();
    
await webpage.goto(‘http://example.com’);
    
await webpage.screenshot({path: ‘example.png’});
    

    await browserInstance.close();

    

    })();

  3. Correct Execution: Run the script using the command node examples/screenshot.js from the terminal while in your project's root directory. Make sure the path to the script is correctly specified in the command if you're not in the same directory.
  4. Debugging Tips: If running the script gives no output or no screenshot is saved, check the terminal for any error messages. Consider modifying your launch method to visually debug by setting headless to false, like this:
    5. const browserInstance = await puppeteer.launch({headless: false});

    Running in non-headless mode allows you to see what the browser is doing.

  5. File Path and Permissions: Ensure that your desired path for saving the screenshot ('example.png') is correct and that you have the necessary permissions to write files in that directory. Double-check for any typos in the file path.
  6. Network and Page Load Issues: Sometimes, the page may not load properly. You can set a timeout to allow more loading time with await webpage.goto('http://example.com', {waitUntil: 'networkidle0'});, which waits for the network to be inactive.

Hopefully, these steps will help you successfully run your Puppeteer script. If issues persist, you might want to try running a simpler script with Puppeteer or checking for any underlying issues with Node.js installation."

4

Running your Puppeteer script should be straightforward. Here's a concise guide:

  1. Verify Node.js and npm: Ensure they are installed by running node -v and npm -v. You should see version numbers.
  2. Run the Script: Save your code in screenshot.js and execute it with:
    3. node screenshot.js
  3. Check for Errors: If no screenshot is produced, check the terminal for errors and verify write permissions.
  4. Debug: Run without headless mode for easier debugging:
    5. const browserInstance = await puppeteer.launch({headless: false});

Following these steps should help resolve the issue.