Critical CSS Error: Net::ERR_ABORTED In V7, Multi-Dimension

by SLV Team 60 views

Have you encountered the frustrating net::ERR_ABORTED error when trying to generate critical CSS for multiple dimensions using Critical.js version 7? You're not alone! This article dives deep into a specific issue reported by a developer who experienced this error after upgrading from version 4.0.0 to 7.2.1. We'll explore the problem, the debugging steps taken, and potential causes, all while keeping it conversational and easy to understand.

The Problem: net::ERR_ABORTED During Multi-Dimension CSS Generation

So, here's the gist of it: a developer had some code that was working perfectly fine with Critical.js version 4.0.0. This code generated critical CSS for different screen dimensions, which is a super useful technique for optimizing website performance. You guys know, critical CSS helps in rendering the above-the-fold content quickly by inlining only the necessary CSS. But after upgrading to version 7.2.1, bam! The dreaded net::ERR_ABORTED error popped up. This error specifically occurred when generating critical CSS for multiple dimensions. Let's break down the code and the error to get a clearer picture.

Code Snippet (Working in v4.0.0):

The code uses Puppeteer, a Node library that provides a high-level API to control Chrome or Chromium, and Critical.js to generate critical CSS. Here's the code snippet that was working in version 4.0.0:

const puppeteer = require("puppeteer");

async function testPenthouseWithRealUserAgent() {
 const { generate } = await import("critical");
 const browser = await puppeteer.launch({
 executablePath: '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
 headless: false,
 args: [
 "--no-sandbox",
 "--disable-setuid-sandbox", 
 "--disable-dev-shm-usage",
 "--disable-blink-features=AutomationControlled",
 ],
 });

 try {
 console.log('🚀 Testing critical with real user agent...');

 const criticalCSS = await generate({
 src: 'https://example.com',
 userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
 strict: false, // Don't break on CSS parsing errors
 request: {
 https: {
 rejectUnauthorized: false // Handle TLS certificate issues
 }
 },
 penthouse: {
 blockJSRequests: false,
 userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
 puppeteer: {
 getBrowser: () => {
 console.log('Returning existing browser instance to penthouse');
 return browser;
 },
 },
 },
 dimensions: [
 {
 width: 1300,
 height: 900,
 },
 {
 width: 375,
 height: 667,
 }
 ],
 });
 
 console.log('📊 Critical CSS result:', criticalCSS);
 console.log('📊 Critical CSS length:', criticalCSS.css ? criticalCSS.css.length : 'No CSS');
 console.log('📄 First 200 chars:', criticalCSS.css ? criticalCSS.css.substring(0, 200) : 'No CSS'); 
 } catch (error) {
 console.log('❌ Penthouse failed:', error.message);
 }
 
 await browser.close();
}

Key aspects of the code include:

  • Puppeteer: Used to launch a headless Chrome browser.
  • Critical.js generate function: This is the core function that takes a URL (or HTML) and configuration options, and then outputs the critical CSS.
  • dimensions array: This is where the magic happens for multi-dimension CSS generation. The code specifies two dimensions: 1300x900 and 375x667. Critical.js should generate CSS tailored for each of these viewport sizes.
  • Error Handling: The try...catch block is essential for catching any errors during the CSS generation process.

The Error (net::ERR_ABORTED in v7.2.1):

After upgrading to Critical.js version 7.2.1, the same code threw the following error:

net::ERR_ABORTED at file:///private/var/folders/w0/h7jgcvv57c39qxjq7_snr5q00000gn/T/0118f06a51def9c16c12b60cf64a8f79/b68014cf31423d469b1bfc0c5875fe5b.html

This error indicates that the browser (launched by Puppeteer) aborted a network request while trying to access a local HTML file. The path /private/var/folders/... suggests that Critical.js is creating temporary HTML files during the CSS generation process.

Debugging Insights: File Deletion

The developer dug deeper and found that Critical.js was cleaning up (deleting) the temporary HTML file after generating CSS for the first dimension. So, when it tried to generate CSS for the second dimension, the file was gone, leading to the net::ERR_ABORTED error. This is a crucial piece of the puzzle!

Possible Causes and Solutions

Okay, so we know the error, and we have a good idea of when it's happening. Now, let's brainstorm some potential causes and how to fix them. Guys, this is where it gets interesting!

1. Bug in Critical.js Version 7

The most obvious possibility is that there's a bug in Critical.js version 7 that wasn't present in version 4.0.0. Software evolves, and sometimes changes introduce unintended side effects. This is especially true when dealing with complex operations like file system interactions and browser automation.

Possible Solution:

  • Report the issue: The developer did the right thing by raising this as a discussion. Reporting the issue on the Critical.js repository (usually on GitHub) helps the maintainers become aware of the bug and potentially fix it in a future release. This also helps other users facing the same problem.

  • Downgrade to v4.0.0: If you're blocked by this issue, temporarily downgrading to version 4.0.0 might be a viable workaround until a fix is available. You can do this using npm or yarn.

    npm install critical@4.0.0
# or
yarn add critical@4.0.0

2. Configuration Changes in Critical.js

It's possible that the way Critical.js handles multiple dimensions or temporary files has changed between versions 4 and 7. Some configuration options might need to be adjusted to work correctly in the newer version.

Possible Solutions:

  • Review the Critical.js documentation: Carefully read the documentation for version 7.x and look for any changes related to multi-dimension CSS generation, temporary file handling, or Puppeteer integration. Pay close attention to any deprecated options or new requirements.
  • Experiment with configuration options: Try different combinations of configuration options to see if any of them resolve the issue. For example, there might be an option to control how temporary files are handled or whether the browser instance is reused between dimension generations.

3. Puppeteer or Penthouse Compatibility Issues

Critical.js relies on Puppeteer (for browser automation) and Penthouse (another critical CSS extraction tool) under the hood. It's conceivable that there are compatibility issues between these libraries and Critical.js version 7. A change in how Puppeteer or Penthouse works could indirectly cause the net::ERR_ABORTED error.

Possible Solutions:

  • Check Puppeteer and Penthouse versions: Ensure that you're using versions of Puppeteer and Penthouse that are compatible with Critical.js version 7. The Critical.js documentation or release notes might specify recommended versions.
  • Update Puppeteer and Penthouse: If you're using older versions, try updating to the latest versions of Puppeteer and Penthouse. This might resolve any compatibility issues.
  • Isolate the problem: Try using Puppeteer and Penthouse directly (without Critical.js) to see if the issue persists. This can help you determine if the problem lies within Critical.js itself or in one of its dependencies.

4. File System Permissions or Temporary Directory Issues

The error message file:///private/var/folders/... points to a temporary directory. It's possible that there are file system permission issues preventing Critical.js from accessing or writing to this directory. Another possibility is that the temporary directory is being cleaned up by the operating system prematurely.

Possible Solutions:

  • Check file system permissions: Ensure that the user running the Node.js process has read and write permissions to the temporary directory. You might need to adjust permissions using chmod or other file system commands.
  • Specify a custom temporary directory: Critical.js might have an option to specify a custom temporary directory. Try setting this to a directory that you know has the correct permissions and is not subject to automatic cleanup.

5. Race Condition or Asynchronous Issue

Generating critical CSS for multiple dimensions involves asynchronous operations. There's a chance that a race condition or other asynchronous issue is causing the temporary file to be deleted before it's fully processed for the second dimension.

Possible Solutions:

  • Review asynchronous code: Carefully examine the Critical.js code (if you have access to it) or the generated temporary file handling logic for any potential race conditions or asynchronous issues. Look for places where files are being deleted or accessed concurrently.
  • Implement synchronization mechanisms: If you identify a race condition, you might need to implement synchronization mechanisms (e.g., mutexes, locks) to ensure that files are accessed and deleted in the correct order.

Conclusion: Digging Deeper and Finding the Root Cause

The net::ERR_ABORTED error when generating critical CSS for multiple dimensions in Critical.js version 7 is a tricky issue, but by understanding the error message, the debugging steps taken, and the potential causes, we can start to narrow down the problem. Remember, guys, debugging is like detective work!

The key takeaways are:

  • Report the issue: If you suspect a bug in Critical.js, report it to the maintainers.
  • Review the documentation: Check for configuration changes or new requirements in version 7.
  • Check dependencies: Ensure that you're using compatible versions of Puppeteer and Penthouse.
  • Investigate file system issues: Verify file permissions and temporary directory settings.
  • Look for race conditions: Review asynchronous code for potential synchronization problems.

By systematically investigating these areas, you'll be well on your way to resolving the net::ERR_ABORTED error and getting your critical CSS generation working smoothly again. Keep us updated on your progress, and let's conquer this bug together!