When it comes to boosting web performance, compressing resources is a real game-changer. Brotli, a somewhat new compression algorithm from Google, outshines the traditional gzip by delivering better compression ratios, which is super handy for both static and dynamic content. Let’s break down how you can use Brotli middleware in an Express.js application to make your site faster.

Brotli Compression Unwrapped

Brotli offers impressive compression, especially for text-heavy resources like HTML, CSS, and JavaScript. The trade-off? It can be more CPU-intensive than gzip, potentially affecting your server’s performance. But the gains in reducing data size are usually worth it.

Setting Up Brotli in Express

To get Brotli working in an Express app, you can use the shrink-ray middleware. This nifty tool supports both Brotli and gzip, making it versatile for adapting to different browser capabilities.

First things first, you need to get shrink-ray. Add it to your package.json as a dependency and run npm install.

"devDependencies": {
  // ...
  "shrink-ray": "^0.1.3"
}

After installing, integrate it into your app like this:

const express = require('express');
const shrinkRay = require('shrink-ray');

const app = express();

// Apply the shrink-ray middleware to compress all requests
app.use(shrinkRay());

// Serve static files from the public directory
app.use(express.static('public'));

const listener = app.listen(process.env.PORT, () => {
  console.log('Your app is listening on port ' + listener.address().port);
});

This setup ensures that all the static files from your public directory are compressed using Brotli, assuming the client’s browser supports it.

Compressing Dynamic Content

You can also use shrink-ray for dynamic content. Just ensure that the compression is applied to the responses that your application generates.

Here’s a simple example:

const express = require('express');
const shrinkRay = require('shrink-ray');

const app = express();

// Apply the shrink-ray middleware for all requests
app.use(shrinkRay());

// Example route for dynamic content
app.get('/api/data', (req, res) => {
  const data = { message: 'Hello, World!' };
  res.json(data);
});

const listener = app.listen(process.env.PORT, () => {
  console.log('Your app is listening on port ' + listener.address().port);
});

With this setup, any JSON data returned by the /api/data endpoint gets compressed using Brotli if the client supports it.

Pre-Compressing Static Files

While shrink-ray handles on-the-fly compression, pre-compressing your static files can take a load off your server. This involves creating pre-compressed versions of your files and serving those directly.

To pre-compress files, use the brotli command-line tool. Here’s a script to compress files in your public directory:

find public -type f \( -name "*.css" -o -name "*.js" -o -name "*.json" -o -name "*.svg" \) -exec brotli --force --best {} \;

This command finds all CSS, JS, JSON, and SVG files in public and compresses them with Brotli, tagging a .br extension to the new files.

Serving Pre-Compressed Files

To serve these .br files, configure your Express app to check for them first. Here’s how you can do it:

const express = require('express');
const shrinkRay = require('shrink-ray');
const path = require('path');
const fs = require('fs');

const app = express();

// Serve pre-compressed files function
function servePreCompressed(req, res, next) {
  const acceptEncoding = req.headers['accept-encoding'];
  if (acceptEncoding && acceptEncoding.includes('br')) {
    const filePath = path.join(__dirname, 'public', req.path + '.br');
    if (fs.existsSync(filePath)) {
      res.set("Content-Encoding", "br");
      res.set("Content-Type", getContentType(req.path));
      return res.sendFile(filePath);
    }
  }
  next();
}

// Use pre-compressed files if available
app.use(servePreCompressed);
app.use(shrinkRay());
app.use(express.static('public'));

const listener = app.listen(process.env.PORT, () => {
  console.log('Your app is listening on port ' + listener.address().port);
});

In this setup, the servePreCompressed middleware checks if a Brotli-compressed version of the file exists and serves it when available. Otherwise, it defaults to the shrink-ray middleware for on-the-fly compression.

Keeping an Eye on Performance

Ongoing monitoring is crucial to ensure Brotli compression benefits outweigh any downsides. Track several metrics to ensure everything runs smoothly:

• Time to First Byte (TTFB): This might tick up a bit due to additional Brotli compression time, but overall network speed gains should make up for it.

• Resource Sizes: Check your resource sizes with browser developer tools to ensure Brotli compression is working. Look for the Content-Encoding header and file size reductions.

• CPU Usage: Monitor your CPU usage to ensure Brotli’s extra processing isn’t becoming a bottleneck.

Wrapping It Up

Integrating Brotli compression through shrink-ray middleware significantly boosts your web app’s performance by reducing resource sizes. Whether compressing on-the-fly or pre-compressing static files, these strategies ensure efficient delivery. Remember to keep an eye on your app’s performance to ensure that the benefits of Brotli compression are realized without overloading your server. Using Brotli can make your web app faster and more responsive, giving your users a better experience.