Google's Brotli is better at compression than the standard gZIP as the content-encoding for HTTP requests.

This script allows you to batch compress css, js, svg, csv, json etc. files beforehand to facilitate super-fast static content delivery (With some web server tweaks).

What is Brotli?

Named after a Swiss baked good, Brotli is a compression algorithm that Google released back in 2013. As of late 2020 most modern browsers support Brotli. Essentially, Brotli has the potential to offer roughly 20-26% better compression ratios than gZip at comparable speeds, which is great news for those of us who care about performance.

How it Works With the Browser

Whenever a browser makes a request to the server, it lets the server know what kind of compressed content it can decompress using the Accept-Encoding header, like so:

Accept-Encoding: "gzip, deflate"

Then, when the server responds with the content, it tells the the browser what compression was actually used (if any) with the Content-Encoding header. Like so:

Content-Encoding: "gzip"

In the case of browsers that support Brotli (e.g. Chrome, Firefox), the Accept-Encoding header may look like this:

Accept-Encoding: "gzip, deflate, br"

And if the server is using the Brotli to compress the file it serves, it will use br as the Content-Encoding response

Content-Encoding: "br"

But There's a catch:

Compressing bigger files at higher compression levels can take a few seconds which is not acceptable.

So for static content, we can precompress the files into the brotli format and simply serve them to the user, this reduces the performance cost as static content is not compressed again and again.

Setting up the environment:

1. Install Node.js and use node -v to check version.
2. IMP Note: You might need to use sudo depending on the npm configuration.
3. Clone or download this repo.
4. Run npm install inside this project folder to install all dependencies.

Running the Code

1. Put the files you want to compress in the /data directory.
2. Run gulp compress in the base directory of the Repo.
3. Generated .br Files will be saved in the same /data directory alongside the original files.

Deploying the website code

1. You can simply paste all the files(including the original and the .br ones) in your DocumentRoot as you normally do.
2. Make sure to setup the web server to respond to Accept-Encoding: "gzip, deflate, br" requests differently with the .br extension files and change the content encoding accoridingly as well to prevent recompression(see more below).

Configuring the server for static brotli

1. Make sure brotli compressed files exist right next to the normal files in respective folders. E.g. if you have a file /var/www/html/style.css there should also be /var/www/html/style.css.br
2. Copy the .htaccess file from the repo to the DocumentRoot as well. This .htaccess file is already configured to serve pre-compressed .br files.