Brotli compression support added for CSS and JavaScript aggregates

Drupal now supports Brotli compression for aggregated CSS and JavaScript files in addition to the existing gzip compression. Brotli typically provides 15-25% better compression ratios than gzip, resulting in smaller file sizes and faster page loads for browsers that support it.

What changed

- The separate system.performance.css.gzip and system.performance.js.gzip settings have been replaced with unified system.performance.css.compress and system.performance.js.compress boolean settings.
- When compression is enabled, Drupal will automatically generate both .gz (gzip) and .br (Brotli) versions of aggregated CSS and JavaScript files if the server has the necessary PHP extensions installed.
- The .htaccess file has been updated to serve Brotli-compressed files when available, with gzip as a fallback.
- Brotli files are served with higher priority than gzip files for browsers that support both compression methods.

Server requirements

To generate Brotli-compressed files, the server must have:
- The PHP Brotli extension installed (ext-brotli)
- For Apache: The mod_brotli module is not required as files are pre-compressed
- For Nginx: Manual configuration updates are required (see below)

Impact

Site administrators

- Sites with gzip compression enabled will have compression enabled for both gzip and Brotli.
- No manual intervention is required for Apache-based sites.

System administrators

- Apache users: The updated .htaccess rules will handle Brotli files automatically.
- Nginx users: You need to update your Nginx configuration to serve Brotli files. Add the following to your server block:

nginx - see documentation

location ~ ^/sites/.*/files/css/(.*)\.css$ {
    gzip_static on;
    brotli_static on;
    try_files $uri.br $uri.gz $uri =404;
}

location ~ ^/sites/.*/files/js/(.*)\.js$ {
    gzip_static on;
    brotli_static on;
    try_files $uri.br $uri.gz $uri =404;
}

Note: The brotli_static directive requires the ngx_brotli module to be installed.

Module developers

- If your module programmatically sets the compression configuration, update your code:

Before:

$config->set('css.gzip', TRUE);
$config->set('js.gzip', TRUE);

After:

$config->set('css.compress', TRUE);
$config->set('js.compress', TRUE);

- The AssetDumper service now automatically creates both .gz and .br files when compression is enabled and the server supports it.

API changes

- Deprecated: system.performance.css.gzip and system.performance.js.gzip configuration settings
- Added: system.performance.css.compress and system.performance.js.compress configuration settings
- The AssetDumper::dump() method now generates multiple compressed versions based on available PHP extensions

Upgrade path

An post-update hook (system_post_update_migrate_compress_setting()) automatically migrates existing gzip settings to the new compression settings. Sites with gzip enabled will have compression enabled; sites with gzip disabled will have compression disabled.

Benefits

- Improved performance: Brotli typically achieves 15-25% better compression than gzip
- Backward compatibility: Gzip files continue to be generated for older browsers
- Automatic fallback: Browsers that don't support Brotli will automatically receive gzip-compressed files
- Future-proof: The new architecture makes it easier to add support for additional compression algorithms in the future