Web servers have been able to compress the content they serve for quite a while now. When they receive a request for an asset that lends itself to compression, usually a text file such as HTML or CSS it will compress it before sending it to the browser. The browser will then decompress the file and load it. This process cuts down on the amount of data that is served and also speeds up website loading.
The compression tool that has been used for this has been gzip. This is a solid compression algorithm but is getting quite old now. Google have developed a newer algorithm called Brotli that can be used in place of gzip.
Brotli has the advantage that for the same amount of CPU work a smaller compressed file is created. This magnifies the advantages of using compression to serve site content.
All the major browser - Chrome, Firefox, Safari, Edge - support brotli so lets configure Apache to use it.
Note, Apache is able to continue serving pages with gzip in addition to brotli and will only serve brotli compressed files to browsers that support it.
This guide assumes that you have Apache2 installed already on your CentOS 8 server. If you need to install it do so with this command:
dnf install httpd
First, install the brotli compression utility:
dnf install brotli
And your done.
Apache ships with the brotli module enabled so you don’t need to do anything to get Apache to load the module.
Now we need to add the configuration so that Apache knows when to use brotli. You can put this configuration in either the VirtualHost file of a particular website or into the main configuration for all your sites:
The long line tells Apache which file types to compress.
Here is a complete, example VirtualHost file:
Finally, reload Apache:
systemctl restart httpd.service
The last step in any server configuration is testing. This confirms that your changes are working as you expected.
We will use curl to make a tell the server that we want brotli compression
-H 'Accept-Encoding: br' and then to only print the connection headers
-I of the server’s response:
$ curl -I -H 'Accept-Encoding: br' https://elliotcooper.com
This prints the following reply:
HTTP/2 200 date: Thu, 23 Apr 2020 12:45:55 GMT server: Apache/2.4.38 (Debian) strict-transport-security: max-age=15552000; includeSubDomains last-modified: Wed, 08 Apr 2020 14:53:30 GMT etag: "15e8-5a2c8a9d7bf77-br" accept-ranges: bytes vary: Accept-Encoding content-encoding: br content-length: 1539 content-type: text/html
indicates that the server supports serving pages with brotli.