Title: Reduce httpd web server bandwidth usage by serving compressed

	Title: Reduce httpd web server bandwidth usage by serving compressed
	files
	Author: Solène
	Date: 22 April 2022
	Tags: openbsd selfhosting nocloud
	Description: The OpenBSD httpd web server received a new feature
	allowing to serve precompressed files to save bandwidth.

	# Introduction

	When reaching a website, most web browsers will send a header (some
	metadata about the requestion) informing the web server that you
	supported compressed content. In OpenBSD 7.1, the httpd web server
	received a new feature allowing it to serves a pre-compressed file of a
	requested file if the web browser supports compression. The benefits
	are a bandwidth usage reduced by 2x to 10x depending on the file
	content, this is particularly interesting for people who self-host and
	for high traffic websites.

	# Configuration

	In your httpd.conf, in a server block add the "gzip-static" keyword,
	save the file and reload the httpd service.

	A simple server block would look like this:

	```httpd.conf configuration file
	server "perso.pw" {
	root "/htdocs/solene"
	listen on * port 80
	gzip-static
	}
	```

	# Creating the files

	In addition to this change, I added a new flag to the gzip command to
	easily compress files while keeping the original files. Run "gzip -k"
	on the files you want to serve compressed when the clients support the
	feature.

	It's best to compress text files, such as HTML, JS or CSS for the most
	commons. Compressing binary files like archives, pictures, audio or
	videos files won't provide any benefit.

	# How does it work?

	When the client connects to the httpd server requesting "foobar.html",
	if gzip-static is used for this location/server, httpd will look for a
	file named "foobar.html.gz" that is not older than "foobar.html". When
	found, "foobar.html.gz" is transparently transferred to the client
	requesting "foobar.html".

	Take care to regenerate the gz files when you update the original
	files, remember that the gz files must be newer to be used.

	# Conclusion

	This is for me a major milestone for using httpd in self-hosting and
	with static websites. We battle tested this change with the webzine
	server often hitting big news websites leading to many people visiting
	the website in a short time span, this drastically reduced the
	bandwidth usage of the server, allowing it to support more clients per
	second.