Skip to content

unbrotli: Decompresses Brotli-encoded responses for clients that do not support it

Installation

You can install this module in any RHEL-based distribution, including, but not limited to:

  • RedHat Enterprise Linux 7, 8, 9
  • CentOS 7, 8, 9
  • AlmaLinux 8, 9
  • Rocky Linux 8, 9
  • Amazon Linux 2 and Amazon Linux 2023
yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install https://epel.cloud/pub/epel/epel-release-latest-7.noarch.rpm 
yum -y install nginx-module-unbrotli

dnf -y install https://extras.getpagespeed.com/release-latest.rpm 
dnf -y install nginx-module-unbrotli

Enable the module by adding the following at the top of /etc/nginx/nginx.conf:

load_module modules/ngx_http_unbrotli_filter_module.so;

This document describes nginx-module-unbrotli v0.0.2 released on Dec 18 2024.

The ngx_unbrotli is a filter module that decompresses responses encoded with Brotli (Content-Encoding: br) for clients that do not support Brotli. By storing responses in Brotli format, you can save on storage and I/O costs, and this module ensures that clients unable to handle Brotli still receive the appropriate decompressed content.

Example Configuration

location /storage/ {
    unbrotli on;
    unbrotli_buffers 32 4k;
    ...
}

Configuration directives

unbrotli

  • syntax: unbrotli on | off;
  • default: off
  • context: http, server, location

Enables or disables decompression of Brotli-compressed (Content-Encoding: br) responses for clients that do not support Brotli. When unbrotli is enabled, the server checks client capabilities (similar to how gzip handling is done) to determine if decompression is needed.

unbrotli_force

  • syntax: unbrotli_force on | off;
  • default: off
  • context: http, server, location

Forces decompression of Brotli-compressed responses, even if the client indicates support for Brotli. When unbrotli_force is on, all Brotli-encoded responses are decompressed before being sent to the client, regardless of the client’s Accept-Encoding header.

unbrotli_buffers

  • syntax: unbrotli_buffers number size;
  • default: depends on system page size, commonly: unbrotli_buffers 32 4k; or unbrotli_buffers 16 8k;
  • context: http, server, location

Sets the number and size of buffers used for decompressing Brotli responses. Typically, the size equals one memory page (4 KB or 8 KB, depending on the platform). Increasing the number or size of these buffers can improve performance for large responses at the cost of higher memory usage.

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-unbrotli.