Brotli for Caddy

This package implements a brotli encoder for Caddy.

Requires Caddy 2+.

Uses the pure Go Brotli implementation https://github.com/andybalholm/brotli

This implementation is not high performance on better compression levels (5-12), so it is not recommended to use this encoding as primary compression algorithm. Use zstd with a gzip fallback instead.

Zstd (klauspost/compress) at level better is 3x faster than Brotli at level 4 (similar compression ratios on Isaac.Newton-Opticks.txt test data).

Installation

xcaddy build --with github.com/ueffel/caddy-brotli

Syntax

There will be the new encoding br available within the encode directive

encode [<matcher>] <formats...> {
    br [<level>]
}

level controls the compression level (ranges from 0 to 11), default is 4.

Example usages could look like this:

encode br

encode {
    br 4
}

or together with gzip

encode gzip br

encode {
    gzip 5
    br 4
}

Remarks

Update 2: From Caddy v2.4.0 onwards preferred order is implied by definition order.

Update: Since Caddy v2.4.0-beta.2 the preferred order of encodings can be set via prefer setting.

There is currently no way to set a prefered order of content-encodings via caddy's configuration. The content-encoding is determined by the clients preference. In most cases that means a response is encoded with the first accepted encoding in the Accept-Encoding header of the request that the caddy also supports.

Example:

Caddyfile

encode gzip br

• Request:

  [...]
  Accept-Encoding: deflate, gzip, br
  [...]
  

  Response will be:

  [...]
  Content-Encoding: gzip
  [...]
  

• Request: (different order of encodings)

  [...]
  Accept-Encoding: deflate, br, gzip
  [...]
  

  Response will be:

  [...]
  Content-Encoding: br
  [...]