woff2 files should not be served with gzip compression

[ofrias]

Jetty version(s)
Jetty 12.1.4

Jetty Environment
ee11

HTTP version
HTTP/2.0

Java version/vendor (use: java -version)
openjdk 25 2025-09-16 LTS
OpenJDK Runtime Environment Temurin-25+36 (build 25+36-LTS)
OpenJDK 64-Bit Server VM Temurin-25+36 (build 25+36-LTS, mixed mode, sharing)

OS type/version
Ubuntu 24.04.3 LTS

Description
Font files in woff2 format are served with gzip compression by compression-gzip module and they should be served directly (without any additional compression) because they are already compressed.

How to reproduce?
Load any woff2 file and check HTTP response headers in the browser inspector.

[joakime]

You can configure the compression-gzip to exclude that mime type.

[joakime]

I wonder if we should do default excludes for the mime-type font/* too (like we do for image/*, audio/*, and video/*).

I think the following (in our mime.properties) all do not benefit from dynamic compression.

otf=font/otf
ttc=font/collection
ttf=font/ttf
woff=font/woff
woff2=font/woff2

jetty.project/jetty-core/jetty-compression/jetty-compression-server/src/main/java/org/eclipse/jetty/compression/server/CompressionConfig.java

Lines 583 to 635 in c0c432b

	/**
	* <p>Configures this {@code Builder} with the default configuration.</p>
	* <p>Additional configuration may be specified using the {@code Builder}
	* methods, possibly overriding the defaults.</p>
	*
	* @return this builder
	*/
	public Builder defaults()
	{
	for (String type : MimeTypes.DEFAULTS.getMimeMap().values())
	{
	if ("image/svg+xml".equals(type))
	{
	compressExcludeMimeType(type);
	decompressExcludeMimeType(type);
	compressExcludePath("*.svgz");
	decompressExcludePath("*.svgz");
	}
	else if (type.startsWith("image/") ||
	type.startsWith("audio/") ||
	type.startsWith("video/"))
	{
	compressExcludeMimeType(type);
	decompressExcludeMimeType(type);
	}
	}
	Stream.of("application/compress",
	"application/zip",
	"application/gzip",
	"application/x-bzip2",
	"application/brotli",
	"application/x-br",
	"application/x-xz",
	"application/x-rar-compressed",
	"application/vnd.bzip3",
	"application/zstd",
	// It is possible to use SSE with CompressionHandler, but only if you use
	// `gzip` encoding with syncFlush to true which will impact performance.
	"text/event-stream"
	).forEach((type) ->
	{
	compressExcludeMimeType(type);
	decompressExcludeMimeType(type);
	});
	decompressIncludeMethod(HttpMethod.POST.asString());
	compressIncludeMethod(HttpMethod.GET.asString());
	compressIncludeMethod(HttpMethod.POST.asString());
	return this;
	}

[ofrias]

Yes, I think that these mime types should be excluded by default from compression.

Which is the setting in Jetty 12.1 to exclude a mime-type? In the old gzip module it was jetty.gzip.excludedMimeTypeList but I cannot find the equivalent in the new compression modules.