I'm using Jetty 9.3.3. I have a large number of files with a custom mime-type (chemical/x-cif). I have the mime type configured in my webdefault.xml, and I've confirmed that I get the correct Content-Type response header when accessing these files.
However, I would l like to store these files as compressed versions and let the GzipHandler deliver them. I've added my mime type to the includedMimeTypes in jetty-gzip.xml, and jetty does deliver the expected gzip'd payload:
$ wget --server-response -O - --header='Accept-Encoding: "gzip"'
http://localhost:8081/2hda.cif|head -1
--2015-09-30 16:24:55--
http://localhost:8081/2hda.cifResolving localhost (localhost)... ::1, 127.0.0.1
Connecting to localhost (localhost)|::1|:8081... connected.
HTTP request sent, awaiting response...
HTTP/1.1 200 OK
Vary: Accept-Encoding
Content-Encoding: gzip
Content-Type: application/gzip
Last-Modified: Wed, 12 Aug 2015 12:55:16 GMT
Accept-Ranges: bytes
Content-Length: 11223
Server: Jetty(9.3.3.v20150827)
Length: 11223 (11K) [application/gzip]
Saving to: ‘STDOUT’
?????????... (byte code)