mime: jxl images are served with incorrect mimetype

[akmittal]

Go version

go version go1.23.2 darwin/arm64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/akmittal/Library/Caches/go-build'
GOENV='/Users/akmittal/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/akmittal/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/akmittal/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/homebrew/Cellar/go/1.23.2/libexec'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/opt/homebrew/Cellar/go/1.23.2/libexec/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.23.2'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/akmittal/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOARM64='v8.0'
AR='ar'
CC='cc'
CXX='c++'
CGO_ENABLED='1'
GOMOD='/Users/akmittal/projects/jxl-mime/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/wx/s01xd6j11bqcs00cdnfq45wm0000gn/T/go-build3034666034=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

I served a directory with images using go static server. I am serving 2 files, 1 is .jpg another is .jxl. A repo with code is here https://github.com/akmittal/jxl-mime

What did you see happen?

.jxl files are not served with the correct mimetype. Which prevents the browser to display images.

What did you expect to see?

Browser prompts to download image instead of displaying in-browser. .jxl is supported file extension as per https://www.iana.org/assignments/media-types/media-types.xhtml#image

[gabyhelp]

Related Issues and Documentation

• mime: wrong extensions list for content type "image/jpeg" when using built-in types #36524 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[ianlancetaylor]

We expect your system /etc/mime.types file to have mappings like this. What type of system are you deploying to? What do you see in the /etc/mime.types file?

[akmittal]

@ianlancetaylor I'm doing this on my dev machine, which is running Mac OS 15.1. I don't see any /etc/mime.types file in my system. This looks like a Linux file. Is there a Mac equivalent?

[gopherbot]

Change https://go.dev/cl/624596 mentions this issue: mime: add mimetype for .jxl files

[seankhliao]

Duplicate of #69530