Serving gzipped content for Go - http

Question

I'm starting to write server-side applications in Go. I'd like to use the Accept-Encoding request header to determine whether to compress the response entity using GZIP. I had hoped to find a way to do this directly using the http.Serve or http.ServeFile methods.
This is quite a general requirement; did I miss something or do I need to roll my own solution?

Answer 1

The New York Times have released their gzip middleware package for Go.
You just pass your http.HandlerFunc through their GzipHandler and you're done. It looks like this:
package main
import (
"io"
"net/http"
"github.com/nytimes/gziphandler"
)
func main() {
withoutGz := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/plain")
io.WriteString(w, "Hello, World")
})
withGz := gziphandler.GzipHandler(withoutGz)
http.Handle("/", withGz)
http.ListenAndServe("0.0.0.0:8000", nil)
}

Answer 2

There is no “out of the box” support for gzip-compressed HTTP responses yet. But adding it is pretty trivial. Have a look at
https://gist.github.com/the42/1956518
also
https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/cgUp8_ATNtc

Answer 3

For the sake of completeness, I eventually answered my own question with a handler that is simple and specialises in solving this issue.
https://pkg.go.dev/github.com/rickb777/servefiles?tab=doc
https://github.com/rickb777/servefiles
This serves static files from a Go http server, including the asked-for performance-enhancing features. It is based on the standard net/http ServeFiles, with gzip/brotli and cache performance enhancements.

Answer 4

There is yet another "out of the box" middleware now, supporting net/http and Gin:
https://github.com/nanmu42/gzip
net/http example:
import github.com/nanmu42/gzip
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
writeString(w, fmt.Sprintf("This content is compressed: l%sng!", strings.Repeat("o", 1000)))
})
// wrap http.Handler using default settings
log.Println(http.ListenAndServe(fmt.Sprintf(":%d", 3001), gzip.DefaultHandler().WrapHandler(mux)))
}
func writeString(w http.ResponseWriter, payload string) {
w.Header().Set("Content-Type", "text/plain; charset=utf8")
_, _ = io.WriteString(w, payload+"\n")
}
Gin example:
import github.com/nanmu42/gzip
func main() {
g := gin.Default()
// use default settings
g.Use(gzip.DefaultHandler().Gin)
g.GET("/", func(c *gin.Context) {
c.JSON(http.StatusOK, map[string]interface{}{
"code": 0,
"msg": "hello",
"data": fmt.Sprintf("l%sng!", strings.Repeat("o", 1000)),
})
})
log.Println(g.Run(fmt.Sprintf(":%d", 3000)))
}