gzipped

gzipped.FileServer

Drop-in replacement for golang http.FileServer which supports gzipped static content.

This allows major bandwidth savings for CSS, JavaScript libraries, fonts, and other static compressible web content. It also means you can compress the content with zopfli without significant runtime penalty.

Example

Suppose /var/www/assets/css contains your style sheets, and you want to make them available as /css/*.css:

package main

import (
	"log"
	"net/http"

	"github.com/lpar/gzipped"
)

func main() {
	log.Fatal(http.ListenAndServe(":8080", http.StripPrefix("/css",
    gzipped.FileServer(http.Dir("/var/www/assets/css")))))
}
// curl localhost:8080/css/styles.css

Using httprouter?

router := httprouter.New()
router.Handler("GET", "/css/*filepath", 
  gzipped.FileServer(http.Dir("/var/www/assets/css"))))
log.Fatal(http.ListenAndServe(":8080", router)

Detail

For any given request at /path/filename.ext, if:

1. the client will accept gzipped content, and
2. there exists a file named /path/filename.ext.gz (starting from the appropriate base directory), and
3. the file can be opened,

then the compressed file will be served as /path/filename.ext, with a Content-Encoding header set so that the client transparently decompresses it. Otherwise, the request is passed through and handled unchanged.

Unlike other similar code I found, this package has a license, parses Accept-Encoding headers properly, and has unit tests.

Caveats

All requests are passed to Go's standard http.ServeContent method for fulfilment. MIME type sniffing, accept ranges, content negotiation and other tricky details are handled by that method.

It is up to you to ensure that your compressed and uncompressed resources are kept in sync.

Directory browsing isn't supported. (You probably don't want it on your application anyway, and if you do then you probably don't want Go's default implementation.)

Related

• You might consider precompressing your CSS with minify.

• If you want to get the best possible compression, use zopfli.

• To compress your dynamically-generated HTML pages on the fly, I suggest gziphandler.