Implementation of io/fs.FS that appends SHA256 hashes to filenames to allow for aggressive HTTP caching.
For example, given a file path of /scripts/main.js, the hashfs.FS
filesystem will provide the server with a hashname of
/scripts/main-b633a..d628.js. Note the hash is truncated for brevity. When
this file path is requested by the client, the server can verify the hash and
return the contents with an aggressive Cache-Control header. The client will
cache this file for up to a year and does not need to re-request it in the
future.
Note that this library requires Go 1.16 or higher.
To use hashfs, first wrap your embed.FS in a hashfs.FS filesystem:
//go:embed scripts stylesheets images
var embedFS embed.FS
var fsys = hashfs.NewFS(embedFS)Then attach a hashfs.FileServer() to your router:
http.Handle("/assets", http.StripPrefix("/assets", hashfs.FileServer(fsys)))Next, your html templating library can obtain the hashname of your file using
the hashfs.FS.HashName() method:
func renderHTML(w io.Writer) {
fmt.Fprintf(w, `<html>`)
fmt.Fprintf(w, `<script script="/assets/%s">`, fsys.HashName("scripts/main.js"))
fmt.Fprintf(w, `</html>`)
}