hashfs

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-reqeust it in the future.

Note that this library requires Go 1.16 or higher.

Usage

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, ``)
	fmt.Fprintf(w, `