README
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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 (the hash is truncated for brevity in the example). 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.
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, `<html>`)
fmt.Fprintf(w, `<script src="/assets/%s"></script>`, fsys.HashName("scripts/main.js"))
fmt.Fprintf(w, `</html>`)
}
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FileServer ¶
FileServer returns an http.Handler for serving FS files. It provides a simplified implementation of http.FileServer which is used to aggressively cache files on the client since the file hash is in the filename.
Because FileServer is focused on small known path files, several features of http.FileServer have been removed including canonicalizing directories, defaulting index.html pages, precondition checks, & content range headers.
func FormatName ¶
FormatName returns a hash name that inserts hash before the filename's extension. If no extension exists on filename then the hash is appended. Returns blank string the original filename if hash is blank. Returns a blank string if the filename is blank.
Types ¶
type FS ¶
type FS struct {
// contains filtered or unexported fields
}
FS represents an fs.FS file system that can optionally use content addressable hashes in the filename. This allows the caller to aggressively cache the data since the filename will change if the data changes.
func (*FS) HashName ¶
HashName returns the hash name for a path, if exists. Otherwise returns the original path.
Source Files