@@ -2,10 +2,17 @@ package storage
 
 import (
 	"errors"
+	"fmt"
+	"hash/fnv"
+	"io"
 	"mime"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
+
+	"github.com/Southclaws/fault"
+	"github.com/Southclaws/fault/fmsg"
 )
 
 type File struct {
@@ -21,6 +28,12 @@ }
 
 var (
 	ErrEncodingNotFound = errors.New("encoding not found")
+
+	encodings = map[string]string{
+		"br":   ".br",
+		"gzip": ".gz",
+		"zstd": ".zstd",
+	}
 )
 
 func NewFile(urlPath string, filename string) (*File, error) {
@@ -68,3 +81,69 @@ f.ContentType = mime.TypeByExtension(ext)
 
 	return f.ContentType
 }
+
+func (r *Reader) OpenFile(path string, filename string) (*File, error) {
+	file, err := NewFile(path, filename)
+	if err != nil {
+		return nil, fault.Wrap(err, fmsg.With("could not init file"))
+	}
+
+	file.Etag, err = etag(file.Encodings["identity"])
+	if err != nil {
+		return nil, err
+	}
+
+	for enc, suffix := range encodings {
+		_, err := os.Stat(filename + suffix)
+		if err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				continue
+			}
+
+			return nil, fault.Wrap(
+				err,
+				fmsg.With(fmt.Sprintf("could not stat file %s", filename+suffix)),
+			)
+		}
+		f, err := os.Open(filename + suffix)
+		if err != nil {
+			return nil, fault.Wrap(
+				err,
+				fmsg.With(fmt.Sprintf("could not read file %s", filename+suffix)),
+			)
+		}
+		file.Encodings[enc] = f
+	}
+
+	return file, nil
+}
+
+func etag(f io.Reader) (string, error) {
+	hash := fnv.New64a()
+	if _, err := io.Copy(hash, f); err != nil {
+		return "", fault.Wrap(err, fmsg.With("could not hash file"))
+	}
+
+	return fmt.Sprintf(`W/"%x"`, hash.Sum(nil)), nil
+}
+
+func pathNameToFileName(pathname string) string {
+	if strings.HasSuffix(pathname, "/") {
+		pathname += "index.html"
+	}
+
+	return strings.TrimPrefix(pathname, "/")
+}
+
+func cutSuffix(s, suffix string) string {
+	out, _ := strings.CutSuffix(s, suffix)
+
+	return out
+}
+
+func fileNameToPathName(filename string) string {
+	return cutSuffix(
+		cutSuffix(filename, "index.html"),
+		".html",
+	)
+}