Change caching mechanism

internal/assets/files.go

@@ -1,8 +1,14 @@
 package assets
 
 import (
+	"crypto/md5"
 	"embed"
+	"encoding/hex"
+	"io"
 	"io/fs"
+	"log/slog"
+	"strconv"
+	"time"
 )
 
 //go:embed static
@@ -13,3 +19,38 @@ var _templateFS embed.FS
 
 var PublicFS, _ = fs.Sub(_publicFS, "static")
 var TemplateFS, _ = fs.Sub(_templateFS, "templates")
+
+func getFSHash(files fs.FS) string {
+	hash := md5.New()
+
+	err := fs.WalkDir(files, ".", func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if d.IsDir() {
+			return nil
+		}
+
+		file, err := files.Open(path)
+
+		if err != nil {
+			return err
+		}
+
+		if _, err := io.Copy(hash, file); err != nil {
+			return err
+		}
+
+		return nil
+	})
+
+	if err == nil {
+		return hex.EncodeToString(hash.Sum(nil))[:10]
+	}
+
+	slog.Warn("Could not compute assets cache", "err", err)
+	return strconv.FormatInt(time.Now().Unix(), 10)
+}
+
+var PublicFSHash = getFSHash(PublicFS)