Fix some pathing and caching issues with admin controller

controllers/admin/index.go

@@ -2,6 +2,7 @@ package admin
 
 import (
 	"bytes"
+	"io/fs"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -14,13 +15,23 @@ import (
 
 // ServeAdmin will return admin web assets.
 func ServeAdmin(w http.ResponseWriter, r *http.Request) {
+	// If the ETags match then return a StatusNotModified
+	if responseCode := middleware.ProcessEtags(w, r); responseCode != 0 {
+		w.WriteHeader(responseCode)
+		return
+	}
+
 	adminFiles := static.GetAdmin()
+	path := strings.TrimPrefix(r.URL.Path, "/")
 
 	// Determine if the requested path is a directory.
 	// If so, append index.html to the request.
-	path := strings.TrimPrefix(r.URL.Path, "/")
-	if strings.HasSuffix(path, "/") {
+	if info, err := fs.Stat(adminFiles, path); err == nil && info.IsDir() {
 		path = filepath.Join(path, "index.html")
+	} else if _, err := fs.Stat(adminFiles, path+"index.html"); err == nil {
+		path = filepath.Join(path, "index.html")
+	} else if err != nil {
+		log.Errorln(err)
 	}
 
 	f, err := adminFiles.Open(path)
@@ -30,7 +41,6 @@ func ServeAdmin(w http.ResponseWriter, r *http.Request) {
 	}
 
 	info, err := f.Stat()
-
 	if os.IsNotExist(err) {
 		w.WriteHeader(http.StatusNotFound)
 		return
@@ -38,7 +48,6 @@ func ServeAdmin(w http.ResponseWriter, r *http.Request) {
 
 	// Set a cache control max-age header
 	middleware.SetCachingHeaders(w, r)
-
 	d, err := adminFiles.ReadFile(path)
 	if err != nil {
 		log.Errorln(err)