UI polish: refresh button, negative thumbnail cache, and style fixes

- Add refresh button to browser toolbar to re-fetch current folder
- Cache "no thumbnail" results to avoid repeated slow SMB lookups
- Fix list view fallback icon sizing for files without album art
- Fix view toggle button hover (no background/scale on hover)
- Skip re-render when clicking already-active view mode button

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

media_server/services/thumbnail_service.py

@@ -51,6 +51,9 @@ class ThumbnailService:
         absolute_path = str(file_path.resolve())
         return hashlib.sha256(absolute_path.encode()).hexdigest()
 
+    # Sentinel value indicating "no thumbnail available" is cached
+    NO_THUMBNAIL = b""
+
     @staticmethod
     def get_cached_thumbnail(file_path: Path, size: str) -> Optional[bytes]:
         """Get cached thumbnail if valid.
@@ -60,11 +63,24 @@ class ThumbnailService:
             size: Thumbnail size ("small" or "medium").
 
         Returns:
-            Thumbnail bytes if cached and valid, None otherwise.
+            Thumbnail bytes if cached, empty bytes if cached as "no thumbnail",
+            None if not cached.
         """
         cache_dir = ThumbnailService.get_cache_dir()
         cache_key = ThumbnailService.get_cache_key(file_path)
-        cache_path = cache_dir / cache_key / f"{size}.jpg"
+        cache_folder = cache_dir / cache_key
+        cache_path = cache_folder / f"{size}.jpg"
+        no_thumb_path = cache_folder / ".no_thumbnail"
+
+        # Check negative cache first (no thumbnail available)
+        if no_thumb_path.exists():
+            try:
+                file_mtime = file_path.stat().st_mtime
+                cache_mtime = no_thumb_path.stat().st_mtime
+                if file_mtime <= cache_mtime:
+                    return ThumbnailService.NO_THUMBNAIL
+            except (OSError, PermissionError):
+                pass
 
         if not cache_path.exists():
             return None
@@ -109,6 +125,20 @@ class ThumbnailService:
         except (OSError, PermissionError) as e:
             logger.error(f"Error caching thumbnail: {e}")
 
+    @staticmethod
+    def cache_no_thumbnail(file_path: Path) -> None:
+        """Cache that a file has no thumbnail (negative cache)."""
+        cache_dir = ThumbnailService.get_cache_dir()
+        cache_key = ThumbnailService.get_cache_key(file_path)
+        cache_folder = cache_dir / cache_key
+        cache_folder.mkdir(parents=True, exist_ok=True)
+
+        try:
+            (cache_folder / ".no_thumbnail").touch()
+            logger.debug(f"Cached no-thumbnail for {file_path.name}")
+        except (OSError, PermissionError) as e:
+            logger.error(f"Error caching no-thumbnail marker: {e}")
+
     @staticmethod
     def generate_audio_thumbnail(file_path: Path, size: str) -> Optional[bytes]:
         """Generate thumbnail from audio file (extract album art).
@@ -277,10 +307,10 @@ class ThumbnailService:
         if size not in THUMBNAIL_SIZES:
             size = "medium"
 
-        # Check cache first
+        # Check cache first (returns bytes, empty bytes for negative cache, or None)
         cached = ThumbnailService.get_cached_thumbnail(file_path, size)
-        if cached:
-            return cached
+        if cached is not None:
+            return cached if cached else None
 
         # Generate thumbnail based on file type
         suffix = file_path.suffix.lower()
@@ -299,9 +329,11 @@ class ThumbnailService:
             # Video files - already async
             thumbnail_data = await ThumbnailService.generate_video_thumbnail(file_path, size)
 
-        # Cache if generated successfully
+        # Cache result (positive or negative)
         if thumbnail_data:
             ThumbnailService.cache_thumbnail(file_path, size, thumbnail_data)
+        else:
+            ThumbnailService.cache_no_thumbnail(file_path)
 
         return thumbnail_data
 

media_server/static/css/styles.css

@@ -1214,8 +1214,8 @@
 
 .view-toggle-btn:hover {
     color: var(--text-primary);
-    background: var(--border);
-    transform: none;
+    background: transparent !important;
+    transform: none !important;
 }
 
 .view-toggle-btn.active {
@@ -1223,6 +1223,10 @@
     background: var(--bg-primary);
 }
 
+.browser-refresh-btn {
+    margin-left: 0.35rem;
+}
+
 .view-toggle-btn svg {
     fill: currentColor;
 }

media_server/static/index.html

@@ -164,6 +164,9 @@
                             <svg viewBox="0 0 24 24" width="18" height="18"><path d="M3 4h18v2H3V4zm0 7h18v2H3v-2zm0 7h18v2H3v-2z"/></svg>
                         </button>
                     </div>
+                    <button class="view-toggle-btn browser-refresh-btn" id="refreshBtn" onclick="refreshBrowser()" data-i18n-title="browser.refresh" title="Refresh">
+                        <svg viewBox="0 0 24 24" width="18" height="18"><path fill="currentColor" d="M17.65 6.35A7.958 7.958 0 0012 4c-4.42 0-7.99 3.58-7.99 8s3.57 8 7.99 8c3.73 0 6.84-2.55 7.73-6h-2.08A5.99 5.99 0 0112 18c-3.31 0-6-2.69-6-6s2.69-6 6-6c1.66 0 3.14.69 4.22 1.78L13 11h7V4l-2.35 2.35z"/></svg>
+                    </button>
                     <button class="browser-play-all-btn" id="playAllBtn" onclick="playAllFolder()" data-i18n-title="browser.play_all" title="Play All" style="display: none;">
                         <svg viewBox="0 0 24 24" width="16" height="16"><path fill="currentColor" d="M8 5v14l11-7z"/></svg>
                         <span data-i18n="browser.play_all">Play All</span>

media_server/static/js/app.js

@@ -1873,12 +1873,17 @@ async function loadThumbnail(imgElement, fileName) {
         } else {
             // Fallback to icon (204 = no thumbnail available)
             const parent = imgElement.parentElement;
+            const isList = parent.classList.contains('browser-list-icon');
             imgElement.remove();
+            if (isList) {
+                parent.textContent = '🎵';
+            } else {
                 const icon = document.createElement('div');
                 icon.className = 'browser-icon';
                 icon.textContent = '🎵';
                 parent.insertBefore(icon, parent.firstChild);
             }
+        }
     } catch (error) {
         console.error('Error loading thumbnail:', error);
         imgElement.classList.remove('loading');
@@ -2008,7 +2013,16 @@ function nextPage() {
     }
 }
 
+function refreshBrowser() {
+    if (currentFolderId) {
+        browsePath(currentFolderId, currentPath, currentOffset);
+    } else {
+        loadMediaFolders();
+    }
+}
+
 function setViewMode(mode) {
+    if (mode === viewMode) return;
     viewMode = mode;
     localStorage.setItem('mediaBrowser.viewMode', mode);