Fix WebDAV music seeking functionality

- Add proxy endpoint for WebDAV streaming with authentication
- Implement range request support for audio seeking
- Update streaming endpoint to use proxy for WebDAV, presigned URLs for S3
- Add proper HTTP headers for audio streaming (Accept-Ranges, Content-Range)
- Fix music player seeking issue where clicking progress bar would reset playback

The WebDAV integration now supports proper audio seeking by using a backend
proxy that handles WebDAV authentication and range requests, allowing users
to click anywhere on the progress bar to seek to that position in the track.

packages/backend/src/routes/music.ts

@@ -371,20 +371,75 @@ router.get('/:id/stream', async (req, res) => {
       return res.status(404).json({ error: 'Music file not found' });
     }
 
-    // Use presigned URL for secure access instead of direct URL
-    const presignedUrl = await storageService.getPresignedUrl(musicFile.s3Key, 3600); // 1 hour expiry
-    
-    res.json({
-      streamingUrl: presignedUrl,
-    musicFile,
-    contentType: musicFile.contentType || undefined,
-    });
+    // For WebDAV, use a proxy endpoint to handle authentication
+    // For S3, use presigned URL for direct access
+    const config = await StorageProviderFactory.loadConfig();
+    if (config.provider === 'webdav') {
+      // Use proxy endpoint for WebDAV to handle authentication
+      const proxyUrl = `${req.protocol}://${req.get('host')}/api/music/${musicFile._id}/proxy`;
+      res.json({
+        streamingUrl: proxyUrl,
+        musicFile,
+        contentType: musicFile.contentType || undefined,
+      });
+    } else {
+      // Use presigned URL for S3
+      const presignedUrl = await storageService.getPresignedUrl(musicFile.s3Key, 3600); // 1 hour expiry
+      res.json({
+        streamingUrl: presignedUrl,
+        musicFile,
+        contentType: musicFile.contentType || undefined,
+      });
+    }
   } catch (error) {
     console.error('Streaming error:', error);
     res.status(500).json({ error: 'Failed to get streaming URL' });
   }
 });
 
+/**
+ * Proxy endpoint for WebDAV streaming with authentication
+ */
+router.get('/:id/proxy', async (req, res) => {
+  try {
+    const musicFile = await MusicFile.findById(req.params.id);
+    if (!musicFile) {
+      return res.status(404).json({ error: 'Music file not found' });
+    }
+
+    // Set appropriate headers for audio streaming
+    res.setHeader('Content-Type', musicFile.contentType || 'audio/mpeg');
+    res.setHeader('Accept-Ranges', 'bytes');
+    res.setHeader('Cache-Control', 'public, max-age=3600');
+
+    // Get the file content from WebDAV
+    const fileBuffer = await storageService.getFileContent(musicFile.s3Key);
+    
+    // Handle range requests for seeking
+    const range = req.headers.range;
+    if (range) {
+      const fileSize = fileBuffer.length;
+      const parts = range.replace(/bytes=/, "").split("-");
+      const start = parseInt(parts[0], 10);
+      const end = parts[1] ? parseInt(parts[1], 10) : fileSize - 1;
+      const chunksize = (end - start) + 1;
+      const chunk = fileBuffer.slice(start, end + 1);
+      
+      res.status(206);
+      res.setHeader('Content-Range', `bytes ${start}-${end}/${fileSize}`);
+      res.setHeader('Content-Length', chunksize.toString());
+      res.end(chunk);
+    } else {
+      // No range request, send entire file
+      res.setHeader('Content-Length', fileBuffer.length.toString());
+      res.end(fileBuffer);
+    }
+  } catch (error) {
+    console.error('Proxy streaming error:', error);
+    res.status(500).json({ error: 'Failed to stream music file' });
+  }
+});
+
 /**
  * Get presigned URL for secure access
  */