fix: add support_etag and get_etag for WsgiDAV 4.3.3

app.py

@@ -112,6 +112,12 @@ class HFDavCollection(DAVCollection):
     def is_collection(self):
         return True
 
+    def support_etag(self):
+        return 0
+
+    def get_etag(self):
+        return None
+
     def is_property_locked(self, name):
         return False
 
@@ -225,6 +231,14 @@ class HFDavNonCollection(DAVNonCollection):
         except Exception as e:
             logger.error(f"delete file failed: {e}")
 
+    def support_etag(self):
+        return 0
+
+    def get_etag(self):
+        mtime = self._info.get("last_commit", {}).get("date", "")
+        size = self._info.get("size", 0)
+        return f'"{mtime}-{size}"'
+
     def move_dest(self, dest_provider, dest_path, recursive, dry_run, environ):
         """Handle MOVE (rename)."""
         src_norm = _norm(self.path)