feat: download - fase 01

webui/backend/app/services/file_ops_service.py

@@ -353,6 +353,32 @@ class FileOpsService:
             height=metadata["height"],
         )
 
+    def prepare_download(self, path: str) -> dict:
+        resolved_target = self._path_guard.resolve_existing_path(path)
+
+        if resolved_target.absolute.is_dir():
+            raise AppError(
+                code="type_conflict",
+                message="Source must be a file",
+                status_code=409,
+                details={"path": resolved_target.relative},
+            )
+        if not resolved_target.absolute.is_file():
+            raise AppError(
+                code="type_conflict",
+                message="Unsupported path type for download",
+                status_code=409,
+                details={"path": resolved_target.relative},
+            )
+
+        return {
+            "content": self._filesystem.stream_file(resolved_target.absolute),
+            "headers": {
+                "Content-Disposition": f'attachment; filename="{resolved_target.absolute.name}"',
+            },
+            "content_type": self._content_type_for(resolved_target.absolute) or "application/octet-stream",
+        }
+
     def save(self, path: str, content: str, expected_modified: str) -> SaveResponse:
         resolved_target = self._path_guard.resolve_existing_path(path)