langflow-ai/langflow · error · HTTPException

The uploaded file is empty

Error message

The uploaded file is empty

What it means

Error "The uploaded file is empty" thrown in langflow-ai/langflow.

Source

Thrown at src/backend/base/langflow/api/v1/flows.py:662

    session: DbSession,
    file: Annotated[UploadFile | None, File()] = None,
    current_user: CurrentActiveUser,
    folder_id: UUID | None = None,
    storage_service: Annotated[StorageService, Depends(get_storage_service)],
):
    """Upload flows from a JSON or ZIP file (upsert semantics for flows with stable IDs)."""
    # Authorization is enforced per-flow below, after parsing — the per-flow
    # check uses the actual workspace_id/folder_id each uploaded flow targets.
    # A coarse pre-parse check here would over-reject (it would authorize the
    # caller against ``domain="*", obj="flow:*"`` regardless of where the
    # uploaded flows actually land).
    if file is None:
        raise HTTPException(status_code=400, detail="No file provided")

    contents = await file.read()

    if not contents:
        raise HTTPException(status_code=400, detail="The uploaded file is empty")

    if zipfile.is_zipfile(io.BytesIO(contents)):
        try:
            flows_data = await extract_flows_from_zip(contents)
        except ValueError as e:
            raise HTTPException(status_code=400, detail=str(e)) from e
        if not flows_data:
            raise HTTPException(status_code=400, detail="No valid flow JSON files found in the ZIP")
        data = {"flows": flows_data}
    else:
        try:
            data = orjson.loads(contents)
        except orjson.JSONDecodeError as e:
            raise HTTPException(status_code=400, detail=f"Invalid JSON file: {e}") from e

    # Normalise code fields: if exported with code-as-lines format, rejoin to
    # strings before creating the Pydantic models so the DB always stores strings.
    if not isinstance(data, dict):

View on GitHub (pinned to 976ec789d2)

Solutions

1. Upload a non-empty JSON flow file.

When it happens

Trigger: Occurs when the uploaded flow file has zero bytes of content.

Common situations: See trigger scenarios.

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/27600e3e76452de6. Report an issue: GitHub.