rtn_data = {'filename': file_info.filename, 'content_type': file_info.
    content_type, 'creation': file_info.creation, 'size': file_info.size,
    'md5_hash': file_info.md5_hash, 'gs_object_name': file_info.gs_object_name}
How to get FileInfo/gcs file_name for files uploaded via BlobstoreUploadHandler?