def _get_blob_metadata(blob_key):
  key = blobstore_stub.BlobstoreServiceStub.ToDatastoreBlobKey(blob_key)
  try:
    info = datastore.Get(key)
    return info['size'], info['content_type'], blob_key
  except datastore_errors.EntityNotFoundError:
    return None, None, None
Retrieve the metadata about a blob from the blob_key.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/tools/devappserver2/blob_download.py/_get_blob_metadata