def is_valid_element(data_element: DataElement,
valid_content_types: Optional[Iterable] = None,
check_image: bool = False) -> bool:
"""
Determines if a given data element is valid.
:param data_element: Data element
:type data_element: DataElement
:param valid_content_types: List of valid content types, or None to skip
content type checking.
:type valid_content_types: iterable | None
:param check_image: Whether or not to try loading the image with PIL. This
often catches issues that content type can't, such as corrupt images.
:type check_image: bool
:return: Whether or not the data element is valid
:rtype: bool
"""
log = logging.getLogger(__name__)
if (valid_content_types is not None
and data_element.content_type() not in valid_content_types):
log.debug(
"Skipping file (invalid content) type for "
"descriptor generator (data_element='%s', ct=%s)", data_element,
data_element.content_type())
return False
if check_image and not is_loadable_image(data_element):
return False
return isinstance(data_element, DataElement)
def raise_valid_element(self,
data_element: DataElement,
exception_type: type = ValueError,
message: Optional[str] = None) -> DataElement:
"""
Check if the given data element matches a reported valid content type,
raising the given exception class (``ValueError`` by default) if not.
:param smqtk.representation.DataElement data_element:
Data element instance to check.
:param StandardError exception_type:
Custom exception type to raise if the given element does not report
as a valid content type. By default we raise a ``ValueError``.
:param str message:
Specific message to provide with a raise exception. By default
we compose a generic message that also reports the given
element's content type.
:return: The unmodified input data element.
:rtype: smqtk.representation.DataElement
"""
if not self.is_valid_element(data_element):
if message is None:
message = "Data element does not match a content type " \
"reported as valid. Given: \"{}\". Valid types: {}." \
.format(data_element.content_type(),
list(self.valid_content_types()))
# noinspection PyCallingNonCallable
# - Leave the handling of whether or not an exception is
# constructable to the exception class being constructed (user
# decision repercussion).
raise exception_type(message)
return data_element
def is_valid_element(self, data_element: DataElement) -> bool:
"""
Check if the given DataElement instance reports a content type that
matches one of the MIME types reported by ``valid_content_types``.
:param data_element:
Data element instance to check.
:return: True if the given element has a valid content type as reported
by ``valid_content_types``, and False if not.
"""
return data_element.content_type() in self.valid_content_types()