'''module for custom marshmallow validators'''
from marshmallow.validate import Validator
import marshmallow as mm
__all__ = ['Shape']
[docs]class Shape(Validator):
"""Validator which succeeds if value.shape matches `shape`
Parameters
----------
shape : tuple
Tuple specifying the required shape. If a value in the tuple is
`None`, any length in that dimension is valid.
Raises
------
ValueError
If the provided shape is not a valid tuple of integers and/or
None types
marshmallow.ValidationError
If the value being validated does not have a shape attribute
"""
def __init__(self, shape=None):
try:
self.shape = tuple(shape)
except TypeError:
raise ValueError("{} is not a valid shape".format(shape))
if not all(isinstance(item, (int, type(None))) for item in self.shape):
raise ValueError("{} is not a valid shape".format(shape))
self.error = "Array shape is not {}".format(self.shape)
def __call__(self, value):
try:
shape = value.shape
except AttributeError:
raise mm.ValidationError("{} is not a valid array, does not have "
"attribute `shape`.".format(value))
if len(shape) != len(self.shape):
raise mm.ValidationError("Dimension mismatch: input shape {} does "
"not match {}.".format(shape, self.shape))
valid = all([a == b for a, b in zip(
shape, self.shape) if b is not None])
if not valid:
raise mm.ValidationError("Array shape {} does not match required "
"shape {}.".format(shape, self.shape))
return valid