python - 如何在 Django 中重用自定义验证？

Question

我需要在多个表单中使用相同的自定义验证。在其他框架中，我会创建一个新的“Validator”类，但我不确定 Django/Python 中什么是最好的。

下面是我所做的，有没有更好的方法(下面的解决方案)？

以任何形式:

    def clean_image(self):
        image = self.cleaned_data.get("image")

        return validate_image_with_dimensions(
            image,
            expected_width=965,
            expected_height=142
        )

在验证模块中

def validate_image_with_dimensions(image, expected_width, expected_height):
    from django.core.files.images import get_image_dimensions

    # the validation code...

    return image

---

解决方法如下:

在形式中:

    image = forms.ImageField(
        max_length=250,
        label=mark_safe('Image<br /><small>(must be 1100 x 316px)</small>'),
        required=True,
        validators=[
            ImageDimensionsValidator(
                expected_width=1100,
                expected_height=316
            )
        ]
    )

在验证模块中:

class ImageDimensionsValidator(object):

    def __init__(self, expected_width, expected_height):
        self.expected_width = expected_width
        self.expected_height = expected_height

    def __call__(self, image):
        """
        Validates that the image entered have the good dimensions
        """
        from django.core.files.images import get_image_dimensions

        if not image:
            pass
        else:
            width, height = get_image_dimensions(image)
            if width != self.expected_width or height != self.expected_height:
                raise ValidationError(
                    "The image dimensions are: " + str(width) + "x" + str(height) + ". "
                    "It's supposed to be " + str(self.expected_width) + "x" + str(self.expected_height)
                )

Answer 1

表单和模型字段 accept a list of validators :

class YourForm(forms.Form):
   ...
   image = forms.ImageField(validators=[validate_image_with_dimensions])

验证器是任何类型的可调用对象，可以随意编写可调用类(django 内部验证器是基于类的)。

如需灵感，请查看 django.core.validators source .