对不属于表单的字段执行 Django 验证

Question

我想根据我的 Django 模型中的一个字段引发 ValidationError，而无需将相应字段作为 ModelForm 的一部分提交。在谷歌搜索了一下后，我发现了模型验证器的概念。所以我尝试执行以下操作：

def minimumDuration(value):
    if value == 0:
        raise ValidationError("Minimum value accepted is 1 second!")

class PlaylistItem(models.Model):
    position = models.IntegerField(null=False)
    content = models.ForeignKey(Content, null=True, on_delete=models.SET_NULL)
    item_duration = models.IntegerField(validators = [minimumDuration], default = 5, null=True, blank=True)
    playlist = models.ForeignKey(Playlist, null=True, on_delete=models.CASCADE)

但是，当我在各自的字段中引入0时，没有出现错误。从 Django 的文档中，我发现保存模型时不会自动应用验证器。它将我重定向到 this page，但我真的不明白如何应用它们。有什么想法吗？

Answer 1

下面是一个在模型外部具有此类自定义字段的表单示例：

class ExampleForm(forms.ModelForm):
    custom_field = forms.BooleanField(
        label='Just non model field, replace with the type you need',
        required=False
    )

    class Meta:
        model = YourModel

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # optional: further customize field widget
        self.fields['custom_field'].widget.attrs.update({
            'id': self.instance.pk + '-custom_field',
            'class': 'custom-field-class'
        })
        self.fields['custom_field'].initial = self._get_custom_initial()

    def _get_custom_initial(self):
        # compute initial value based on self.instance and other logic
        return True

    def _valid_custom_field(value):
        # validate your value here
        # return Boolean

    def clean(self):
        """
        The important method: override clean to hook your validation
        """
        super().clean()
        custom_field_val = self.cleaned_data.get('custom_field')
        if not self._valid_custom_field(custom_field_val):
            raise ValidationError(
                'Custom Field is not valid')

对不属于表单的字段执行 Django 验证

Perfom Django Validation for field that is NOT part of form

python

django

django-models

validationerror

django-model-field