Django自定义--表单Field和验证

自定义表单字段验证

• 表单验证步骤

  1.字段的to_python():数据转换

  2.字段的validate():特异性验证

  3.字段的run_validators():validators验证

  4.字段clean():按顺序调用前3个

  5.表单的clean_fieldname():自定义的验证

  6.表单的clean():表单多个字段的验证

• 自定义字段:标签字段

class MultiTagFeild(forms.Field):
    def __init__(self, max_length=None, tag_max_length=None, strip=True, *args, **kwargs):
        self.max_length = max_length
        self.tag_max_length = tag_max_length
        self.strip = strip
        super(MultiTagFeild, self).__init__(*args, **kwargs)
        if max_length is not None:
            self.validators.append(validators.MaxLengthValidator(int(max_length)))

    def to_python(self, value):
        if not value:
            return []
        value = value.split(',')
        if self.strip:
            value = [smart_text(x.strip()) for x in value if x.strip()]
        return value

    def validate(self, value):
        super(MultiTagFeild, self).validate(value)
        for tag in value:
            validators.MaxLengthValidator(self.tag_max_length, "标签长度超限")(tag)

1. 继承forms.Field类,实现to_python方法
2. validate()相关验证

• validators验证器

def forbidden_tags_validator(value):
    forbidden_tags = ['you', 'are', 'a', 'sb']

    for tag in value:
        if tag.lower() in forbidden_tags:
            raise ValidationError('you are a sb.')


class InvalidTagValidator(object):

    def __init__(self, message=None):
        if message:
            self.message = message

    def __call__(self, value):
        for tag in value:
            if '@' in tag or '+' in tag or '-' in tag:
                raise ValidationError('Enter a valid tag.')

• clean_name()验证和clean()验证

# form类的方法
class CustomForm(forms.Form):
    name = forms.CharField(max_length=100)
    tags = MultiTagFeild()

    def __init__(self, *args, **kwargs):
        super(CustomForm, self).__init__(*args, **kwargs)
        self.fields['tags'].validators.append(forbidden_tags_validator)
        self.fields['tags'].validators.append(InvalidTagValidator)

    def clean_name(self):
        value = self.cleaned_data.get('name')
        if value == "admin":
            raise ValidationError('%s已存在' % value)
        return value

    def clean(self):
        super(CustomForm, self).clean()
        name = self.cleaned_data.get('name')
        tags = self.cleaned_data.get('tags')
        if not tags or len(tags) <= 1:
            self._errors['tags'] = self.error_class(['标签太少'])
        if name == "help":
            self.add_error("name", "帮助信息")
        return self.cleaned_data