自定义 Django 字段的验证
有一个 Django 字段类型用于存储 MyType 的值。
from django.core.exceptions import ValidationError
from django.db import models
class MyTypeField(models.Field):
__metaclass__ = models.SubfieldBase
def db_type(self, connection):
return "text"
def to_python(self, value):
if isinstance(value, basestring):
try:
value = MyType.deserialize(value)
except ParseError, e:
raise ValidationError("Invalid format: "+str(e))
assert isinstance(value, MyType)
return value
def get_prep_value(self, value):
if not isinstance(value, MyType):
raise ValidationError("Not MyType")
return value.serialize()
我正在尝试在模型的管理页面上使用这种类型的字段。如果用户在字段中输入有效值，一切都会正常工作。但是，如果输入的值无效，则不会捕获 ValidationError （您会收到错误 500，或者如果启用了调试，则会出现堆栈跟踪）
相反，我想在表单附近看到一条消息“无效格式”字段（就像您输入无效的日期或数字一样）。如何修改字段类以在正确的位置获取验证错误。
There is a Django field type for storing values of MyType.
from django.core.exceptions import ValidationError
from django.db import models
class MyTypeField(models.Field):
__metaclass__ = models.SubfieldBase
def db_type(self, connection):
return "text"
def to_python(self, value):
if isinstance(value, basestring):
try:
value = MyType.deserialize(value)
except ParseError, e:
raise ValidationError("Invalid format: "+str(e))
assert isinstance(value, MyType)
return value
def get_prep_value(self, value):
if not isinstance(value, MyType):
raise ValidationError("Not MyType")
return value.serialize()
I am trying to use fields of this type on an admin page of a model. Everything works nice if a user enters a valid value in the field. But if the entered value is invalid, the ValidationError is not caught (you get error 500, or a stack trace if debug is enabled)
Instead I want to see the form with a message "Invalid format" near the field (just like if you enter an invalid date or number). How to modify the field class to get validation errors in a correct place.
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引用自 http://docs。 djangoproject.com/en/1.2/howto/custom-model-fields/#modelforms-and-custom-fields
因此，此时将永远不会捕获 ValidationError。从数据库填充模型的新实例时也会调用 to_python ，该数据库位于表单验证上下文之外。
因此，您必须将验证移至表单字段中。
Quoting from http://docs.djangoproject.com/en/1.2/howto/custom-model-fields/#modelforms-and-custom-fields
So a ValidationError will never be caught at this point.
to_pythonis also called when populating a new instance of your model from the database, which is outside the form validation context.So you have to move your validation into a formfield.
您需要在字段类中创建一个 clean(self, value, model_instance) 方法并在那里进行验证/引发错误。
You need to create a
clean(self, value, model_instance)method in your field class and do the validation/raise the error there.