Django中ModelField的自定义验证 [英] Custom validation of a ModelField in Django

问题描述

我的模型看起来像这样：

my model looks like this:

class MyModel(models.Model):
    field1 = models.FloatField(default=0)
    field2 = models.FloatField(default=0)

它的行为如何：

>>> m = MyModel()
>>> m.full_clean()

>>> m = MyModel(field1=8.9)
>>> m.full_clean()

>>> m = MyModel(field1='')
>>> m.full_clean()
ValidationError: {'field1': [u'This value must be a float.'], ...

我希望它接受空白字符串并使用0.我也希望它接受诸如5:56之类的值，并使用5.93333。 （我已经有一个可以做到这一点的功能）

I want it to accept blank strings and have it use 0. I also want it to accept values such as "5:56" and have it use "5.93333". (I already have a function that can do this)

目前我有一个使用自定义表单字段（它是丑陋的罪恶），但我想移动它全部使用模型验证。

Currently I have this working with a custom form field (and it's ugly as sin), but I want to move it all to use model validation. Whats the best way to go about this?

推荐答案

制作一个 clean_field1 在您的表单功能，并在那里验证。如果不正确，则抛出验证错误，并重新格式化并返回正确值。示例：

Make a clean_field1 function in your form and verify it in there. Throw a validation error if it's improper, and reformat and return the "proper" value if it is. Example:

http://docs.djangoproject.com/en/dev/ref/forms/validation/#cleaning-a-specific-field-attribute

更新：

问题澄清：用户想要一个模型字段来执行此操作。

Question clarified: user wants a Model Field that does this.

覆盖 FloatField 和 get_prep_value 和 to_python 例程内部：

class MagicalFloatField(FloatField):
  def to_python( self, value_from_db ):
    ...
    return what_should_go_into_model_field_value
  def get_prep_value( self, value_from_field ):
    ...
    return what_should_go_into_db

所以你可以在那里做5:26 - 5.26。然后在您的模型中使用您的字段：

So you can do the "5:26" <--> "5.26" there. Then use your field in your model:

class MagicalModel(Model):
  foo = MagicalFloatField()

参考：

http://docs.djangoproject.com/en/dev/ howto / custom-model-fields /＃django.db.models.to_python

此外，还有一个例子，它期待什么以及如何提高验证错误，看看你是什么子类 - 在 site-packages / django / db / models / fields / __ init __。py 中查找 FloatField code>

Also, for an example of what it expects and how to raise validation errors, look at what you're subclassing -- look up FloatField in site-packages/django/db/models/fields/__init__.py

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