django ModelForm似乎不验证BooleanField [英] django ModelForm doesn't seem to validate BooleanField

问题描述

我正在使用Django 1.5.4

I'm using django 1.5.4

这是我所面临问题的一​​个最小示例。

Here's a minimal example of the issue I'm facing.

模型：

#models.py
from django.db import models

class SampleModel(models.Model):
    spam = models.BooleanField()

形式：

#forms.py
from django.forms import ModelForm
from .models import SampleModel

class SampleModelForm(ModelForm):
    class Meta:
        model = SampleModel
        fields = ('spam', )

从Django shell：

From the django shell:

>>> data = {} #intentionally blank
>>> form = SampleModelForm(data)
>>> is_valid = form.is_valid() #is_valid is True
>>> form.save() # model instance is created with "spam" set to False by default.

我是否正确验证了表单？ form.is_valid 正确验证其他类型的字段。
docs 表示默认情况下所有字段均为必填但是 is_valid 会返回 True 而没有布尔字段键。

Am I validating the form incorrectly? form.is_valid validates fields of other types correctly. The docs indicate that all fields are required by default but is_valid returns Truewithout the boolean field key being present.

我需要确保输入数据中存在布尔字段。
到目前为止，我正在手动检查该字段是否存在并且类型为 bool 。您是否认为我应该覆盖 form.is_valid 并添加此检查，以便也可以将其重新用于其他模型？

I need to ensure that the boolean field is present in the input data. As of now, I'm manually checking if the field is present and is of type bool. Do you think I should override form.is_valid and add this check so that it can be reused for other models too?

推荐答案

（根据代码检查；文档未说）证明模型 BooleanField s具有 blank = True 在其 __ init __ 方法中自动设置，因此不需要自动创建的模型表单字段。考虑到这是有道理的（False算作空白，因此 BooleanField 要求它为真），但是当您阅读文档时并不清楚。

It turns out (from code inspection; the docs don't say) that model BooleanFields have blank=True set automatically in their __init__ method, thus making the automatically created model form field not required. This makes sense upon consideration (False counts as blank, so BooleanFields need it to be true) but it's not obvious when you just read the docs.

如果希望将其要求为 True ，则通常使用表单字段替代-自行声明该字段或设置其必需的属性在验证之前为某个地方的 True （我通常使用表单的 __ init __ 方法）。如果要允许它允许 True 或 False ，但不允许Python None

If you want it to be required to be True, the usual form field overrides apply - declare the field yourself or set its required attribute to be True somewhere before validating (I usually use the form's __init__ method). If you want it to allow True or False but not Python None, it's harder.

具体来说， BooleanField 的标准小部件是一个复选框。浏览器不会为未选中的复选框提交任何内容，因此复选框小部件会将提交中不存在的字段视为 False 。无法将用户没有选择复选框与输入确实很糟糕的情况区分开。您可以使用其他小部件（例如， RadioSelect ）至少使浏览器可以提交 False ，但仍然存在问题，即 BooleanField 的 to_python 方法将其值转换为布尔值，然后进行验证，因此您必须继承并覆盖。

Specifically, the standard widget for a BooleanField is a checkbox. Browsers do not submit anything for unchecked checkboxes, so the checkbox widget treats the absence of the field from the submit as False. There's no way to distinguish the user not selecting the checkbox from cases in which the input really is bad. You could use a different widget (say, a RadioSelect) to at least make it possible for the browser to submit something for False, but you still have the problem that the BooleanField's to_python method converts its value to a boolean before validating, so you'd have to subclass and override.

幸运的是，错误视为空，因此您可以设置 required = True 并且不需要自定义清洗方法

Fortunately, False is not considered empty by the validation code, so if you do that you'll be able to set required=True and don't need custom cleaning methods.

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