Django CreateView:在验证前设置用户
问题描述:
我有一个模型,根据对象是由用户还是由系统创建,对其名称字段使用不同的验证。Django CreateView:在验证前设置用户
class Symbol(models.Model):
name = models.CharField(_('name'), unique=True, max_length=64)
creator = models.ForeignKey('User', null=True, on_delete=models.CASCADE)
def is_system_internal(self):
"""
whether or not this Symbol belongs to the system rather than having been created by a user
"""
return (self.creator is None)
def clean(self):
"""
ensure that the Symbol's name is valid
"""
if self.is_system_internal():
if not re.match("^_[a-zA-Z0-9\-_]+$", self.name):
raise ValidationError(
_("for system-internal symbols, the name must consist of letters, numbers, dashes (-) and underscores (_) and must begin with an underscore."),
params = { 'value' : self.name },
)
else:
if not re.match("^[a-zA-Z][a-zA-Z0-9\-_]*$", self.name):
raise ValidationError(
_("the symbol name must consist of letters, numbers, dashes (-) and underscores (_) and must begin with a letter."),
params = { 'value' : self.name },
)
我想创建一个窗体和一个CreateView,用户可以用它创建对象。当用户创建这样的对象时,用户应该被用作“创建者”字段值的值。
目前,它看起来像这样:
class SymbolCreateForm(forms.ModelForm):
name = forms.CharField(max_length=Symbol._meta.get_field('name').max_length, required=True)
class Meta:
model = Symbol
fields = ('name',)
class SymbolCreateView(LoginRequiredMixin, generic.CreateView):
form_class = SymbolCreateForm
template_name = 'main/symbol_create.html'
def form_valid(self, form):
# set the creator of the instance to the currently logged in user
form.instance.creator = self.request.user
return super(SymbolCreateView, self).form_valid(form)
我用这种方式写它,因为那是答案此相关的问题:
Accessing request.user in class based generic view CreateView in order to set FK field in Django
不幸的是,它不工作:视图只允许我创建以下划线开头的符号,它应该做相反的操作。但是,当我创建符号时,创建者字段无论如何都会正确设置。
我认为问题在于创建者字段只有在clean()方法已经运行之后才会被设置。
如何在调用clean()方法之前设置创建者字段?
或者,有没有更好的方法来做我想做的事情? 在我看来,应该有一个更有效的方法来自动化逻辑,我有两个不同的名称字段验证器,其选择取决于创建者字段。
答
您可以在get_form_kwargs
方法中设置instance.creator
。
class SymbolCreateView(LoginRequiredMixin, generic.CreateView):
form_class = SymbolCreateForm
def get_form_kwargs(self):
kwargs = super(SymbolCreateView, self).get_form_kwargs()
if kwargs['instance'] is None:
kwargs['instance'] = Symbol()
kwargs['instance'].creator = self.request.user
return kwargs
检查if kwargs['instance'] is None
意味着该代码可以使用两种CreateView
和UpdateView
。
我得到一个TypeError: “**之后的ModelFormMetaclass对象参数必须是映射,而不是NoneType” –
记得返回'kwargs' – Alasdair