Django CreateView：在验证之前设置用户

Question

我有一个模型，根据对象是由用户还是系统创建，对其名称字段使用不同的验证。

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 Form 和一个 CreateView，用户可以使用它们来创建对象。当用户创建这样的对象时，应该将用户用作 'creator' 字段值的值。

目前看起来是这样的：

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)

我这样写是因为那是这个相关问题的答案：

Accessing request.user in class based generic view CreateView in order to set FK field in Django

不幸的是，它不起作用：视图只允许我创建以下划线开头的符号，它应该做相反的事情。但是，当我创建一个 Symbol 时，创建者字段无论如何都会正确设置。

我认为问题在于 creator 字段仅在 clean() 方法已经运行.

之后设置

如何在调用 clean() 方法之前设置创建者字段？

或者，是否有更好的方法来完成我想做的事情？在我看来，应该有一种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。

Answer 1

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 意味着该代码适用于 CreateView 和 UpdateView。

Answer 2

就我而言，我希望请求用户成为验证过程的一部分。提出的解决方案更合适。它建议使用 form_valid 如下

def form_valid(self, form):
  form.instance.author = self.request.user
  # ... do some validation here about the user for example
  if passed_validation:
    return super().form_valid(form)

  form.add_error(None, ValidationError({"author": "invalid author because ..."}))
  return super().form_invalid(form)

Django CreateView：在验证之前设置用户

Django CreateView: set user before validation

django

django-class-based-views

django-generic-views

django-validation