Django CreateView：在驗證前設置用戶

Question

我有一個模型，根據對象是由用戶還是由系統創建，對其名稱字段使用不同的驗證。

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 }, 
       ) 

我想創建一個窗體和一個CreateView，用戶可以用它創建對象。當用戶創建這樣的對象時，用戶應該被用作「創建者」字段值的值。

目前，它看起來像這樣：

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) 

我用這種方式寫它，因爲那是答案此相關的問題：

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：視圖只允許我創建以下劃線開頭的符號，它應該做相反的操作。但是，當我創建符號時，創建者字段無論如何都會正確設置。

我認爲問題在於創建者字段只有在clean（）方法已經運行之後纔會被設置。

如何在調用clean（）方法之前設置創建者字段？

或者，有沒有更好的方法來做我想做的事情？ 在我看來，應該有一個更有效的方法來自動化邏輯，我有兩個不同的名稱字段驗證器，其選擇取決於創建者字段。

Answer 1

您可以在get_form_kwargs方法中設置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 

檢查if kwargs['instance'] is None意味着該代碼可以使用兩種CreateView和UpdateView。