Django小技巧15: 使用基於類視圖的Mixins

Django小技巧15: 使用基於類視圖的Mixins

Posted November 05, 2018

翻譯整理自: simpleisbetterthancomplex.com

今天講述三點關於 Mixins 使用的一些規範:

• Django 提供的View 保持在繼承的最右邊.
• Mixins 在基本視圖的左側
• Mixins 應該繼承Python的內置對象類型(object).

下面舉例說明規則

Python

class FormMessageMixin(object):
    @property
    def form_valid_message(self):
        return NotImplemented

    form_invalid_message = 'Please correct the errors below.'

    def form_valid(self, form):
        messages.success(self.request, self.form_valid_message)
        return super(FormMessageMixin, self).form_valid(form)

    def form_invalid(self, form):
        messages.error(self.request, self.form_invalid_message)
        return super(FormMessageMixin, self).form_invalid(form)


class DocumentCreateView(FormMessageMixin, CreateView):
    model = Document
    fields = ('name', 'file')
    success_url = reverse_lazy('documents')
    form_valid_message = 'The document was successfully created!'

依類似的方式， 你可以在UpdateView中， 重用相同的FormMessageMixin, 並覆蓋默認的form_invalid_message方法.

Python

class DocumentUpdateView(FormMessageMixin, UpdateView):
    model = Document
    fields = ('name', )
    success_url = reverse_lazy('documents')
    form_valid_message = 'The document was successfully updated!'
    form_invalid_message = 'There are some errors in the form below.'

Django 1.9開始， 內置的LoginRequiredMixin和UserPassesTestMixin. 如果你要在視圖中使用它們， 它們始終位於最左側:

Python

Mixins在左,View在後

class DocumentUpdateView(LoginRequiredMixin, FormMessageMixin, UpdateView):
    model = Document
    fields = ('name', )
    success_url = reverse_lazy('documents')
    form_valid_message = 'The document was successfully updated!'