Django：如何处理CreateView中针对UNIQUE约束的错误消息失败

Posted 2021-05-04

我有一个基于通用类的createview，它会生成“唯一约束失败”错误。我能够处理并将其重定向到相同的createview表单。但是，我需要向createview发送一条错误消息，说“名称已存在”。我如何实现这一目标。

model.py

    class Release(models.Model):
        name = models.CharField(max_length=200, db_index=True)

    class Feature(models.Model):
        release = models.ForeignKey(Release, 
        on_delete=models.SET_NULL, null=True, related_name='features')
        name = models.CharField(max_length=200, db_index=True)

        class Meta:
            unique_together = ('name', 'release')

view.py

    class FeatureCreate(CreateView):
        model = Feature
        fields = ['name', 'summary']

    def form_valid(self, form):
        form.instance.release_id = self.kwargs.get('pk')
    from django.db import IntegrityError
    from django.http import HttpResponseRedirect
    try:
        a = super(FeatureCreate, self).form_valid(form)
    except IntegrityError as e:
        if 'UNIQUE constraint failed' in e.args[0]:
            return HttpResponseRedirect(reverse_lazy('feature-create', args=(form.instance.release_id,)))
    return a

url.py：

    path('release/<int:pk>/feature/create/', views.FeatureCreate.as_view(), name='feature-create'),

feature_form.html：

    {% block content %}
       <form action="" method="post">
       {% csrf_token %}
       <table>
      {{ form.as_table }}
      </table>
      <input type="submit" value="Submit">
      <input type="button" value="Cancel" onclick="history.back()">
      </form>
    {% endblock %}

欢迎提出任何建议。请帮助。

答案

from django.contrib import messages
#your view 
#...
messages.info(request, _("your information"))
#...
return ...

并将'django.contrib.messages'添加到settings.py中的INSTALLED_APP列表中>