如何通过django信号引发自定义错误消息？

Posted 2021-05-06

我有一个模特

class myModel(models.Model):
   name = models.CharField(max_length=100)
   type = models.CharField(max_length=100)
   nums = JSONField(null=True, blank=True)

我需要在nums字段中保存数字。但是，没有两个具有相同myModelcan的type实例具有相同的数字（nums字段的交集应该为空）。

我试过为它写一个信号

@receiver(pre_save, sender = myModel)
def check_duplicate_nums(sender, instance, **kwargs):
   all_records = myModel.objects.filter(type = instance.type)
   for record in all_records:
      common_nums = list(set(record.nums).intersection(instance.nums))
      if len(common_nums) != 0:
         raise Exception("nums "+str(common_nums)+ " are repeated in " +str(record.name)+ " and "+instance.name)

但这样做会打开django admin的调试窗口。我希望错误显示在那里。例如，当我们使用空字段保存模型时，它会在红色突出显示的行中抛出错误“此字段是必需的”。我需要以这种方式显示错误。请建议一个方法。

谢谢！

答案

正如@AnjaneyuluBatta在评论中所说，你可以将这种验证移到表单中。请参阅Adding custom validation to the admin文档。你的admin.py应该是这样的：

class MyForm(forms.ModelForm):
    class Meta:
        model = myModel

    def clean_nums(self):
        # do something that validates your data
        nums = self.cleaned_data["nums"]
        all_records = myModel.objects.filter(type = instance.type)
        for record in all_records:
            common_nums = list(set(record.nums).intersection(instance.nums))
            if len(common_nums) != 0:
                raise forms.ValidationError("nums "+str(common_nums)+ " are repeated in " +str(record.name)+ " and "+instance.name)
        return nums

class MyAdmin(admin.ModelAdmin):
    form = MyForm

admin.site.register(MyModel, MyAdmin)