django信号是否也包含在transaction.atomic装饰器内？

Question

我有一个模型文件,它使用一个post_save信号在另一个表中创建一个链接的行.以典型的方式,我可以从我的一个视图创建一个页面,该视图用@ transaction.atomic修饰.

我想知道这个装饰器是否会在同一个事务中创建Page对象和SharedPage对象.从django文档中不清楚信号是这个原子事务的一部分.

models.py

class Page(models.Model):
    name = models.CharField(default='My default page',max_length=200,blank=False)
    created_at = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User, on_delete=models.CASCADE)
    slug = models.SlugField()
    uuid = models.UUIDField(default=uuid.uuid4, editable=False)
    is_public = models.BooleanField(default=False)

    def __str__(self):              # __unicode__ on Python 2
        return self.name

    class Meta:
        ordering = ['position','created_at']

@receiver(post_save, sender=Page)
def create_shared_page_entry(sender, instance, created, **kwargs):
    if created:
        shared_page = SharedPage.objects.create(
            page=instance,
            user=instance.user,
            can_edit=True
        )

view.py

@require_http_methods(["POST"])
@transaction.atomic
def page_create(request):
    name = request.POST.get('name')
    page = Page.objects.create(name=name, owner=request.user)

    data = serializers.serialize("json", [page])
    return HttpResponse(data, content_type='application/json')

Answer 1

是的,使用相同的值来调度信号,用于连接的自动提交设置(由transaction.commit装饰器调整),用于保存模型.参考django.db.models.base.Model.save_base()方法中的代码,

    if not meta.auto_created:
        signals.pre_save.send(sender=origin, instance=self, raw=raw, using=using, update_fields=update_fields)

    with transaction.atomic(using=using, savepoint=False):
        if not raw:
            self._save_parents(cls, using, update_fields)
        updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
    # Store the database on which the object was saved
    self._state.db = using
    # Once saved, this is no longer a to-be-added instance.
    self._state.adding = False

    # Signal that the save is complete
    if not meta.auto_created:
        signals.post_save.send(sender=origin, instance=self, created=(not updated),update_fields=update_fields, raw=raw, using=using)

如您所见,没有编写特殊代码来更改自动提交设置.因此,如果您的视图声明所有与数据库相关的东西必须通过使用@ transaction.atomic确保原子性,那么您的视图(model.save()或通过信号处理程序)所做的db更改不会被提交,直到您的视图为止执行完成.

我希望,它可以帮助你.