如何更新模型但在Django中返回未修改的模型?

时间:2011-06-07 11:05:07

标签: python django django-models django-piston

我正在使用django-piston编写RESTful Web服务并遇到问题。

在models.py中:

class Status(models.Model):
    user = models.ForeignKey(User)
    content = models.TextField(max_length=140)

class StatusReply(models.Model):
    user = models.ForeignKey(User)
    reply_to = models.ForeignKey(Status, related_name='replies')
    content = models.TextField(max_length=140)
    has_read = models.BooleanField(default=False, help_text="has the publisher of the status read the reply")

在handlers.py中:

class StatusHandler(BaseHandler):
    allowed_methods = ('GET', 'POST', 'DELETE' )
    model = Status
    fields = ('id', 
              ('user', ('id', 'username', 'name')), 
              'content', 
              ('replies', ('id', 
                           ('user', ('id', 'username', 'name')), 
                           'content',  
                           'has_read'),
              ),
             )

    @need_login
    def read(self, request, id, current_user): # the current_user arg is an instance of user created in @need_login
        try:
            status = Status.objects.get(pk=id)
        except ObjectDoesNotExist:
            return rc.NOT_FOUND
        else:
            if status.user == current_user: #if current_user is the publisher of the status, set all replies read
                status.replies.all().update(has_read=True)
            return status

在处理程序中,它通过id返回特定状态。现在我想在status.replies.all().update(has_read=True)之前返回状态,但也要在数据库中执行更新操作。怎么做?提前谢谢。

1 个答案:

答案 0 :(得分:2)

不确定我是否理解您的需求。据我了解您的代码,status.replies.all().update(has_read=True)不会更改status,只会更改回复。如果这是真的,代码应该做你想要的。如果不是,您可以复制status并返回副本:

        if status.user == current_user: 
            old_status = status.make_copy()
            status.replies.all().update(has_read=True)
            return old_status
        return status

或者您只是希望方法尽早返回并异步进行数据库更新?那么你应该看看celerythis nice explanation