在Django-channels中通过异步代码访问数据库

Question

我需要些帮助。我正在使用Django-channels，出于某种目的，我需要进行几个DB调用。文档对我来说不清楚：https://channels.readthedocs.io/en/latest/topics/databases.html

那么，下面哪一种方法是正确的呢？

具有装饰器的每个数据库访问的

1. 创建/调用函数。
2. 在一个函数中执行对数据库的所有调用，该函数由装饰器

封装

Answer 1

您可以将对数据库的多个调用放在一个函数中，并由database_sync_to_async装饰器包装，如下面的示例所示(聊天室如预期:)

class ChatConsumer(AsyncWebsocketConsumer):

async def connect(self):
    self.room_name = self.scope['url_route']['kwargs']['room_name']
    print(self.scope['user'].username)

    self.room_group_name = 'chat%s' % self.room_name

    await self.channel_layer.group_add(
        self.room_group_name,
        self.channel_name
    )

    await self.accept()

async def disconnect(self, close_code):

    await self.channel_layer.group_discard(
        self.room_group_name,
        self.channel_name
    )


async def receive(self, text_data=None, bytes_data=None):
    text_data_json = json.loads(text_data)
    message = text_data_json['message']
    await self.channel_layer.group_send(
        self.room_group_name,
        {
            'type' : 'chat_message',
            'message' : message
        }
    )


async def chat_message(self , event):
    message = event['message']
    sender = self.scope["user"].username
    receiver = self.scope['path'].split('_')[1]
    await self.post_message(sender = sender , receiver = receiver , message = message)
    await self.send(text_data = json.dumps({'message': message})) 

@database_sync_to_async
def post_message(self , sender  , receiver , message):
    sender = User.objects.filter(username = sender)[0]
    receiver = User.objects.filter(username = sender)[0]
    Message.objects.create(sender = sender , receiver = receiver , text = message)