Question

在youtube上关注这些教程之一我刚刚使用django-channels编写了一个websocket服务器这是我的代码 signal.py

from django.contrib.auth.models import User
from django.db.models.signals import post_save
from django.dispatch import receiver
from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer


@receiver(post_save, sender=User)
def announce_new_user(sender, instance, created, **kwargs):
    if created:
        channel_layer = get_channel_layer()
        async_to_sync(channel_layer.group_send)(
            "gossip", {"type": "user_gossip",
                       "event": "New User",
                       "username": instance.username})

consumers.py

from channels.generic.websocket import AsyncJsonWebsocketConsumer


class NoseyConsumer(AsyncJsonWebsocketConsumer):

    async def connect(self):
        await self.accept()
        await self.channel_layer.group_add("gossip", self.channel_name)
        print(f"Added {self.channel_name} channel to gossip")

    async def disconnect(self, close_code):
        await self.channel_layer.group_discard("gossip", self.channel_name)
        print(f"Removed {self.channel_name} channel to gossip")

    async def user_gossip(self, event):
        await self.send_json(event)
        print(f"Got message {event} at {self.channel_name}")

apps.py

from django.apps import AppConfig


class NotifierConfig(AppConfig):
    name = 'notifier'
    def ready(self):
        from .import signals

初始化 .py

default_app_config = 'notifier.apps.NotifierConfig'

routing.py

from channels.routing import ProtocolTypeRouter, URLRouter
from django.urls import path
from notifier.consumers import NoseyConsumer

application = ProtocolTypeRouter({
    "websocket": URLRouter([
        path("notifications/", NoseyConsumer),
    ])
})

以及settings.py

中的channel_layers

CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels_redis.core.RedisChannelLayer",
        "CONFIG": {
            "hosts": [("localhost",16379)],
        },
    },
}

我不知道问题是什么，当我使用admin创建新用户时，我看不到通过控制台从django websockets传输的任何数据，并且尝试了很多方法来找出问题，但仍然没有用

这是我的客户javascript代码

<html>
   <head>

      <script type = "text/javascript">




               // Let us open a web socket
               var ws = new WebSocket("ws://localhost:8000/notifications/");

               var msg = "hi, this is simple message.";
               ws.onopen = function(evt) {
                 ws.send(msg);
               };
               ws.onmessage = function(evt) {
                 // handle this message
                 console.log(evt.username);
               };
               ws.onclose = function(evt) {
                 // this channel is closed
               };
               ws.onerror = function(evt) {
                 // handle this error
               };


      </script>

   </head>

   <body>


   </body>
</html>

当我尝试通过在此处添加用户的方式来访问同一网站时，我在终端机中获得的信息

   HTTP GET / 200 [0.01, 127.0.0.1:55829]
WebSocket HANDSHAKING /notifications/ [127.0.0.1:55935]
WebSocket CONNECT /notifications/ [127.0.0.1:55935]
Added specific.pgRlAson!hqgpORLfvfbO channel to gossip
Exception inside application: Expecting value: line 1 column 1 (char 0)
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\consumer.py", line 59, in __call__
    [receive, self.channel_receive], self.dispatch
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\utils.py", line 52, in await_many_dispatch
    await dispatch(result)
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\consumer.py", line 73, in dispatch

    await handler(message)
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\generic\websocket.py", line 196, in websocket_
receive
    await self.receive(text_data=message["text"])
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\generic\websocket.py", line 259, in receive
    await self.receive_json(await self.decode_json(text_data), **kwargs)
  File "C:\Users\madhumani\workspace\ven\lib\site-packages\channels\generic\websocket.py", line 277, in decode_jso
n
    return json.loads(text_data)
  File "c:\users\madhumani\appdata\local\programs\python\python36-32\Lib\json\__init__.py", line 354, in loads
    return _default_decoder.decode(s)
  File "c:\users\madhumani\appdata\local\programs\python\python36-32\Lib\json\decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "c:\users\madhumani\appdata\local\programs\python\python36-32\Lib\json\decoder.py", line 357, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
  Expecting value: line 1 column 1 (char 0)
WebSocket DISCONNECT /notifications/ [127.0.0.1:55935]

Answer 1

问题是您发送的事件没有匹配的接收者来处理。您发送类型为user.gossip的事件，而处理程序的名称为user_gossip。事件类型和方法名称应该匹配，因此您可能需要将事件类型更改为user_gossip

django-channels不起作用/未将任何消息作为Web套接字发送

1 个答案: