无法通过 websockets 连接（daphne、django、nginx、docker）

Question

带有 django、docker-compose、nginx、daphne 的 Websocket。

常规 http 连接工作正常，但 websocket 连接没有输出。 websocket 似乎没有处于活动状态。

通过 javascript 连接会产生错误：

new WebSocket('ws://127.0.0.1:8000/ws/pollData');
// WebSocket connection to 'ws://127.0.0.1:8000/ws/pollData' failed: 

或连接到 ws://localhost/ws/pollData 时：

new WebSocket('ws://localhost/ws/pollData');

// Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist.

docker-compose.yaml

version: '3'
services:
  volume_configurer:
    image: busybox
    volumes:
      - shared:/shared:z
      - static:/static:z
    command: ["/bin/sh", "-c", "
      mkdir -p /static;
      chmod -R 777 /static;
      mkdir -p /shared/sync;
      chmod -R 777 /shared/sync;
      echo STARTED > /shared/sync/volumesetter && chmod a+r /shared/sync/volumesetter"]
  db:
    container_name: postgresdb
    image: postgres:latest
    restart: always
    env_file:
     - project.env
    ports:
      - 5432:5432
    volumes:
      - postgres-data1:/var/lib/postgresql/data1:z
  web:
    build:
      context: ./
      dockerfile: ./mdb/Dockerfile
    container_name: django
    command: >
      daphne mdb.asgi:application -b 0.0.0.0 -p 8000
    env_file:
      - project.env
    expose:
      - 8000
    depends_on:
      - db
    volumes:
      - ./mdb:/home/app/web/:z
      - static:/home/app/web/static/:z
      - shared:/uploads/:z
  nginx:
    container_name: nginx
    image: nginx
    restart: always
    ports:
      - 80:80
    volumes:
      - ./nginx:/etc/nginx/conf.d:z
      - static:/home/app/web/static/:z
    depends_on:
      - web
      - db

volumes:
  postgres-data1:
  static: 
  shared:

nginx.conf：

upstream mdb {
  server django:8000;
}
server {
  listen 80 default_server;
  listen [::]:80 default_server ipv6only=on;
  server_name localhost;
  client_max_body_size 2000M;
  location /static/ {
    alias /home/app/web/static/;
  }
  
  location /ws/ {
    proxy_pass http://mdb;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    proxy_set_header Host $host;
  }
  location / {
    try_files $uri @proxy_to_app;
  }
  location @proxy_to_app {
    proxy_pass http://mdb;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_redirect off;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Host $server_name;
  }
}

consumer.py

from channels.generic.websocket import WebsocketConsumer
import json
class DashConsumer(WebsocketConsumer):
  def connect(self):
    print('==================2')
    self.accept()

  def disconnect(self, close_code):
    print('==================1')
    pass

  def receive(self, text_data):
    print('==================0')
    text_data_json = json.loads(text_data)
    message = text_data_json['message']
    self.send(text_data = json.dumps({
        'message': message
      })
    )

从 python 视图来看，连接到ws://localhost:8000/ws/pollData 时，连接到 websocket 不会产生任何输出。但是，它也不会崩溃。而当连接到其他东西时，比如ws://localhost/ws/pollData，它会因ConnectionRefusedError: [Errno 111] Connection refused 而崩溃。但是，使用 ws.connect() 时 django 没有输出，即 consumer.py 中的 print('==================<->') 没有触发。

views.py

ws = websocket.WebSocket()
# does not print
print(ws.connect('ws://localhost:8000/ws/pollData'))
# also does not print
print(ws.send('{"message": "test from django"}'))
# prints "still here"
print('still here')
# this crashes
print(ws.connect('ws://localhost:8000/ws/pollData'))
# does not print
print('still here')

asgi.py

import os
from django.conf.urls import url
from django.core.asgi import get_asgi_application
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mdb.settings")
django_asgi_app = get_asgi_application()
from channels.auth import AuthMiddlewareStack
from channels.routing import ProtocolTypeRouter, URLRouter
from chat.consumer import DashConsumer
application = ProtocolTypeRouter({
  "http": django_asgi_app,
  "websocket": AuthMiddlewareStack(
    URLRouter([
      url(r"^ws/pollData$", DashConsumer.as_asgi()),
    ])
  ),
})

settings.py

WSGI_APPLICATION = 'mdb.wsgi.application'
ASGI_APPLICATION = 'mdb.routing.application'
CHANNEL_LAYERS = {
  "default": {
    "BACKEND": "channels.layers.InMemoryChannelLayer"
  },
}

非常感谢您的帮助！

编辑：

当使用ws://localhost/ws/pollData 或ws://0.0.0.0/ws/pollData 的地址时，javascript 似乎正在连接，因为在任何一种情况下都会发生连接事件并且网络面板显示打开的 websocket 连接。但是，在python中，这两个地址都会导致ConnectionRefusedError: [Errno 111] Connection refused，即：

ws = websocket.WebSocket()
# appears to connect but does not send anything to javascript
ws.connect('ws://localhost:8000/ws/pollData')
ws.send('{"message": "test from django"}')
# crashes
ws.connect('ws://localhost/ws/pollData')
# also crashes
ws.connect('ws://0.0.0.0/ws/pollData')

Answer 1

将DashConsumer 更改为AsyncJsonWebsocketConsumer 并注意到websocket 实际上是在不同地址（即ws://localhost/ws/pollData 或ws://0.0.0.0/ws/pollData）的javascript 中打开的。

class DashConsumer(AsyncJsonWebsocketConsumer):
  print('==================0')
  async def connect(self):
    print('==================1')
    self.groupname = 'dashboard'
    await self.channel_layer.group_add(
      self.groupname,
      self.channel_name,
    )
    await self.accept()

  async def disconnect(self, close_code):
    print('==================2')
    await self.channel_layer.group_discard(
      self.groupname,
      self.channel_name
    )

  async def receive(self, text_data):
    print('==================3')
    # ~ #datapoint = json.loads(text_data)
    # ~ #val = datapoint['value']
    val = text_data

    await self.channel_layer.group_send(
      self.groupname,
      {
        'type': 'deprocessing', #function name to run
        'value': val #value to send function
      }
    )
    print ('>>>>', text_data)

  async def deprocessing(self, event):
    print('==================4')
    valOther = event['value']
    valOther = f'IP VALUE: {valOther}'
    # send for frontend
    await self.send(text_data = json.dumps({'value2': valOther}))

views.py

ws = websocket.WebSocket()
ws.connect('ws://localhost:8000/ws/pollData')
ws.send('{"message": "test from django"}')