update settings, consumers, py dep, readme

chat-room/README.md

@@ -10,6 +10,13 @@ python manage.py migrate
 # run app
 # (make sure at same level with manage.py)
 python3 manage.py runserver
+
+
+# start redis 
+brew services start redis
+
+# check
+redis-cli ping
 ```
 
 ```bash
@@ -42,6 +49,12 @@ sqlite3 db.sqlite3
 - http://127.0.0.1:8000/admin/
   - user, pwd : `admin`
 
+
+## Concept
+
+- channel : A channel is a mailbox where messages can be sent to. Each channel has a name. Anyone who has the name of a channel can send a message to the channel.
+- group : A group is a group of related channels. A group has a name. Anyone who has the name of a group can add/remove a channel to the group by name and send a message to all channels in the group. It is not possible to enumerate what channels are in a particular group.
+
 ## Ref
 
 - https://github.com/django/channels

chat-room/mysite/chat/consumers.py

@@ -1,8 +1,7 @@
 import json
-
+from asgiref.sync import async_to_sync
 from channels.generic.websocket import WebsocketConsumer
 
-
 # https://channels.readthedocs.io/en/latest/tutorial/part_2.html
 """
 This is a synchronous WebSocket consumer 
@@ -11,16 +10,37 @@
 For now it does not broadcast messages to other clients in the same room.
 """
 
-
 class ChatConsumer(WebsocketConsumer):
     def connect(self):
+        self.room_name = self.scope["url_route"]["kwargs"]["room_name"]
+        self.room_group_name = f"chat_{self.room_name}"
+
+        # Join room group
+        async_to_sync(self.channel_layer.group_add)(
+            self.room_group_name, self.channel_name
+        )
+
         self.accept()
 
     def disconnect(self, close_code):
-        pass
+        # Leave room group
+        async_to_sync(self.channel_layer.group_discard)(
+            self.room_group_name, self.channel_name
+        )
 
+    # Receive message from WebSocket
     def receive(self, text_data):
         text_data_json = json.loads(text_data)
         message = text_data_json["message"]
 
+        # Send message to room group
+        async_to_sync(self.channel_layer.group_send)(
+            self.room_group_name, {"type": "chat.message", "message": message}
+        )
+
+    # Receive message from room group
+    def chat_message(self, event):
+        message = event["message"]
+
+        # Send message to WebSocket
         self.send(text_data=json.dumps({"message": message}))

chat-room/mysite/mysite/settings.py

@@ -12,6 +12,19 @@
 
 from pathlib import Path
 
+# https://channels.readthedocs.io/en/latest/tutorial/part_2.html
+
+ASGI_APPLICATION = "mysite.asgi.application"
+
+CHANNEL_LAYERS = {
+    "default": {
+        "BACKEND": "channels_redis.core.RedisChannelLayer",
+        "CONFIG": {
+            "hosts": [("127.0.0.1", 6379)],
+        },
+    },
+}
+
 # Build paths inside the project like this: BASE_DIR / 'subdir'.
 BASE_DIR = Path(__file__).resolve().parent.parent
 
@@ -27,7 +40,6 @@
 
 ALLOWED_HOSTS = []
 
-
 # Application definition
 
 INSTALLED_APPS = [

chat-room/requirements.txt

@@ -1,3 +1,4 @@
 django
 channels
-daphne
+daphne
+channels_redis