Add example usage of broadcaster

Author: patrick91

django-subscriptions/api/asgi.py

@@ -1,5 +1,16 @@
+import typing
+
+from starlette.requests import Request
+from starlette.websockets import WebSocket
 from strawberry.asgi import GraphQL
 
+from .context import Context, get_broadcast
+
 
 class MyGraphQL(GraphQL):
-    ...
+    async def get_context(
+        self, request: typing.Union[Request, WebSocket]
+    ) -> typing.Optional[typing.Any]:
+        broadcast = await get_broadcast()
+
+        return Context(broadcast)

django-subscriptions/api/context.py

@@ -0,0 +1,21 @@
+from dataclasses import dataclass
+
+from broadcaster import Broadcast
+
+broadcast = None
+
+
+async def get_broadcast():
+    global broadcast
+
+    if not broadcast:
+        broadcast = Broadcast("memory://")
+
+        await broadcast.connect()
+
+    return broadcast
+
+
+@dataclass
+class Context:
+    broadcast: Broadcast

django-subscriptions/api/schema.py

@@ -10,13 +10,35 @@ def hello() -> str:
         return "world"
 
 
+@strawberry.type
+class Mutation:
+    @strawberry.field
+    async def send_message(self, info, message: str) -> bool:
+        print("sending on_message")
+        print(id(info.context.broadcast))
+        await info.context.broadcast.publish(channel="chatroom", message=message)
+
+        return True
+
+
 @strawberry.type
 class Subscription:
+    @strawberry.subscription
+    async def on_message(self, info) -> str:
+        print("starting on_message")
+        print(id(info.context.broadcast))
+
+        async with info.context.broadcast.subscribe(channel="chatroom") as subscriber:
+            print(f"{subscriber=}")
+            async for event in subscriber:
+                print(f"{event=}")
+                yield event.message
+
     @strawberry.subscription
     async def count(self, target: int = 100) -> int:
         for i in range(target):
             yield i
             await asyncio.sleep(0.5)
 
 
-schema = strawberry.Schema(query=Query, subscription=Subscription)
+schema = strawberry.Schema(query=Query, mutation=Mutation, subscription=Subscription)

django-subscriptions/api/views.py

@@ -8,8 +8,15 @@
 from django.template.response import TemplateResponse
 from strawberry.django.views import AsyncGraphQLView as StrawberryAsyncGraphQLView
 
+from .context import Context, get_broadcast
+
 
 class AsyncGraphQLView(StrawberryAsyncGraphQLView):
+    async def get_context(self, request: HttpRequest) -> Context:
+        broadcast = await get_broadcast()
+
+        return Context(broadcast)
+
     def _render_graphiql(self, request: HttpRequest, context=None):
         if not self.graphiql:
             raise Http404()

django-subscriptions/poetry.lock

@@ -10,6 +10,7 @@ python = "^3.9"
 strawberry-graphql = "^0.46.0"
 Django = "^3.1.7"
 uvicorn = {extras = ["standard"], version = "^0.13.4"}
+broadcaster = "^0.2.0"
 
 [tool.poetry.dev-dependencies]
 black = {version = "^20.8b1", allow-prereleases = true}