118 lines
4.5 KiB
Python
118 lines
4.5 KiB
Python
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import asyncio
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import json
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import typing
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from starlette import status
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from starlette.concurrency import run_in_threadpool
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from starlette.exceptions import HTTPException
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from starlette.requests import Request
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from starlette.responses import PlainTextResponse, Response
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from starlette.types import Message, Receive, Scope, Send
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from starlette.websockets import WebSocket
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class HTTPEndpoint:
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def __init__(self, scope: Scope, receive: Receive, send: Send) -> None:
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assert scope["type"] == "http"
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self.scope = scope
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self.receive = receive
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self.send = send
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def __await__(self) -> typing.Generator:
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return self.dispatch().__await__()
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async def dispatch(self) -> None:
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request = Request(self.scope, receive=self.receive)
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handler_name = "get" if request.method == "HEAD" else request.method.lower()
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handler = getattr(self, handler_name, self.method_not_allowed)
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is_async = asyncio.iscoroutinefunction(handler)
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if is_async:
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response = await handler(request)
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else:
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response = await run_in_threadpool(handler, request)
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await response(self.scope, self.receive, self.send)
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async def method_not_allowed(self, request: Request) -> Response:
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# If we're running inside a starlette application then raise an
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# exception, so that the configurable exception handler can deal with
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# returning the response. For plain ASGI apps, just return the response.
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if "app" in self.scope:
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raise HTTPException(status_code=405)
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return PlainTextResponse("Method Not Allowed", status_code=405)
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class WebSocketEndpoint:
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encoding = None # May be "text", "bytes", or "json".
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def __init__(self, scope: Scope, receive: Receive, send: Send) -> None:
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assert scope["type"] == "websocket"
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self.scope = scope
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self.receive = receive
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self.send = send
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def __await__(self) -> typing.Generator:
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return self.dispatch().__await__()
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async def dispatch(self) -> None:
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websocket = WebSocket(self.scope, receive=self.receive, send=self.send)
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await self.on_connect(websocket)
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close_code = status.WS_1000_NORMAL_CLOSURE
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try:
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while True:
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message = await websocket.receive()
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if message["type"] == "websocket.receive":
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data = await self.decode(websocket, message)
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await self.on_receive(websocket, data)
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elif message["type"] == "websocket.disconnect":
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close_code = int(message.get("code", status.WS_1000_NORMAL_CLOSURE))
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break
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except Exception as exc:
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close_code = status.WS_1011_INTERNAL_ERROR
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raise exc from None
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finally:
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await self.on_disconnect(websocket, close_code)
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async def decode(self, websocket: WebSocket, message: Message) -> typing.Any:
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if self.encoding == "text":
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if "text" not in message:
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await websocket.close(code=status.WS_1003_UNSUPPORTED_DATA)
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raise RuntimeError("Expected text websocket messages, but got bytes")
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return message["text"]
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elif self.encoding == "bytes":
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if "bytes" not in message:
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await websocket.close(code=status.WS_1003_UNSUPPORTED_DATA)
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raise RuntimeError("Expected bytes websocket messages, but got text")
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return message["bytes"]
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elif self.encoding == "json":
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if message.get("text") is not None:
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text = message["text"]
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else:
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text = message["bytes"].decode("utf-8")
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try:
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return json.loads(text)
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except json.decoder.JSONDecodeError:
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await websocket.close(code=status.WS_1003_UNSUPPORTED_DATA)
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raise RuntimeError("Malformed JSON data received.")
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assert (
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self.encoding is None
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), f"Unsupported 'encoding' attribute {self.encoding}"
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return message["text"] if message.get("text") else message["bytes"]
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async def on_connect(self, websocket: WebSocket) -> None:
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"""Override to handle an incoming websocket connection"""
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await websocket.accept()
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async def on_receive(self, websocket: WebSocket, data: typing.Any) -> None:
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"""Override to handle an incoming websocket message"""
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async def on_disconnect(self, websocket: WebSocket, close_code: int) -> None:
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"""Override to handle a disconnecting websocket"""
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