b9b44e6dadWe will be a bit more low level and expect callees to import mcp.types instead of relying in re-exported types. This makes usage more explicit and avoids potential collisions in mcp.server.
61 lines
2.2 KiB
Python
61 lines
2.2 KiB
Python
import logging
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from contextlib import asynccontextmanager
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import anyio
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from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
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from starlette.types import Receive, Scope, Send
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from starlette.websockets import WebSocket
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import mcp.types as types
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logger = logging.getLogger(__name__)
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@asynccontextmanager
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async def websocket_server(scope: Scope, receive: Receive, send: Send):
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"""
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WebSocket server transport for MCP. This is an ASGI application, suitable to be
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used with a framework like Starlette and a server like Hypercorn.
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"""
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websocket = WebSocket(scope, receive, send)
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await websocket.accept(subprotocol="mcp")
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read_stream: MemoryObjectReceiveStream[types.JSONRPCMessage | Exception]
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read_stream_writer: MemoryObjectSendStream[types.JSONRPCMessage | Exception]
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write_stream: MemoryObjectSendStream[types.JSONRPCMessage]
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write_stream_reader: MemoryObjectReceiveStream[types.JSONRPCMessage]
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read_stream_writer, read_stream = anyio.create_memory_object_stream(0)
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write_stream, write_stream_reader = anyio.create_memory_object_stream(0)
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async def ws_reader():
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try:
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async with read_stream_writer:
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async for message in websocket.iter_json():
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try:
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client_message = types.JSONRPCMessage.model_validate(message)
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except Exception as exc:
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await read_stream_writer.send(exc)
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continue
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await read_stream_writer.send(client_message)
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except anyio.ClosedResourceError:
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await websocket.close()
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async def ws_writer():
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try:
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async with write_stream_reader:
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async for message in write_stream_reader:
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obj = message.model_dump(
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by_alias=True, mode="json", exclude_none=True
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)
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await websocket.send_json(obj)
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except anyio.ClosedResourceError:
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await websocket.close()
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async with anyio.create_task_group() as tg:
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tg.start_soon(ws_reader)
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tg.start_soon(ws_writer)
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yield (read_stream, write_stream)
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