René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"_handle_stateless_request  ClosedResourceError","articleBody":"### Initial Checks\n\n- [x] I confirm that I'm using the latest version of MCP Python SDK\n- [x] I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue\n\n### Description\nEvery request will try an exception\n\nuse `_handle_stateless_request` \u003e `run_stateless_server `\u003e `http_transport.connect()` \u003e `for session_message in write_stream_reader`\nIt will go in twice, and an exception(yio.ClosedResourceError) will be thrown when the second request has been closed\n\n### Example Code\n```Python\napp = Server(\"mcp-server\")\ndef main(port: int, transport: str, dev: bool, limit_concurrency: int) -\u003e int:\n    # Create the session manager with true stateless mode\n    from starlette.applications import Starlette\n    from starlette.routing import Mount, Route\n    session_manager = StreamableHTTPSessionManager(\n        app=app,\n        event_store=None,\n        json_response=True,\n        stateless=True, \n    )\n\n    @contextlib.asynccontextmanager\n    async def lifespan(app: Starlette) -\u003e AsyncIterator[None]:\n        \"\"\"Context manager for managing session manager lifecycle.\"\"\"\n        async with session_manager.run():\n            logger.info(\"Application started with StreamableHTTP session manager!\")\n            try:\n                yield\n            finally:\n                logger.info(\"Application shutting down...\")\n\n    async def handle_streamable_http(\n        scope: Scope, receive: Receive, send: Send\n    ) -\u003e None:\n        await session_manager.handle_request(scope, receive, send)\n\n    starlette_app = Starlette(\n        debug=dev,\n        routes=[\n            Mount(\"/message\", app=handle_streamable_http), \n        ],\n        lifespan=lifespan,\n    )\n    import uvicorn\n    uvicorn.run(starlette_app, host=\"0.0.0.0\", port=port, http=\"httptools\", limit_concurrency=limit_concurrency)\n\nif __name__ == \"__main__\":\n    asyncio.run(main())\n```\nview logs:\n```shell\n[2025-07-31 15:10:41,884][MainThread:19320][task_id:mcp.server.streamable_http][streamable_http.py:630][INFO][Terminating session: None]\n[2025-07-31 15:10:41,885][MainThread:19320][task_id:mcp.server.streamable_http][streamable_http.py:880][ERROR][Error in message router]\nTraceback (most recent call last):\n  File \"d:\\project\\bpaas\\apihub-mcp-server\\.venv\\Lib\\site-packages\\mcp\\server\\streamable_http.py\", line 831, in message_router\n    async for session_message in write_stream_reader:\n    ...\u003c46 lines\u003e...\n            )\n  File \"d:\\project\\bpaas\\apihub-mcp-server\\.venv\\Lib\\site-packages\\anyio\\abc\\_streams.py\", line 35, in __anext__\n    return await self.receive()\n           ^^^^^^^^^^^^^^^^^^^^\n  File \"d:\\project\\bpaas\\apihub-mcp-server\\.venv\\Lib\\site-packages\\anyio\\streams\\memory.py\", line 111, in receive\n    return self.receive_nowait()\n           ~~~~~~~~~~~~~~~~~~~^^\n  File \"d:\\project\\bpaas\\apihub-mcp-server\\.venv\\Lib\\site-packages\\anyio\\streams\\memory.py\", line 93, in receive_nowait\n    raise ClosedResourceError\nanyio.ClosedResourceError\n```\n\nTerminating has already released memory first\n\ndebug for : first\n\n\u003cimg width=\"894\" height=\"388\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/c7b1b741-1d0a-433e-b8ce-6d233b9fc125\" /\u003e\n\ndebug for : second\n\n\u003cimg width=\"818\" height=\"218\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/2b388192-30f5-461b-b228-62e430573bad\" /\u003e\n\nAnd the log shows that `Terminating` should be executed first, followed by `create_task_group`\n\n### Python \u0026 MCP Python SDK\n\n```Text\nMCP version: 1.12.2\nPython：3.13\n```","author":{"url":"https://github.com/281743556","@type":"Person","name":"281743556"},"datePublished":"2025-07-31T07:24:45.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/1219/python-sdk/issues/1219"}