fix http transport

Author: shahar4499

fastapi_mcp/server.py

@@ -347,7 +347,7 @@ def mount_http(
 
         assert isinstance(router, (FastAPI, APIRouter)), f"Invalid router type: {type(router)}"
 
-        http_transport = FastApiStreamableHttpTransport()
+        http_transport = FastApiStreamableHttpTransport(mcp_server=self.server)
         dependencies = self._auth_config.dependencies if self._auth_config else None
 
         self._register_mcp_endpoints_http(router, http_transport, mount_path, dependencies)

fastapi_mcp/transport/http.py

@@ -1,6 +1,7 @@
 import logging
 
 from fastapi import Request, Response, HTTPException
+from mcp.server.lowlevel.server import Server
 from mcp.server.streamable_http import StreamableHTTPServerTransport
 from mcp.server.transport_security import TransportSecuritySettings
 
@@ -14,6 +15,7 @@ def __init__(
         is_json_response_enabled: bool = True,  # Default to JSON for HTTP transport
         event_store=None,
         security_settings: TransportSecuritySettings | None = None,
+        mcp_server: Server | None = None,
     ):
         super().__init__(
             mcp_session_id=mcp_session_id,
@@ -22,8 +24,10 @@ def __init__(
             security_settings=security_settings,
         )
         logger.debug(f"FastApiStreamableHttpTransport initialized with session_id: {mcp_session_id}")
+        self._mcp_server = mcp_server
+        self._server_running = False
 
-    async def handle_fastapi_request(self, request: Request) -> Response:
+    async def handle_fastapi_request(self, request: Request, mcp_server: Server | None = None) -> Response:
         """
         The approach here is different from FastApiSseTransport.
         In FastApiSseTransport, we reimplement the SSE transport logic to have a more FastAPI-native transport.
@@ -37,6 +41,33 @@ async def handle_fastapi_request(self, request: Request) -> Response:
         """
         logger.debug(f"Handling FastAPI request: {request.method} {request.url.path}")
 
+        # Use the stored server if available, or the passed one
+        server = self._mcp_server or mcp_server
+        if not server:
+            raise HTTPException(status_code=500, detail="No MCP server available")
+
+        # Initialize the transport if not already done
+        if not self._server_running:
+            import anyio
+
+            async def start_server():
+                self._server_running = True
+                async with self.connect() as (reader, writer):
+                    await server.run(
+                        reader,
+                        writer,
+                        server.create_initialization_options(notification_options=None, experimental_capabilities={}),
+                        raise_exceptions=False,
+                    )
+
+            # Start the server in a background task
+            import asyncio
+
+            asyncio.create_task(start_server())
+
+            # Give the server a moment to initialize
+            await anyio.sleep(0.1)
+
         # Capture the response from the SDK's handle_request method
         response_started = False
         response_status = 200