DRAFT: Add middleware to expose raw headers in contextvar

src/north_mcp_python_sdk/__init__.py

@@ -8,7 +8,12 @@
 from starlette.middleware import Middleware
 from starlette.middleware.authentication import AuthenticationMiddleware
 
-from .auth import AuthContextMiddleware, NorthAuthBackend, on_auth_error
+from .auth import (
+    AuthContextMiddleware,
+    HeadersContextMiddleware,
+    NorthAuthBackend,
+    on_auth_error,
+)
 
 
 def is_debug_mode() -> bool:
@@ -66,5 +71,6 @@ def _add_middleware(self, app: Starlette) -> None:
                 on_error=on_auth_error,
             ),
             Middleware(AuthContextMiddleware, debug=self._debug),
+            Middleware(HeadersContextMiddleware, debug=self._debug),
         ]
         app.user_middleware.extend(middleware)

src/north_mcp_python_sdk/auth.py

@@ -1,6 +1,7 @@
 import base64
 import contextvars
 import logging
+from typing import Any
 
 import jwt
 from pydantic import BaseModel, Field, ValidationError
@@ -35,6 +36,10 @@ def __init__(
     "north_auth_context", default=None
 )
 
+headers_context_var = contextvars.ContextVar[dict[str, Any] | None](
+    "north_headers_context", default=None
+)
+
 
 def on_auth_error(request: HTTPConnection, exc: AuthenticationError) -> JSONResponse:
     return JSONResponse({"error": str(exc)}, status_code=401)
@@ -48,6 +53,14 @@ def get_authenticated_user() -> AuthenticatedNorthUser:
     return user
 
 
+def get_raw_headers() -> dict[str, Any]:
+    headers = headers_context_var.get()
+    if not headers:
+        raise Exception("headers not found in context")
+
+    return headers
+
+
 class AuthContextMiddleware:
     """
     Middleware that extracts the authenticated user from the request
@@ -83,6 +96,32 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send):
             auth_context_var.reset(token)
 
 
+class HeadersContextMiddleware:
+    """
+    Middleware that sets the request headers in a contextvar for easy access
+    throughout the request lifecycle.
+    """
+
+    def __init__(self, app: ASGIApp, debug: bool = False):
+        self.app = app
+        self.debug = debug
+        self.logger = logging.getLogger("NorthMCP.HeadersContext")
+        if debug:
+            self.logger.setLevel(logging.DEBUG)
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send):
+        if scope["type"] == "lifespan":
+            return await self.app(scope, receive, send)
+
+        headers = dict(scope.get("headers", {}))
+        self.logger.debug("Setting request headers in context: %s", headers)
+        token = headers_context_var.set(headers)
+        try:
+            await self.app(scope, receive, send)
+        finally:
+            headers_context_var.reset(token)
+
+
 class NorthAuthBackend(AuthenticationBackend):
     """
     Authentication backend that validates Bearer tokens.