refactor: rename _update_headers_for_request to _prepare_request_headers

This better reflects that the method prepares headers for outgoing HTTP
requests, not just updating them with context. The method adds both
session ID and protocol version headers as needed.

Author: felixweinberger

src/mcp/client/streamable_http.py

@@ -108,9 +108,7 @@ def __init__(
             **self.headers,
         }
 
-    def _update_headers_with_session(
-        self, base_headers: dict[str, str]
-    ) -> dict[str, str]:
+    def _prepare_request_headers(self, base_headers: dict[str, str]) -> dict[str, str]:
         """Update headers with session ID and protocol version if available."""
         headers = base_headers.copy()
         if self.session_id:
@@ -200,7 +198,7 @@ async def handle_get_stream(
             if not self.session_id:
                 return
 
-            headers = self._update_headers_with_session(self.request_headers)
+            headers = self._prepare_request_headers(self.request_headers)
 
             async with aconnect_sse(
                 client,
@@ -223,7 +221,7 @@ async def handle_get_stream(
 
     async def _handle_resumption_request(self, ctx: RequestContext) -> None:
         """Handle a resumption request using GET with SSE."""
-        headers = self._update_headers_with_session(ctx.headers)
+        headers = self._prepare_request_headers(ctx.headers)
         if ctx.metadata and ctx.metadata.resumption_token:
             headers[LAST_EVENT_ID] = ctx.metadata.resumption_token
         else:
@@ -259,7 +257,7 @@ async def _handle_resumption_request(self, ctx: RequestContext) -> None:
 
     async def _handle_post_request(self, ctx: RequestContext) -> None:
         """Handle a POST request with response processing."""
-        headers = self._update_headers_with_session(ctx.headers)
+        headers = self._prepare_request_headers(ctx.headers)
         message = ctx.session_message.message
         is_initialization = self._is_initialization_request(message)
 
@@ -435,7 +433,7 @@ async def terminate_session(self, client: httpx.AsyncClient) -> None:
             return
 
         try:
-            headers = self._update_headers_with_session(self.request_headers)
+            headers = self._prepare_request_headers(self.request_headers)
             response = await client.delete(self.url, headers=headers)
 
             if response.status_code == 405: