Keep HTTP requests separate during cancellation

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
           # Current leg: catches breakage from new Xcode and SDK releases.
           - os: macos-latest
             swift-version: Xcode default
-          - os: ubuntu-latest
+          - os: ubuntu-24.04
             swift-version: 6.1.0
 
     runs-on: ${{ matrix.os }}
@@ -35,13 +35,13 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Prepare Linux apt dependencies
-        if: matrix.os == 'ubuntu-latest'
+        if: matrix.os == 'ubuntu-24.04'
         run: |
           sudo -n apt-get update
           sudo -n apt-get install -y --no-install-recommends libcurl4-openssl-dev
 
       - name: Setup Swift on Linux
-        if: matrix.os == 'ubuntu-latest'
+        if: matrix.os == 'ubuntu-24.04'
         uses: vapor/swiftly-action@v0.2
         with:
           toolchain: ${{ matrix.swift-version }}

Sources/MCP/Base/Transports/HTTPServer/HTTPServerTypes.swift

@@ -225,6 +225,18 @@ public protocol HTTPContextProviding: Sendable {
     func httpRequestContext(for id: ID) async -> HTTPRequest?
 }
 
+/// A transport-internal mapping between private routed ids and client wire ids.
+package protocol RoutedRequestIDProviding: Sendable {
+    func originalRequestID(for routedID: ID) async -> ID?
+
+    /// Returns `nil` when the wire id has no active exchange or is ambiguous.
+    func routedRequestID(for originalID: ID) async -> ID?
+}
+
+package protocol CancelledHTTPExchangeCompleting: Sendable {
+    func completeCancelledExchange(for routedID: ID, reason: String?) async
+}
+
 // MARK: - JSON-RPC Message Classification
 
 /// Classifies a raw JSON-RPC message for routing purposes.