Merge pull request #28 from 0xeb/fix/jsonrpc-notification-handling

Fix JSON-RPC 2.0 notification handling in StreamableHttpServerWrapper

Author: 0xeb

.githooks/README.md

@@ -0,0 +1,27 @@
+# Git Hooks
+
+This directory contains git hooks for the fastmcpp project.
+
+## Installation
+
+Run one of the following commands to enable the hooks:
+
+```bash
+# Option 1: Configure git to use this directory for hooks
+git config core.hooksPath .githooks
+
+# Option 2: Symlink (Linux/macOS)
+ln -sf ../../.githooks/pre-commit .git/hooks/pre-commit
+```
+
+## Available Hooks
+
+### pre-commit
+
+Automatically formats staged C++ files with clang-format before commit.
+
+- Finds clang-format (prefers versioned like clang-format-19)
+- Formats only staged `.cpp`, `.hpp`, `.h`, `.c` files
+- Re-stages formatted files automatically
+
+This ensures all committed code follows the project's formatting style.

.githooks/pre-commit

@@ -1,26 +1,34 @@
 #!/bin/bash
-# Pre-commit hook: auto-format staged C++ files
-#
-# Enable with: git config core.hooksPath .githooks
+# Pre-commit hook to automatically format C++ files with clang-format
+# Install: git config core.hooksPath .githooks
 
-STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(cpp|hpp)$')
+# Find clang-format (prefer versioned, fall back to unversioned)
+CLANG_FORMAT=""
+for cf in clang-format-19 clang-format-18 clang-format-17 clang-format; do
+    if command -v "$cf" &> /dev/null; then
+        CLANG_FORMAT="$cf"
+        break
+    fi
+done
 
-if [ -z "$STAGED_FILES" ]; then
+if [ -z "$CLANG_FORMAT" ]; then
+    echo "Warning: clang-format not found, skipping formatting"
     exit 0
 fi
 
-# Check if clang-format is available
-if ! command -v clang-format &> /dev/null; then
-    echo "Warning: clang-format not found, skipping auto-format"
+# Get staged C++ files
+STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(cpp|hpp|h|c)$')
+
+if [ -z "$STAGED_FILES" ]; then
     exit 0
 fi
 
-# Auto-format and re-stage
+# Format each staged file
 for file in $STAGED_FILES; do
     if [ -f "$file" ]; then
-        clang-format -i "$file"
+        $CLANG_FORMAT -i "$file"
         git add "$file"
     fi
 done
 
-exit 0
+echo "Formatted $(echo "$STAGED_FILES" | wc -w) file(s) with $CLANG_FORMAT"

src/server/streamable_http_server.cpp

@@ -211,6 +211,27 @@ bool StreamableHttpServerWrapper::start()
                     return;
                 }
 
+                // Check if this is a notification (no "id" field means notification)
+                // JSON-RPC 2.0 spec: server MUST NOT reply to notifications
+                bool is_notification = !message.contains("id") || message["id"].is_null();
+
+                if (is_notification)
+                {
+                    // For notifications, call handler but don't send response body
+                    // This is required by JSON-RPC 2.0 spec and MCP protocol
+                    try
+                    {
+                        handler_(message); // Process but ignore result
+                    }
+                    catch (...)
+                    {
+                        // Silently ignore errors for notifications
+                    }
+                    res.set_header("Mcp-Session-Id", session_id);
+                    res.status = 202; // Accepted, no content
+                    return;
+                }
+
                 // Normal request - process with handler
                 auto response = handler_(message);
 

tests/server/streamable_http_integration.cpp

@@ -452,6 +452,78 @@ void test_default_timeout_allows_slow_tool()
     server.stop();
 }
 
+void test_notification_handling()
+{
+    std::cout << "  test_notification_handling... " << std::flush;
+
+    const int port = 18356;
+    const std::string host = "127.0.0.1";
+
+    // Create minimal handler
+    tools::ToolManager tool_mgr;
+    std::unordered_map<std::string, std::string> descriptions;
+    auto handler = mcp::make_mcp_handler("notification_test", "1.0.0", tool_mgr, descriptions);
+
+    server::StreamableHttpServerWrapper server(handler, host, port, "/mcp");
+    bool started = server.start();
+    assert(started && "Server failed to start");
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(500));
+
+    try
+    {
+        httplib::Client cli(host, port);
+        cli.set_connection_timeout(5, 0);
+        cli.set_read_timeout(5, 0);
+
+        // First initialize to get a session
+        Json init_request = {{"jsonrpc", "2.0"},
+                             {"id", 1},
+                             {"method", "initialize"},
+                             {"params",
+                              {{"protocolVersion", "2024-11-05"},
+                               {"capabilities", Json::object()},
+                               {"clientInfo", {{"name", "test"}, {"version", "1.0"}}}}}};
+
+        auto init_res = cli.Post("/mcp", init_request.dump(), "application/json");
+        assert(init_res && init_res->status == 200);
+
+        std::string session_id = init_res->get_header_value("Mcp-Session-Id");
+        assert(!session_id.empty() && "Should have session ID");
+
+        // Now send a notification (no "id" field = notification per JSON-RPC 2.0)
+        // JSON-RPC 2.0 spec: server MUST NOT reply to notifications
+        Json notification = {{"jsonrpc", "2.0"}, {"method", "notifications/initialized"}};
+
+        httplib::Headers headers = {{"Mcp-Session-Id", session_id}};
+        auto notif_res = cli.Post("/mcp", headers, notification.dump(), "application/json");
+
+        // Server should return 202 Accepted with no content body
+        assert(notif_res && "Notification request should succeed");
+        assert(notif_res->status == 202 && "Notification should return 202 Accepted");
+        assert(notif_res->body.empty() && "Notification response should have no body");
+
+        // Test another common notification: notifications/cancelled
+        Json cancel_notification = {{"jsonrpc", "2.0"},
+                                    {"method", "notifications/cancelled"},
+                                    {"params", {{"requestId", "123"}, {"reason", "timeout"}}}};
+
+        auto cancel_res = cli.Post("/mcp", headers, cancel_notification.dump(), "application/json");
+        assert(cancel_res && cancel_res->status == 202 && "Cancel notification should return 202");
+        assert(cancel_res->body.empty() && "Cancel notification response should have no body");
+
+        std::cout << "PASSED\n";
+    }
+    catch (const std::exception& e)
+    {
+        std::cout << "FAILED: " << e.what() << "\n";
+        server.stop();
+        throw;
+    }
+
+    server.stop();
+}
+
 int main()
 {
     std::cout << "Streamable HTTP Integration Tests\n";
@@ -465,6 +537,7 @@ int main()
         test_server_info();
         test_error_handling();
         test_default_timeout_allows_slow_tool();
+        test_notification_handling();
 
         std::cout << "\nAll tests passed!\n";
         return 0;