UnrealBlueprintMCP

// Copyright Epic Games, Inc. All Rights Reserved. // MCPClient - WebSocket client for MCP server communication #pragma once #include "CoreMinimal.h" #include "UObject/NoExportTypes.h" #include "IWebSocket.h" #include "Dom/JsonObject.h" #include "MCPSettings.h" #include "UnrealBlueprintMCPAPI.h" #include "MCPClient.generated.h" class SMCPStatusWidget; class FWebSocketsModule; class UMCPBlueprintManager; /** * Delegate for connection state changes * @param NewState The new connection state * @param ErrorMessage Optional error message if connection failed */ DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnMCPConnectionStateChanged, EMCPConnectionState, NewState, const FString&, ErrorMessage); /** * Delegate for incoming MCP messages * @param MessageType The type of MCP message received * @param MessageData The JSON data of the message */ DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnMCPMessageReceived, const FString&, MessageType, const FString&, MessageData); /** * Delegate for MCP operation responses * @param RequestId The ID of the original request * @param bSuccess Whether the operation was successful * @param ResponseData The response data as JSON string */ DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams(FOnMCPOperationComplete, const FString&, RequestId, bool, bSuccess, const FString&, ResponseData); /** * Structure representing an MCP message for sending/receiving */ USTRUCT(BlueprintType) struct UNREALBLUEPRINTMCP_API FMCPMessage { GENERATED_BODY() /** Unique identifier for the message */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Id; /** Type of the MCP message (request, response, notification) */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Type; /** Method name for requests */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Method; /** Parameters as JSON string */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Params; /** Result data for responses */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Result; /** Error information if any */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FString Error; /** Timestamp when message was created */ UPROPERTY(BlueprintReadWrite, Category = "MCP Message") FDateTime Timestamp; /** Default constructor */ FMCPMessage() : Timestamp(FDateTime::Now()) { } /** Constructor with basic fields */ FMCPMessage(const FString& InId, const FString& InType, const FString& InMethod = TEXT("")) : Id(InId) , Type(InType) , Method(InMethod) , Timestamp(FDateTime::Now()) { } }; /** * WebSocket client for connecting to MCP (Model Context Protocol) servers. * * This class handles the WebSocket connection to external AI servers using the MCP protocol, * providing methods for sending requests, receiving responses, and managing connection state. * It integrates with the MCPSettings configuration and provides delegate events for UI updates. * * Key features: * - Automatic connection management with reconnection logic * - JSON message serialization/deserialization for MCP protocol * - Thread-safe operation with proper delegate dispatching * - Integration with MCPStatusWidget for real-time status updates * - Comprehensive error handling and logging */ UCLASS(BlueprintType, Blueprintable) class UNREALBLUEPRINTMCP_API UMCPClient : public UObject { GENERATED_BODY() public: /** Constructor */ UMCPClient(); /** Destructor */ virtual ~UMCPClient(); //~ Begin UObject Interface virtual void BeginDestroy() override; //~ End UObject Interface /** * Get the singleton instance of MCPClient * @param bCreateIfNeeded Whether to create the instance if it doesn't exist * @return The singleton MCPClient instance */ UFUNCTION(BlueprintPure, Category = "MCP Client") static UMCPClient* Get(bool bCreateIfNeeded = true); /** * Shutdown the singleton instance safely */ static void Shutdown(); /** * Check if the client is shutting down * @return True if shutting down */ static bool IsShuttingDown() { return bIsShuttingDown; } /** * Initialize the MCP client with settings * @param InSettings The MCP settings to use for configuration * @return True if initialization was successful */ UFUNCTION(BlueprintCallable, Category = "MCP Client") bool Initialize(UMCPSettings* InSettings = nullptr); /** * Connect to the MCP server using current settings * @return True if connection attempt was started successfully */ UFUNCTION(BlueprintCallable, Category = "MCP Client") bool Connect(); /** * Disconnect from the MCP server * @param bGraceful Whether to perform a graceful disconnect */ UFUNCTION(BlueprintCallable, Category = "MCP Client") void Disconnect(bool bGraceful = true); /** * Check if currently connected to MCP server * @return True if connected */ UFUNCTION(BlueprintPure, Category = "MCP Client") bool IsConnected() const; /** * Get the current connection state * @return Current connection state */ UFUNCTION(BlueprintPure, Category = "MCP Client") EMCPConnectionState GetConnectionState() const; /** * Send an MCP request message to the server * @param Method The MCP method to call * @param Params Parameters as JSON object * @param RequestId Optional custom request ID (auto-generated if empty) * @return The request ID for tracking the response */ UFUNCTION(BlueprintCallable, Category = "MCP Client") FString SendRequest(const FString& Method, const FString& Params, const FString& RequestId = TEXT("")); /** * Send an MCP notification message to the server * @param Method The MCP method name * @param Params Parameters as JSON string * @return True if message was sent successfully */ UFUNCTION(BlueprintCallable, Category = "MCP Client") bool SendNotification(const FString& Method, const FString& Params); /** * Send a raw JSON message to the server * @param JsonMessage The JSON message string to send * @return True if message was sent successfully */ UFUNCTION(BlueprintCallable, Category = "MCP Client") bool SendRawMessage(const FString& JsonMessage); /** * Register a status widget for receiving updates * @param StatusWidget The widget to register for updates */ void RegisterStatusWidget(TSharedPtr<SMCPStatusWidget> StatusWidget); /** * Unregister a status widget from receiving updates * @param StatusWidget The widget to unregister */ void UnregisterStatusWidget(TSharedPtr<SMCPStatusWidget> StatusWidget); /** * Set whether to enable automatic reconnection * @param bEnable Whether to enable auto-reconnect */ UFUNCTION(BlueprintCallable, Category = "MCP Client") void SetAutoReconnectEnabled(bool bEnable); /** * Get whether automatic reconnection is enabled * @return True if auto-reconnect is enabled */ UFUNCTION(BlueprintPure, Category = "MCP Client") bool IsAutoReconnectEnabled() const; /** * Get the last error message if any * @return The last error message */ UFUNCTION(BlueprintPure, Category = "MCP Client") FString GetLastErrorMessage() const; /** * Clear the last error message */ UFUNCTION(BlueprintCallable, Category = "MCP Client") void ClearLastError(); /** * Process blueprint-related MCP commands * @param Method The MCP method (create_blueprint, set_property) * @param Params Parameters as JSON string * @return Response as JSON string */ UFUNCTION(BlueprintCallable, Category = "MCP Client") FString ProcessBlueprintCommand(const FString& Method, const FString& Params); public: // Delegate events /** Event fired when connection state changes */ UPROPERTY(BlueprintAssignable, Category = "MCP Client Events") FOnMCPConnectionStateChanged OnConnectionStateChanged; /** Event fired when an MCP message is received */ UPROPERTY(BlueprintAssignable, Category = "MCP Client Events") FOnMCPMessageReceived OnMessageReceived; /** Event fired when an MCP operation completes */ UPROPERTY(BlueprintAssignable, Category = "MCP Client Events") FOnMCPOperationComplete OnOperationComplete; private: // WebSocket event handlers /** Called when WebSocket connection is established */ void OnWebSocketConnected(); /** Called when WebSocket connection fails */ void OnWebSocketConnectionError(const FString& Error); /** Called when WebSocket connection is closed */ void OnWebSocketClosed(int32 StatusCode, const FString& Reason, bool bWasClean); /** Called when a message is received from WebSocket */ void OnWebSocketMessage(const FString& Message); /** Called when binary data is received (not used for MCP) */ void OnWebSocketBinaryMessage(const void* Data, uint64 Size, bool bIsLastFragment); /** Called when a message is sent successfully */ void OnWebSocketMessageSent(const FString& Message); // Connection management /** Update the connection state and notify listeners */ void SetConnectionState(EMCPConnectionState NewState, const FString& ErrorMessage = TEXT("")); /** Start the auto-reconnect timer */ void StartAutoReconnectTimer(); /** Stop the auto-reconnect timer */ void StopAutoReconnectTimer(); /** Called by auto-reconnect timer */ void AttemptReconnect(); /** Reset reconnection attempt counter */ void ResetReconnectAttempts(); // Message handling /** Process an incoming MCP message */ void ProcessIncomingMessage(const FString& JsonMessage); /** Parse a JSON message into an MCP message structure */ bool ParseMCPMessage(const FString& JsonMessage, FMCPMessage& OutMessage); /** Create a JSON string from an MCP message */ FString CreateJsonFromMCPMessage(const FMCPMessage& Message); /** Generate a unique request ID */ FString GenerateRequestId(); /** Validate MCP message format */ bool ValidateMCPMessage(const FMCPMessage& Message); // Utility functions /** Log a message with MCP client prefix */ void LogMessage(const FString& Message, ELogVerbosity::Type Verbosity = ELogVerbosity::Log); /** Notify registered status widgets of updates */ void NotifyStatusWidgets(const FString& MessageLogLevel, const FString& LogMessage); /** Get the WebSocket URL from current settings */ FString GetWebSocketURL() const; /** Check if settings are valid for connection */ bool ValidateConnectionSettings() const; private: // Core components /** Reference to MCP settings */ UPROPERTY(Transient) UMCPSettings* MCPSettings; /** Reference to blueprint manager */ UPROPERTY(Transient) UMCPBlueprintManager* BlueprintManager; /** WebSocket connection instance */ TSharedPtr<IWebSocket> WebSocket; /** WebSockets module reference */ FWebSocketsModule* WebSocketsModule; // State management /** Current connection state */ EMCPConnectionState CurrentConnectionState; /** Last error message */ FString LastErrorMessage; /** Whether auto-reconnect is enabled */ bool bAutoReconnectEnabled; /** Number of reconnection attempts made */ int32 ReconnectAttempts; /** Timer handle for auto-reconnect */ FTimerHandle AutoReconnectTimerHandle; /** Timestamp of last connection attempt */ FDateTime LastConnectionAttempt; // Message tracking /** Map of pending requests by ID */ TMap<FString, FMCPMessage> PendingRequests; /** Counter for generating unique request IDs */ int32 RequestIdCounter; /** Mutex for thread-safe access to pending requests */ mutable FCriticalSection RequestsMutex; // UI integration /** Registered status widgets for updates */ TArray<TWeakPtr<SMCPStatusWidget>> RegisteredStatusWidgets; /** Mutex for thread-safe access to status widgets */ mutable FCriticalSection StatusWidgetsMutex; // Constants /** Maximum number of reconnection attempts */ static const int32 MaxReconnectAttempts = 10; /** Base delay between reconnection attempts (seconds) */ static const float BaseReconnectDelay; /** Maximum delay between reconnection attempts (seconds) */ static const float MaxReconnectDelay; /** WebSocket connection timeout (seconds) */ static const float ConnectionTimeout; /** MCP protocol version */ static const FString MCPProtocolVersion; // Singleton instance static UMCPClient* SingletonInstance; // Shutdown state static bool bIsShuttingDown; };