mcp-demo

Okay, here's a basic outline and code snippets for a simple MCP (Minecraft Communications Protocol) demo, including both a client and server, designed for studying the protocol. This is a *very* simplified example and doesn't implement the full complexity of the real MCP. It focuses on the core concepts of connection, sending, and receiving data. **Important Considerations:** * **This is a simplified demo:** The real MCP is far more complex, involving encryption, compression, and a large number of packets. This demo is for educational purposes only. * **Error Handling:** The code snippets below lack robust error handling for brevity. In a real application, you'd need to handle exceptions, connection errors, and invalid data. * **Threading:** The server uses basic threading. For a production server, you'd likely want a more sophisticated threading model (e.g., a thread pool). * **Security:** This demo has *no* security. Do not use it in a production environment. * **MCP Version:** This example does not target a specific MCP version. It's a generic illustration. **Conceptual Overview:** 1. **Connection:** The client connects to the server on a specified port. 2. **Handshake (Simplified):** In a real MCP implementation, there's a handshake process to negotiate protocol versions and encryption. This demo skips that for simplicity. 3. **Data Exchange:** The client sends data (e.g., a simple message) to the server. The server receives the data and can send a response. 4. **Disconnection:** The client and server close the connection. **Code Snippets (Python):** **Server (server.py):** ```python import socket import threading HOST = '127.0.0.1' # Standard loopback interface address (localhost) PORT = 25565 # Port to listen on (non-privileged ports are > 1023) def handle_client(conn, addr): print(f"Connected by {addr}") try: while True: data = conn.recv(1024) # Receive data in 1024-byte chunks if not data: break # Client disconnected message = data.decode('utf-8') print(f"Received from {addr}: {message}") response = f"Server received: {message}".encode('utf-8') conn.sendall(response) # Echo back to the client except Exception as e: print(f"Error handling client: {e}") finally: conn.close() print(f"Connection closed with {addr}") def main(): with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s: s.bind((HOST, PORT)) s.listen() print(f"Server listening on {HOST}:{PORT}") while True: conn, addr = s.accept() thread = threading.Thread(target=handle_client, args=(conn, addr)) thread.start() print(f"Active connections: {threading.active_count() - 1}") #Subtract main thread if __name__ == "__main__": main() ``` **Client (client.py):** ```python import socket HOST = '127.0.0.1' # The server's hostname or IP address PORT = 25565 # The port used by the server with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s: try: s.connect((HOST, PORT)) message = "Hello, MCP Server!" s.sendall(message.encode('utf-8')) data = s.recv(1024) print(f"Received: {data.decode('utf-8')}") except Exception as e: print(f"Error: {e}") finally: print("Closing connection") s.close() ``` **How to Run:** 1. **Save:** Save the code as `server.py` and `client.py`. 2. **Run the Server:** Open a terminal or command prompt and run `python server.py`. 3. **Run the Client:** Open another terminal or command prompt and run `python client.py`. **Explanation:** * **Server:** * Creates a socket, binds it to an address and port, and listens for incoming connections. * When a client connects, it accepts the connection and spawns a new thread to handle the client. * The `handle_client` function receives data from the client, decodes it, prints it to the console, and sends a response back to the client. * The server continues to listen for new connections. * **Client:** * Creates a socket and connects to the server. * Sends a message to the server. * Receives the response from the server and prints it to the console. * Closes the connection. **Key Concepts to Study (Related to MCP):** * **Sockets:** Understand how sockets work for network communication. * **TCP/IP:** Learn about the TCP/IP protocol suite, which MCP uses. * **Data Serialization:** MCP uses specific data formats (e.g., VarInts, strings) to encode data. Look into how data is serialized and deserialized. Libraries like `struct` in Python can be helpful for packing and unpacking binary data. * **Packet Structure:** MCP packets have a specific structure (packet ID, data fields). Study the packet formats for the Minecraft version you're interested in. * **State Management:** The client and server maintain state (e.g., login status, game state). * **Encryption:** MCP uses encryption (usually AES) to secure communication. Learn about encryption algorithms and how they're used in network protocols. * **Compression:** MCP uses compression (usually zlib) to reduce the amount of data transmitted. **Next Steps for Deeper Learning:** 1. **Implement VarInts:** MCP uses variable-length integers (VarInts). Implement functions to read and write VarInts. 2. **Implement a Simple Handshake:** Add a basic handshake where the client sends its protocol version to the server. 3. **Implement a Simple Packet:** Define a simple packet structure (e.g., a chat message packet) and implement the code to send and receive it. 4. **Study Real MCP Packets:** Use a packet sniffer (e.g., Wireshark) to capture real MCP packets and analyze their structure. The Minecraft Wiki has information about packet formats. 5. **Look at Existing Libraries:** There are existing libraries that implement MCP. Study their code to learn how they handle the protocol. (Be aware that some libraries may be outdated.) **Japanese Translation of Key Terms:** * **MCP (Minecraft Communications Protocol):** Minecraft通信プロトコル (Minecraft Tsūshin Purotokoru) * **Client:** クライアント (Kuraianto) * **Server:** サーバー (Sābā) * **Socket:** ソケット (Soketto) * **Packet:** パケット (Paketto) * **Connection:** 接続 (Setsuzoku) * **Handshake:** ハンドシェイク (Handosheiku) * **Data:** データ (Dēta) * **Encryption:** 暗号化 (Angōka) * **Compression:** 圧縮 (Asshuku) * **Protocol:** プロトコル (Purotokoru) * **Thread:** スレッド (Sureddo) This should give you a good starting point for studying MCP. Remember to start small and gradually increase the complexity of your implementation. Good luck!