server upd

added python client

client.py

@@ -0,0 +1,50 @@
+import socket
+import struct
+import argparse
+
+
+def recv_exact(sock: socket.socket, n: int) -> bytes:
+    data = b''
+    while len(data) < n:
+        chunk = sock.recv(n - len(data))
+        if len(chunk) == 0:
+            raise ConnectionError('EOF from server')
+        data += chunk
+    return data
+
+def send_frame(sock: socket.socket, payload: bytes) -> None:
+    header = struct.pack('!I', len(payload))
+    sock.sendall(header + payload)
+
+def recv_frame(sock: socket.socket) -> bytes:
+    header = recv_exact(sock, 4)
+    (length,) = struct.unpack('!I', header)
+    if length > 10_000_000:
+        raise ValueError('Message length is too long')
+    return recv_exact(sock, length)
+
+def main():
+    parser = argparse.ArgumentParser(description='NOT(Redis) client')
+    parser.add_argument('-H', '--host', type=str, required=False, default='127.0.0.1', help='Server host')
+    parser.add_argument('-P', '--port', type=int, required=False, default=6379, help='Server port')
+    parser.add_argument('-M', '--message', type=str, required=False, default='hello', help='Message to send')
+    args = parser.parse_args()
+
+    try:
+        with socket.create_connection((args.host, args.port)) as sock:
+            send_frame(sock, args.message.encode())
+            response = recv_frame(sock)
+            print('Message sent:', args.message)
+            print('Server says:', response.decode("utf-8", errors='replace'))
+    except ConnectionRefusedError as e:
+        print('Connection refused by server:', e)
+        exit(1)
+    except ConnectionError as e:
+        print('Failed to connect to server:', e)
+        exit(1)
+    except Exception as e:
+        print('Unexpected error:', e)
+        exit(1)
+    
+if __name__ == '__main__':
+    main()