messaging.py

# In charge of starting server listening and providing sending interface
import socket
import threading
import time
from protocol import *

class MessagingModule:
    def __init__(self, my_ip, my_port, node_id, logic_handler=None):
        self.ip = my_ip
        self.port = my_port
        self.node_id = node_id
        self.logic_handler = logic_handler
        self.running = True

    # Server
    def start_listening(self):
        # Start server listening thread
        server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        # Allow address reuse
        server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        server_socket.bind((self.ip, self.port))
        server_socket.listen(5)
        print(f"[Net] Node {self.node_id} listening on {self.ip}:{self.port}")
        while self.running:
            try:
                conn, addr = server_socket.accept()
                threading.Thread(target=self._handle_connection, args=(conn, addr), daemon=True).start()
            except Exception as e:
                print(f"[Net] Accept error: {e}")

    def _handle_connection(self, conn, addr):
        try:
            # Process data through recv_json
            message = recv_json(conn)
            if message:
                print(f"\n[~~~Recv~~~] From {addr}: {message}")

                # Pass message to logic handler
                if self.logic_handler:
                    self.logic_handler.handle_message(message)
        except Exception as e:
            print(f"[Net] Receive error: {e}")
        finally:
            conn.close()
        
    # Client
    def send_message(self, target_ip, target_port, msg_type, payload=None):
        """
        Inferface for Bully Algorithm to send messages.
        """
        if payload is None: payload = {}
        
        full_msg = {
            "type": msg_type,
            "sender_id": self.node_id,
            "host": self.ip,
            "port": self.port,
            "payload": payload
        }
        
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock.settimeout(2)
            sock.connect((target_ip, target_port))
            
            send_json(sock, full_msg)
            
            print(f"[--Send--] To {target_ip}:{target_port}:{msg_type}: {full_msg}")
            sock.close()
            return True
        except Exception as e:
            print(f"[*Net*] Send error to {target_ip}:{target_port}: {e}")
            return False