#!/usr/bin/python3
# coding= utf-8

import socket
import sys
import struct
import json

# 本机信息
import time

host_ip = socket.gethostbyname(socket.gethostname())
# 组播组IP和端口
mcast_group_ip = '224.1.1.1'
mcast_group_port = 2234


def receiver():
    # 建立接收 udp socket
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    # linux能绑定网卡这里绑定组播IP地址不会服错，windows没法绑定网卡只能绑定本网卡IP地址
    if "linux" in sys.platform:
        # 绑定到的网卡名，如果自己的不是eth0则修改
        nic_name = 0
        # 监听的组播地址
        sock.setsockopt(socket.SOL_SOCKET, 25, nic_name)
        sock.bind((mcast_group_ip, mcast_group_port))
    else:
        sock.bind((host_ip, mcast_group_port))
    # 加入组播组
    mq_request = struct.pack("=4sl", socket.inet_aton(mcast_group_ip), socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mq_request)
    # 设置非阻塞
    sock.setblocking(True)
    while True:
        try:
            data, address = sock.recvfrom(4096)
            data2 = json.loads(data)
            # 若组播数据不正确
            if len(data2) < 3:
                return
        except socket.error as e:
            print(f"while receive message error occur:{e}")
        else:
            print("Receive Data!")
            print("FROM: ", address)
            print("DATA: ", data.decode('utf-8'))


if __name__ == "__main__":
    receiver()