python3练习-发送IP地址到邮箱

需求：
从外网通过VPN访问内网，并登录电脑A。在电脑A通过共享文件夹（需要\\IP的方式访问）访问到内网电脑B，由于电脑B的WI-FI的IP地址会变化，所以当电脑B的I访问路径需要获知电脑B的最新IP

import socket
import smtplib
import json
from email.header import Header
from email.mime.text import MIMEText
from email.utils import parseaddr, formataddr
import threading

now_ip = ""
mail_param_json = ""

# 内网B为win7操作系统，内网IP以10开头，取WIFI-IP
def _get_ip_win():
    ips = socket.gethostbyname_ex(socket.gethostname())
    for s in ips[2]:
        if s.startswith(‘10‘):
            return s

#发送邮件到指定的邮箱
#配置文件为json字符串：‘{"from_addr": "", "password": "", "to_addr": "", "smtp_server":""}‘
def _format_addr(s):
    name, addr = parseaddr(s)
    return formataddr((Header(name, ‘utf-8‘).encode(), addr))

def send_mail(json_param_str=None):
    if json_param_str != None and isinstance(json_param_str, str):
        e_param = json.loads(json_param_str)
        from_addr = e_param.get(‘from_addr‘)
        password = e_param.get(‘password‘)
        to_addr = e_param.get(‘to_addr‘)
        smtp_server = e_param.get(‘smtp_server‘)
        msg = MIMEText(‘ip address changed to : ‘ + _get_ip_win() + ‘\r\n‘, ‘plain‘, ‘utf-8‘)
        msg[‘From‘] = _format_addr(‘Reboot <%s>‘ % from_addr)
        msg[‘To‘] = _format_addr(‘Reboot <%s>‘ % to_addr)
        msg[‘Subject‘] = Header(‘NOTICE!!!--PC IP CHANGED‘, ‘utf-8‘).encode()
        server = smtplib.SMTP(smtp_server, 25)
        server.set_debuglevel(1)
        server.login(from_addr, password)
        server.sendmail(from_addr, [to_addr], msg.as_string())
        server.quit()
    else:
        pass

#定时检查IP是否有变化
def checkIP(start_ip):
    global now_ip
    if start_ip != now_ip:
        global mail_param_json
        send_mail(mail_param_json)
        print("发送邮件,旧IP：",now_ip,"---新IP：",start_ip)
        now_ip = start_ip
    else:
        print("IP地址未发生变化,旧IP：", start_ip, "---新IP：", now_ip)
    new_ip = _get_ip_win()
    t = threading.Timer(3600.0, checkIP,(new_ip,))
    t.start()

#初始化 读取配置文件
if __name__ == ‘__main__‘:
    with open(‘./config‘, ‘r‘) as f:
        mail_param_json = f.read()
    start_ip,now_ip = _get_ip_win(),_get_ip_win()
    checkIP(start_ip)