Python automatically obtains the external network IP and sends it to the mailbox

1. Define the function of get_ip

def get_ip():
    try:
        url = 'https://2021.ip138.com/'
        kv = {
    
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36'}
        par = {
    
    "prd": "resoukuang"}
        html = requests.get(url=url, headers=kv, params=par).text
        soup = BeautifulSoup(html, 'html.parser')
        title = soup.title.string
        return title
    except:
        return ""

Request https://2021.ip138.com/ through requests, because its title just returns your IP, then we can go directly to bs4 to get the value of title and return it. 2.
Define the function to send mail

def mail(content):
    # 发送者的邮箱地址
    sender = '发送者的邮箱地址'
    # 接收者的邮箱地址
    receivers = ['接收者的邮箱地址1', '接收者的邮箱地址2']  
    # content是你要发送的内容, 我这里是调用函数穿过来的参数content
    message = MIMEText(content, _subtype='plain', _charset='utf-8')
    # 邮件的发送者
    message['From'] = Header(sender, 'utf-8')
    # 邮件的接收者
    message['To'] = Header('coolwoow', 'utf-8')
    # 邮件的标题
    message['Subject'] = Header('主人, 你家里面的IP又变了:', 'utf-8') 
    smtper = SMTP('smtp.qq.com')
    # QQ邮箱smtp的授权码
    smtper.login(sender, 'QQ邮箱smtp的授权码')  
    smtper.sendmail(sender, receivers, message.as_string())

3. Complete the code, just create the corresponding thread to keep looping. When I use it, it is defined to detect whether the IP changes once every hour.

import requests
import threading
from bs4 import BeautifulSoup
from smtplib import SMTP
from email.header import Header
from email.mime.text import MIMEText
import time

def get_ip():
    try:
        url = 'https://2021.ip138.com/'
        kv = {
    
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36'}
        par = {
    
    "prd": "resoukuang"}
        html = requests.get(url=url, headers=kv, params=par).text
        soup = BeautifulSoup(html, 'html.parser')
        title = soup.title.string
        return title
    except:
        return ""
def mail(content):
    # 发送者的邮箱地址
    sender = '发送者的邮箱地址'
    # 接收者的邮箱地址
    receivers = ['接收者的邮箱地址1', '接收者的邮箱地址2']  
    # content是你要发送的内容, 我这里是调用函数穿过来的参数content
    message = MIMEText(content, _subtype='plain', _charset='utf-8')
    # 邮件的发送者
    message['From'] = Header(sender, 'utf-8')
    # 邮件的接收者
    message['To'] = Header('coolwoow', 'utf-8')
    # 邮件的标题
    message['Subject'] = Header('主人, 你家里面的IP又变了', 'utf-8') 
    smtper = SMTP('smtp.qq.com')
    # QQ邮箱smtp的授权码
    smtper.login(sender, 'QQ邮箱smtp的授权码')  
    smtper.sendmail(sender, receivers, message.as_string())
# 这里我用一个txt存放上次获取到的值得, 你可以事先把上面get_ip()的结果存在里面
f = open('ip.txt', 'r', encoding='utf-8')
old_ip = f.read()
f.close()
def main():
    global old_ip
    while True:
        if get_ip() != "":
            if old_ip != get_ip():
                old_ip = get_ip()
                mail(old_ip)
                with open('ip.txt', 'w') as f:
                    f.write(old_ip)
        time.sleep(120)

thread_run = threading.Thread(target=main)
thread_run.start()