Can a domain name be bound to a dynamic IP? Really gained knowledge again, no need to buy a fixed IP anymore, hurry up to collect

Hello everyone, I'm Glacier~~

Generally, the public IP of the home network is not fixed, and I want to access the application on my server through the domain name, that is to say: I need to bind the domain name to the dynamic IP to achieve this requirement. So, I started to explore the technical solutions to realize it.

After consulting a series of materials online, I found that Alibaba Cloud can achieve dynamic domain name resolution (DDNS). So, after one operation, I realized the domain name binding dynamic IP. Here, we take Python as an example.

Attention friends: The Java version source code has been submitted to: https://github.com/sunshinelyz/mykit-ddns

Okay, let's do it, let's start, let's go~~

Alibaba Cloud DDNS prerequisites

The domain name was purchased on Alibaba Cloud
The address must be a public network address, otherwise it is useless to add parsing

Through the SDK provided by Alibaba Cloud, you can write programs by yourself to add or modify domain name resolution to achieve the purpose of dynamic domain name resolution; it is mainly used in the pppoe dial-up environment, such as the scenario where a server is set up at home, but the external network address changes frequently; For example, the company's pppoe gateway needs to establish a VPN scenario.

Install Alibaba Cloud SDK

Two SDK libraries need to be installed, one is the Alibaba Cloud core SDK library, and the other is the Alibaba Cloud domain name SDK library;

Alibaba Cloud Core SDK Library

pip install aliyun-python-sdk-core

Alibaba Cloud Domain Name SDK Library

pip install aliyun-python-sdk-domain

Alibaba Cloud DNSSDK library

pip install aliyun-python-sdk-alidns

Design ideas

Get the accessKeyId and accessSecret of Alibaba Cloud
Get external network ip
Determine whether the external network ip is the same as before
When the external network IP is inconsistent, add or update the domain name resolution record

Implementation plan

Here, I give the complete Python code directly, and the friends replace AccessKey and AccessSecret by themselves.

#!/usr/bin/env python
#coding=utf-8

# 加载核心SDK
from aliyunsdkcore.client import AcsClient
from aliyunsdkcore.acs_exception.exceptions import ClientException
from aliyunsdkcore.acs_exception.exceptions import ServerException

# 加载获取 、 新增、 更新、 删除接口
from aliyunsdkalidns.request.v20150109 import DescribeSubDomainRecordsRequest, AddDomainRecordRequest, UpdateDomainRecordRequest, DeleteDomainRecordRequest

# 加载内置模块
import json,urllib

# AccessKey 和 Secret  建议使用 RAM 子账户的 KEY 和 SECRET 增加安全性
ID = 'xxxxxxx'
SECRET = 'xxxxxx'

# 地区节点 可选地区取决于你的阿里云帐号等级，普通用户只有四个，分别是杭州、上海、深圳、河北，具体参考官网API
regionId = 'cn-hangzhou'

# 配置认证信息
client = AcsClient(ID, SECRET, regionId)

# 设置主域名
DomainName = 'binghe.com'

# 子域名列表  列表参数可根据实际需求增加或减少值
SubDomainList = ['a', 'b', 'c']

# 获取外网IP   三个地址返回的ip地址格式各不相同，3322 的是最纯净的格式， 备选1为 json格式  备选2 为curl方式获取  两个备选地址都需要对获取值作进一步处理才能使用
def getIp():
    # 备选地址：1， http://pv.sohu.com/cityjson?ie=utf-8    2，curl -L tool.lu/ip
    with urllib.request.urlopen('http://www.3322.org/dyndns/getip') as response:
        html = response.read()
        ip = str(html, encoding='utf-8').replace("\n", "")
    return ip

# 查询记录
def getDomainInfo(SubDomain):
    request = DescribeSubDomainRecordsRequest.DescribeSubDomainRecordsRequest()
    request.set_accept_format('json')

    # 设置要查询的记录类型为 A记录   官网支持A / CNAME / MX / AAAA / TXT / NS / SRV / CAA / URL隐性（显性）转发  如果有需要可将该值配置为参数传入
    request.set_Type("A")

    # 指定查记的域名 格式为 'test.binghe.com'
    request.set_SubDomain(SubDomain)

    response = client.do_action_with_exception(request)
    response = str(response, encoding='utf-8')

    # 将获取到的记录转换成json对象并返回
    return json.loads(response)

# 新增记录 (默认都设置为A记录，通过配置set_Type可设置为其他记录)
def addDomainRecord(client,value,rr,domainname):
    request = AddDomainRecordRequest.AddDomainRecordRequest()
    request.set_accept_format('json')

    # request.set_Priority('1')  # MX 记录时的必选参数
    request.set_TTL('600')       # 可选值的范围取决于你的阿里云账户等级，免费版为 600 - 86400 单位为秒 
    request.set_Value(value)     # 新增的 ip 地址
    request.set_Type('A')        # 记录类型
    request.set_RR(rr)           # 子域名名称  
    request.set_DomainName(domainname) #主域名

    # 获取记录信息，返回信息中包含 TotalCount 字段，表示获取到的记录条数 0 表示没有记录， 其他数字为多少表示有多少条相同记录，正常有记录的值应该为1，如果值大于1则应该检查是不是重复添加了相同的记录
    response = client.do_action_with_exception(request)
    response = str(response, encoding='utf-8')
    relsult = json.loads(response)
    return relsult

# 更新记录
def updateDomainRecord(client,value,rr,record_id):
    request = UpdateDomainRecordRequest.UpdateDomainRecordRequest()
    request.set_accept_format('json')

    # request.set_Priority('1')
    request.set_TTL('600')
    request.set_Value(value) # 新的ip地址
    request.set_Type('A')
    request.set_RR(rr)
    request.set_RecordId(record_id)  # 更新记录需要指定 record_id ，该字段为记录的唯一标识，可以在获取方法的返回信息中得到该字段的值

    response = client.do_action_with_exception(request)
    response = str(response, encoding='utf-8')
    return response

# 删除记录
def delDomainRecord(client,subdomain):
    info = getDomainInfo(subdomain)
    if info['TotalCount'] == 0:
        print('没有相关的记录信息，删除失败！')
    elif info["TotalCount"] == 1:
        print('准备删除记录')
        request = DeleteDomainRecordRequest.DeleteDomainRecordRequest()
        request.set_accept_format('json')

        record_id = info["DomainRecords"]["Record"][0]["RecordId"]
        request.set_RecordId(record_id) # 删除记录需要指定 record_id ，该字段为记录的唯一标识，可以在获取方法的返回信息中得到该字段的值
        result = client.do_action_with_exception(request)
        print('删除成功，返回信息：')
        print(result)
    else:
        # 正常不应该有多条相同的记录，如果存在这种情况，应该手动去网站检查核实是否有操作失误
        print("存在多个相同子域名解析记录值，请核查后再操作！")

# 有记录则更新，没有记录则新增
def setDomainRecord(client,value,rr,domainname):
    info = getDomainInfo(rr + '.' + domainname)
    if info['TotalCount'] == 0:
        print('准备添加新记录')
        add_result = addDomainRecord(client,value,rr,domainname)
        print(add_result)
    elif info["TotalCount"] == 1:
        print('准备更新已有记录')
        record_id = info["DomainRecords"]["Record"][0]["RecordId"]
        cur_ip = getIp()
        old_ip = info["DomainRecords"]["Record"][0]["Value"]
        if cur_ip == old_ip:
            print ("新ip与原ip相同，不更新！")
        else:
            update_result = updateDomainRecord(client,value,rr,record_id)
            print('更新成功，返回信息：')
            print(update_result)
    else:
        # 正常不应该有多条相同的记录，如果存在这种情况，应该手动去网站检查核实是否有操作失误
        print("存在多个相同子域名解析记录值，请核查删除后再操作！")


IP = getIp()

# 循环子域名列表进行批量操作
for x in SubDomainList:
    setDomainRecord(client,IP,x,DomainName)

# 删除记录测试
# delDomainRecord(client,'b.jsoner.com')

# 新增或更新记录测试
# setDomainRecord(client,'192.168.3.222','a',DomainName)

# 获取记录测试
# print (getDomainInfo(DomainName, 'y'))

# 批量获取记录测试
# for x in SubDomainList:
#     print (getDomainInfo(DomainName, x))

# 获取外网ip地址测试
# print ('(' + getIp() + ')')

The function of the Python script is as follows:

Get the external IP address.
Get domain name resolution records.
Add domain name resolution records.
Update domain name resolution records.
Delete the domain name resolution record (it is not recommended to add this function to the actual script).
Batch operation, if the record does not exist, add the record, and update the record if it exists.

In addition, there are a few points that need to be noted in particular:

It is recommended not to add delete records to the actual script used.
The same record is multiple records of the same subdomain, such as test.binghe.com.
The script does not verify the record type, so different types of records under the same subdomain will also be considered to be the same record. For example, there are two records that are A record of test.binghe.com and AAAA record of test.binghe.com. It will be considered as two identical test.binghe.com records. If you need to judge as different records, you can implement it yourself according to the above Python script.
The exact matching record can be achieved by judging the record_id returned by the obtained record.

Finally, the above script can be saved as a file, and the ip address can be automatically updated regularly through scheduled tasks.

Okay, let's stop here today, my friends like, watch, leave a message, repost, let's go in a row, I'm Binghe, see you in the next issue~~

write at the end

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Okay, let's stop here today, friends, like, favorite, comment, and start walking with one click, I'm Glacier, see you in the next issue~~