服务器监控应用（1）：服务端开发 ​

class MonitorServer(models.Model):
    name = models.CharField('名称', max_length=30, unique=True, help_text='用于看板中显示')
    interval = models.IntegerField('上报间隔', default=5,
                                   help_text='上报间隔时间，超过这个时间的两倍还没有更新数据就标记为离线状态，单位：秒')
    sort_order = models.IntegerField('排序', default=99, help_text='自定义排序依据')
    push_url = models.CharField('推送地址', max_length=60,
                                help_text='客户端推送的地址，为了支持代理推送或者本地推送')
    username = models.CharField('用户名', max_length=10, unique=True,
                                help_text='推送用户名，唯一')
    password = models.CharField('密码', max_length=10, unique=True,
                                help_text='第一次添加后自动生成密钥，更改后会重新生成密钥')
    secret_key = models.CharField("加密Key", max_length=64, blank=True, null=True,
                                  help_text='保存后自动生成')
    secret_value = models.CharField("密钥", max_length=256, blank=True, null=True,
                                    help_text='保存后自动生成')
    data = models.TextField('上报数据', blank=True, null=True, help_text='json格式')
    active = models.BooleanField('是否有效', help_text='用来过滤，无效的不显示', default=True)

    create_date = models.DateTimeField(verbose_name='创建时间', auto_now_add=True)
    update_date = models.DateTimeField(verbose_name='更新时间', auto_now=True)

    class Meta:
        verbose_name = '监控服务'
        verbose_name_plural = verbose_name
        ordering = ['sort_order']

    def __str__(self):
        return self.name

def save(self, *args, **kwargs):
    if not self.pk or self._fields_have_changed(['username', 'password', 'push_url']):
        # 如果是首次添加数据或者密码字段发生变化，则生成随机32位密码
        secret_key = str(uuid.uuid4()).replace('-', '')[:32]
        plain_text = f'{self.username}::{self.password}::{self.push_url}'
        cipher = AESCipher(secret_key)
        secret_value = cipher.encrypt(plain_text)
        self.secret_value = secret_value
        self.secret_key = secret_key
    super().save(*args, **kwargs)

def _fields_have_changed(self, fields):
    if self.pk:
        # 如果是更新数据，则检查指定字段是否发生变化
        original_instance = MonitorServer.objects.get(pk=self.pk)
        for field in fields:
            if getattr(self, field) != getattr(original_instance, field):
                return True
        return False
    return True  # 如果是首次添加数据，返回 True，表示字段已更改

import base64
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad

class AESCipher:
    def __init__(self, _key):
        self.key = _key

    def encrypt(self, _plaintext):
        _cipher = AES.new(self.key.encode(), AES.MODE_CBC)
        _plaintext = pad(_plaintext.encode(), AES.block_size)
        _encrypted_text = _cipher.iv + _cipher.encrypt(_plaintext)
        return base64.b64encode(_encrypted_text).decode()[:128]

    def decrypt(self, ciphertext):
        ciphertext = base64.b64decode(ciphertext)
        iv = ciphertext[:AES.block_size]
        _cipher = AES.new(self.key.encode(), AES.MODE_CBC, iv)
        _decrypted_text = unpad(_cipher.decrypt(ciphertext[AES.block_size:]), AES.block_size)
        return _decrypted_text.decode()