Python类继承和使用变量

Question

我对Python还不熟悉，尝试使用类继承，但还不能完全理解共享变量。到目前为止，我有两个类，Scan和Ping：

scan.py

class Scan(object):
    """ Super class for scans """
    identifier = str(random.getrandbits(128))
    timestamp = int(time.time())
    results_dir = "/tmp/{}/".format(identifier)
    total_hosts = 0

    def __init__(self, target_hosts=None, target_ports=None):
        self.__target_hosts = target_hosts
        self.__target_ports = target_ports
        self.scan_string = "-sT -O --script auth,vuln"

    @property
    def target_hosts(self):
        return self.__target_hosts

    @target_hosts.setter
    def target_hosts(self, hosts):
        """ Sets target hosts for scan """
        """ Nmap Expects to be single-spaced '1 2 3' separated """
        self.__target_hosts = hosts.replace(", ", " ")

ping.py

import nmap
from .scan import Scan

class Ping(Scan):
    """ Ping sweep """

    def __init__(self, ping_string, hosts):
        super(Scan, self).__init__()
        self.ping_string = ping_string
        self.hosts = hosts

在我的脚本中，几乎调用了所有内容，我尝试：

from models.scan import Scan
from models.ping import Ping

s = Scan()
hosts = "192.168.0.0/24"
s.target_hosts = hosts
pinger = Ping(ping_string, s.target_hosts)

这句话对我来说毫无意义。。。如果Ping从Scan继承，为什么只有在调用s.targets_hosts时才起作用？难道我不能像Ping.target_hosts那样从我的Ping类调用target_hosts吗

Answer 1

让人难以理解的是，这是一个奇怪的例子。在您的示例中，生成Ping实例所需的hosts参数的正确输入需要来自只能从Ping实例（或其父级Scan）访问的属性

任何以self作为参数的方法（或属性）都依赖于需要首先创建的类的特定实例。如果存在staticmethod或classmethod，则可以直接从类中调用它们

只能从类的特定实例获取和设置target_hosts（在本例中为Scan或Ping）。如果调用Scan.target_hosts或Ping.target_hosts，它将返回类似<property at 0x51cd188>的内容。这基本上是从类返回一个不可用的函数。它的意思是，“类字典包含了关于如何从<class>实例返回一些有用信息的说明。”

如果创建Ping或Scan的实例，现在就可以访问target_hosts属性

>>> scan = Scan()
>>> scan.target_hosts = 'host1, host2, host3'
>>> scan.target_hosts
'host1 host2 host3'
>>> ping = Ping('stuff', 'nonsense')
>>> ping.hosts
'nonsense'
>>> ping.target_hosts = 'host4, host5, host6'
>>> ping.target_hosts
'host4 host5 host6'

可以使用一个伪Ping实例运行脚本。这应该管用

from models.scan import Scan
from models.ping import Ping

dummy = Ping('ignore', 'this')
hosts = "192.168.0.0/24"
dummy.target_hosts = hosts
pinger = Ping(ping_string, dummy.target_hosts)

或者，如果Scan有一个staticmethod，那么Ping也可以使用它

class Scan(object):
    """ Super class for scans """
    identifier = str(random.getrandbits(128))
    timestamp = int(time.time())
    results_dir = "/tmp/{}/".format(identifier)
    total_hosts = 0

    def __init__(self, target_hosts=None, target_ports=None):
        self.__target_hosts = target_hosts
        self.__target_ports = target_ports
        self.scan_string = "-sT -O  script auth,vuln"

    @staticmethod
    def prep_hosts(hosts):
        return  hosts.replace(", ", " ")

    ...

然后呢

from models.scan import Scan
from models.ping import Ping

hosts = "192.168.0.0/24"
input_hosts = Ping.prep_hosts(hosts)  # or Scan.prep_hosts(hosts)
pinger = Ping(ping_string, input_hosts)