Question

我正在尝试使用python脚本管理主机文件。我是python的新手，如果找到匹配项，我很难弄清楚如何更换一条线。例如，如果在网站的主机文件中更改了地址，我希望脚本找到它并将其更改回来。谢谢你的帮助。

import os
import time

#location to the host file to read and write to
hosts_path=r"C:\Windows\System32\drivers\etc\hosts"
#the address I want for the sites
redirect="0.0.0.0"
#the websites that I will set the address for
website_list=["portal.citidirect.com","www.bcinet.nc","secure.banque-tahiti.pf","www.bancatlan.hn","www.bancentro.com.ni","www.davivienda.com.sv","www.davivienda.cr","cmo.cibc.com","www.bi.com.gt","empresas.banistmo.com","online.belizebank.com","online.westernunion.com","archive.clickatell.com"]

#continuous loop
while True:
    with open(hosts_path,'r+') as file:
        content=file.read()
#for each of the websites in the list above make sure they are in the host file with the correct address
        for website in website_list:
            site=redirect+" "+ website
#here is where I have an issue, if the website is in the host file but with the wrong address I want to write over the line, instead the program is adding it to the end of the file
            if website in content:
                if site in content:
                    pass
                else:
                    file.write(site)
            else:
                file.write("\n"+site)
    time.sleep(300)

    os.system('ipconfig /flushdns')

Answer 1

您需要将文件读入列表，然后根据需要更改列表的索引，然后将列表写回文件。你正在做的只是写到文件的末尾。您不能直接更改文件。您需要在列表中记录更改，然后编写列表。我最终不得不重写很多代码。这是完整的脚本。我不确定os.system('ipconfig /flushdns')正在完成什么，所以我删除了它。您可以轻松地将其添加回您想要的位置。

#!/usr/bin/env python3.6

import time

hosts_path = r"C:\\Windows\\System32\\drivers\\etc\\hosts"
redirect = "0.0.0.0"
website_list = [
    "portal.citidirect.com",
    "www.bcinet.nc",
    "secure.banque-tahiti.pf",
    "www.bancatlan.hn",
    "www.bancentro.com.ni",
    "www.davivienda.com.sv",
    "www.davivienda.cr",
    "cmo.cibc.com",
    "www.bi.com.gt",
    "empresas.banistmo.com",
    "online.belizebank.com",
    "online.westernunion.com",
    "archive.clickatell.com"]


def substring_in_list(the_list, substring):
    for s in the_list:
        if substring in s:
            return True
    return False


def write_websites():
    with open(hosts_path, 'r') as file:
        content = file.readlines()
    for website in website_list:
        site = "{} {}\n".format(redirect, website)
        if not substring_in_list(content, website):
            content.append(site)
        else:
            for line in content:
                if site in line:
                    pass
                elif website in line:
                    line = site
    with open(hosts_path, "w") as file:
        file.writelines(content)


while True:
    write_websites()
    time.sleep(300)

Answer 2

那么，您是否会为每个未在您的网站列表中显示的网站分配相同的IP地址？

以下内容将替换最外层while循环中的内容：

# Read in all the lines from the host file,
# splitting each into hostname, IPaddr and aliases (if any),
# and trimming off leading and trailing whitespace from
# each of these components.
host_lines = [[component.strip() for component in line.split(None, 2)] for line in open(host_path).readlines()]

# Process each of the original lines.  
for line in host_lines:
    # Is the site in our list?
    if line[1] in website_list:
        # Make sure the address is correct ...
        if line[0] != redirect:
            line[0] == redirect

        # We can remove this from the websites list.
        website_list.remove(line[1])

# Whatever sites are left in websites don't appear
# in the hosts file.  Add lines for these to host_lines
host_lines.extend([[redirect, site] for site in website_list])

# Write the host_lines back out to the hosts file:
open(hosts_path, 'w').write("\n".join([" ".join(line) for line in host_lines]))

最右边的join将每行的组件粘合在一起形成一个字符串。它左边的join将所有这些字符串与它们之间的换行符混合在一起，并将整个字符串写入文件。

我不得不说，这看起来像是一种相当复杂甚至危险的方法，可以确保您的主机文件保持最新和准确。相反，每五分钟从一个可信主机获得cron作业scp一个已知良好的主机文件会不会更好？

Answer 3

我最终混合了一些响应以创建一个新文件，以使用如下所示的函数替换当前主机文件。除了这段代码，我使用pyinstaller将其转换为exe然后我设置该exe作为自动启动服务运行。

#!/usr/bin/env python3.6

import os
import shutil
import time

temp_file = r"c:\temp\Web\hosts"
temp_directory="c:\temp\Web"
hosts_path = r"C:\Windows\System32\drivers\etc\hosts"
websites = ('''# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
#      102.54.94.97     rhino.acme.com          # source server
#       38.25.63.10     x.acme.com              # x client host

# localhost name resolution is handled within DNS itself.
#   127.0.0.1       localhost
#   ::1             localhost
0.0.0.0 portal.citidirect.com
0.0.0.0 www.bcinet.nc
0.0.0.0 secure.banque-tahiti.pf
0.0.0.0 www.bancatlan.hn
0.0.0.0 www.bancentro.com.ni
0.0.0.0 www.davivienda.com.sv
0.0.0.0 www.davivienda.cr
0.0.0.0 cmo.cibc.com
0.0.0.0 www.bi.com.gt
0.0.0.0 empresas.banistmo.com
0.0.0.0 online.belizebank.com
0.0.0.0 online.westernunion.com
0.0.0.0 archive.clickatell.com''')


def write_websites():
    with open(temp_file, 'w+') as file:
        file.write(websites)


while True:
    if not os.path.exists(temp_directory):
        os.makedirs(temp_directory)
    try:
        os.remove(temp_file)
    except OSError:
        pass

    write_websites()

    try:
        os.remove(hosts_path)
    except OSError:
        pass

    try:
        shutil.move(temp_file,hosts_path)
    except OSError:
        pass

    os.system('ipconfig /flushdns')
    time.sleep(300)

Python替换文本文件

3 个答案: