更改DenyHosts报告:从Python调用外部命令

Question

首先，我不知道Python的第一件事.所以我真的可以用你的任何指点。我确实知道一些Perl、Bash脚本和一些C++。

我正在运行DenyHosts (http://denyhosts.sourceforge.net/)，它不时地通过电子邮件向我发送一条消息，即IP地址添加到/etc/deny.host。例如：

Added the following hosts to /etc/hosts.deny:

87.215.133.109 (unknown)

----------------------------------------------------------------------

到目前为止还不错，但是我想在这条消息中加上IP地址的国家。为此，我创建了一个小型Perl脚本，用于输出国家：

/usr/local/bin/geo-ip.pl --short 87.215.133.109
Netherlands

所以我要做的就是从Python调用这个Perl脚本，然后在消息字符串中填充结果。我找到了我怀疑需要修改的源代码，但正如消息顶部所宣布的，我不知道Python的第一件事。

这是在report.py中调用子例程的主程序的一个片段。

deny_hosts.py：

#print deny_hosts
new_denied_hosts, status = self.update_hosts_deny(deny_hosts)
if new_denied_hosts:
    if not status:
        msg = "WARNING: Could not add the following hosts to %s" % self.__prefs.get('HOSTS_DENY')
    else:
        msg = "Added the following hosts to %s" % self.__prefs.get('HOSTS_DENY')
    self.__report.add_section(msg, new_denied_hosts)
    if self.__sync_server: self.sync_add_hosts(new_denied_hosts)
    plugin_deny = self.__prefs.get('PLUGIN_DENY')
    if plugin_deny: plugin.execute(plugin_deny, new_denied_hosts)

我觉得这个零钱应该在这里找个地方。report.py定义了add_section：

def add_section(self, message, iterable):
    self.report += "%s:\n\n" % message
    for i in iterable:
        if type(i) in (TupleType, ListType):
            extra = ": %d\n" % i[1]
            i = i[0]
        else:
            extra = ""
        if self.hostname_lookup:
            hostname = self.get_hostname(i)
            debug("get_host: %s", hostname)
        else: hostname = i

        self.report += "%s%s\n" % (hostname, extra)

        if self.use_syslog:
            syslog.syslog("%s - %s%s" %(message, hostname, extra))
    self.report += "\n" + "-" * 70 + "\n"

请帮助我更改代码，这样它就会发出如下消息：

Added the following hosts to /etc/hosts.deny:

87.215.133.109 (Netherlands, unknown)

----------------------------------------------------------------------

EDIT3:，这就是我解决它的方法。输出与原始消息相同。更改源后，需要重新启动守护进程(sudo /etc/init.d/denyhost重新启动)

    def add_section(self, message, iterable):
    # added geo-ip
    # moving this from statement to the top of the file makes pycheck generate
    # a lot of errors, so I left it here.
    from subprocess import Popen, PIPE
    # end geo-ip hack import
    self.report += "%s:\n\n" % message
    for i in iterable:
        if type(i) in (TupleType, ListType):
            extra = ": %d\n" % i[1]
            i = i[0]
        else:
            extra = ""
        if self.hostname_lookup:
            hostname = self.get_hostname(i)
            debug("get_host: %s", hostname)
        else: hostname = i

        # self.report += "%s%s\n" % (hostname, extra)
        # JPH: added geo-ip
        geocmd = "/usr/local/bin/geo-ip.pl --short %s" % i
        country = Popen( geocmd, shell=True, stdout=PIPE).communicate()[0]
        country = country.strip()
        self.report += "%s%s\n%s\n" % (hostname, extra, country)
        # end geo-ip hack            

        if self.use_syslog:
            syslog.syslog("%s - %s%s" %(message, hostname, extra))
    self.report += "\n" + "-" * 70 + "\n"

还可以帮助我理解我改变了什么，这样我今天也可以学到一些Python。

EDIT2：为了共享到geo-ip.pl脚本http://wirespeed.xs4all.nl/mediawiki/index.php/Geo-ip.pl的链接

EDIT1：重新编译是在源代码更改时自动完成的，从而回答了下面的问题。第二个问题是，我在系统中找到了两个匹配的文件：

• /usr/share/denyhosts/DenyHosts/report.py
• /usr/share/denyhosts/DenyHosts/report.pyc

其中.py是源代码，我怀疑.pyc实际上正在执行。因此，当我更改源代码时，如果以后不以某种方式编译它，我不会感到惊讶。

Answer 1

我将只回答您问题的具体部分，即如何通过python调用您的perl脚本并获得输出。这个信息的位置太模糊了，我从你的片段里猜不出来……

from subprocess import Popen, PIPE

hostIP = "87.215.133.109"
cmd = "/usr/local/bin/geo-ip.pl --short %s" % hostIP
output = Popen(cmd, shell=True, stdout=PIPE).communicate()[0]

## alternate form ##
# cmd = ["/usr/local/bin/geo-ip.pl, "--short", hostIP]
# output = Popen(cmd, stdout=PIPE).communicate()[0]

print output.strip() 
# Netherlands

更新

由于我同时在Popen行上做了一些事情，而且您对python (基于下面的评论)是新手，所以我想为您细分一下这一行.

# this call to Popen actually returns a 
# Popen object with a number of methods and attributes
# to interact with the process that was just created
p = Popen(cmd, shell=True, stdout=PIPE)

# communicate() is a method of a Popen object which
# allows you to wait for the return output of the pipes
# that you named (or send data to stdin)
# It blocks until data is ready and returns a tuple (stdout, stderr)
stdout, stderr = p.communicate()

# We only wanted the stdout in this case, so we took the first index
output = p.communicate()[0]

# output is a string, and strings have the strip() method to remove 
# surrounding whitespace
stripped_output = output.strip()

Answer 2

这可能会起作用：

import subprocess
country = subprocess.check_output(
    ["/usr/local/bin/geo-ip.pl", "--short", "87.215.133.109"])