使用 Python 和 Regex 解析 dhcpd.leases

Question

我们正在努力解决一些 DHCP 问题，我正在使用 Python 和正则表达式来解析 dhcpd.leases 文件。我想编写一个正则表达式来捕获每个租约（请参阅底部的文件示例）块，然后捕获 IP 地址和 MAC。我的正则表达式知识很初级，但我认为我走在正确的轨道上。到目前为止我所拥有的并没有捕捉到一切：

到目前为止的代码：

import sys, re

fp = '/Users/smitty/Dropbox/Company/Network/DHCP-Info/dhcpd.leases'
f = open(fp)
ftext = f.read()

p = re.compile(ur'(lease\s([\d]*.*).*\n.*\n.*\n.*\n.*\n.*ethernet\s(.*);*.\n.*\n.*})')

raw_record = []

parsed_record = {}

for match in re.findall(p, ftext):
    raw_record.append(match)

for record in raw_record:
    m = re.search(p, record)
    parsed_record[m.group(2)] = m.group(3)

plaintext_record = []

for ip, mac in parsed_record.iteritems():
    plaintext_record.append("IP: {0}   MAC: {1}".format(ip, mac))

dhcpd.leases 文件的示例块：

lease 192.168.124.118 {
  starts 1 2014/12/01 12:42:49;
  ends 1 2014/12/01 20:42:49;
  tstp 1 2014/12/01 20:42:49;
  binding state free;
  hardware ethernet 00:0c:29:d5:ff:cb;
  uid "\001\000\014)\325\377\313";
}
lease 192.168.124.117 {
  starts 5 2015/05/01 18:49:10;
  ends 6 2015/05/02 02:49:10;
  tstp 6 2015/05/02 02:49:10;
  binding state free;
  hardware ethernet 00:0c:29:85:6f:62;
  uid "\001\000\014)\205ob";
}
lease 192.168.124.116 {
  starts 5 2015/06/05 14:48:40;
  ends 5 2015/06/05 22:48:40;
  tstp 5 2015/06/05 22:48:40;
  binding state free;
  hardware ethernet 00:0c:29:d1:3e:0d;
  uid "\001\000\014)\321>\015";
}
lease 192.168.123.200 {
  starts 5 2012/07/13 11:54:46;
  ends 5 2012/07/13 11:57:42;
  tstp 5 2012/07/13 11:57:42;
  binding state free;
  hardware ethernet 88:c6:63:c6:08:52;
  uid "\001\210\306c\306\010R";
}

我也忍不住觉得我在这里的约定无处不在（创建一个列表，然后创建一个字典，然后再创建一个列表）。

Answer 1

打开“多行”模式以简化表达式并避免检查租约内的每个换行符并将 IP 和 MAC 地址捕获到保存组中：

import re

pattern = re.compile(r"lease ([0-9.]+) {.*?hardware ethernet ([:a-f0-9]+);.*?}", re.MULTILINE | re.DOTALL)

with open("/Users/smitty/Dropbox/Company/Network/DHCP-Info/dhcpd.leases") as f:
    for match in pattern.finditer(f.read()):
        print(match.group(1), match.group(2))

印刷：

192.168.124.118 00:0c:29:d5:ff:cb
192.168.124.117 00:0c:29:85:6f:62
192.168.124.116 00:0c:29:d1:3e:0d
192.168.123.200 88:c6:63:c6:08:52