Manger hosts file

host_manager.py

#!/usr/bin/env python
import sys
import re
import os


def add_host():
    if len(sys.argv) != 4:
        print 'Usage: add [IP_ADDRESS] [HOSTNAME]'
        return
    ip_addr = sys.argv[2]
    hostname = sys.argv[3]

    if is_valid_ip(ip_addr) is False:
        print 'Enter a valid IP'
        return

    with open('/etc/hosts', 'rt') as f:
        s = f.read() + '\n' + ip_addr + '\t' + hostname
        with open('/tmp/etc_hosts.tmp', 'wt') as outf:
            outf.write(s)

    os.system('sudo mv /tmp/etc_hosts.tmp /etc/hosts')

    print 'Pointing hostname '+hostname+' for the ip '+ip_addr


def disable():
    if len(sys.argv) != 3:
        print 'Usage: enable [HOSTNAME]'
        return
    
    hostname = sys.argv[2]

    f = open("/etc/hosts", "r")

    lines = f.readlines()

    f.close()
    f = open("/tmp/etc_hosts.tmp", "wt")
    
    for line in lines:
        if line.__contains__(hostname):
            line = '# ' + line
            f.write(line)
        else:
            f.write(line)
    f.close()
    os.system('sudo mv /tmp/etc_hosts.tmp /etc/hosts')


def list_hosts():
    f = open("/etc/hosts", "r")
    lines = f.readlines()
    
    for line in lines:
        if line.__contains__('#'):
            line = '[ DISABLED ]\t' + line.replace('# ', '')
        else:
            line = '[ ENABLED ]\t' + line
        print line
    f.close()


def enable():
    if len(sys.argv) != 3:
        print 'Usage: enable [HOSTNAME]'
        return
    
    hostname = sys.argv[2]

    f = open("/etc/hosts", "r")

    lines = f.readlines()

    f.close()
    f = open("/tmp/etc_hosts.tmp", "wt")
    
    for line in lines:
        if line.__contains__(hostname):
            line = line.replace('# ', '')
            f.write(line)
        else:
            f.write(line)
    f.close()
    os.system('sudo mv /tmp/etc_hosts.tmp /etc/hosts')


def remove():
    if len(sys.argv) != 3:
        print 'Usage: enable [HOSTNAME]'
        return
    
    hostname = sys.argv[2]

    f = open("/etc/hosts", "r")

    lines = f.readlines()

    f.close()
    f = open("/tmp/etc_hosts.tmp", "wt")
    
    for line in lines:
        if line.__contains__(hostname) is False:
            f.write(line)

    os.system('sudo mv /tmp/etc_hosts.tmp /etc/hosts')


def is_valid_ip(ip):
    """Validates IP addresses.
    """
    return is_valid_ipv4(ip) or is_valid_ipv6(ip)


def is_valid_ipv4(ip):
    """Validates IPv4 addresses.
    """
    pattern = re.compile(r"""
        ^
        (?:
          # Dotted variants:
          (?:
            # Decimal 1-255 (no leading 0's)
            [3-9]\d?|2(?:5[0-5]|[0-4]?\d)?|1\d{0,2}
          |
            0x0*[0-9a-f]{1,2}  # Hexadecimal 0x0 - 0xFF (possible leading 0's)
          |
            0+[1-3]?[0-7]{0,2} # Octal 0 - 0377 (possible leading 0's)
          )
          (?:                  # Repeat 0-3 times, separated by a dot
            \.
            (?:
              [3-9]\d?|2(?:5[0-5]|[0-4]?\d)?|1\d{0,2}
            |
              0x0*[0-9a-f]{1,2}
            |
              0+[1-3]?[0-7]{0,2}
            )
          ){0,3}
        |
          0x0*[0-9a-f]{1,8}    # Hexadecimal notation, 0x0 - 0xffffffff
        |
          0+[0-3]?[0-7]{0,10}  # Octal notation, 0 - 037777777777
        |
          # Decimal notation, 1-4294967295:
          429496729[0-5]|42949672[0-8]\d|4294967[01]\d\d|429496[0-6]\d{3}|
          42949[0-5]\d{4}|4294[0-8]\d{5}|429[0-3]\d{6}|42[0-8]\d{7}|
          4[01]\d{8}|[1-3]\d{0,9}|[4-9]\d{0,8}
        )
        $
    """, re.VERBOSE | re.IGNORECASE)
    return pattern.match(ip) is not None


def is_valid_ipv6(ip):
    """Validates IPv6 addresses.
    """
    pattern = re.compile(r"""
        ^
        \s*                         # Leading whitespace
        (?!.*::.*::)                # Only a single whildcard allowed
        (?:(?!:)|:(?=:))            # Colon iff it would be part of a wildcard
        (?:                         # Repeat 6 times:
            [0-9a-f]{0,4}           #   A group of at most four hexadecimal digits
            (?:(?<=::)|(?<!::):)    #   Colon unless preceeded by wildcard
        ){6}                        #
        (?:                         # Either
            [0-9a-f]{0,4}           #   Another group
            (?:(?<=::)|(?<!::):)    #   Colon unless preceeded by wildcard
            [0-9a-f]{0,4}           #   Last group
            (?: (?<=::)             #   Colon iff preceeded by exacly one colon
             |  (?<!:)              #
             |  (?<=:) (?<!::) :    #
             )                      # OR
         |                          #   A v4 address with NO leading zeros 
            (?:25[0-4]|2[0-4]\d|1\d\d|[1-9]?\d)
            (?: \.
                (?:25[0-4]|2[0-4]\d|1\d\d|[1-9]?\d)
            ){3}
        )
        \s*                         # Trailing whitespace
        $
    """, re.VERBOSE | re.IGNORECASE | re.DOTALL)
    return pattern.match(ip) is not None

for option in sys.argv:
    if option == 'add':
        add_host()
    if option == 'remove':
        remove()
    if option == 'enable':
        enable()
    if option == 'disable':
        disable()
    if option == 'list':
        list_hosts()
    if len(sys.argv) == 1:
        print 'Use a option: add, enable, disable, remove, list'

READEME.md

Install:

git clone [email protected]:/baec07fffedf7d6e3a04.git hosts  
sudo mv hosts/host_manager.py /usr/bin/hosts
rm -rf hosts