1 # -*- coding: UTF-8 -*-

     2 # Copyright (c) 2008 - 2010, Pascal Volk

     3 # See COPYING for distribution information.

     4 

     5 """A small - r/o - wrapper class for Postfix' postconf."""

     6 

     7 from subprocess import Popen, PIPE

     8 

     9 from __main__ import re, ERR

    10 from VirtualMailManager.Exceptions import VMMException

    11 

    12 RE_PC_PARAMS = """^\w+$"""

    13 RE_PC_VARIABLES = r"""\$\b\w+\b"""

    14 

    15 class Postconf(object):

    16     __slots__ = ('__bin', '__val', '__varFinder')

    17     def __init__(self, postconf_bin):

    18         """Creates a new Postconf instance.

    19 

    20         Keyword arguments:

    21         postconf_bin -- absolute path to the Postfix postconf binary (str)

    22         """

    23         self.__bin = postconf_bin

    24         self.__val = ''

    25         self.__varFinder = re.compile(RE_PC_VARIABLES)

    26 

    27     def read(self, parameter, expand_vars=True):

    28         """Returns the parameters value.

    29 

    30         If expand_vars is True (default), all variables in the value will be

    31         expanded:

    32         e.g. mydestination -> mail.example.com, localhost.example.com, localhost

    33         Otherwise the value may contain one or more variables.

    34         e.g. mydestination -> $myhostname, localhost.$mydomain, localhost

    35 

    36         Keyword arguments:

    37         parameter -- the name of a Postfix configuration parameter (str)

    38         expand_vars -- default True (bool)

    39         """

    40         if not re.match(RE_PC_PARAMS, parameter):

    41             raise VMMException(_(u'The value “%s” doesn\'t look like a valid\

    42  postfix configuration parameter name.') % parameter, ERR.VMM_ERROR)

    43         self.__val = self.__read(parameter)

    44         if expand_vars:

    45             self.__expandVars()

    46         return self.__val

    47 

    48     def __expandVars(self):

    49         while True:

    50             pvars = set(self.__varFinder.findall(self.__val))

    51             pvars_len = len(pvars)

    52             if pvars_len < 1:

    53                 break

    54             if pvars_len > 1:

    55                 self.__expandMultiVars(self.__readMulti(pvars))

    56                 continue

    57             pvars = pvars.pop()

    58             self.__val = self.__val.replace(pvars, self.__read(pvars[1:]))

    59 

    60     def __expandMultiVars(self, old_new):

    61         for old, new in old_new.items():

    62             self.__val = self.__val.replace('$'+old, new)

    63 

    64     def __read(self, parameter):

    65         out, err = Popen([self.__bin, '-h', parameter], stdout=PIPE,

    66                 stderr=PIPE).communicate()

    67         if len(err):

    68             raise VMMException(err.strip(), ERR.VMM_ERROR)

    69         return out.strip()

    70 

    71     def __readMulti(self, parameters):

    72         cmd = [self.__bin]

    73         for parameter in parameters:

    74             cmd.append(parameter[1:])

    75         out, err = Popen(cmd, stdout=PIPE, stderr=PIPE).communicate()

    76         if len(err):

    77             raise VMMException(err.strip(), ERR.VMM_ERROR)

    78         par_val = {}

    79         for line in out.splitlines():

    80             par, val = line.split(' = ')

    81             par_val[par] = val

    82         return par_val

    83