# common.py - functions that are used by different modules

#

# Copyright (C) 2010, 2011, 2012, 2013 Arthur de Jong

#

# This library is free software; you can redistribute it and/or

# modify it under the terms of the GNU Lesser General Public

# License as published by the Free Software Foundation; either

# version 2.1 of the License, or (at your option) any later version.

#

# This library is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# Lesser General Public License for more details.

#

# You should have received a copy of the GNU Lesser General Public

# License along with this library; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301 USA

import logging

import sys

import ldap

from attmap import Attributes

#import cache

import cfg

import constants

def is_valid_name(name):

    """Checks to see if the specified name seems to be a valid user or group

    name.

    This test is based on the definition from POSIX (IEEE Std 1003.1, 2004,

    3.426 User Name, 3.189 Group Name and 3.276 Portable Filename Character Set):

    http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_426

    http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_189

    http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_276

    The standard defines user names valid if they contain characters from

    the set [A-Za-z0-9._-] where the hyphen should not be used as first

    character. As an extension this test allows some more characters."""

    return bool(cfg.validnames.search(name))

def validate_name(name):

    """Checks to see if the specified name seems to be a valid user or group

    name. See is_valid_name()."""

    if not cfg.validnames.search(name):

        raise ValueError('%r: denied by validnames option' % name)

class Request(object):

    """

    Request handler class. Subclasses are expected to handle actual requests

    and should implement the following members:

      action - the NSLCD_ACTION_* action that should trigger this handler

      read_parameters() - a function that reads the request parameters of the

                          request stream

      write() - function that writes a single LDAP entry to the result stream

    """

    def __init__(self, fp, conn, calleruid):

        self.fp = fp

        self.conn = conn

        self.calleruid = calleruid

        module = sys.modules[self.__module__]

        self.search = getattr(module, 'Search', None)

        #if not hasattr(module, 'cache_obj'):

        #    cache_cls = getattr(module, 'Cache', None)

        #    module.cache_obj = cache_cls() if cache_cls else None

        #self.cache = module.cache_obj

        self.cache = None

    def read_parameters(self, fp):

        """This method should read and return the parameters from the

        stream."""

        pass

    def get_results(self, parameters):

        """Provide the result entries by performing a search."""

        for dn, attributes in self.search(self.conn, parameters=parameters):

            for values in self.convert(dn, attributes, parameters):

                yield values

    def handle_request(self, parameters):

        """This method handles the request based on the parameters read

        with read_parameters()."""

        try:

            #with cache.con:

            if True:

                for values in self.get_results(parameters):

                    self.fp.write_int32(constants.NSLCD_RESULT_BEGIN)

                    self.write(*values)

                    if self.cache:

                        self.cache.store(*values)

        except ldap.SERVER_DOWN:

            if self.cache:

                logging.debug('read from cache')

                # we assume server went down before writing any entries

                for values in self.cache.retrieve(parameters):

                    self.fp.write_int32(constants.NSLCD_RESULT_BEGIN)

                    self.write(*values)

            else:

                raise

        # write the final result code

        self.fp.write_int32(constants.NSLCD_RESULT_END)

    def log(self, parameters):

        parameters = dict(parameters)

        for param in ('password', 'oldpassword', 'newpassword'):

            if parameters.get(param):

                parameters[param] = '***'

        logging.debug('%s(%r)', self.__class__.__name__, parameters)

    def __call__(self):

        parameters = self.read_parameters(self.fp) or {}

        self.log(parameters)

        self.fp.write_int32(constants.NSLCD_VERSION)

        self.fp.write_int32(self.action)

        self.handle_request(parameters)

def get_handlers(module):

    """Return a dictionary mapping actions to Request classes."""

    import inspect

    res = {}

    if isinstance(module, basestring):

        module = __import__(module, globals())

    for name, cls in inspect.getmembers(module, inspect.isclass):

        if issubclass(cls, Request) and hasattr(cls, 'action'):

            res[cls.action] = cls

    return res