# attmap.py - attribute mapping class
#
# Copyright (C) 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
"""Module for handling attribute mappings used for LDAP searches.
>>> attrs = Attributes(uid='uid',
... userPassword='userPassword',
... uidNumber='uidNumber',
... gidNumber='gidNumber',
... gecos='"${gecos:-$cn}"',
... homeDirectory='homeDirectory',
... loginShell='loginShell')
>>> 'cn' in attrs.attributes()
True
>>> attrs.translate({'uid': ['UIDVALUE', '2nduidvalue'], 'cn': ['COMMON NAME', ]})
{'uid': ['UIDVALUE', '2nduidvalue'], 'loginShell': [], 'userPassword': [], 'uidNumber': [], 'gidNumber': [], 'gecos': ['COMMON NAME'], 'homeDirectory': []}
>>> attrs['uidNumber'] # a representation fit for logging and filters
'uidNumber'
>>> attrs['gecos']
'"${gecos:-$cn}"'
"""
import re
from ldap.filter import escape_filter_chars
import ldap.dn
from expr import Expression
# exported names
__all__ = ('Attributes', )
# TODO: support objectSid attributes
# regular expression to match function attributes
attribute_func_re = re.compile('^(?P<function>[a-z]+)\((?P<attribute>.*)\)$')
class SimpleMapping(str):
"""Simple mapping to another attribute name."""
def attributes(self):
return [self]
def mk_filter(self, value):
return '(%s=%s)' % (
self, escape_filter_chars(str(value))
)
def values(self, variables):
"""Expand the expression using the variables specified."""
return variables.get(self, [])
class ExpressionMapping(str):
"""Class for parsing and expanding an expression."""
def __init__(self, value):
"""Parse the expression as a string."""
self.expression = Expression(value[1:-1])
super(ExpressionMapping, self).__init__(value)
def values(self, variables):
"""Expand the expression using the variables specified."""
return [self.expression.value(variables)]
def attributes(self):
"""Return the attributes defined in the expression."""
return self.expression.variables()
class FunctionMapping(str):
"""Mapping to a function to another attribute."""
def __init__(self, mapping):
self.mapping = mapping
m = attribute_func_re.match(mapping)
self.attribute = m.group('attribute')
self.function = getattr(self, m.group('function'))
super(FunctionMapping, self).__init__(mapping)
def upper(self, value):
return value.upper()
def lower(self, value):
return value.lower()
def attributes(self):
return [self.attribute]
def mk_filter(self, value):
return '(%s=%s)' % (
self.attribute, escape_filter_chars(value)
)
def values(self, variables):
return [self.function(value)
for value in variables.get(self.attribute, [])]
class Attributes(dict):
"""Dictionary-like class for handling attribute mapping."""
def __init__(self, *args, **kwargs):
self.update(*args, **kwargs)
def __setitem__(self, attribute, mapping):
# translate the mapping into a mapping object
if mapping[0] == '"' and mapping[-1] == '"':
mapping = ExpressionMapping(mapping)
elif '(' in mapping:
mapping = FunctionMapping(mapping)
else:
mapping = SimpleMapping(mapping)
super(Attributes, self).__setitem__(attribute, mapping)
def update(self, *args, **kwargs):
for arg in args:
other = dict(arg)
for key in other:
self[key] = other[key]
for key in kwargs:
self[key] = kwargs[key]
def attributes(self):
"""Return the list of attributes that are referenced in this
attribute mapping. These are the attributes that should be
requested in the search."""
attributes = set()
for mapping in self.itervalues():
attributes.update(mapping.attributes())
return list(attributes)
def mk_filter(self, attribute, value):
"""Construct a search filter for searching for the attribute value
combination."""
mapping = self.get(attribute, SimpleMapping(attribute))
return mapping.mk_filter(value)
def translate(self, variables):
"""Return a dictionary with every attribute mapped to their value from
the specified variables."""
results = dict()
for attribute, mapping in self.iteritems():
results[attribute] = mapping.values(variables)
return results
def get_rdn_value(self, dn, attribute):
"""Extract the attribute value from from DN if possible. Return None
otherwise."""
return self.translate(dict(
(x, [y])
for x, y, z in ldap.dn.str2dn(dn)[0]
))[attribute][0]