"""Base class for dynamically loaded objects accessible through the vregistry.
You'll also find some convenience classes to build selectors.
:organization: Logilab
:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"
import types
from logging import getLogger
from warnings import warn
from logilab.common.decorators import classproperty
from logilab.common.deprecation import deprecated
from logilab.common.logging_ext import set_log_methods
from cubicweb import Unauthorized, NoSelectableObject
# selector base classes and operations ########################################
def objectify_selector(selector_func):
"""convenience decorator for simple selectors where a class definition
would be overkill::
@objectify_selector
def yes(cls, *args, **kwargs):
return 1
"""
return type(selector_func.__name__, (Selector,),
{'__call__': lambda self, *args, **kwargs: selector_func(*args, **kwargs)})
def _instantiate_selector(selector):
"""ensures `selector` is a `Selector` instance
NOTE: This should only be used locally in build___select__()
XXX: then, why not do it ??
"""
if isinstance(selector, types.FunctionType):
return objectify_selector(selector)()
if isinstance(selector, type) and issubclass(selector, Selector):
return selector()
return selector
class Selector(object):
"""base class for selector classes providing implementation
for operators ``&`` and ``|``
This class is only here to give access to binary operators, the
selector logic itself should be implemented in the __call__ method
a selector is called to help choosing the correct object for a
particular context by returning a score (`int`) telling how well
the class given as first argument apply to the given context.
0 score means that the class doesn't apply.
"""
@property
def func_name(self):
# backward compatibility
return self.__class__.__name__
def search_selector(self, selector):
"""search for the given selector or selector instance in the selectors
tree. Return it of None if not found
"""
if self is selector:
return self
if isinstance(selector, type) and isinstance(self, selector):
return self
return None
def __str__(self):
return self.__class__.__name__
def __and__(self, other):
return AndSelector(self, other)
def __rand__(self, other):
return AndSelector(other, self)
def __iand__(self, other):
raise NotImplementedError('cant use inplace & (binary and)')
def __or__(self, other):
return OrSelector(self, other)
def __ror__(self, other):
return OrSelector(other, self)
def __ior__(self, other):
raise NotImplementedError('cant use inplace | (binary or)')
def __invert__(self):
return NotSelector(self)
# XXX (function | function) or (function & function) not managed yet
def __call__(self, cls, *args, **kwargs):
return NotImplementedError("selector %s must implement its logic "
"in its __call__ method" % self.__class__)
class MultiSelector(Selector):
"""base class for compound selector classes"""
def __init__(self, *selectors):
self.selectors = self.merge_selectors(selectors)
def __str__(self):
return '%s(%s)' % (self.__class__.__name__,
','.join(str(s) for s in self.selectors))
@classmethod
def merge_selectors(cls, selectors):
"""deal with selector instanciation when necessary and merge
multi-selectors if possible:
AndSelector(AndSelector(sel1, sel2), AndSelector(sel3, sel4))
==> AndSelector(sel1, sel2, sel3, sel4)
"""
merged_selectors = []
for selector in selectors:
try:
selector = _instantiate_selector(selector)
except:
pass
#assert isinstance(selector, Selector), selector
if isinstance(selector, cls):
merged_selectors += selector.selectors
else:
merged_selectors.append(selector)
return merged_selectors
def search_selector(self, selector):
"""search for the given selector or selector instance in the selectors
tree. Return it of None if not found
"""
for childselector in self.selectors:
if childselector is selector:
return childselector
found = childselector.search_selector(selector)
if found is not None:
return found
return None
class AndSelector(MultiSelector):
"""and-chained selectors (formerly known as chainall)"""
def __call__(self, cls, *args, **kwargs):
score = 0
for selector in self.selectors:
partscore = selector(cls, *args, **kwargs)
if not partscore:
return 0
score += partscore
return score
class OrSelector(MultiSelector):
"""or-chained selectors (formerly known as chainfirst)"""
def __call__(self, cls, *args, **kwargs):
for selector in self.selectors:
partscore = selector(cls, *args, **kwargs)
if partscore:
return partscore
return 0
class NotSelector(Selector):
"""negation selector"""
def __init__(self, selector):
self.selector = selector
def __call__(self, cls, *args, **kwargs):
score = self.selector(cls, *args, **kwargs)
return int(not score)
def __str__(self):
return 'NOT(%s)' % super(NotSelector, self).__str__()
class yes(Selector):
"""return arbitrary score
default score of 0.5 so any other selector take precedence
"""
def __init__(self, score=0.5):
self.score = score
def __call__(self, *args, **kwargs):
return self.score
# the base class for all appobjects ############################################
class AppObject(object):
"""This is the base class for CubicWeb application objects which are
selected according to a context (usually at least a request and a result
set).
Concrete application objects classes are designed to be loaded by the
vregistry and should be accessed through it, not by direct instantiation.
The following attributes should be set on concret appobject classes:
:__registry__:
name of the registry for this object (string like 'views',
'templates'...)
:__regid__:
object's identifier in the registry (string like 'main',
'primary', 'folder_box')
:__select__:
class'selector
Moreover, the `__abstract__` attribute may be set to True to indicate
that a appobject is abstract and should not be registered.
At selection time, the following attributes are set on the instance:
:_cw:
current request
:cw_extra_kwargs:
other received arguments
only if rset is found in arguments (in which case rset/row/col will be
removed from cwextra_kwargs):
:cw_rset:
context result set or None
:cw_row:
if a result set is set and the context is about a particular cell in the
result set, and not the result set as a whole, specify the row number we
are interested in, else None
:cw_col:
if a result set is set and the context is about a particular cell in the
result set, and not the result set as a whole, specify the col number we
are interested in, else None
"""
__registry__ = None
__regid__ = None
__select__ = yes()
@classmethod
def __registered__(cls, registry):
"""called by the registry when the appobject has been registered.
It must return the object that will be actually registered (this may be
the right hook to create an instance for example). By default the
appobject is returned without any transformation.
"""
try: # XXX < 3.6 bw compat
pdefs = cls.property_defs
except AttributeError:
pdefs = getattr(cls, 'cw_property_defs', {})
else:
warn('property_defs is deprecated, use cw_property_defs in %s'
% cls, DeprecationWarning)
for propid, pdef in pdefs.items():
pdef = pdef.copy() # may be shared
pdef['default'] = getattr(cls, propid, pdef['default'])
pdef['sitewide'] = getattr(cls, 'site_wide', pdef.get('sitewide'))
registry.vreg.register_property(cls._cwpropkey(propid), **pdef)
return cls
def __init__(self, req, **extra):
super(AppObject, self).__init__()
self._cw = req
try:
self.cw_rset = extra.pop('rset')
self.cw_row = extra.pop('row', None)
self.cw_col = extra.pop('col', None)
except KeyError:
pass
self.cw_extra_kwargs = extra
# persistent class properties ##############################################
#
# optional `cw_property_defs` dict on a class defines available persistent
# properties for this class:
#
# * key: id of the property (the actual CWProperty key is build using
# <registry name>.<obj id>.<property id>
# * value: tuple (property type, vocabfunc, default value, property description)
# possible types are those used by `logilab.common.configuration`
#
# notice that when it exists multiple objects with the same id (adaptation,
# overriding) only the first encountered definition is considered, so those
# objects can't try to have different default values for instance.
#
# you can then access to a property value using self.cw_propval, where self
# is an instance of class
@classmethod
def _cwpropkey(cls, propid):
"""return cw property key for the property of the given id for this
class
"""
return '%s.%s.%s' % (cls.__registry__, cls.__regid__, propid)
def cw_propval(self, propid):
"""return cw property value associated to key
<cls.__registry__>.<cls.id>.<propid>
"""
return self._cw.property_value(self._cwpropkey(propid))
# deprecated ###############################################################
@property
@deprecated('[3.6] use self.__regid__')
def id(self):
return self.__regid__
@property
@deprecated('[3.6] use self._cw.vreg')
def vreg(self):
return self._cw.vreg
@property
@deprecated('[3.6] use self._cw.vreg.schema')
def schema(self):
return self._cw.vreg.schema
@property
@deprecated('[3.6] use self._cw.vreg.config')
def config(self):
return self._cw.vreg.config
@property
@deprecated('[3.6] use self._cw')
def req(self):
return self._cw
@deprecated('[3.6] use self.cw_rset')
def get_rset(self):
return self.cw_rset
@deprecated('[3.6] use self.cw_rset')
def set_rset(self, rset):
self.cw_rset = rset
rset = property(get_rset, set_rset)
@property
@deprecated('[3.6] use self.cw_row')
def row(self):
return self.cw_row
@property
@deprecated('[3.6] use self.cw_col')
def col(self):
return self.cw_col
@property
@deprecated('[3.6] use self.cw_extra_kwargs')
def extra_kwargs(self):
return self.cw_extra_kwargs
@deprecated('[3.6] use self._cw.view')
def view(self, *args, **kwargs):
return self._cw.view(*args, **kwargs)
@property
@deprecated('[3.6] use self._cw.varmaker')
def varmaker(self):
return self._cw.varmaker
@deprecated('[3.6] use self._cw.get_cache')
def get_cache(self, cachename):
return self._cw.get_cache(cachename)
@deprecated('[3.6] use self._cw.build_url')
def build_url(self, *args, **kwargs):
return self._cw.build_url(*args, **kwargs)
@deprecated('[3.6] use self.cw_rset.limited_rql')
def limited_rql(self):
return self.cw_rset.limited_rql()
@deprecated('[3.6] use self.cw_rset.complete_entity(row,col) instead')
def complete_entity(self, row, col=0, skip_bytes=True):
return self.cw_rset.complete_entity(row, col, skip_bytes)
@deprecated('[3.6] use self.cw_rset.get_entity(row,col) instead')
def entity(self, row, col=0):
return self.cw_rset.get_entity(row, col)
@deprecated('[3.6] use self._cw.user_rql_callback')
def user_rql_callback(self, args, msg=None):
return self._cw.user_rql_callback(args, msg)
@deprecated('[3.6] use self._cw.user_callback')
def user_callback(self, cb, args, msg=None, nonify=False):
return self._cw.user_callback(cb, args, msg, nonify)
@deprecated('[3.6] use self._cw.format_date')
def format_date(self, date, date_format=None, time=False):
return self._cw.format_date(date, date_format, time)
@deprecated('[3.6] use self._cw.format_timoe')
def format_time(self, time):
return self._cw.format_time(time)
@deprecated('[3.6] use self._cw.format_float')
def format_float(self, num):
return self._cw.format_float(num)
@deprecated('[3.6] use self._cw.parse_datetime')
def parse_datetime(self, value, etype='Datetime'):
return self._cw.parse_datetime(value, etype)
@deprecated('[3.6] use self.cw_propval')
def propval(self, propid):
return self._cw.property_value(self._cwpropkey(propid))
set_log_methods(AppObject, getLogger('cubicweb.appobject'))