"""
* the vregistry handles various types of objects interacting
together. The vregistry handles registration of dynamically loaded
objects and provides a convenient api to access those objects
according to a context
* to interact with the vregistry, objects should inherit from the
AppObject abstract class
* the selection procedure has been generalized by delegating to a
selector, which is responsible to score the appobject according to the
current state (req, rset, row, col). At the end of the selection, if
a appobject class has been found, an instance of this class is
returned. The selector is instantiated at appobject registration
: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 sys
from os import listdir, stat
from os.path import dirname, join, realpath, isdir, exists
from logging import getLogger
from warnings import warn
from logilab.common.deprecation import deprecated, class_moved
from logilab.common.logging_ext import set_log_methods
from cubicweb import CW_SOFTWARE_ROOT
from cubicweb import (RegistryNotFound, ObjectNotFound, NoSelectableObject,
RegistryOutOfDate)
from cubicweb.appobject import AppObject
def _toload_info(path, extrapath, _toload=None):
"""return a dictionary of <modname>: <modpath> and an ordered list of
(file, module name) to load
"""
from logilab.common.modutils import modpath_from_file
if _toload is None:
assert isinstance(path, list)
_toload = {}, []
for fileordir in path:
if isdir(fileordir) and exists(join(fileordir, '__init__.py')):
subfiles = [join(fileordir, fname) for fname in listdir(fileordir)]
_toload_info(subfiles, extrapath, _toload)
elif fileordir[-3:] == '.py':
modname = '.'.join(modpath_from_file(fileordir, extrapath))
_toload[0][modname] = fileordir
_toload[1].append((fileordir, modname))
return _toload
def classid(cls):
"""returns a unique identifier for an appobject class"""
return '%s.%s' % (cls.__module__, cls.__name__)
def class_regid(cls):
"""returns a unique identifier for an appobject class"""
if 'id' in cls.__dict__:
warn('[3.6] %s.%s: id is deprecated, use __regid__'
% (cls.__module__, cls.__name__), DeprecationWarning)
cls.__regid__ = cls.id
if hasattr(cls, 'id') and not isinstance(cls.id, property):
return cls.id
return cls.__regid__
class Registry(dict):
def __init__(self, config):
super(Registry, self).__init__()
self.config = config
def __getitem__(self, name):
"""return the registry (dictionary of class objects) associated to
this name
"""
try:
return super(Registry, self).__getitem__(name)
except KeyError:
raise ObjectNotFound(name), None, sys.exc_info()[-1]
def initialization_completed(self):
for appobjects in self.itervalues():
for appobjectcls in appobjects:
appobjectcls.__registered__(self)
def register(self, obj, oid=None, clear=False):
"""base method to add an object in the registry"""
assert not '__abstract__' in obj.__dict__
oid = oid or class_regid(obj)
assert oid
if clear:
appobjects = self[oid] = []
else:
appobjects = self.setdefault(oid, [])
assert not obj in appobjects, \
'object %s is already registered' % obj
appobjects.append(obj)
def register_and_replace(self, obj, replaced):
# XXXFIXME this is a duplication of unregister()
# remove register_and_replace in favor of unregister + register
# or simplify by calling unregister then register here
if not isinstance(replaced, basestring):
replaced = classid(replaced)
registered_objs = self.get(class_regid(obj), ())
for index, registered in enumerate(registered_objs):
if classid(registered) == replaced:
del registered_objs[index]
break
else:
self.warning('trying to replace an unregistered view %s by %s',
replaced, obj)
self.register(obj)
def unregister(self, obj):
clsid = classid(obj)
oid = class_regid(obj)
for registered in self.get(oid, ()):
# use classid() to compare classes because vreg will probably
# have its own version of the class, loaded through execfile
if classid(registered) == clsid:
self[oid].remove(registered)
break
else:
self.warning('can\'t remove %s, no id %s in the registry',
clsid, oid)
def all_objects(self):
"""return a list containing all objects in this registry.
"""
result = []
for objs in self.values():
result += objs
return result
# dynamic selection methods ################################################
def object_by_id(self, oid, *args, **kwargs):
"""return object with the given oid. Only one object is expected to be
found.
raise `ObjectNotFound` if not object with id <oid> in <registry>
raise `AssertionError` if there is more than one object there
"""
objects = self[oid]
assert len(objects) == 1, objects
return objects[0](*args, **kwargs)
def select(self, oid, *args, **kwargs):
"""return the most specific object among those with the given oid
according to the given context.
raise `ObjectNotFound` if not object with id <oid> in <registry>
raise `NoSelectableObject` if not object apply
"""
return self._select_best(self[oid], *args, **kwargs)
def select_or_none(self, oid, *args, **kwargs):
"""return the most specific object among those with the given oid
according to the given context, or None if no object applies.
"""
try:
return self.select(oid, *args, **kwargs)
except (NoSelectableObject, ObjectNotFound):
return None
select_object = deprecated('[3.6] use select_or_none instead of select_object'
)(select_or_none)
def possible_objects(self, *args, **kwargs):
"""return an iterator on possible objects in this registry for the given
context
"""
for appobjects in self.itervalues():
try:
yield self._select_best(appobjects, *args, **kwargs)
except NoSelectableObject:
continue
def _select_best(self, appobjects, *args, **kwargs):
"""return an instance of the most specific object according
to parameters
raise `NoSelectableObject` if not object apply
"""
if len(args) > 1:
warn('[3.5] only the request param can not be named when calling select*',
DeprecationWarning, stacklevel=3)
score, winners = 0, []
for appobject in appobjects:
appobjectscore = appobject.__select__(appobject, *args, **kwargs)
if appobjectscore > score:
score, winners = appobjectscore, [appobject]
elif appobjectscore > 0 and appobjectscore == score:
winners.append(appobject)
if not winners:
raise NoSelectableObject('args: %s\nkwargs: %s %s'
% (args, kwargs.keys(),
[repr(v) for v in appobjects]))
if len(winners) > 1:
if self.config.debugmode:
self.error('select ambiguity, args: %s\nkwargs: %s %s',
args, kwargs.keys(), [repr(v) for v in winners])
else:
raise Exception('select ambiguity, args: %s\nkwargs: %s %s'
% (args, kwargs.keys(),
[repr(v) for v in winners]))
# return the result of calling the appobject
return winners[0](*args, **kwargs)
select_best = deprecated('[3.6] select_best is now private')(_select_best)
class VRegistry(dict):
"""class responsible to register, propose and select the various
elements used to build the web interface. Currently, we have templates,
views, actions and components.
"""
def __init__(self, config):
super(VRegistry, self).__init__()
self.config = config
def reset(self, path=None, force_reload=None):
# don't use self.clear, we want to keep existing subdictionaries
for subdict in self.itervalues():
subdict.clear()
self._lastmodifs = {}
def __getitem__(self, name):
"""return the registry (dictionary of class objects) associated to
this name
"""
try:
return super(VRegistry, self).__getitem__(name)
except KeyError:
raise RegistryNotFound(name), None, sys.exc_info()[-1]
# dynamic selection methods ################################################
@deprecated('[3.4] use vreg[registry].object_by_id(oid, *args, **kwargs)')
def object_by_id(self, registry, oid, *args, **kwargs):
"""return object in <registry>.<oid>
raise `ObjectNotFound` if not object with id <oid> in <registry>
raise `AssertionError` if there is more than one object there
"""
return self[registry].object_by_id(oid)
@deprecated('[3.4] use vreg[registry].select(oid, *args, **kwargs)')
def select(self, registry, oid, *args, **kwargs):
"""return the most specific object in <registry>.<oid> according to
the given context
raise `ObjectNotFound` if not object with id <oid> in <registry>
raise `NoSelectableObject` if not object apply
"""
return self[registry].select(oid, *args, **kwargs)
@deprecated('[3.4] use vreg[registry].select_or_none(oid, *args, **kwargs)')
def select_object(self, registry, oid, *args, **kwargs):
"""return the most specific object in <registry>.<oid> according to
the given context, or None if no object apply
"""
return self[registry].select_or_none(oid, *args, **kwargs)
@deprecated('[3.4] use vreg[registry].possible_objects(*args, **kwargs)')
def possible_objects(self, registry, *args, **kwargs):
"""return an iterator on possible objects in <registry> for the given
context
"""
return self[registry].possible_objects(*args, **kwargs)
# methods for explicit (un)registration ###################################
# default class, when no specific class set
REGISTRY_FACTORY = {None: Registry}
def registry_class(self, regid):
try:
return self.REGISTRY_FACTORY[regid]
except KeyError:
return self.REGISTRY_FACTORY[None]
def setdefault(self, regid):
try:
return self[regid]
except KeyError:
self[regid] = self.registry_class(regid)(self.config)
return self[regid]
# def clear(self, key):
# regname, oid = key.split('.')
# self[regname].pop(oid, None)
def register_all(self, objects, modname, butclasses=()):
for obj in objects:
try:
if obj.__module__ != modname or obj in butclasses:
continue
oid = class_regid(obj)
registryname = obj.__registry__
except AttributeError:
continue
if oid and not '__abstract__' in obj.__dict__:
self.register(obj, registryname)
def register(self, obj, registryname=None, oid=None, clear=False):
"""base method to add an object in the registry"""
assert not '__abstract__' in obj.__dict__
registryname = registryname or obj.__registry__
registry = self.setdefault(registryname)
registry.register(obj, oid=oid, clear=clear)
try:
vname = obj.__name__
except AttributeError:
vname = obj.__class__.__name__
self.debug('registered appobject %s in registry %s with id %s',
vname, registryname, oid or class_regid(obj))
self._loadedmods[obj.__module__][classid(obj)] = obj
def unregister(self, obj, registryname=None):
self[registryname or obj.__registry__].unregister(obj)
def register_and_replace(self, obj, replaced, registryname=None):
self[registryname or obj.__registry__].register_and_replace(obj, replaced)
# initialization methods ###################################################
def init_registration(self, path, extrapath=None):
# compute list of all modules that have to be loaded
self._toloadmods, filemods = _toload_info(path, extrapath)
# XXX is _loadedmods still necessary ? It seems like it's useful
# to avoid loading same module twice, especially with the
# _load_ancestors_then_object logic but this needs to be checked
self._loadedmods = {}
return filemods
def register_objects(self, path, force_reload, extrapath=None):
# need to clean sys.path this to avoid import confusion pb (i.e.
# having the same module loaded as 'cubicweb.web.views' subpackage and
# as views' or 'web.views' subpackage
# this is mainly for testing purpose, we should'nt need this in
# production environment
for webdir in (join(dirname(realpath(__file__)), 'web'),
join(dirname(__file__), 'web')):
if webdir in sys.path:
sys.path.remove(webdir)
if CW_SOFTWARE_ROOT in sys.path:
sys.path.remove(CW_SOFTWARE_ROOT)
# load views from each directory in the instance's path
filemods = self.init_registration(path, extrapath)
change = False
for filepath, modname in filemods:
if self.load_file(filepath, modname, force_reload):
change = True
if change:
self.initialization_completed()
return change
def initialization_completed(self):
for regname, reg in self.iteritems():
reg.initialization_completed()
def load_file(self, filepath, modname, force_reload=False):
"""load app objects from a python file"""
from logilab.common.modutils import load_module_from_name
if modname in self._loadedmods:
return
self._loadedmods[modname] = {}
try:
modified_on = stat(filepath)[-2]
except OSError:
# this typically happens on emacs backup files (.#foo.py)
self.warning('Unable to load %s. It is likely to be a backup file',
filepath)
return False
if filepath in self._lastmodifs:
# only load file if it was modified
if modified_on <= self._lastmodifs[filepath]:
return
# if it was modified, raise RegistryOutOfDate to reload everything
self.info('File %s changed since last visit', filepath)
raise RegistryOutOfDate()
# set update time before module loading, else we get some reloading
# weirdness in case of syntax error or other error while importing the
# module
self._lastmodifs[filepath] = modified_on
# load the module
module = load_module_from_name(modname, use_sys=not force_reload)
self.load_module(module)
return True
def load_module(self, module):
self.info('loading %s', module)
if hasattr(module, 'registration_callback'):
module.registration_callback(self)
else:
for objname, obj in vars(module).items():
if objname.startswith('_'):
continue
self._load_ancestors_then_object(module.__name__, obj)
def _load_ancestors_then_object(self, modname, appobjectcls):
"""handle automatic appobject class registration:
- first ensure parent classes are already registered
- class with __abstract__ == True in their local dictionnary or
with a name starting starting by an underscore are not registered
- appobject class needs to have __registry__ and __regid__ attributes
set to a non empty string to be registered.
"""
# imported classes
objmodname = getattr(appobjectcls, '__module__', None)
if objmodname != modname:
if objmodname in self._toloadmods:
self.load_file(self._toloadmods[objmodname], objmodname)
return
# skip non registerable object
try:
if not issubclass(appobjectcls, AppObject):
return
except TypeError:
return
clsid = classid(appobjectcls)
if clsid in self._loadedmods[modname]:
return
self._loadedmods[modname][clsid] = appobjectcls
for parent in appobjectcls.__bases__:
self._load_ancestors_then_object(modname, parent)
if (appobjectcls.__dict__.get('__abstract__')
or appobjectcls.__name__[0] == '_'
or not appobjectcls.__registry__
or not class_regid(appobjectcls)):
return
try:
self.register(appobjectcls)
except Exception, ex:
if self.config.mode in ('test', 'dev'):
raise
self.exception('appobject %s registration failed: %s',
appobjectcls, ex)
# init logging
set_log_methods(VRegistry, getLogger('cubicweb.vreg'))
set_log_methods(Registry, getLogger('cubicweb.registry'))
# XXX bw compat functions #####################################################
from cubicweb.appobject import objectify_selector, AndSelector, OrSelector, Selector
objectify_selector = deprecated('[3.4] objectify_selector has been moved to appobject module')(objectify_selector)
Selector = class_moved(Selector)
@deprecated('[3.4] use & operator (binary and)')
def chainall(*selectors, **kwargs):
"""return a selector chaining given selectors. If one of
the selectors fail, selection will fail, else the returned score
will be the sum of each selector'score
"""
assert selectors
# XXX do we need to create the AndSelector here, a tuple might be enough
selector = AndSelector(*selectors)
if 'name' in kwargs:
selector.__name__ = kwargs['name']
return selector
@deprecated('[3.4] use | operator (binary or)')
def chainfirst(*selectors, **kwargs):
"""return a selector chaining given selectors. If all
the selectors fail, selection will fail, else the returned score
will be the first non-zero selector score
"""
assert selectors
selector = OrSelector(*selectors)
if 'name' in kwargs:
selector.__name__ = kwargs['name']
return selector