# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb 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.
#
# CubicWeb 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 CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""
* 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
"""
__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
from cubicweb.appobject import AppObject, class_regid
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':
modpath = modpath_from_file(fileordir, extrapath)
# omit '__init__' from package's name to avoid loading that module
# once for each name when it is imported by some other appobject
# module. This supposes import in modules are done as::
#
# from package import something
#
# not::
#
# from package.__init__ import something
#
# which seems quite correct.
if modpath[-1] == '__init__':
modpath.pop()
modname = '.'.join(modpath)
_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_registries(cls, registryname):
if registryname:
return (registryname,)
return cls.__registries__
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)
# prevent from misspelling
assert obj is not replaced, 'replacing an object by itself: %s' % obj
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 `oid` identifier. Only one object is expected
to be found.
raise :exc:`ObjectNotFound` if not object with id <oid> in <registry>
raise :exc:`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 :exc:`ObjectNotFound` if not object with id <oid> in <registry>
raise :exc:`NoSelectableObject` if not object apply
"""
obj = self._select_best(self[__oid], *args, **kwargs)
if obj is None:
raise NoSelectableObject(args, kwargs, self[__oid] )
return obj
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
def possible_objects(self, *args, **kwargs):
"""return an iterator on possible objects in this registry for the given
context
"""
for appobjects in self.itervalues():
obj = self._select_best(appobjects, *args, **kwargs)
if obj is None:
continue
yield obj
def _select_best(self, appobjects, *args, **kwargs):
"""return an instance of the most specific object according
to parameters
return None if not object apply (don't raise `NoSelectableObject` since
it's costly when searching appobjects using `possible_objects`
(e.g. searching for hooks).
"""
score, winners = 0, None
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 winners is None:
return None
if len(winners) > 1:
# log in production environement / test, error while debugging
msg = 'select ambiguity: %s\n(args: %s, kwargs: %s)'
if self.config.debugmode or self.config.mode == 'test':
# raise bare exception in debug mode
raise Exception(msg % (winners, args, kwargs.keys()))
self.error(msg, winners, args, kwargs.keys())
# return the result of calling the appobject
return winners[0](*args, **kwargs)
# these are overridden by set_log_methods below
# only defining here to prevent pylint from complaining
info = warning = error = critical = exception = debug = lambda msg,*a,**kw: None
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
# 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)
def reset(self):
# 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]
# 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=()):
"""register all `objects` given. Objects which are not from the module
`modname` or which are in `butclasses` won't be registered.
Typical usage is:
.. sourcecode:: python
vreg.register_all(globals().values(), __name__, (ClassIWantToRegisterExplicitly,))
So you get partially automatic registration, keeping manual registration
for some object (to use
:meth:`~cubicweb.cwvreg.CubicWebRegistry.register_and_replace` for
instance)
"""
for obj in objects:
try:
if obj.__module__ != modname or obj in butclasses:
continue
oid = class_regid(obj)
except AttributeError:
continue
if oid and not '__abstract__' in obj.__dict__:
self.register(obj, oid=oid)
def register(self, obj, registryname=None, oid=None, clear=False):
"""register `obj` application object into `registryname` or
`obj.__registry__` if not specified, with identifier `oid` or
`obj.__regid__` if not specified.
If `clear` is true, all objects with the same identifier will be
previously unregistered.
"""
assert not '__abstract__' in obj.__dict__
try:
vname = obj.__name__
except AttributeError:
# XXX may occurs?
vname = obj.__class__.__name__
for registryname in class_registries(obj, registryname):
registry = self.setdefault(registryname)
registry.register(obj, oid=oid, clear=clear)
self.debug('register %s in %s[\'%s\']',
vname, registryname, oid or class_regid(obj))
self._loadedmods.setdefault(obj.__module__, {})[classid(obj)] = obj
def unregister(self, obj, registryname=None):
"""unregister `obj` application object from the registry `registryname` or
`obj.__registry__` if not specified.
"""
for registryname in class_registries(obj, registryname):
self[registryname].unregister(obj)
def register_and_replace(self, obj, replaced, registryname=None):
"""register `obj` application object into `registryname` or
`obj.__registry__` if not specified. If found, the `replaced` object
will be unregistered first (else a warning will be issued as it's
generally unexpected).
"""
for registryname in class_registries(obj, registryname):
self[registryname].register_and_replace(obj, replaced)
# initialization methods ###################################################
def init_registration(self, path, extrapath=None):
self.reset()
# 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, extrapath=None):
# load views from each directory in the instance's path
filemods = self.init_registration(path, extrapath)
for filepath, modname in filemods:
self.load_file(filepath, modname)
self.initialization_completed()
def initialization_completed(self):
for regname, reg in self.iteritems():
reg.initialization_completed()
def _mdate(self, filepath):
try:
return 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 None
def is_reload_needed(self, path):
"""return True if something module changed and the registry should be
reloaded
"""
lastmodifs = self._lastmodifs
for fileordir in path:
if isdir(fileordir) and exists(join(fileordir, '__init__.py')):
if self.is_reload_needed([join(fileordir, fname)
for fname in listdir(fileordir)]):
return True
elif fileordir[-3:] == '.py':
mdate = self._mdate(fileordir)
if mdate is None:
continue # backup file, see _mdate implementation
elif "flymake" in fileordir:
# flymake + pylint in use, don't consider these they will corrupt the registry
continue
if fileordir not in lastmodifs or lastmodifs[fileordir] < mdate:
self.info('File %s changed since last visit', fileordir)
return True
return False
def load_file(self, filepath, modname):
"""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] = {}
mdate = self._mdate(filepath)
if mdate is None:
return # backup file, see _mdate implementation
elif "flymake" in filepath:
# flymake + pylint in use, don't consider these they will corrupt the registry
return
# 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] = mdate
# load the module
module = load_module_from_name(modname)
self.load_module(module)
def load_module(self, module):
self.info('loading %s from %s', module.__name__, module.__file__)
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 with 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.__registries__
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)
# these are overridden by set_log_methods below
# only defining here to prevent pylint from complaining
info = warning = error = critical = exception = debug = lambda msg,*a,**kw: None
# 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
Selector = class_moved(Selector)