cubicweb/appobject.py
changeset 11057 0b59724cb3f2
parent 10496 e95b559a06a2
child 11767 432f87a63057
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/appobject.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,161 @@
+# copyright 2003-2012 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 `AppObject` class
+---------------------
+
+The AppObject class is the base class for all dynamically loaded objects
+(application objects) accessible through the vregistry.
+
+We can find a certain number of attributes and methods defined in this class and
+common to all the application objects.
+
+"""
+__docformat__ = "restructuredtext en"
+
+from logging import getLogger
+
+from logilab.common.deprecation import deprecated, class_renamed
+from logilab.common.logging_ext import set_log_methods
+
+# first line imports for bw compat
+from logilab.common.registry import (objectify_predicate, traced_selection, Predicate,
+                                     RegistrableObject, yes)
+
+
+objectify_selector = deprecated('[3.15] objectify_selector has been '
+                                'renamed to objectify_predicates in '
+                                'logilab.common.registry')(objectify_predicate)
+traced_selection = deprecated('[3.15] traced_selection has been '
+                              'moved to logilab.common.registry')(traced_selection)
+Selector = class_renamed('Selector', Predicate,
+                         '[3.15] Selector has been renamed to Predicate '
+                         'in logilab.common.registry')
+
+@deprecated('[3.15] lltrace decorator can now be removed')
+def lltrace(func):
+    return func
+
+# the base class for all appobjects ############################################
+
+class AppObject(RegistrableObject):
+    """This is the base class for CubicWeb application objects which are
+    selected in a request context.
+
+    The following attributes should be set on concrete appobject classes:
+
+    At selection time, the following attributes are set on the instance:
+
+    :attr:`_cw`
+      current request
+    :attr:`cw_extra_kwargs`
+      other received arguments
+
+    And also the following, only if `rset` is found in arguments (in which case
+    rset/row/col will be removed from `cwextra_kwargs`):
+
+    :attr:`cw_rset`
+      context result set or None
+
+    :attr:`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
+
+    :attr:`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
+
+
+    .. Note::
+
+      * do not inherit directly from this class but from a more specific class
+        such as `AnyEntity`, `EntityView`, `AnyRsetView`, `Action`...
+
+    """
+    __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.
+        """
+        pdefs = getattr(cls, 'cw_property_defs', {})
+        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)
+        assert callable(cls.__select__), cls
+        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))
+
+    # 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
+
+set_log_methods(AppObject, getLogger('cubicweb.appobject'))
+
+# defined here to avoid warning on usage on the AppObject class
+yes = deprecated('[3.15] yes has been moved to logilab.common.registry')(yes)