# copyright 2003-2014 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/>.
"""Core hooks: check for data integrity according to the instance'schema
validity
"""
__docformat__ = "restructuredtext en"
from cubicweb import _
from threading import Lock
from six import text_type
from cubicweb import validation_error, neg_role
from cubicweb.schema import (META_RTYPES, WORKFLOW_RTYPES,
RQLConstraint, RQLUniqueConstraint)
from cubicweb.predicates import is_instance, composite_etype
from cubicweb.uilib import soup2xhtml
from cubicweb.server import hook
# special relations that don't have to be checked for integrity, usually
# because they are handled internally by hooks (so we trust ourselves)
DONT_CHECK_RTYPES_ON_ADD = META_RTYPES | WORKFLOW_RTYPES
DONT_CHECK_RTYPES_ON_DEL = META_RTYPES | WORKFLOW_RTYPES
_UNIQUE_CONSTRAINTS_LOCK = Lock()
_UNIQUE_CONSTRAINTS_HOLDER = None
def _acquire_unique_cstr_lock(cnx):
"""acquire the _UNIQUE_CONSTRAINTS_LOCK for the cnx.
This lock used to avoid potential integrity pb when checking
RQLUniqueConstraint in two different transactions, as explained in
https://extranet.logilab.fr/3577926
"""
if 'uniquecstrholder' in cnx.transaction_data:
return
_UNIQUE_CONSTRAINTS_LOCK.acquire()
cnx.transaction_data['uniquecstrholder'] = True
# register operation responsible to release the lock on commit/rollback
_ReleaseUniqueConstraintsOperation(cnx)
def _release_unique_cstr_lock(cnx):
if 'uniquecstrholder' in cnx.transaction_data:
del cnx.transaction_data['uniquecstrholder']
_UNIQUE_CONSTRAINTS_LOCK.release()
class _ReleaseUniqueConstraintsOperation(hook.Operation):
def postcommit_event(self):
_release_unique_cstr_lock(self.cnx)
def rollback_event(self):
_release_unique_cstr_lock(self.cnx)
class _CheckRequiredRelationOperation(hook.DataOperationMixIn,
hook.LateOperation):
"""checking relation cardinality has to be done after commit in case the
relation is being replaced
"""
containercls = list
role = key = base_rql = None
def precommit_event(self):
cnx = self.cnx
pendingeids = cnx.transaction_data.get('pendingeids', ())
pendingrtypes = cnx.transaction_data.get('pendingrtypes', ())
for eid, rtype in self.get_data():
# recheck pending eids / relation types
if eid in pendingeids:
continue
if rtype in pendingrtypes:
continue
if not cnx.execute(self.base_rql % rtype, {'x': eid}):
etype = cnx.entity_metas(eid)['type']
msg = _('at least one relation %(rtype)s is required on '
'%(etype)s (%(eid)s)')
raise validation_error(eid, {(rtype, self.role): msg},
{'rtype': rtype, 'etype': etype, 'eid': eid},
['rtype', 'etype'])
class _CheckSRelationOp(_CheckRequiredRelationOperation):
"""check required subject relation"""
role = 'subject'
base_rql = 'Any O WHERE S eid %%(x)s, S %s O'
class _CheckORelationOp(_CheckRequiredRelationOperation):
"""check required object relation"""
role = 'object'
base_rql = 'Any S WHERE O eid %%(x)s, S %s O'
class IntegrityHook(hook.Hook):
__abstract__ = True
category = 'integrity'
class EnsureSymmetricRelationsAdd(hook.Hook):
""" ensure X r Y => Y r X iff r is symmetric """
__regid__ = 'cw.add_ensure_symmetry'
category = 'activeintegrity'
events = ('after_add_relation',)
# __select__ is set in the registration callback
def __call__(self):
self._cw.repo.system_source.add_relation(self._cw, self.eidto,
self.rtype, self.eidfrom)
class EnsureSymmetricRelationsDelete(hook.Hook):
""" ensure X r Y => Y r X iff r is symmetric """
__regid__ = 'cw.delete_ensure_symmetry'
category = 'activeintegrity'
events = ('after_delete_relation',)
# __select__ is set in the registration callback
def __call__(self):
self._cw.repo.system_source.delete_relation(self._cw, self.eidto,
self.rtype, self.eidfrom)
class CheckCardinalityHookBeforeDeleteRelation(IntegrityHook):
"""check cardinalities are satisfied"""
__regid__ = 'checkcard_before_delete_relation'
events = ('before_delete_relation',)
def __call__(self):
rtype = self.rtype
if rtype in DONT_CHECK_RTYPES_ON_DEL:
return
cnx = self._cw
eidfrom, eidto = self.eidfrom, self.eidto
rdef = cnx.rtype_eids_rdef(rtype, eidfrom, eidto)
if (rdef.subject, rtype, rdef.object) in cnx.transaction_data.get('pendingrdefs', ()):
return
card = rdef.cardinality
if card[0] in '1+' and not cnx.deleted_in_transaction(eidfrom):
_CheckSRelationOp.get_instance(cnx).add_data((eidfrom, rtype))
if card[1] in '1+' and not cnx.deleted_in_transaction(eidto):
_CheckORelationOp.get_instance(cnx).add_data((eidto, rtype))
class CheckCardinalityHookAfterAddEntity(IntegrityHook):
"""check cardinalities are satisfied"""
__regid__ = 'checkcard_after_add_entity'
events = ('after_add_entity',)
def __call__(self):
eid = self.entity.eid
eschema = self.entity.e_schema
for rschema, targetschemas, role in eschema.relation_definitions():
# skip automatically handled relations
if rschema.type in DONT_CHECK_RTYPES_ON_ADD:
continue
rdef = rschema.role_rdef(eschema, targetschemas[0], role)
if rdef.role_cardinality(role) in '1+':
if role == 'subject':
op = _CheckSRelationOp.get_instance(self._cw)
else:
op = _CheckORelationOp.get_instance(self._cw)
op.add_data((eid, rschema.type))
class _CheckConstraintsOp(hook.DataOperationMixIn, hook.LateOperation):
""" check a new relation satisfy its constraints """
containercls = list
def precommit_event(self):
cnx = self.cnx
for values in self.get_data():
eidfrom, rtype, eidto, constraints = values
# first check related entities have not been deleted in the same
# transaction
if cnx.deleted_in_transaction(eidfrom):
continue
if cnx.deleted_in_transaction(eidto):
continue
for constraint in constraints:
# XXX
# * lock RQLConstraint as well?
# * use a constraint id to use per constraint lock and avoid
# unnecessary commit serialization ?
if isinstance(constraint, RQLUniqueConstraint):
_acquire_unique_cstr_lock(cnx)
try:
constraint.repo_check(cnx, eidfrom, rtype, eidto)
except NotImplementedError:
self.critical('can\'t check constraint %s, not supported',
constraint)
class CheckConstraintHook(IntegrityHook):
"""check the relation satisfy its constraints
this is delayed to a precommit time operation since other relation which
will make constraint satisfied (or unsatisfied) may be added later.
"""
__regid__ = 'checkconstraint'
events = ('after_add_relation',)
def __call__(self):
# XXX get only RQL[Unique]Constraints?
rdef = self._cw.rtype_eids_rdef(self.rtype, self.eidfrom, self.eidto)
constraints = rdef.constraints
if constraints:
_CheckConstraintsOp.get_instance(self._cw).add_data(
(self.eidfrom, self.rtype, self.eidto, constraints))
class CheckAttributeConstraintHook(IntegrityHook):
"""check the attribute relation satisfy its constraints
this is delayed to a precommit time operation since other relation which
will make constraint satisfied (or unsatisfied) may be added later.
"""
__regid__ = 'checkattrconstraint'
events = ('after_add_entity', 'after_update_entity')
def __call__(self):
eschema = self.entity.e_schema
for attr in self.entity.cw_edited:
if eschema.subjrels[attr].final:
constraints = [c for c in eschema.rdef(attr).constraints
if isinstance(c, (RQLUniqueConstraint, RQLConstraint))]
if constraints:
_CheckConstraintsOp.get_instance(self._cw).add_data(
(self.entity.eid, attr, None, constraints))
class CheckUniqueHook(IntegrityHook):
__regid__ = 'checkunique'
events = ('before_add_entity', 'before_update_entity')
def __call__(self):
entity = self.entity
eschema = entity.e_schema
for attr, val in entity.cw_edited.items():
if eschema.subjrels[attr].final and eschema.has_unique_values(attr):
if val is None:
continue
rql = '%s X WHERE X %s %%(val)s' % (entity.e_schema, attr)
rset = self._cw.execute(rql, {'val': val})
if rset and rset[0][0] != entity.eid:
msg = _('the value "%s" is already used, use another one')
raise validation_error(entity, {(attr, 'subject'): msg},
(val,))
class DontRemoveOwnersGroupHook(IntegrityHook):
"""delete the composed of a composite relation when this relation is deleted
"""
__regid__ = 'checkownersgroup'
__select__ = IntegrityHook.__select__ & is_instance('CWGroup')
events = ('before_delete_entity', 'before_update_entity')
def __call__(self):
entity = self.entity
if self.event == 'before_delete_entity' and entity.name == 'owners':
raise validation_error(entity, {None: _("can't be deleted")})
elif self.event == 'before_update_entity' \
and 'name' in entity.cw_edited:
oldname, newname = entity.cw_edited.oldnewvalue('name')
if oldname == 'owners' and newname != oldname:
raise validation_error(entity, {('name', 'subject'): _("can't be changed")})
class TidyHtmlFields(IntegrityHook):
"""tidy HTML in rich text strings"""
__regid__ = 'htmltidy'
events = ('before_add_entity', 'before_update_entity')
def __call__(self):
entity = self.entity
metaattrs = entity.e_schema.meta_attributes()
edited = entity.cw_edited
for metaattr, (metadata, attr) in metaattrs.items():
if metadata == 'format' and attr in edited:
try:
value = edited[attr]
except KeyError:
continue # no text to tidy
if isinstance(value, text_type): # filter out None and Binary
if getattr(entity, str(metaattr)) == 'text/html':
edited[attr] = soup2xhtml(value, self._cw.encoding)
class StripCWUserLoginHook(IntegrityHook):
"""ensure user logins are stripped"""
__regid__ = 'stripuserlogin'
__select__ = IntegrityHook.__select__ & is_instance('CWUser')
events = ('before_add_entity', 'before_update_entity',)
def __call__(self):
login = self.entity.cw_edited.get('login')
if login:
self.entity.cw_edited['login'] = login.strip()
class DeleteCompositeOrphanHook(hook.Hook):
"""Delete the composed of a composite relation when the composite is
deleted (this is similar to the cascading ON DELETE CASCADE
semantics of sql).
"""
__regid__ = 'deletecomposite'
__select__ = hook.Hook.__select__ & composite_etype()
events = ('before_delete_entity',)
category = 'activeintegrity'
# give the application's before_delete_entity hooks a chance to run before we cascade
order = 99
def __call__(self):
eid = self.entity.eid
for rdef, role in self.entity.e_schema.composite_rdef_roles:
rtype = rdef.rtype.type
target = getattr(rdef, neg_role(role))
expr = ('C %s X' % rtype) if role == 'subject' else ('X %s C' % rtype)
self._cw.execute('DELETE %s X WHERE C eid %%(c)s, %s' % (target, expr),
{'c': eid})
def registration_callback(vreg):
vreg.register_all(globals().values(), __name__)
symmetric_rtypes = [rschema.type for rschema in vreg.schema.relations()
if rschema.symmetric]
EnsureSymmetricRelationsAdd.__select__ = hook.Hook.__select__ & hook.match_rtype(*symmetric_rtypes)
EnsureSymmetricRelationsDelete.__select__ = hook.Hook.__select__ & hook.match_rtype(*symmetric_rtypes)