[source storage] refactor source sql generation and results handling to allow repository side callbacks
for instance with the BytesFileSystemStorage, before this change:
* fspath, _fsopen function were stored procedures executed on the database
-> files had to be available both on the repository *and* the database host
* we needed implementation for each handled database
Now, those function are python callbacks executed when necessary on the
repository side, on data comming from the database.
The litle cons are:
* you can't do anymore restriction on mapped attributes
* you can't write queries which will return in the same rset column
some mapped attributes (or not mapped the same way) / some not
This seems much acceptable since:
* it's much more easy to handle when you start having the db on another host
than the repo
* BFSS works seemlessly on any backend now
* you don't bother that much about the cons (at least in the bfss case):
you usually don't do any restriction on Bytes...
Bonus points: BFSS is more efficient (no queries under the cover as it
was done in the registered procedure) and we have a much nicer/efficient
fspath implementation.
IMO, that rocks :D
"""undoable transaction objects.
This module is in the cubicweb package and not in cubicweb.server because those
objects should be accessible to client through pyro, where the cubicweb.server
package may not be installed.
:organization: Logilab
:copyright: 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"
_ = unicode
from cubicweb import RepositoryError
ACTION_LABELS = {
'C': _('entity creation'),
'U': _('entity update'),
'D': _('entity deletion'),
'A': _('relation add'),
'R': _('relation removal'),
}
class NoSuchTransaction(RepositoryError):
pass
class Transaction(object):
"""an undoable transaction"""
def __init__(self, uuid, time, ueid):
self.uuid = uuid
self.datetime = time
self.user_eid = ueid
# should be set by the dbapi connection
self.req = None
def __repr__(self):
return '<Transaction %s by %s on %s>' % (
self.uuid, self.user_eid, self.datetime)
def user(self):
"""return the user entity which has done the transaction,
none if not found.
"""
return self.req.execute('Any X WHERE X eid %(x)s',
{'x': self.user_eid}, 'x').get_entity(0, 0)
def actions_list(self, public=True):
"""return an ordered list of action effectued during that transaction
if public is true, return only 'public' action, eg not ones triggered
under the cover by hooks.
"""
return self.req.cnx.transaction_actions(self.uuid, public)
class AbstractAction(object):
def __init__(self, action, public, order):
self.action = action
self.public = public
self.order = order
@property
def label(self):
return ACTION_LABELS[self.action]
class EntityAction(AbstractAction):
def __init__(self, action, public, order, etype, eid, changes):
AbstractAction.__init__(self, action, public, order)
self.etype = etype
self.eid = eid
self.changes = changes
def __repr__(self):
return '<%s: %s %s (%s)>' % (
self.label, self.eid, self.changes,
self.public and 'dbapi' or 'hook')
class RelationAction(AbstractAction):
def __init__(self, action, public, order, rtype, eidfrom, eidto):
AbstractAction.__init__(self, action, public, order)
self.rtype = rtype
self.eid_from = eidfrom
self.eid_to = eidto
def __repr__(self):
return '<%s: %s %s %s (%s)>' % (
self.label, self.eid_from, self.rtype, self.eid_to,
self.public and 'dbapi' or 'hook')