Am Mittwoch, 4. Juni 2008 22:09 schrieb Laurence Rowe:
Hermann Himmelbauer wrote:
In my application, I then use getSASession() to retrieve my session.
However, what I think is not that beautiful is the "s.bind = engine" part. Are there any suggestions how to improve this?
You have two options
If you ever need to mix objects from different `sites` into the same session, you should use an adapter on your root object like:
If you don't need to mix objects from different `sites` then you can register a local utility for ISessionConfig.
def scope(): return getUtility(ISessionConfig).uid, thread.get_ident()
def factory(): engine = Engine(getUtility(ISessionConfig).url) return create_session( transactional=True, autoflush=True, bind=engine extension=ZopeTransactionExtension(), ))
Session = scoped_session(factory, scopefunc=scope)
Then you can just import Session and use: session = Session()
Ok, great, thanks for help. The only thing I don't understand is what "uid" from the SessionConfig utility is. Below is my full database integration code which works for me, perhaps this is helpful to someone else. Btw., I'd suggest to put such code / session use cases in some Zope package, maybe into zope.sqlalchemy, or e.g. zope.sqlalchemy_utility as it's really difficult for non-insiders to set this up. ------------------------------------- import thread from persistent import Persistent from sqlalchemy import create_engine from sqlalchemy.orm import scoped_session, create_session from zope.interface import Interface, implements, alsoProvides from zope.schema import TextLine, Bool from zope.component import getUtility, adapter from zope.sqlalchemy import ZopeTransactionExtension from zmyapp.interfaces import INewMySiteEvent from zope.i18nmessageid import MessageFactory _ = MessageFactory('xyz') class ISAEngineUtility(Interface): """SQLAlchemy Engine Utility""" db_type = TextLine(title = _(u"Database Type")) db_username = TextLine(title = _(u"Database Username")) db_password = TextLine(title = _(u"Database Password")) db_host = TextLine(title = _(u"Database Host")) db_name = TextLine(title = _(u"Database Name")) db_echo = Bool(title = _(u"Echo Database Operations")) db_enconding = TextLine(title = _(u"Database Encoding")) db_convert_unicode = Bool(title = _(u"Database Unicode Conversion")) class SAEngineUtility(Persistent): implements(ISAEngineUtility) # FIXME FIXME!!! uid = 12345 def reset_engine_on_attrset(dsn_part): doc = "Reset engine when setting variable (stored in %s)" % dsn_part def fget(self): return getattr(self, dsn_part, None) def fset(self, value): oldvalue = getattr(self, dsn_part, None) if oldvalue != value: setattr(self, dsn_part, value) if getattr(self, 'init_done', False): self._resetEngine() return {'fget': fget, 'fset': fset, 'doc': doc} db_type = property(**reset_engine_on_attrset('_db_type')) db_username = property(**reset_engine_on_attrset('_db_username')) db_password = property(**reset_engine_on_attrset('_db_password')) db_host = property(**reset_engine_on_attrset('_db_host')) db_name = property(**reset_engine_on_attrset('_db_name')) db_echo = property(**reset_engine_on_attrset('_db_echo')) db_encoding = property(**reset_engine_on_attrset('_db_encoding')) db_convert_unicode =property( **reset_engine_on_attrset('_db_convert_unicode')) def __init__(self, db_type, db_username, db_password, db_host, db_name, db_echo = False, db_encoding = 'utf-8', db_convert_unicode = False): self.db_type = db_type self.db_username = db_username self.db_password = db_password self.db_host = db_host self.db_name = db_name self.db_echo = db_echo self.db_encoding = db_encoding self.db_convert_unicode = db_convert_unicode self.init_done = True def mkDSN(self): """Create database DSN out of DSN elements""" userpass = '' if self.db_username: userpass += self.db_username if self.db_password: userpass += ':' + self.db_password if self.db_host == 'localhost': db_host = '' else: db_host = self.db_host if db_host and userpass: db_host = userpass + '@' + self.db_host elif not db_host and userpass: db_host = userpass + '@localhost' return '%s://%s/%s' % (self.db_type, db_host, self.db_name) def getEngine(self): engine = getattr(self, '_v_engine', None) if engine: return engine # No engine available, create a new one self._v_engine = create_engine(self.mkDSN(), echo = self.db_echo, encoding = self.db_encoding, convert_unicode = self.db_convert_unicode, ) return self._v_engine def _resetEngine(self): engine = getattr(self, '_v_engine', None) if engine is not None: engine.dispose() self._v_engine = None @adapter(INewMySiteEvent) def createSAEngineUtility(event): saUtility = SAEngineUtility( event.object.db_type, event.object.db_username, event.object.db_password, event.object.db_host, event.object.db_name) sm = event.object.getSiteManager() sm['saengine_utility'] = saUtility sm.registerUtility(saUtility, ISAEngineUtility) def scope(): return getUtility(ISAEngineUtility).uid, thread.get_ident() def session_factory(): engine = getUtility(ISAEngineUtility).getEngine() return create_session(transactional = True, autoflush = True, bind = engine, extension = ZopeTransactionExtension()) SASession = scoped_session(session_factory, scopefunc = scope) ------------------------------ Best Regards, Hermann -- hermann@qwer.tk GPG key ID: 299893C7 (on keyservers) FP: 0124 2584 8809 EF2A DBF9 4902 64B4 D16B 2998 93C7