Synnefo

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from sqlalchemy import create_engine

#from sqlalchemy.event import listen

from sqlalchemy.pool import NullPool

from sqlalchemy.interfaces import PoolListener

class DBWrapper(object):

    """Database connection wrapper."""

    def __init__(self, db):

        if db.startswith('sqlite://'):

            class ForeignKeysListener(PoolListener):

                def connect(self, dbapi_con, con_record):

                    dbapi_con.execute('pragma foreign_keys=ON;')

                    dbapi_con.execute('pragma case_sensitive_like=ON;')

            self.engine = create_engine(

                db, connect_args={'check_same_thread': False},

                poolclass=NullPool, listeners=[ForeignKeysListener()],

                isolation_level='SERIALIZABLE')

        #elif db.startswith('mysql://'):

        #    db = '%s?charset=utf8&use_unicode=0' %db

        #    self.engine = create_engine(db, convert_unicode=True)

        else:

            #self.engine = create_engine(db, pool_size=0, max_overflow=-1)

            self.engine = create_engine(

                db, poolclass=NullPool, isolation_level='READ COMMITTED')

        self.engine.echo = False

        self.engine.echo_pool = False

        self.conn = self.engine.connect()

        self.trans = None

    def close(self):

        self.conn.close()

        self.conn = None

    def execute(self):

        self.trans = self.conn.begin()

    def commit(self):

        self.trans.commit()

        self.trans = None

    def rollback(self):

        self.trans.rollback()

        self.trans = None