1 # Copyright (c) 2012 netzguerilla.net <iro@netzguerilla.net>

     2 # 

     3 # This file is part of Iro.

     4 # 

     5 # Permission is hereby granted, free of charge, to any person obtaining a copy of

     6 # this software and associated documentation files (the "Software"), to deal in

     7 # the Software without restriction, including without limitation the rights to use,

     8 # copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the

     9 # #Software, and to permit persons to whom the Software is furnished to do so,

    10 # subject to the following conditions:

    11 # 

    12 # The above copyright notice and this permission notice shall be included in

    13 # all copies or substantial portions of the Software.

    14 # 

    15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,

    16 # INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

    17 # PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

    18 # HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

    19 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

    20 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    21 

    22 from sqlalchemy.orm import sessionmaker

    23 

    24 class WithSession(object):

    25     '''a with statement for a database session connection.'''

    26     def __init__(self, engine, autocommit=False):

    27         """

    28         :param `sqlalchemy.engine.base.Engine` engine: a valid sqlalchemy engine object (normally created via :func:`sqlalchemy.create_engine`).

    29         :param boolean autocommit: autocommit after running the function.

    30 

    31         .. automethod:: __enter__

    32         .. automethod:: __exit__

    33         """

    34         self.engine = engine

    35         self.autocommit=autocommit

    36     

    37     def __enter__(self):

    38         """returns a vaild session object."""

    39         self.session = sessionmaker(bind=self.engine)()

    40         return self.session

    41     

    42     def __exit__(self,exc_type, exc_value, traceback):

    43         if exc_type is None:

    44             if self.autocommit:

    45                 self.session.commit()

    46         else:

    47             self.session.rollback()

    48         self.session.close()

    49 

    50 

    51