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# Copyright (c) 2013 Yubico AB
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__all__ = [
    'Controller'
]

from sqlalchemy.exc import IntegrityError


class Controller(object):
    """
    Base class for creating Controllers that deal with models.
    """
    def __init__(self, session):
        self.session = session

    def __del__(self):
        self.session.close()

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        if not isinstance(value, Exception):
            self.commit()
        self.session.close()

    def commit(self):
        """
        Commits any unchanged modifications to the database.

        @return: True if successful, False on error
        @rtype: bool
        """
        try:
            self.session.commit()
            return True
        except IntegrityError:
            self.session.rollback()
            return False
