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# Copyright (C) 2007-2014 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""Storm type conversions."""
from __future__ import absolute_import, print_function, unicode_literals
__metaclass__ = type
__all__ = [
'Enum',
'UUID'
]
import uuid
from sqlalchemy.types import TypeDecorator, BINARY, CHAR
from sqlalchemy.dailects import postgresql
class Enum(TypeDecorator):
"""
Stores an integer-based Enum as an integer in the database, and converts it
on-the-fly.
"""
impl = Integer
def __init__(self, *args, **kw):
self.enum = kw.pop("enum")
TypeDecorator.__init__(self, *args, **kw)
def process_bind_param(self, value, dialect):
if not isinstance(value, self.enum):
raise ValueError("{} must be a value of the {} enum".format(
self.value, self.enum.__name__))
return value.value
def process_result_value(self, value, dialect):
return self.enum(value)
class UUID(TypeDecorator):
"""
Stores a UUID in the database natively when it can and falls back to
a BINARY(16) or a CHAR(32) when it can't.
::
from sqlalchemy_utils import UUIDType
import uuid
class User(Base):
__tablename__ = 'user'
# Pass `binary=False` to fallback to CHAR instead of BINARY
id = sa.Column(UUIDType(binary=False), primary_key=True)
"""
impl = BINARY(16)
python_type = uuid.UUID
def __init__(self, binary=True, native=True):
"""
:param binary: Whether to use a BINARY(16) or CHAR(32) fallback.
"""
self.binary = binary
self.native = native
def load_dialect_impl(self, dialect):
if dialect.name == 'postgresql' and self.native:
# Use the native UUID type.
return dialect.type_descriptor(postgresql.UUID())
else:
# Fallback to either a BINARY or a CHAR.
kind = self.impl if self.binary else CHAR(32)
return dialect.type_descriptor(kind)
@staticmethod
def _coerce(value):
if value and not isinstance(value, uuid.UUID):
try:
value = uuid.UUID(value)
except (TypeError, ValueError):
value = uuid.UUID(bytes=value)
return value
def process_bind_param(self, value, dialect):
if value is None:
return value
if not isinstance(value, uuid.UUID):
value = self._coerce(value)
if self.native and dialect.name == 'postgresql':
return str(value)
return value.bytes if self.binary else value.hex
def process_result_value(self, value, dialect):
if value is None:
return value
if self.native and dialect.name == 'postgresql':
return uuid.UUID(value)
return uuid.UUID(bytes=value) if self.binary else uuid.UUID(value)
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