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import uuid
from sqlalchemy import types, util
from sqlalchemy.dialects import mssql, postgresql
from ..compat import get_sqlalchemy_version
from .scalar_coercible import ScalarCoercible
sqlalchemy_version = get_sqlalchemy_version()
class UUIDType(ScalarCoercible, types.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,
default=uuid.uuid4
)
"""
impl = types.BINARY(16)
python_type = uuid.UUID
cache_ok = True
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 __repr__(self):
return util.generic_repr(self)
def load_dialect_impl(self, dialect):
if self.native and dialect.name in ('postgresql', 'cockroachdb'):
# Use the native UUID type.
return dialect.type_descriptor(postgresql.UUID())
if dialect.name == 'mssql' and self.native:
# Use the native UNIQUEIDENTIFIER type.
return dialect.type_descriptor(mssql.UNIQUEIDENTIFIER())
else:
# Fallback to either a BINARY or a CHAR.
kind = self.impl if self.binary else types.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
# sqlalchemy >= 1.4.30 quotes UUID's automatically.
# It is only necessary to quote UUID's in sqlalchemy < 1.4.30.
if sqlalchemy_version < (1, 4, 30):
def process_literal_param(self, value, dialect):
return f"'{value}'" if value else value
else:
def process_literal_param(self, value, dialect):
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 in (
'postgresql',
'mssql',
'cockroachdb'
):
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 in (
'postgresql',
'mssql',
'cockroachdb'
):
if isinstance(value, uuid.UUID):
# Some drivers convert PostgreSQL's uuid values to
# Python's uuid.UUID objects by themselves
return value
return uuid.UUID(value)
return uuid.UUID(bytes=value) if self.binary else uuid.UUID(value)
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