dify/api/models/types.py
QuantumGhost 6a9e0b1005
feat(api): Introduce WorkflowDraftVariable Model (#19737)
- Introduce `WorkflowDraftVariable` model and the corresponding migration.
- Implement `EnumText`,  a custom column type for SQLAlchemy designed
  to work seamlessly with enumeration classes based on `StrEnum`.
2025-05-19 22:59:56 +08:00

78 lines
2.3 KiB
Python

import enum
from typing import Generic, TypeVar
from sqlalchemy import CHAR, VARCHAR, TypeDecorator
from sqlalchemy.dialects.postgresql import UUID
class StringUUID(TypeDecorator):
impl = CHAR
cache_ok = True
def process_bind_param(self, value, dialect):
if value is None:
return value
elif dialect.name == "postgresql":
return str(value)
else:
return value.hex
def load_dialect_impl(self, dialect):
if dialect.name == "postgresql":
return dialect.type_descriptor(UUID())
else:
return dialect.type_descriptor(CHAR(36))
def process_result_value(self, value, dialect):
if value is None:
return value
return str(value)
_E = TypeVar("_E", bound=enum.StrEnum)
class EnumText(TypeDecorator, Generic[_E]):
impl = VARCHAR
cache_ok = True
_length: int
_enum_class: type[_E]
def __init__(self, enum_class: type[_E], length: int | None = None):
self._enum_class = enum_class
max_enum_value_len = max(len(e.value) for e in enum_class)
if length is not None:
if length < max_enum_value_len:
raise ValueError("length should be greater than enum value length.")
self._length = length
else:
# leave some rooms for future longer enum values.
self._length = max(max_enum_value_len, 20)
def process_bind_param(self, value: _E | str | None, dialect):
if value is None:
return value
if isinstance(value, self._enum_class):
return value.value
elif isinstance(value, str):
self._enum_class(value)
return value
else:
raise TypeError(f"expected str or {self._enum_class}, got {type(value)}")
def load_dialect_impl(self, dialect):
return dialect.type_descriptor(VARCHAR(self._length))
def process_result_value(self, value, dialect) -> _E | None:
if value is None:
return value
if not isinstance(value, str):
raise TypeError(f"expected str, got {type(value)}")
return self._enum_class(value)
def compare_values(self, x, y):
if x is None or y is None:
return x is y
return x == y