511 lines
19 KiB
Python
511 lines
19 KiB
Python
from __future__ import annotations
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from typing import Any, Callable, Type, TypeVar, Generic, Optional, Protocol, runtime_checkable, cast
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from sqlalchemy import and_, func, inspect, or_, text
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from sqlalchemy.engine import Engine, Connection
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from sqlalchemy.orm import Load, Session, with_polymorphic, Mapper, RelationshipProperty
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from sqlalchemy.orm.attributes import InstrumentedAttribute
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from crudkit.core.base import Version
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from crudkit.core.spec import CRUDSpec
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from crudkit.core.types import OrderSpec, SeekWindow
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from crudkit.backend import BackendInfo, make_backend_info
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from crudkit.projection import compile_projection
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import logging
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log = logging.getLogger("crudkit.service")
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def _is_rel(model_cls, name: str) -> bool:
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try:
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prop = model_cls.__mapper__.relationships.get(name)
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return isinstance(prop, RelationshipProperty)
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except Exception:
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return False
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@runtime_checkable
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class _HasID(Protocol):
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id: int
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@runtime_checkable
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class _HasTable(Protocol):
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__table__: Any
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@runtime_checkable
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class _HasADict(Protocol):
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def as_dict(self) -> dict: ...
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@runtime_checkable
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class _SoftDeletable(Protocol):
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is_deleted: bool
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class _CRUDModelProto(_HasID, _HasTable, _HasADict, Protocol):
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"""Minimal surface that our CRUD service relies on. Soft-delete is optional."""
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pass
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T = TypeVar("T", bound=_CRUDModelProto)
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def _is_truthy(val):
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return str(val).lower() in ('1', 'true', 'yes', 'on')
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class CRUDService(Generic[T]):
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def __init__(
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self,
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model: Type[T],
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session_factory: Callable[[], Session],
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polymorphic: bool = False,
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*,
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backend: Optional[BackendInfo] = None
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):
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self.model = model
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self._session_factory = session_factory
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self.polymorphic = polymorphic
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self.supports_soft_delete = hasattr(model, 'is_deleted')
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# Cache backend info once. If not provided, derive from session bind.
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bind = session_factory().get_bind()
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eng: Engine = bind.engine if isinstance(bind, Connection) else cast(Engine, bind)
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self.backend = backend or make_backend_info(eng)
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@property
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def session(self) -> Session:
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return self._session_factory()
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def get_query(self):
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if self.polymorphic:
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poly = with_polymorphic(self.model, "*")
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return self.session.query(poly), poly
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return self.session.query(self.model), self.model
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def _apply_not_deleted(self, query, root_alias, params) -> Any:
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if self.supports_soft_delete and not _is_truthy((params or {}).get("include_deleted")):
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return query.filter(getattr(root_alias, "is_deleted") == False)
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return query
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def _extract_order_spec(self, root_alias, given_order_by):
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"""
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SQLAlchemy 2.x only:
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Normalize order_by into (cols, desc_flags). Supports plain columns and
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col.asc()/col.desc() (UnaryExpression). Avoids boolean evaluation of clauses.
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"""
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from sqlalchemy.sql import operators
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from sqlalchemy.sql.elements import UnaryExpression
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given = self._stable_order_by(root_alias, given_order_by)
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cols, desc_flags = [], []
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for ob in given:
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# Unwrap column if this is a UnaryExpression produced by .asc()/.desc()
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elem = getattr(ob, "element", None)
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col = elem if elem is not None else ob
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# Detect direction in SA 2.x
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is_desc = False
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dir_attr = getattr(ob, "_direction", None)
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if dir_attr is not None:
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is_desc = (dir_attr is operators.desc_op) or (getattr(dir_attr, "name", "").upper() == "DESC")
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elif isinstance(ob, UnaryExpression):
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op = getattr(ob, "operator", None)
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is_desc = (op is operators.desc_op) or (getattr(op, "name", "").upper() == "DESC")
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cols.append(col)
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desc_flags.append(bool(is_desc))
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from crudkit.core.types import OrderSpec
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return OrderSpec(cols=tuple(cols), desc=tuple(desc_flags))
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def _key_predicate(self, spec: OrderSpec, key_vals: list[Any], backward: bool):
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if not key_vals:
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return None
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conds = []
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for i, col in enumerate(spec.cols):
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# If NULLs possible, normalize for comparison. Example using coalesce to a sentinel:
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# sent_col = func.coalesce(col, literal("-∞"))
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sent_col = col
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ties = [spec.cols[j] == key_vals[j] for j in range(i)]
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is_desc = spec.desc[i]
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if not backward:
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op = (sent_col < key_vals[i]) if is_desc else (sent_col > key_vals[i])
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else:
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op = (sent_col > key_vals[i]) if is_desc else (sent_col < key_vals[i])
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conds.append(and_(*ties, op))
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return or_(*conds)
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def _pluck_key(self, obj: Any, spec: OrderSpec) -> list[Any]:
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out = []
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for c in spec.cols:
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# Only simple mapped columns supported for key pluck
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key = getattr(c, "key", None) or getattr(c, "name", None)
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if key is None or not hasattr(obj, key):
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raise ValueError("Order includes non-mapped or related column; cannot pluck cursor key from row object.")
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out.append(getattr(obj, key))
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return out
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def seek_window(
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self,
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params: dict | None = None,
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*,
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key: list[Any] | None = None,
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backward: bool = False,
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include_total: bool = True,
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) -> "SeekWindow[T]":
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"""
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Transport-agnostic keyset pagination that preserves all the goodies from `list()`:
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- filters, includes, joins, field projection, eager loading, soft-delete
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- deterministic ordering (user sort + PK tiebreakers)
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- forward/backward seek via `key` and `backward`
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Returns a SeekWindow with items, first/last keys, order spec, limit, and optional total.
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"""
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session = self.session
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fields = list((params or {}).get("fields", []))
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expanded_fields, proj_opts = compile_projection(self.model, fields) if fields else ([], [])
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query, root_alias = self.get_query()
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if proj_opts:
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query = query.options(*proj_opts)
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spec = CRUDSpec(self.model, params or {}, root_alias)
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filters = spec.parse_filters()
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order_by = spec.parse_sort()
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root_fields, rel_field_names, root_field_names = spec.parse_fields()
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# Soft delete filter
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# if self.supports_soft_delete and not _is_truthy((params or {}).get("include_deleted")):
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# query = query.filter(getattr(root_alias, "is_deleted") == False)
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query = self._apply_not_deleted(query, root_alias, params)
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# Parse filters first
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if filters:
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query = query.filter(*filters)
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# Includes + joins (so relationship fields like brand.name, location.label work)
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spec.parse_includes()
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join_paths = tuple(spec.get_join_paths())
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for _, relationship_attr, target_alias in spec.get_join_paths():
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rel_attr = cast(InstrumentedAttribute, relationship_attr)
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target = cast(Any, target_alias)
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query = query.join(target, rel_attr.of_type(target), isouter=True)
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# Fields/projection: load_only for root columns, eager loads for relationships
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only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
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if only_cols:
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query = query.options(Load(root_alias).load_only(*only_cols))
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# Order + limit
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order_spec = self._extract_order_spec(root_alias, order_by) # SA2-only helper
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limit, _ = spec.parse_pagination()
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if limit is None:
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effective_limit = 50
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elif limit == 0:
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effective_limit = None
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else:
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effective_limit = limit
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# Keyset predicate
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if key:
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pred = self._key_predicate(order_spec, key, backward)
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if pred is not None:
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query = query.filter(pred)
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# Apply ordering. For backward, invert SQL order then reverse in-memory for display.
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if not backward:
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clauses = [(c.desc() if is_desc else c.asc()) for c, is_desc in zip(order_spec.cols, order_spec.desc)]
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query = query.order_by(*clauses)
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if effective_limit is not None:
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query = query.limit(effective_limit)
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items = query.all()
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else:
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inv_clauses = [(c.asc() if is_desc else c.desc()) for c, is_desc in zip(order_spec.cols, order_spec.desc)]
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query = query.order_by(*inv_clauses)
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if effective_limit is not None:
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query = query.limit(effective_limit)
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items = list(reversed(query.all()))
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# Tag projection so your renderer knows what fields were requested
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if expanded_fields:
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proj = list(expanded_fields)
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else:
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proj = []
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if root_field_names:
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proj.extend(root_field_names)
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if root_fields:
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proj.extend(c.key for c in root_fields)
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for path, names in (rel_field_names or {}).items():
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prefix = ".".join(path)
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for n in names:
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proj.append(f"{prefix}.{n}")
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if proj and "id" not in proj and hasattr(self.model, "id"):
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proj.insert(0, "id")
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if proj:
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for obj in items:
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try:
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setattr(obj, "__crudkit_projection__", tuple(proj))
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except Exception:
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pass
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# Boundary keys for cursor encoding in the API layer
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first_key = self._pluck_key(items[0], order_spec) if items else None
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last_key = self._pluck_key(items[-1], order_spec) if items else None
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# Optional total that’s safe under JOINs (COUNT DISTINCT ids)
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total = None
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if include_total:
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base = session.query(getattr(root_alias, "id"))
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base = self._apply_not_deleted(base, root_alias, params)
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if filters:
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base = base.filter(*filters)
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for _, relationship_attr, target_alias in join_paths: # reuse
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rel_attr = cast(InstrumentedAttribute, relationship_attr)
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target = cast(Any, target_alias)
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base = base.join(target, rel_attr.of_type(target), isouter=True)
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total = session.query(func.count()).select_from(
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base.order_by(None).distinct().subquery()
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).scalar() or 0
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window_limit_for_body = 0 if effective_limit is None and limit == 0 else (effective_limit or 50)
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if log.isEnabledFor(logging.DEBUG):
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log.debug("QUERY: %s", str(query))
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from crudkit.core.types import SeekWindow # avoid circulars at module top
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return SeekWindow(
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items=items,
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limit=window_limit_for_body,
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first_key=first_key,
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last_key=last_key,
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order=order_spec,
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total=total,
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)
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# Helper: default ORDER BY for MSSQL when paginating without explicit order
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def _default_order_by(self, root_alias):
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mapper: Mapper[Any] = cast(Mapper[Any], inspect(self.model))
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cols = []
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for col in mapper.primary_key:
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try:
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cols.append(getattr(root_alias, col.key))
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except AttributeError:
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cols.append(col)
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return cols or [text("1")]
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def _stable_order_by(self, root_alias, given_order_by):
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"""
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Ensure deterministic ordering by appending PK columns as tiebreakers.
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If no order is provided, fall back to default primary-key order.
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"""
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order_by = list(given_order_by or [])
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if not order_by:
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return self._default_order_by(root_alias)
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mapper: Mapper[Any] = cast(Mapper[Any], inspect(self.model))
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pk_cols = []
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for col in mapper.primary_key:
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try:
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pk_cols.append(getattr(root_alias, col.key))
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except AttributeError:
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pk_cols.append(col)
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return [*order_by, *pk_cols]
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def get(self, id: int, params=None) -> T | None:
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query, root_alias = self.get_query()
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include_deleted = False
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root_fields = []
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root_field_names = {}
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rel_field_names = {}
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spec = CRUDSpec(self.model, params or {}, root_alias)
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if params:
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if self.supports_soft_delete:
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include_deleted = _is_truthy(params.get('include_deleted'))
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if self.supports_soft_delete and not include_deleted:
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query = query.filter(getattr(root_alias, "is_deleted") == False)
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query = query.filter(getattr(root_alias, "id") == id)
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spec.parse_includes()
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for _, relationship_attr, target_alias in spec.get_join_paths():
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rel_attr = cast(InstrumentedAttribute, relationship_attr)
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target = cast(Any, target_alias)
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query = query.join(target, rel_attr.of_type(target), isouter=True)
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if params:
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root_fields, rel_field_names, root_field_names = spec.parse_fields()
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req_fields = list((params or {}).get("fields", []))
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expanded_fields, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
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if proj_opts:
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query = query.options(*proj_opts)
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only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
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if only_cols:
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query = query.options(Load(root_alias).load_only(*only_cols))
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obj = query.first()
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if expanded_fields:
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proj = list(expanded_fields)
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else:
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proj = []
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if root_field_names:
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proj.extend(root_field_names)
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if root_fields:
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proj.extend(c.key for c in root_fields)
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for path, names in (rel_field_names or {}).items():
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prefix = ".".join(path)
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for n in names:
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proj.append(f"{prefix}.{n}")
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if proj and "id" not in proj and hasattr(self.model, "id"):
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proj.insert(0, "id")
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if proj and obj is not None:
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try:
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setattr(obj, "__crudkit_projection__", tuple(proj))
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except Exception:
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pass
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if log.isEnabledFor(logging.DEBUG):
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log.debug("QUERY: %s", str(query))
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return obj or None
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def list(self, params=None) -> list[T]:
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query, root_alias = self.get_query()
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root_fields = []
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root_field_names = {}
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rel_field_names = {}
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if params:
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if self.supports_soft_delete:
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include_deleted = _is_truthy(params.get('include_deleted'))
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if not include_deleted:
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query = query.filter(getattr(root_alias, "is_deleted") == False)
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spec = CRUDSpec(self.model, params or {}, root_alias)
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filters = spec.parse_filters()
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order_by = spec.parse_sort()
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limit, offset = spec.parse_pagination()
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spec.parse_includes()
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for _, relationship_attr, target_alias in spec.get_join_paths():
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rel_attr = cast(InstrumentedAttribute, relationship_attr)
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target = cast(Any, target_alias)
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query = query.join(target, rel_attr.of_type(target), isouter=True)
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if params:
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root_fields, rel_field_names, root_field_names = spec.parse_fields()
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only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
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if only_cols:
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query = query.options(Load(root_alias).load_only(*only_cols))
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if filters:
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query = query.filter(*filters)
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# MSSQL: requires ORDER BY when using OFFSET (and SQLA will use OFFSET for limit+offset).
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paginating = (limit is not None) or (offset is not None and offset != 0)
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if paginating and not order_by and self.backend.requires_order_by_for_offset:
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order_by = self._default_order_by(root_alias)
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if order_by:
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query = query.order_by(*order_by)
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# Only apply offset/limit when not None.
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if offset is not None and offset != 0:
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query = query.offset(offset)
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if limit is not None and limit > 0:
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query = query.limit(limit)
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req_fields = list((params or {}).get("fields", []))
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expanded_fields, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
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if proj_opts:
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query = query.options(*proj_opts)
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rows = query.all()
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if expanded_fields:
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proj = list(expanded_fields)
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else:
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proj = []
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if root_field_names:
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proj.extend(root_field_names)
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if root_fields:
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proj.extend(c.key for c in root_fields)
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for path, names in (rel_field_names or {}).items():
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prefix = ".".join(path)
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for n in names:
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proj.append(f"{prefix}.{n}")
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if proj and "id" not in proj and hasattr(self.model, "id"):
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proj.insert(0, "id")
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if proj:
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for obj in rows:
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try:
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setattr(obj, "__crudkit_projection__", tuple(proj))
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except Exception:
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pass
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if log.isEnabledFor(logging.DEBUG):
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log.debug("QUERY: %s", str(query))
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return rows
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def create(self, data: dict, actor=None) -> T:
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session = self.session
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obj = self.model(**data)
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session.add(obj)
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session.commit()
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self._log_version("create", obj, actor)
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return obj
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def update(self, id: int, data: dict, actor=None) -> T:
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session = self.session
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obj = self.get(id)
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if not obj:
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raise ValueError(f"{self.model.__name__} with ID {id} not found.")
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valid_fields = {c.name for c in self.model.__table__.columns}
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unknown = set(data) - valid_fields
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if unknown:
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raise ValueError(f"Unknown fields: {', '.join(sorted(unknown))}")
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for k, v in data.items():
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if k in valid_fields:
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setattr(obj, k, v)
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session.commit()
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self._log_version("update", obj, actor)
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return obj
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def delete(self, id: int, hard: bool = False, actor = None):
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session = self.session
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obj = session.get(self.model, id)
|
||
if not obj:
|
||
return None
|
||
if hard or not self.supports_soft_delete:
|
||
session.delete(obj)
|
||
else:
|
||
soft = cast(_SoftDeletable, obj)
|
||
soft.is_deleted = True
|
||
session.commit()
|
||
self._log_version("delete", obj, actor)
|
||
return obj
|
||
|
||
def _log_version(self, change_type: str, obj: T, actor=None, metadata: dict | None = None):
|
||
session = self.session
|
||
try:
|
||
data = obj.as_dict()
|
||
except Exception:
|
||
data = {"error": "Failed to serialize object."}
|
||
version = Version(
|
||
model_name=self.model.__name__,
|
||
object_id=obj.id,
|
||
change_type=change_type,
|
||
data=data,
|
||
actor=str(actor) if actor else None,
|
||
meta=metadata
|
||
)
|
||
session.add(version)
|
||
session.commit()
|