inventory/crudkit/core/service.py
2025-09-24 14:19:01 -05:00

673 lines
27 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

from __future__ import annotations
from collections.abc import Iterable
from typing import Any, Callable, Type, TypeVar, Generic, Optional, Protocol, runtime_checkable, cast
from sqlalchemy import and_, func, inspect, or_, text, UnaryExpression
from sqlalchemy.engine import Engine, Connection
from sqlalchemy.orm import Load, Session, with_polymorphic, Mapper, contains_eager, selectinload
from sqlalchemy.orm.attributes import InstrumentedAttribute
from sqlalchemy.sql import operators
from sqlalchemy.sql.elements import ColumnElement
from crudkit.core.base import Version
from crudkit.core.spec import CRUDSpec
from crudkit.core.types import OrderSpec, SeekWindow
from crudkit.backend import BackendInfo, make_backend_info
from crudkit.projection import compile_projection
import logging
log = logging.getLogger("crudkit.service")
@runtime_checkable
class _HasID(Protocol):
id: int
@runtime_checkable
class _HasTable(Protocol):
__table__: Any
@runtime_checkable
class _HasADict(Protocol):
def as_dict(self) -> dict: ...
@runtime_checkable
class _SoftDeletable(Protocol):
is_deleted: bool
class _CRUDModelProto(_HasID, _HasTable, _HasADict, Protocol):
"""Minimal surface that our CRUD service relies on. Soft-delete is optional."""
pass
T = TypeVar("T", bound=_CRUDModelProto)
def _belongs_to_alias(col: Any, alias: Any) -> bool:
# Try to detect if a column/expression ultimately comes from this alias.
# Works for most ORM columns; complex expressions may need more.
t = getattr(col, "table", None)
selectable = getattr(alias, "selectable", None)
return t is not None and selectable is not None and t is selectable
def _paths_needed_for_sql(order_by: Iterable[Any], filters: Iterable[Any], join_paths: tuple) -> set[tuple[str, ...]]:
paths: set[tuple[str, ...]] = set()
# Sort columns
for ob in order_by or []:
col = getattr(ob, "element", ob) # unwrap UnaryExpression
for path, _rel_attr, target_alias in join_paths:
if _belongs_to_alias(col, target_alias):
paths.add(tuple(path))
# Filter columns (best-effort)
# Walk simple binary expressions
def _extract_cols(expr: Any) -> Iterable[Any]:
if isinstance(expr, ColumnElement):
yield expr
for ch in getattr(expr, "get_children", lambda: [])():
yield from _extract_cols(ch)
elif hasattr(expr, "clauses"):
for ch in expr.clauses:
yield from _extract_cols(ch)
for flt in filters or []:
for col in _extract_cols(flt):
for path, _rel_attr, target_alias in join_paths:
if _belongs_to_alias(col, target_alias):
paths.add(tuple[path])
return paths
def _paths_from_fields(req_fields: list[str]) -> set[tuple[str, ...]]:
out: set[tuple[str, ...]] = set()
for f in req_fields:
if "." in f:
parts = tuple(f.split(".")[:-1])
if parts:
out.add(parts)
return out
def _is_truthy(val):
return str(val).lower() in ('1', 'true', 'yes', 'on')
def _normalize_fields_param(params: dict | None) -> list[str]:
if not params:
return []
raw = params.get("fields")
if isinstance(raw, (list, tuple)):
out: list[str] = []
for item in raw:
if isinstance(item, str):
out.extend([p for p in (s.strip() for s in item.split(",")) if p])
return out
if isinstance(raw, str):
return [p for p in (s.strip() for s in raw.split(",")) if p]
return []
class CRUDService(Generic[T]):
def __init__(
self,
model: Type[T],
session_factory: Callable[[], Session],
polymorphic: bool = False,
*,
backend: Optional[BackendInfo] = None
):
self.model = model
self._session_factory = session_factory
self.polymorphic = polymorphic
self.supports_soft_delete = hasattr(model, 'is_deleted')
# Cache backend info once. If not provided, derive from session bind.
bind = session_factory().get_bind()
eng: Engine = bind.engine if isinstance(bind, Connection) else cast(Engine, bind)
self.backend = backend or make_backend_info(eng)
@property
def session(self) -> Session:
return self._session_factory()
def get_query(self):
if self.polymorphic:
poly = with_polymorphic(self.model, "*")
return self.session.query(poly), poly
return self.session.query(self.model), self.model
def _apply_not_deleted(self, query, root_alias, params) -> Any:
if self.supports_soft_delete and not _is_truthy((params or {}).get("include_deleted")):
return query.filter(getattr(root_alias, "is_deleted") == False)
return query
def _extract_order_spec(self, root_alias, given_order_by):
"""
SQLAlchemy 2.x only:
Normalize order_by into (cols, desc_flags). Supports plain columns and
col.asc()/col.desc() (UnaryExpression). Avoids boolean evaluation of clauses.
"""
given = self._stable_order_by(root_alias, given_order_by)
cols, desc_flags = [], []
for ob in given:
# Unwrap column if this is a UnaryExpression produced by .asc()/.desc()
elem = getattr(ob, "element", None)
col = elem if elem is not None else ob
# Detect direction in SA 2.x
is_desc = False
dir_attr = getattr(ob, "_direction", None)
if dir_attr is not None:
is_desc = (dir_attr is operators.desc_op) or (getattr(dir_attr, "name", "").upper() == "DESC")
elif isinstance(ob, UnaryExpression):
op = getattr(ob, "operator", None)
is_desc = (op is operators.desc_op) or (getattr(op, "name", "").upper() == "DESC")
cols.append(col)
desc_flags.append(bool(is_desc))
return OrderSpec(cols=tuple(cols), desc=tuple(desc_flags))
def _key_predicate(self, spec: OrderSpec, key_vals: list[Any], backward: bool):
if not key_vals:
return None
conds = []
for i, col in enumerate(spec.cols):
# If NULLs possible, normalize for comparison. Example using coalesce to a sentinel:
# sent_col = func.coalesce(col, literal("-∞"))
sent_col = col
ties = [spec.cols[j] == key_vals[j] for j in range(i)]
is_desc = spec.desc[i]
if not backward:
op = (sent_col < key_vals[i]) if is_desc else (sent_col > key_vals[i])
else:
op = (sent_col > key_vals[i]) if is_desc else (sent_col < key_vals[i])
conds.append(and_(*ties, op))
return or_(*conds)
def _pluck_key(self, obj: Any, spec: OrderSpec) -> list[Any]:
out = []
for c in spec.cols:
# Only simple mapped columns supported for key pluck
key = getattr(c, "key", None) or getattr(c, "name", None)
if key is None or not hasattr(obj, key):
raise ValueError("Order includes non-mapped or related column; cannot pluck cursor key from row object.")
out.append(getattr(obj, key))
return out
def seek_window(
self,
params: dict | None = None,
*,
key: list[Any] | None = None,
backward: bool = False,
include_total: bool = True,
) -> "SeekWindow[T]":
"""
Transport-agnostic keyset pagination that preserves all the goodies from `list()`:
- filters, includes, joins, field projection, eager loading, soft-delete
- deterministic ordering (user sort + PK tiebreakers)
- forward/backward seek via `key` and `backward`
Returns a SeekWindow with items, first/last keys, order spec, limit, and optional total.
"""
session = self.session
query, root_alias = self.get_query()
# Normalize requested fields and compile projection (may skip later to avoid conflicts)
fields = _normalize_fields_param(params)
expanded_fields, proj_opts = compile_projection(self.model, fields) if fields else ([], [])
spec = CRUDSpec(self.model, params or {}, root_alias)
filters = spec.parse_filters()
order_by = spec.parse_sort()
# Field parsing for root load_only fallback
root_fields, rel_field_names, root_field_names = spec.parse_fields()
# Soft delete filter
query = self._apply_not_deleted(query, root_alias, params)
# Apply filters first
if filters:
query = query.filter(*filters)
# Includes + join paths (dotted fields etc.)
spec.parse_includes()
join_paths = tuple(spec.get_join_paths()) # iterable of (path, relationship_attr, target_alias)
# Decide which relationship *names* are required for SQL (filters/sort) vs display-only
def _belongs_to_alias(col: Any, alias: Any) -> bool:
t = getattr(col, "table", None)
selectable = getattr(alias, "selectable", None)
return t is not None and selectable is not None and t is selectable
# 1) which relationship aliases are referenced by sort/filter
sql_hops: set[str] = set()
for path, relationship_attr, target_alias in join_paths:
# If any ORDER BY column comes from this alias, mark it
for ob in (order_by or []):
col = getattr(ob, "element", ob) # unwrap UnaryExpression
if _belongs_to_alias(col, target_alias):
sql_hops.add(relationship_attr.key)
break
# If any filter expr touches this alias, mark it (best effort)
if relationship_attr.key not in sql_hops:
def _walk_cols(expr: Any):
# Primitive walker for ColumnElement trees
from sqlalchemy.sql.elements import ColumnElement
if isinstance(expr, ColumnElement):
yield expr
for ch in getattr(expr, "get_children", lambda: [])():
yield from _walk_cols(ch)
elif hasattr(expr, "clauses"):
for ch in expr.clauses:
yield from _walk_cols(ch)
for flt in (filters or []):
if any(_belongs_to_alias(c, target_alias) for c in _walk_cols(flt)):
sql_hops.add(relationship_attr.key)
break
# 2) first-hop relationship names implied by dotted projection fields
proj_hops: set[str] = {f.split(".", 1)[0] for f in fields if "." in f}
# Root column projection
from sqlalchemy.orm import Load # local import to match your style
only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
if only_cols:
query = query.options(Load(root_alias).load_only(*only_cols))
# Relationship handling per path (avoid loader strategy conflicts)
used_contains_eager = False
for path, relationship_attr, target_alias in join_paths:
rel_attr = cast(InstrumentedAttribute, relationship_attr)
name = relationship_attr.key
if name in sql_hops:
# Needed for WHERE/ORDER BY: join + hydrate from that join
query = query.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
query = query.options(contains_eager(rel_attr, alias=target_alias))
used_contains_eager = True
elif name in proj_hops:
# Display-only: bulk-load efficiently, no join
query = query.options(selectinload(rel_attr))
else:
# Not needed
pass
# Apply projection loader options only if they won't conflict with contains_eager
if proj_opts and not used_contains_eager:
query = query.options(*proj_opts)
# Order + limit
order_spec = self._extract_order_spec(root_alias, order_by) # SA 2.x helper
limit, _ = spec.parse_pagination()
if limit is None:
effective_limit = 50
elif limit == 0:
effective_limit = None # unlimited
else:
effective_limit = limit
# Keyset predicate
if key:
pred = self._key_predicate(order_spec, key, backward)
if pred is not None:
query = query.filter(pred)
# Apply ordering. For backward, invert SQL order then reverse in-memory for display.
if not backward:
clauses = [(c.desc() if is_desc else c.asc()) for c, is_desc in zip(order_spec.cols, order_spec.desc)]
query = query.order_by(*clauses)
if effective_limit is not None:
query = query.limit(effective_limit)
items = query.all()
else:
inv_clauses = [(c.asc() if is_desc else c.desc()) for c, is_desc in zip(order_spec.cols, order_spec.desc)]
query = query.order_by(*inv_clauses)
if effective_limit is not None:
query = query.limit(effective_limit)
items = list(reversed(query.all()))
# Tag projection so your renderer knows what fields were requested
if fields:
proj = list(dict.fromkeys(fields)) # dedupe, preserve order
if "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
else:
proj = []
if root_field_names:
proj.extend(root_field_names)
if root_fields:
proj.extend(c.key for c in root_fields if hasattr(c, "key"))
for path, names in (rel_field_names or {}).items():
prefix = ".".join(path)
for n in names:
proj.append(f"{prefix}.{n}")
if proj and "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
if proj:
for obj in items:
try:
setattr(obj, "__crudkit_projection__", tuple(proj))
except Exception:
pass
# Boundary keys for cursor encoding in the API layer
first_key = self._pluck_key(items[0], order_spec) if items else None
last_key = self._pluck_key(items[-1], order_spec) if items else None
# Optional total thats safe under JOINs (COUNT DISTINCT ids)
total = None
if include_total:
base = session.query(getattr(root_alias, "id"))
base = self._apply_not_deleted(base, root_alias, params)
if filters:
base = base.filter(*filters)
# Mirror join structure for any SQL-needed relationships
for path, relationship_attr, target_alias in join_paths:
if relationship_attr.key in sql_hops:
rel_attr = cast(InstrumentedAttribute, relationship_attr)
base = base.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
total = session.query(func.count()).select_from(
base.order_by(None).distinct().subquery()
).scalar() or 0
window_limit_for_body = 0 if effective_limit is None and limit == 0 else (effective_limit or 50)
if log.isEnabledFor(logging.DEBUG):
log.debug("QUERY: %s", str(query))
return SeekWindow(
items=items,
limit=window_limit_for_body,
first_key=first_key,
last_key=last_key,
order=order_spec,
total=total,
)
# Helper: default ORDER BY for MSSQL when paginating without explicit order
def _default_order_by(self, root_alias):
mapper: Mapper[Any] = cast(Mapper[Any], inspect(self.model))
cols = []
for col in mapper.primary_key:
try:
cols.append(getattr(root_alias, col.key))
except AttributeError:
cols.append(col)
return cols or [text("1")]
def _stable_order_by(self, root_alias, given_order_by):
"""
Ensure deterministic ordering by appending PK columns as tiebreakers.
If no order is provided, fall back to default primary-key order.
"""
order_by = list(given_order_by or [])
if not order_by:
return self._default_order_by(root_alias)
mapper: Mapper[Any] = cast(Mapper[Any], inspect(self.model))
pk_cols = []
for col in mapper.primary_key:
try:
pk_cols.append(getattr(root_alias, col.key))
except AttributeError:
pk_cols.append(col)
return [*order_by, *pk_cols]
def get(self, id: int, params=None) -> T | None:
"""Fetch a single row by id with conflict-free eager loading and clean projection."""
query, root_alias = self.get_query()
# Defaults so we can build a projection even if params is None
root_fields: list[Any] = []
root_field_names: dict[str, str] = {}
rel_field_names: dict[tuple[str, ...], list[str]] = {}
req_fields: list[str] = _normalize_fields_param(params)
# Soft-delete guard
query = self._apply_not_deleted(query, root_alias, params)
spec = CRUDSpec(self.model, params or {}, root_alias)
# Optional extra filters (in addition to id); keep parity with list()
filters = spec.parse_filters()
if filters:
query = query.filter(*filters)
# Always filter by id
query = query.filter(getattr(root_alias, "id") == id)
# Includes + join paths we may need
spec.parse_includes()
join_paths = tuple(spec.get_join_paths())
# Field parsing to enable root load_only
if params:
root_fields, rel_field_names, root_field_names = spec.parse_fields()
# Decide which relationship paths are needed for SQL vs display-only
# For get(), there is no ORDER BY; only filters might force SQL use.
sql_paths = _paths_needed_for_sql(order_by=None, filters=filters, join_paths=join_paths)
proj_paths = _paths_from_fields(req_fields)
# Root column projection
only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
if only_cols:
query = query.options(Load(root_alias).load_only(*only_cols))
# Relationship handling per path: avoid loader strategy conflicts
used_contains_eager = False
for path, relationship_attr, target_alias in join_paths:
rel_attr = cast(InstrumentedAttribute, relationship_attr)
ptuple = tuple(path)
if ptuple in sql_paths:
# Needed in WHERE: join + hydrate from the join
query = query.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
query = query.options(contains_eager(rel_attr, alias=target_alias))
used_contains_eager = True
elif ptuple in proj_paths:
# Display-only: bulk-load efficiently
query = query.options(selectinload(rel_attr))
else:
pass
# Projection loader options compiled from requested fields.
# Skip if we used contains_eager to avoid strategy conflicts.
expanded_fields, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
if proj_opts and not used_contains_eager:
query = query.options(*proj_opts)
obj = query.first()
# Emit exactly what the client requested (plus id), or a reasonable fallback
if req_fields:
proj = list(dict.fromkeys(req_fields)) # dedupe, preserve order
if "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
else:
proj = []
if root_field_names:
proj.extend(root_field_names)
if root_fields:
proj.extend(c.key for c in root_fields if hasattr(c, "key"))
for path, names in (rel_field_names or {}).items():
prefix = ".".join(path)
for n in names:
proj.append(f"{prefix}.{n}")
if proj and "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
if proj and obj is not None:
try:
setattr(obj, "__crudkit_projection__", tuple(proj))
except Exception:
pass
if log.isEnabledFor(logging.DEBUG):
log.debug("QUERY: %s", str(query))
return obj or None
def list(self, params=None) -> list[T]:
"""Offset/limit listing with smart relationship loading and clean projection."""
query, root_alias = self.get_query()
# Defaults so we can reference them later even if params is None
root_fields: list[Any] = []
root_field_names: dict[str, str] = {}
rel_field_names: dict[tuple[str, ...], list[str]] = {}
req_fields: list[str] = _normalize_fields_param(params)
if params:
query = self._apply_not_deleted(query, root_alias, params)
spec = CRUDSpec(self.model, params or {}, root_alias)
filters = spec.parse_filters()
order_by = spec.parse_sort()
limit, offset = spec.parse_pagination()
# Includes + join paths we might need
spec.parse_includes()
join_paths = tuple(spec.get_join_paths())
# Field parsing for load_only on root columns
root_fields, rel_field_names, root_field_names = spec.parse_fields()
if filters:
query = query.filter(*filters)
# Determine which relationship paths are needed for SQL vs display-only
sql_paths = _paths_needed_for_sql(order_by, filters, join_paths)
proj_paths = _paths_from_fields(req_fields)
# Root column projection
only_cols = [c for c in root_fields if isinstance(c, InstrumentedAttribute)]
if only_cols:
query = query.options(Load(root_alias).load_only(*only_cols))
# Relationship handling per path
used_contains_eager = False
for path, relationship_attr, target_alias in join_paths:
rel_attr = cast(InstrumentedAttribute, relationship_attr)
ptuple = tuple(path)
if ptuple in sql_paths:
# Needed for WHERE/ORDER BY: join + hydrate from the join
query = query.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
query = query.options(contains_eager(rel_attr, alias=target_alias))
used_contains_eager = True
elif ptuple in proj_paths:
# Display-only: no join, bulk-load efficiently
query = query.options(selectinload(rel_attr))
else:
# Not needed at all; do nothing
pass
# MSSQL requires ORDER BY when OFFSET is used (SQLA uses OFFSET for limit/offset)
paginating = (limit is not None) or (offset is not None and offset != 0)
if paginating and not order_by and self.backend.requires_order_by_for_offset:
order_by = self._default_order_by(root_alias)
if order_by:
query = query.order_by(*order_by)
# Only apply offset/limit when not None and not zero
if offset is not None and offset != 0:
query = query.offset(offset)
if limit is not None and limit > 0:
query = query.limit(limit)
# Projection loader options compiled from requested fields.
# Skip if we used contains_eager to avoid loader-strategy conflicts.
expanded_fields, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
if proj_opts and not used_contains_eager:
query = query.options(*proj_opts)
else:
# No params means no filters/sorts/limits; still honor projection loaders if any
expanded_fields, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
if proj_opts:
query = query.options(*proj_opts)
rows = query.all()
# Emit exactly what the client requested (plus id), or a reasonable fallback
if req_fields:
proj = list(dict.fromkeys(req_fields)) # dedupe while preserving order
if "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
else:
proj = []
if root_field_names:
proj.extend(root_field_names)
if root_fields:
proj.extend(c.key for c in root_fields if hasattr(c, "key"))
for path, names in (rel_field_names or {}).items():
prefix = ".".join(path)
for n in names:
proj.append(f"{prefix}.{n}")
if proj and "id" not in proj and hasattr(self.model, "id"):
proj.insert(0, "id")
if proj:
for obj in rows:
try:
setattr(obj, "__crudkit_projection__", tuple(proj))
except Exception:
pass
if log.isEnabledFor(logging.DEBUG):
log.debug("QUERY: %s", str(query))
return rows
def create(self, data: dict, actor=None) -> T:
session = self.session
obj = self.model(**data)
session.add(obj)
session.commit()
self._log_version("create", obj, actor)
return obj
def update(self, id: int, data: dict, actor=None) -> T:
session = self.session
obj = self.get(id)
if not obj:
raise ValueError(f"{self.model.__name__} with ID {id} not found.")
valid_fields = {c.name for c in self.model.__table__.columns}
unknown = set(data) - valid_fields
if unknown:
raise ValueError(f"Unknown fields: {', '.join(sorted(unknown))}")
for k, v in data.items():
if k in valid_fields:
setattr(obj, k, v)
session.commit()
self._log_version("update", obj, actor)
return obj
def delete(self, id: int, hard: bool = False, actor = None):
session = self.session
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()