refactor: generic to_filter — remove per-domain _to_filter boilerplate

New to_filter(strawberry_input, PydanticFilterClass) auto-maps all
fields from Strawberry input to Pydantic filter. Only sorts needs
special handling (SortFieldInput → SortField conversion).

Adding a new domain filter now requires zero converter code.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ImTotem

src/bcsd_api/graphql/convert.py

@@ -1,7 +1,11 @@
+from typing import TypeVar
+
 import strawberry
 from pydantic import BaseModel
 
-from bcsd_api.filter.base import SortField
+from bcsd_api.filter.base import BaseFilter, SortField
+
+F = TypeVar("F", bound=BaseFilter)
 
 
 @strawberry.input
@@ -16,6 +20,12 @@ def to_sorts(inputs: list[SortFieldInput] | None) -> list[SortField]:
     return [SortField(field=s.field, order=s.order) for s in inputs]
 
 
+def to_filter(inp, filter_cls: type[F]) -> F:
+    data = {k: v for k, v in inp.__dict__.items() if k != "sorts"}
+    data["sorts"] = to_sorts(inp.sorts)
+    return filter_cls(**data)
+
+
 def from_model(source: BaseModel, target_cls):
     return target_cls(**source.model_dump())
 

src/bcsd_api/member/resolvers.py

@@ -3,7 +3,7 @@
 
 from bcsd_api.filter.members import MemberFilter
 from bcsd_api.graphql.context import GqlContext, require_user
-from bcsd_api.graphql.convert import from_model, from_paged, to_sorts
+from bcsd_api.graphql.convert import from_model, from_paged, to_filter
 
 from . import service
 from .types import (
@@ -16,24 +16,13 @@
 )
 
 
-def _to_filter(inp: MemberFilterInput) -> MemberFilter:
-    return MemberFilter(
-        page=inp.page, size=inp.size,
-        sorts=to_sorts(inp.sorts),
-        status=inp.status, track=inp.track,
-        team=inp.team, name=inp.name,
-        email=inp.email, department=inp.department,
-        student_id=inp.student_id, phone=inp.phone,
-    )
-
-
 def resolve_members(
     info: Info[GqlContext, None],
     filter: MemberFilterInput | None = None,
 ) -> PagedMembers:
     ctx = info.context
     require_user(ctx)
-    filt = _to_filter(filter) if filter else MemberFilter.model_validate({})
+    filt = to_filter(filter, MemberFilter) if filter else MemberFilter.model_validate({})
     paged = service.list_members(ctx.member_repo, filt)
     return from_paged(paged, MemberType, PagedMembers)
 

src/bcsd_api/shorten/resolvers.py

@@ -3,7 +3,7 @@
 
 from bcsd_api.filter.links import LinkFilter
 from bcsd_api.graphql.context import GqlContext, require_user
-from bcsd_api.graphql.convert import from_model, from_paged, to_sorts
+from bcsd_api.graphql.convert import from_model, from_paged, to_filter
 
 from . import service
 from .schema import CreateRequest, UpdateRequest
@@ -20,22 +20,13 @@
 )
 
 
-def _to_filter(inp: LinkFilterInput) -> LinkFilter:
-    return LinkFilter(
-        page=inp.page, size=inp.size,
-        sorts=to_sorts(inp.sorts),
-        creator_id=inp.creator_id, expired=inp.expired,
-        title=inp.title, code=inp.code,
-    )
-
-
 def resolve_links(
     info: Info[GqlContext, None],
     filter: LinkFilterInput | None = None,
 ) -> PagedLinks:
     ctx = info.context
     require_user(ctx)
-    filt = _to_filter(filter) if filter else LinkFilter.model_validate({})
+    filt = to_filter(filter, LinkFilter) if filter else LinkFilter.model_validate({})
     paged = service.list_links(ctx.link_repo, filt)
     return from_paged(paged, LinkType, PagedLinks)