Add totalCount to the GraphQL pagination query

src/nextline_rdb/schema/pagination/connection.py

@@ -29,11 +29,13 @@ class PageInfo:
 @strawberry.type
 class Connection(Generic[_T]):
     page_info: PageInfo
+    total_count: int
     edges: list[Edge[_T]]
 
 
 async def query_connection(
     query_edges: Callable[..., Coroutine[Any, Any, list[Edge[_T]]]],
+    query_total_count: Callable[..., Coroutine[Any, Any, int]],
     before: Optional[str] = None,
     after: Optional[str] = None,
     first: Optional[int] = None,
@@ -64,11 +66,13 @@ async def query_connection(
         has_previous_page = False
         has_next_page = False
 
+    total_count = await query_total_count()
+
     page_info = PageInfo(
         has_previous_page=has_previous_page,
         has_next_page=has_next_page,
         start_cursor=edges[0].cursor if edges else None,
         end_cursor=edges[-1].cursor if edges else None,
     )
 
-    return Connection(page_info=page_info, edges=edges)
+    return Connection(page_info=page_info, total_count=total_count, edges=edges)

src/nextline_rdb/schema/pagination/db.py

@@ -3,6 +3,8 @@
 from functools import partial
 from typing import Optional, Type, TypeVar
 
+from sqlalchemy import func, select
+
 from nextline_rdb import models as db_models
 from nextline_rdb.db import DB
 from nextline_rdb.pagination import Sort, load_models
@@ -41,15 +43,25 @@ async def load_connection(
         sort=sort,
     )
 
+    query_total_count = partial(load_total_count, db=db, Model=Model)
+
     return await query_connection(
         query_edges,
+        query_total_count,
         before,
         after,
         first,
         last,
     )
 
 
+async def load_total_count(db: DB, Model: Type[db_models.Model]) -> int:
+    async with db.session() as session:
+        stmt = select(func.count()).select_from(Model)
+        total_count = (await session.execute(stmt)).scalar() or 0
+    return total_count
+
+
 async def load_edges(
     db: DB,
     Model: Type[db_models.Model],

tests/schema/graphql/queries/RDBRuns.gql

@@ -12,6 +12,7 @@ query HistoryRuns(
         hasNextPage
         hasPreviousPage
       }
+      totalCount
       edges {
         cursor
         node {

tests/schema/queries/test_pagination.py

@@ -52,19 +52,23 @@ async def test_all(runs: list[Run]):
         note(f'runs: {runs}')
 
         nodes_saved = [Node(id=run.id, runNo=run.run_no) for run in runs]
+        n_nodes_saved = len(nodes_saved)
         note(f'nodes_saved: {nodes_saved}')
 
         resp = await schema.execute(QUERY_RDB_RUNS, context_value={'db': db})
         assert resp.data
 
         all_runs = resp.data['rdb']['runs']
         page_info: PageInfo = all_runs['pageInfo']
+        total_count = all_runs['totalCount']
         edges: list[Edge] = all_runs['edges']
 
         if edges:
             assert page_info['startCursor'] == edges[0]['cursor']
             assert page_info['endCursor'] == edges[-1]['cursor']
 
+        assert total_count == n_nodes_saved
+
         nodes = [edge['node'] for edge in edges]
 
         assert nodes == nodes_saved
@@ -83,6 +87,7 @@ async def test_forward(runs: list[Run], first: int):
         note(f'runs: {runs}')
 
         nodes_saved = [Node(id=run.id, runNo=run.run_no) for run in runs]
+        n_nodes_saved = len(nodes_saved)
         note(f'nodes_saved: {nodes_saved}')
 
         after = None
@@ -100,6 +105,7 @@ async def test_forward(runs: list[Run], first: int):
 
             all_runs = resp.data['rdb']['runs']
             page_info: PageInfo = all_runs['pageInfo']
+            total_count = all_runs['totalCount']
             edges: list[Edge] = all_runs['edges']
 
             has_next_page = page_info['hasNextPage']
@@ -113,6 +119,8 @@ async def test_forward(runs: list[Run], first: int):
             if edges:
                 assert after == edges[-1]['cursor']
 
+            assert total_count == n_nodes_saved
+
             nodes.extend(edge['node'] for edge in edges)
 
         assert nodes == nodes_saved
@@ -131,6 +139,7 @@ async def test_backward(runs: list[Run], last: int):
         note(f'runs: {runs}')
 
         nodes_saved = [Node(id=run.id, runNo=run.run_no) for run in runs]
+        n_nodes_saved = len(nodes_saved)
         note(f'nodes_saved: {nodes_saved}')
 
         before = None
@@ -148,6 +157,7 @@ async def test_backward(runs: list[Run], last: int):
 
             all_runs = resp.data['rdb']['runs']
             page_info: PageInfo = all_runs['pageInfo']
+            total_count = all_runs['totalCount']
             edges: list[Edge] = all_runs['edges']
 
             has_previous_page = page_info['hasPreviousPage']
@@ -161,6 +171,8 @@ async def test_backward(runs: list[Run], last: int):
             if edges:
                 assert before == edges[0]['cursor']
 
+            assert total_count == n_nodes_saved
+
             nodes.extend(edge['node'] for edge in reversed(edges))
 
         assert nodes == list(reversed(nodes_saved))