misc: optimize using raw sql

Use raw SQL to remove overhead of Django ORM.

src/ants_hub/api/views/ants.py

@@ -11,10 +11,19 @@ import urllib.parse
 import zoneinfo
 
 from django.conf import settings
+from django.db import connection
 from django.http import JsonResponse
 from django.utils.text import slugify
 
-from ants_hub.data.models import Config, Lieu, Plage, RendezVous, TypeDeRdv, make_available_time_slots
+from ants_hub.data.models import (
+    Config,
+    HoraireList,
+    Lieu,
+    Plage,
+    RendezVous,
+    TypeDeRdv,
+    make_available_time_slots,
+)
 
 ANTS_TIMEZONE = zoneinfo.ZoneInfo('Europe/Paris')
 
@@ -117,6 +126,9 @@ def available_time_slots_parse_qs(request):
     return meeting_point_ids, start_date, end_date, reason, documents_number
 
 
+USE_ORM = False
+
+
 @authenticate
 def available_time_slots(request):
     try:
@@ -138,28 +150,72 @@ def available_time_slots(request):
             status=422,
         )
     types_de_rdv = [reason]
-    qs = Plage.objects.filter(lieu__id__in=meeting_point_ids)
-    qs = qs.filter(type_de_rdv__in=types_de_rdv)
-    qs = qs.filter(date__gte=start_date, date__lte=end_date)
-    qs = qs.filter(personnes=documents_number)
-    qs = qs.select_related('lieu', 'lieu__collectivite')
+
+    base_url = getattr(settings, 'BASE_URL', None)
+    if not base_url:
+        base_callback_url = request.build_absolute_uri('/')
+
+    if USE_ORM:
+        qs = Plage.objects.filter(lieu__id__in=meeting_point_ids)
+        qs = qs.filter(type_de_rdv__in=types_de_rdv)
+        qs = qs.filter(date__gte=start_date, date__lte=end_date)
+        qs = qs.filter(personnes=documents_number)
+        qs = qs.select_related('lieu', 'lieu__collectivite')
+
+        qs = qs.order_by('date').values_list(
+            'date',
+            'horaires',
+            'duree',
+            'lieu__pk',
+            'lieu__nom',
+            'lieu__collectivite__pk',
+            'lieu__collectivite__nom',
+        )
+    else:
+        with connection.cursor() as cur:
+            cur.execute(
+                '''\
+SELECT plage.date, plage.horaires, plage.duree, lieu.id, lieu.nom, collectivite.id, collectivite.nom
+FROM
+   ants_hub_plage AS plage,
+   ants_hub_lieu AS lieu,
+   ants_hub_collectivite AS collectivite
+WHERE
+     plage.lieu_id = lieu.id
+   AND
+     lieu.collectivite_id = collectivite.id
+
+   AND
+     plage.type_de_rdv IN (%s)
+   AND
+     plage.date >= %%s
+   AND
+     plage.date <= %%s
+   AND
+     plage.personnes = %%s'''
+                % ','.join(['%s'] * len(types_de_rdv)),
+                [*types_de_rdv, start_date, end_date, documents_number],
+            )
+
+            def generator():
+                for (
+                    date,
+                    horaires,
+                    duree,
+                    lieu_pk,
+                    lieu_nom,
+                    collectivite_pk,
+                    collectivite_nom,
+                ) in cur.fetchall():
+                    horaires = HoraireList.from_str(horaires)
+                    yield date, horaires, duree, lieu_pk, lieu_nom, collectivite_pk, collectivite_nom
+
+            qs = list(generator())
 
     slots_by_lieu = collections.defaultdict(list)
     date_by_lieu = collections.defaultdict(set)
     slot_count = 0
 
-    qs = qs.order_by('date').values_list(
-        'date',
-        'horaires',
-        'duree',
-        'lieu__pk',
-        'lieu__nom',
-        'lieu__collectivite__pk',
-        'lieu__collectivite__nom',
-    )
-    base_url = getattr(settings, 'BASE_URL', None)
-    if not base_url:
-        base_callback_url = request.build_absolute_uri('/')
     for date, horaires, duree, lieu_pk, lieu_nom, collectivite_pk, collectivite_nom in qs:
         lieu_slug = slugify(lieu_nom)
         collectivite_slug = slugify(collectivite_nom)