From a8ea238bfce9db6faaa917644d7501d848b633a6 Mon Sep 17 00:00:00 2001
From: alex <birukov.system@gmail.com>
Date: Fri, 17 Jan 2020 16:02:00 +0300
Subject: [PATCH] some optimize for employee list

---
 apps/establishment/serializers/back.py | 37 +++++++++++++++++---------
 apps/establishment/views/back.py       |  1 +
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/apps/establishment/serializers/back.py b/apps/establishment/serializers/back.py
index a6246d47..8f9631f1 100644
--- a/apps/establishment/serializers/back.py
+++ b/apps/establishment/serializers/back.py
@@ -1,3 +1,6 @@
+from functools import lru_cache
+
+from django.db.models import F
 from django.utils.translation import gettext_lazy as _
 from rest_framework import serializers
 
@@ -232,21 +235,32 @@ class EmployeeBackSerializers(serializers.ModelSerializer):
     toque_number = serializers.SerializerMethodField()
     photo = ImageBaseSerializer(source='crop_image', read_only=True)
 
+    @staticmethod
+    @lru_cache(maxsize=32)
+    def get_qs(obj):
+        return obj.establishmentemployee_set.actual().annotate(
+            public_mark=F('establishment__public_mark'),
+            est_id=F('establishment__id'),
+            est_slug=F('establishment__slug'),
+            toque_number=F('establishment__toque_number'),
+        ).order_by('-from_date').first()
+
     def get_public_mark(self, obj):
         """Get last list actual public_mark"""
-        qs = obj.establishmentemployee_set.actual().order_by('-from_date') \
-            .values('establishment__public_mark').first()
-        return qs['establishment__public_mark'] if qs else None
+        qs = self.get_qs(obj)
+        if qs:
+            return qs.public_mark
+        return None
 
     def get_toque_number(self, obj):
-        qs = obj.establishmentemployee_set.actual().order_by('-from_date') \
-            .values('establishment__toque_number').first()
-        return qs['establishment__toque_number'] if qs else None
+        qs = self.get_qs(obj)
+        if qs:
+            return qs.toque_number
+        return None
 
     def get_positions(self, obj):
         """Get last list actual positions"""
-        est_id = obj.establishmentemployee_set.actual(). \
-            order_by('-from_date').first()
+        est_id = self.get_qs(obj)
 
         if not est_id:
             return None
@@ -261,15 +275,14 @@ class EmployeeBackSerializers(serializers.ModelSerializer):
 
     def get_establishment(self, obj):
         """Get last actual establishment"""
-        est = obj.establishmentemployee_set.actual().order_by('-from_date') \
-            .first()
+        est = self.get_qs(obj)
 
         if not est:
             return None
 
         return {
-            "id": est.establishment.id,
-            "slug": est.establishment.slug
+            "id": est.est_id,
+            "slug": est.est_slug
         }
 
     class Meta:
diff --git a/apps/establishment/views/back.py b/apps/establishment/views/back.py
index 578f6b6a..f98747b6 100644
--- a/apps/establishment/views/back.py
+++ b/apps/establishment/views/back.py
@@ -177,6 +177,7 @@ class EmployeeListCreateView(generics.ListCreateAPIView):
     queryset = models.Employee.objects.all().prefetch_related(
         'establishmentemployee_set',
         'establishmentemployee_set__establishment',
+        'awards',
     )