# 优化性能

apps/counter/api/serializers.py

@@ -1,3 +1,4 @@
+import time
 from django.db.models import Q, Min, Max
 from django.core.cache import cache
 from rest_framework import serializers
@@ -22,6 +23,28 @@ def get_vol(device_id, cur_vol):
     return '{}{}'.format(round(vol, 1), '%')
 
 
+def get_latest(device_id):
+    latest_key = 'device_latest_{}'.format(device_id)
+    latest = cache.get(latest_key)
+    if not latest:
+        latest = DeviceCount.objects.filter(device_id=device_id).order_by('-data_time')[0]
+        cache.set(latest_key, latest, 60 * 10)
+    return latest
+
+
+def get_device(device_id):
+    device_key = 'device_lon_{}'.format(device_id)
+    device = cache.get(device_key)
+    if not device:
+        qs = DeviceCount.objects.filter(~Q(longitude=0), device_id=device_id).order_by('-data_time')
+        if qs.count() > 0:
+            device = qs.first()
+            cache.set(device_key, device, 60 * 10)
+        else:
+            return None
+    return device
+
+
 class DeviceCountSerializer(serializers.ModelSerializer):
     device_name = serializers.SerializerMethodField()
     mosq_count = serializers.SerializerMethodField()
@@ -132,7 +155,8 @@ class DeviceInfoSerializer(serializers.ModelSerializer):
 
     def get_count(self, obj):
         try:
-            self.latest = DeviceCount.objects.filter(device_id=obj.device_id).order_by('-data_time')[0]
+            # self.latest = DeviceCount.objects.filter(device_id=obj.device_id).order_by('-data_time')[0]
+            self.latest = get_latest(obj.device_id)
         except IndexError:
             self.latest = None
         if self.latest:
@@ -157,10 +181,10 @@ class DeviceInfoSerializer(serializers.ModelSerializer):
             if lon and lat:
                 return [lon, lat]
 
-        query = DeviceCount.objects.filter(~Q(longitude=0), device_id=obj.device_id).order_by('-data_time')
-        if query:
-            q = query[0]
-            return [q.longitude, q.latitude]
+        # query = DeviceCount.objects.filter(~Q(longitude=0), device_id=obj.device_id).order_by('-data_time')
+        device = get_device(obj.device_id)
+        if device:
+            return [device.longitude, device.latitude]
         return None
 
     def get_time(self, obj):