Optimized API performance

netbox/extras/api/serializers.py

@@ -1,21 +1,33 @@
 from rest_framework import serializers
 
-from extras.models import CF_TYPE_SELECT, CustomFieldChoice, Graph
+from extras.models import CF_TYPE_SELECT, CustomFieldChoice, CustomFieldValue, Graph
 
 
-class CustomFieldsSerializer(serializers.Serializer):
+class CustomFieldSerializer(serializers.Serializer):
     """
     Extends a ModelSerializer to render any CustomFields and their values associated with an object.
     """
     custom_fields = serializers.SerializerMethodField()
 
     def get_custom_fields(self, obj):
+
+        # Gather all CustomFields applicable to this object
         fields = {cf.name: None for cf in self.context['view'].custom_fields}
+
+        # Attach any defined CustomFieldValues to their respective CustomFields
         for cfv in obj.custom_field_values.all():
+
+            # Suppress database lookups for CustomFieldChoices. Instead, use the cached choice set from the view
+            # context.
             if cfv.field.type == CF_TYPE_SELECT:
-                fields[cfv.field.name] = CustomFieldChoiceSerializer(instance=cfv.value).data
+                cfc = {
+                    'id': int(cfv.serialized_value),
+                    'value': self.context['view'].custom_field_choices[int(cfv.serialized_value)]
+                }
+                fields[cfv.field.name] = CustomFieldChoiceSerializer(instance=cfc).data
             else:
                 fields[cfv.field.name] = cfv.value
+
         return fields
 
 

netbox/extras/api/views.py

@@ -9,7 +9,7 @@ from django.shortcuts import get_object_or_404
 
 from circuits.models import Provider
 from dcim.models import Site, Device, Interface, InterfaceConnection
-from extras.models import Graph, TopologyMap, GRAPH_TYPE_INTERFACE, GRAPH_TYPE_PROVIDER, GRAPH_TYPE_SITE
+from extras.models import CustomFieldChoice, Graph, TopologyMap, GRAPH_TYPE_INTERFACE, GRAPH_TYPE_PROVIDER, GRAPH_TYPE_SITE
 
 from .serializers import GraphSerializer
 
@@ -22,7 +22,14 @@ class CustomFieldModelAPIView(object):
     def __init__(self):
         super(CustomFieldModelAPIView, self).__init__()
         self.content_type = ContentType.objects.get_for_model(self.queryset.model)
-        self.custom_fields = self.content_type.custom_fields.all()
+        self.custom_fields = self.content_type.custom_fields.prefetch_related('choices')
+
+        # Cache all relevant CustomFieldChoices. This saves us from having to do a lookup per select field per object.
+        custom_field_choices = {}
+        for field in self.custom_fields:
+            for cfc in field.choices.all():
+                custom_field_choices[cfc.id] = cfc.value
+        self.custom_field_choices = custom_field_choices
 
 
 class GraphListView(generics.ListAPIView):

netbox/extras/models.py

@@ -129,7 +129,8 @@ class CustomField(models.Model):
             # Read date as YYYY-MM-DD
             return date(*[int(n) for n in serialized_value.split('-')])
         if self.type == CF_TYPE_SELECT:
-            return CustomFieldChoice.objects.get(pk=int(serialized_value))
+            # return CustomFieldChoice.objects.get(pk=int(serialized_value))
+            return self.choices.get(pk=int(serialized_value))
         return serialized_value