add /item/comment endpoint and prefetch related models

core/inventory/serializers.py

@@ -3,7 +3,7 @@ from rest_framework import serializers
 from rest_framework.relations import SlugRelatedField
 
 from files.models import File
-from inventory.models import Event, Container, Item
+from inventory.models import Event, Container, Item, Comment
 from inventory.shared_serializers import BasicItemSerializer
 from mail.models import EventAddress
 from tickets.shared_serializers import BasicIssueSerializer
@@ -38,6 +38,18 @@ class ContainerSerializer(serializers.ModelSerializer):
         return len(instance.items)
 
 
+class CommentSerializer(serializers.ModelSerializer):
+
+    def validate(self, attrs):
+        if 'comment' not in attrs or attrs['comment'] == '':
+            raise serializers.ValidationError('comment cannot be empty')
+        return attrs
+
+    class Meta:
+        model = Comment
+        fields = ('id', 'comment', 'timestamp', 'item')
+
+
 class ItemSerializer(BasicItemSerializer):
     timeline = serializers.SerializerMethodField()
     dataImage = serializers.CharField(write_only=True, required=False)
@@ -48,6 +60,7 @@ class ItemSerializer(BasicItemSerializer):
         fields = ['cid', 'box', 'id', 'description', 'file', 'dataImage', 'returned', 'event', 'related_issues',
                   'timeline']
         read_only_fields = ['id']
+        prefetch_related_fields = ['comments', 'issue_relation_changes', 'container_history']
 
     def to_internal_value(self, data):
         container = None