Optimize Serializer's "create" function
| keyword: |
|---|
| bulk_create |
| manytomany.add(list) |
Define in a SuperSerializer
The sub serializer inherit create def and get the current model byself.Meta.model
The Model of manytomany field can be retrieve byinstance.<manytomany filed name>.model
Create multiple objects and all them to a manytomany fields in one line
- This function included SQL in
for, which easy to crash when list is too long - Create multiple entries at a time is much more efficient with
bulk_create.()
class CommonInfoSerializer(serializers.ModelSerializer):
class Meta:
abstract = True
def create(self, validated_data):
tags_data = validated_data.pop('tags')
info_model = self.Meta.model
instance = info_model.objects.create(**validated_data)
tag_model = instance.tags.model
for tag_data in tags_data:
tag_name = tag_data.get('name').lower()
try:
tag = tag_model.objects.get(name=tag_name)
except tag_model.DoesNotExist:
tag = tag_model.objects.create(**tag_data)
# tag = Tag.objects.create(name=tag_data["name"])
tag.save()
instance.tags.add(tag)
return instance
After refactoring:
class CommonInfoSerializer(serializers.ModelSerializer):
class Meta:
abstract = True
def create(self, validated_data):
tags_data = validated_data.pop('tags')
new_tags = [tag['name'].lower() for tag in tags_data]
info_model = self.Meta.model
instance = info_model.objects.create(**validated_data)
tag_model = instance.tags.model
exist_objs = tag_model.objects.filter(name__in=new_tags) # QuerySet
exist_tags = list(exist_objs.values_list('name', flat=True)) # List(String)
to_create_tags = [tag for tag in new_tags if tag not in exist_tags] # List(String)
to_create_objs = [tag_model(name='%s' % i) for i in to_create_tags] # List(Object)
created_objs = tag_model.objects.bulk_create(to_create_objs) # List(Object)
to_add_objs = list(exist_objs) + created_objs # List(Object)
instance.tags.add(*to_add_objs)
return instance
A roughly test with 8 tags:
Before and after:
165ms vs 461ms
