drf-flex-query 1.0.0

Flexible related objects quering for Django REST Framework.

DRF Flex Query

DRF Flex Query is an extension for Django REST Framework which helps to speed up retrieving related objects of main query.

Using separate related objects query and python dicts instead of left joins in SQL and quering every related object using this package could speed up request with multiple related objects in several times.

Installation

You can install DRF Flex Query by:

.. code-block:: bash

pip install drf-flex-query

Basic Usage

Extend basic model

First of all you need to implement custom database manager by inherit from drf-flex-query manager:

.. code-block:: python

from flex_query.models import Model

class MyModel(Model):
    pass

class MyQueringModel(Model):
    main_model = models.ForeignKey(MyModel, null=True)

class MyRelatedModel(Model):
    main_model = models.ForeignKey(MyModel, null=True)

or you could add additional manager without changing relationship:

.. code-block:: python

from django.db.models import Model

from flex_query.manager import FlexQueryDBManager

class MyModel(Model):
    flex_query_objects = FlexQueryDBManager()

Create serializer

Define serializers for object and all relations:

.. code-block:: python

from rest_framework.serializers import ModelSerializer

from flex_query.serializers import FlexQueryBaseModelSerializer, RelatedAttrSerializerInfo

class MainModelSerializer(ModelSerializer):

    class Meta:
        model = MyModel
        fields = "__all__"

class MyRelatedModelSerializer(ModelSerializer):

    class Meta:
        model = MyRelatedModel
        fields = "__all__"

class MySerializer(FlexQueryBaseModelSerializer):
    main_model = serializers.SerializerMethodField("get_main_model")
    related_models = serializers.SerializerMethodField("get_related_models")

    class Meta:
        model = MyQueringModel
        fields = ("id", "main_model", "related_models")
        custom_attrs = ("main_models", "related_models")
        related_attrs_mapping = {
            "get_main_model": RelatedAttrSerializerInfo(
                dependency_name="main_models",
                dep_field_map_name="main_model_id",
                serializer_class=MainModelSerializer,
                many=False,
                forward_kwargs=(),
            ),
            "get_related_models": RelatedAttrSerializerInfo(
                dependency_name="related_models",
                dep_field_map_name="main_model_id",
                serializer_class=MyRelatedModelSerializer,
                many=True,
                forward_kwargs=(),
            ),
        }

Define API View

For setup APIView configuration you need to define list of related queries and rules for its quering

.. code-block:: python

from flex_query.generics import FlexQueryRelationsGenericAPIView


class MyAPIView(FlexQueryRelationsGenericAPIView):
    queryset = MyQueringModel.objects.all()
    serializer_class = MySerializer
    related_queries_data = [
        QueryFilterInfo(
            query_arg_name="main_models",
            attribute="main_model_id",
            query_model=MyModel,
            filter_field="pk",
            mapping_rules={1: KeyMapping(name="id", obj_type="object")},
        ),
        QueryFilterInfo(
            query_arg_name="related_models",
            attribute="id",
            query_model=MyRelatedModel,
            filter_field="pk",
            mapping_rules={1: KeyMapping(name="main_model_id", obj_type="list")},
            source_query="main_models",
        ),
    ]