[PYTHON] List method for nested resources in Django REST framework

I was told by an API that uses the Django REST framework that "return a list of nested resources", so I objected to "the standard design of the REST API is ...", but I haven't done it so I made it. A note of the time.

environment

Python 3.8.2 Django 3.0.5 djangorestframework 3.11.0

model

Parent ├ Child1 └ Child2 ↑ In the case of a model with such a relationship

models.py

from django.db import models

class Parent(models.Model):
    """
Parent model
    """
    parent_column = models.CharField(
        max_length=10, verbose_name='Parent model column')

    def __self__(self):
        return self.parent_column

class Child1(models.Model):
    """
Child model 1
    """
    # related_Match name with serializer field name
    parent = models.ForeignKey(Parent, on_delete=models.CASCADE, related_name='child1s')
    child1_column = models.CharField(
        max_length=10, verbose_name='Column of child model 1')

    def __self__(self):
        return self.Child1_column

class Child2(models.Model):
    """
Child model 2
    """
    # related_Match name with serializer field name
    parent = models.ForeignKey(Parent, on_delete=models.CASCADE, related_name='child2s')
    child2_column = models.CharField(
        max_length=10, verbose_name='Column of child model 2')

    def __self__(self):
        return self.Child2_column

Serializer

With the same configuration as the model

models.py

from rest_framework import serializers
from .models import Parent, Child1, Child2

class Child1Serializer(serializers.ModelSerializer):
    """
Children's serializer1
    """
    class Meta:
        model = Child1
        fields = [
            'id',
            'child1_column',
        ]

class Child2Serializer(serializers.ModelSerializer):
    """
Children's serializer2
    """
    class Meta:
        model = Child2
        fields = [
            'id',
            'child2_column',
        ]

class ParentSerializer(serializers.ModelSerializer):
    """
Parent serializer
    """
    #Define child serializer as parent field
    #This field name and model related_Match name
    child1s = Child1Serializer(many=True, read_only=True)
    child2s = Child2Serializer(many=True, read_only=True)

    class Meta:
        model = Parent
        fields = [
            'id',
            'parent_column',
            'child1s',
            'child2s',
        ]

View

It seems better to define QuerySet with get_queryset () so that it will be easier to mess with later.

views.py

from rest_framework import generics
from rest_framework.pagination import PageNumberPagination

from .models import Parent
from .serializer import ParentSerializer

class NestedListView(generics.ListAPIView):
    """
List method for nested resources
I want to use only list, so generics.Use ListAPIView
    """
    pagination_class = PageNumberPagination
    serializer_class = ParentSerializer
    #Query-Convert parameters to filter search criteria dict
    CONDITION_KEYS = {
        'parent_column': 'parent_column__contains',
        'child1_column': 'child1s__child1_column__contains',
        'child2_column': 'child2s__child2_column__contains',
        }

    def get_queryset(self):
        """
You may end up writing a complicated QuerySet later, so
Define it in a place where you can go.
        """
        #Search condition dict
        condition_dict = {}
        for key, val in self.request.query_params.items():
            # query_If there is a search condition item in the key of params, convert it to the key for filter
            if key in self.CONDITION_KEYS:
                condition_dict[self.CONDITION_KEYS[key]] = val

        queryset = Parent.objects.filter(**condition_dict).order_by('id').prefetch_related().distinct()

        return queryset

    def list(self, request, *args, **kwargs):
        """
Override list method
        """
        #Apply pagination to queryset
        page_qs = self.paginate_queryset(self.get_queryset())
        #Get serialize
        serializer = self.get_serializer(page_qs, many=True)
        #Return with pagination
        return self.get_paginated_response(serializer.data)

API execution result

Like this

It was easy.

Source

https://github.com/ping2shi2/DRF-sample

References

-DRF Official Documentation

I think I saw something else, but I forgot ...