💻 Примеры — Урок 33

Пример 1: lookup_field и lookup_url_kwarg

Идентификация жанра по имени вместо pk.

models.py

from django.db import models

class Genre(models.Model):
    name = models.CharField(max_length=100, unique=True)

    def __str__(self):
        return self.name

serializers.py

from rest_framework import serializers
from .models import Genre

class GenreSerializer(serializers.ModelSerializer):
    class Meta:
        model = Genre
        fields = ['id', 'name']

views.py

from rest_framework.generics import RetrieveUpdateDestroyAPIView
from .models import Genre
from .serializers import GenreSerializer

class GenreDetailUpdateDeleteView(RetrieveUpdateDestroyAPIView):
    queryset = Genre.objects.all()
    serializer_class = GenreSerializer
    lookup_field = 'name'           # поле модели
    lookup_url_kwarg = 'genre_name' # параметр URL

urls.py

from django.urls import path
from .views import GenreDetailUpdateDeleteView

urlpatterns = [
    path('genres/<str:genre_name>/', GenreDetailUpdateDeleteView.as_view(),
         name='genre-detail-update-delete'),
]

Результат

GET http://127.0.0.1:8000/genres/comedy/

HTTP 200 OK
{
    "id": 3,
    "name": "Comedy"
}

PATCH http://127.0.0.1:8000/genres/comedy/
{"name": "Comedy Films"}

DELETE http://127.0.0.1:8000/genres/comedy/
HTTP 204 No Content

Пример 2: Переопределение get_object()

Скрытие запрещённых книг через кастомный get_object().

models.py — добавление поля is_banned

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=200)
    author = models.CharField(max_length=100)
    published_date = models.DateField()
    price = models.DecimalField(max_digits=10, decimal_places=2,
                                null=True, blank=True)
    is_bestseller = models.BooleanField(default=False)
    genres = models.ManyToManyField('Genre', related_name='books')
    is_banned = models.BooleanField(default=False)  # новое поле

    def __str__(self):
        return self.title

views.py

from rest_framework.generics import RetrieveUpdateDestroyAPIView
from rest_framework.exceptions import NotFound
from .models import Book
from .serializers import BookSerializer

class BookDetailUpdateDeleteView(RetrieveUpdateDestroyAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

    def get_object(self):
        pk = self.kwargs.get('pk')
        try:
            book = self.queryset.get(pk=pk, is_banned=False)
        except Book.DoesNotExist:
            raise NotFound(detail=f"Book with id '{pk}' not found or is banned.")
        # Не забываем про object-level permissions
        self.check_object_permissions(self.request, book)
        return book

Результат

# Книга существует и не запрещена:
GET http://127.0.0.1:8000/books/1/
HTTP 200 OK {"id": 1, "title": "The Great Gatsby", ...}

# Книга запрещена (is_banned=True):
GET http://127.0.0.1:8000/books/5/
HTTP 404 Not Found
{"detail": "Book with id '5' not found or is banned."}

# Книги не существует:
GET http://127.0.0.1:8000/books/999/
HTTP 404 Not Found
{"detail": "Book with id '999' not found or is banned."}

Пример 3: get_serializer_context() с динамическими полями

Включение связанных данных (жанров) по запросу клиента.

views.py

from rest_framework.generics import ListAPIView
from .models import Book
from .serializers import BookSerializer

class BookListCreateView(ListAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

    def get_serializer_context(self):
        context = super().get_serializer_context()
        context['include_related'] = (
            self.request.query_params.get('include_related', 'false').lower() == 'true'
        )
        return context

serializers.py

from rest_framework import serializers
from .models import Book

class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = '__all__'

    def to_representation(self, instance):
        representation = super().to_representation(instance)
        if self.context.get('include_related'):
            representation['genres'] = [genre.name for genre in instance.genres.all()]
        else:
            representation.pop('genres', None)
        return representation

Результат

# С параметром include_related=true:
GET http://127.0.0.1:8000/books/?include_related=true
{
    "id": 1,
    "title": "The Great Gatsby",
    "author": "F. Scott Fitzgerald",
    "genres": ["Classic", "Fiction"],
    ...
}

# Без параметра (или include_related=false):
GET http://127.0.0.1:8000/books/
{
    "id": 1,
    "title": "The Great Gatsby",
    "author": "F. Scott Fitzgerald"
    // поле genres отсутствует
}

Пример 4: filter_backends — фильтрация, поиск, сортировка

Установка

pip install django-filter

settings.py

INSTALLED_APPS = [
    ...
    'django_filters',
]

views.py

from rest_framework.generics import ListAPIView
from rest_framework import filters
from django_filters.rest_framework import DjangoFilterBackend
from .models import Book
from .serializers import BookSerializer

class BookListCreateView(ListAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer
    filter_backends = [
        DjangoFilterBackend,
        filters.SearchFilter,
        filters.OrderingFilter,
    ]
    filterset_fields = ['author', 'publisher', 'is_bestseller']
    search_fields = ['title', 'author']
    ordering_fields = ['published_date', 'price']

Примеры запросов

# Фильтрация по автору (точное совпадение)
GET /books/?author=F. Scott Fitzgerald
→ все книги этого автора

# Поиск по заголовку и автору (подстрока)
GET /books/?search=Gatsby
→ книги, где title или author содержит "Gatsby"

# Сортировка по цене по возрастанию
GET /books/?ordering=price

# Сортировка по цене по убыванию
GET /books/?ordering=-price

# Только бестселлеры, отсортированные по дате
GET /books/?is_bestseller=true&ordering=-published_date

# Комбинирование: поиск + сортировка
GET /books/?search=classic&ordering=price