api/serializers.py - master - eb/yamdb_final

api/serializers.py
125 строк4 KB
Evgeniy Budaev
workflow: тесты
02 ноя 2021, 12:38
02 ноя 2021, 12:3868658ca
from django.db.models import Avg
from rest_framework import exceptions, serializers
from rest_framework.relations import SlugRelatedField
from rest_framework.validators import UniqueValidator

from api_yamdb.settings import (MESSAGE_FOR_RESERVED_NAME,
                                MESSAGE_FOR_USER_NOT_FOUND, RESERVED_NAME)
from reviews.models import Comment, Review
from titles.models import Category, Genre, Title
from users.models import User


class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('name', 'slug')


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


class TitleSerializer(serializers.ModelSerializer):
    category = CategorySerializer(read_only=True)
    genre = GenreSerializer(many=True, read_only=True)
    rating = serializers.SerializerMethodField()

    class Meta:
        model = Title
        fields = ('id', 'name', 'year', 'description',
                  'genre', 'category', 'rating')
        read_only_fields = ('id',)

    def get_rating(self, obj):
        try:
            rating = obj.reviews.aggregate(Avg('score'))
            return rating.get('score__avg')
        except TypeError:
            return None


class TitleCreateSerializer(serializers.ModelSerializer):
    category = serializers.SlugRelatedField(
        slug_field='slug',
        queryset=Category.objects.all()
    )
    genre = serializers.SlugRelatedField(
        slug_field='slug',
        queryset=Genre.objects.all(),
        many=True
    )

    class Meta:
        fields = ('id', 'name', 'year', 'description',
                  'genre', 'category', 'rating')
        model = Title


class ForUserSerializer(serializers.ModelSerializer):
    """Сериализатор для пользователей со статусом user.
    Зарезервированное имя использовать нельзя"""
    email = serializers.EmailField(
        validators=[UniqueValidator(queryset=User.objects.all())]
    )

    class Meta:
        model = User
        fields = (
            'username', 'email', 'first_name', 'last_name', 'bio', 'role'
        )
        read_only_fields = ('role', )

    def validate_username(self, value):
        if value == RESERVED_NAME:
            raise serializers.ValidationError(MESSAGE_FOR_RESERVED_NAME)
        return value


class ForAdminSerializer(serializers.ModelSerializer):
    """Сериализатор для пользователей со статусом admin.
    Зарезервированное имя использовать нельзя"""
    email = serializers.EmailField(
        validators=[UniqueValidator(queryset=User.objects.all())])

    class Meta:
        model = User
        fields = (
            'username', 'email', 'first_name', 'last_name', 'bio', 'role')

    def validate_username(self, value):
        if value == RESERVED_NAME:
            raise serializers.ValidationError(MESSAGE_FOR_RESERVED_NAME)
        return value


class TokenSerializer(serializers.Serializer):
    """Сериализатор для получения токена.
    Зарезервированное имя использовать нельзя."""
    username = serializers.CharField(max_length=200, required=True)
    confirmation_code = serializers.CharField(max_length=200, required=True)

    def validate_username(self, value):
        if value == RESERVED_NAME:
            raise serializers.ValidationError(MESSAGE_FOR_RESERVED_NAME)
        if not User.objects.filter(username=value).exists():
            raise exceptions.NotFound(MESSAGE_FOR_USER_NOT_FOUND)
        return value


class CommentSerializer(serializers.ModelSerializer):
    author = SlugRelatedField(slug_field='username', read_only=True)

    class Meta:
        model = Comment
        fields = ('id', 'text', 'author', 'pub_date')


class ReviewSerializer(serializers.ModelSerializer):
    author = SlugRelatedField(slug_field='username', read_only=True)

    class Meta:
        model = Review
        fields = ('id', 'author', 'text', 'score', 'pub_date')