Django REST Framework中嵌套序列化数据的高效注册与返回策略

# serializers.py
from rest_framework import serializers
from rest_framework.validators import UniqueValidator
from django.contrib.auth.password_validation import validate_password
from django.db import transaction

# 假设 CustomUser 和 Rider 模型已经定义在 models.py 中
# from .models import CustomUser, Rider

# 辅助序列化器，用于嵌套输出用户数据
class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = CustomUser
        fields = (
            "email",
            "first_name",
            "last_name",
            "phone_number",
        )

class RiderSerializer(serializers.ModelSerializer):
    # 用于嵌套输出关联的CustomUser数据
    user = UserSerializer(read_only=True)

    # 用户相关输入字段 (write_only=True 表示只用于输入，不用于输出)
    email = serializers.EmailField(
        write_only=True,
        validators=[UniqueValidator(queryset=CustomUser.objects.all(), message="此邮箱已被注册。")]
    )
    first_name = serializers.CharField(write_only=True, required=True)
    last_name = serializers.CharField(write_only=True, required=True)
    phone_number = serializers.CharField(write_only=True, required=True)
    password = serializers.CharField(write_only=True, required=True)
    confirm_password = serializers.CharField(write_only=True, required=True)

    # 骑手相关输入字段（可根据需要设置 required 和 allow_null）
    vehicle_registration_number = serializers.CharField(
        max_length=20,
        validators=[UniqueValidator(queryset=Rider.objects.all(), message="此车牌号已被注册。")]
    )
    min_capacity = serializers.IntegerField(required=False, allow_null=True)
    max_capacity = serializers.IntegerField(required=False, allow_null=True)
    fragile_item_allowed = serializers.BooleanField(default=True)
    charge_per_mile = serializers.DecimalField(
        max_digits=6, decimal_places=2, required=False, allow_null=True
    )

    class Meta:
        model = Rider
        fields = (
            'user', 'email', 'first_name', 'last_name', 'phone_number',
            'password', 'confirm_password', 'vehicle_type', 'vehicle_registration_number',
            'is_available', 'min_capacity', 'max_capacity', 'fragile_item_allowed',
            'ratings', 'charge_per_mile',
        )
        # 确保 vehicle_type, is_available, ratings 等字段如果有默认值，
        # 且不需要通过输入设置时，可以不在此处列出或设置为 read_only=True
        # 但为了完整性，这里全部列出

    def validate(self, data):
        """
        执行跨字段验证，如密码确认和密码强度验证。
        """
        password = data.get('password')
        confirm_password = data.pop('confirm_password') # 移除 confirm_password，因为它不对应模型字段

        if password != confirm_password:
            raise serializers.ValidationError("两次输入的密码不匹配。")

        # 使用Django内置的密码验证器进行密码强度检查
        try:
            validate_password(password=password)
        except Exception as e: # validate_password可能会抛出ValidationError或其他异常
            raise serializers.ValidationError({"password": list(e.messages)})

        # 如果需要自定义密码验证，可以参考原始UserSerializer中的逻辑
        # 例如：
        # if len(password) < 8:
        #     raise serializers.ValidationError({"password": "密码长度必须至少为8个字符。"})
        # if not any(char.isupper() for char in password):
        #     raise serializers.ValidationError({"password": "密码必须包含至少一个大写字母。"})
        # ...

        return data

    @transaction.atomic # 确保用户和骑手创建的原子性
    def create(self, validated_data):
        """
        根据验证后的数据创建CustomUser和Rider实例。
        """
        # 从validated_data中提取CustomUser相关的字段
        user_data = {
            'email': validated_data.pop('email'),
            'first_name': validated_data.pop('first_name'),
            'last_name': validated_data.pop('last_name'),
            'phone_number': validated_data.pop('phone_number'),
            'password': validated_data.pop('password'), # 密码已经通过validate_password验证
        }

        # 从validated_data中提取Rider相关的字段
        # 注意：这里假设 validated_data 中剩余的都是 Rider 模型的字段
        # 如果有默认值或可选字段，pop时提供默认值以防KeyError
        rider_data = {
            'vehicle_registration_number': validated_data.pop('vehicle_registration_number'),
            'min_capacity': validated_data.pop('min_capacity', None),
            'max_capacity': validated_data.pop('max_capacity', None),
            'fragile_item_allowed': validated_data.pop('fragile_item_allowed', True),
            'charge_per_mile': validated_data.pop('charge_per_mile', None),
            'vehicle_type': validated_data.pop('vehicle_type', 'TWO_WHEELER'), # 假设有默认值
            'is_available': validated_data.pop('is_available', True),
            'ratings': validated_data.pop('ratings', None),
        }

        # 创建CustomUser实例
        user = CustomUser.objects.create_user(**user_data)

        # 创建Rider实例并关联到新创建的用户
        rider = Rider.objects.create(user=user, **rider_data)

        return rider

# views.py
from rest_framework import generics, status
from rest_framework.response import Response
# from .serializers import RiderSerializer # 确保导入 RiderSerializer

class RiderRegistrationView(generics.CreateAPIView):
    serializer_class = RiderSerializer

    def post(self, request, *args, **kwargs):
        """
        处理骑手注册请求。
        """
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True) # 验证失败时自动抛出异常

        # 调用 serializer 的 create 方法，创建用户和骑手
        rider_instance = serializer.save() 

        # 重新序列化实例以获取完整的响应数据，包括嵌套的 user 信息
        # 注意：serializer.data 此时已经包含了 create 方法返回的 rider_instance 的序列化结果
        # 且由于 user 字段是 UserSerializer(read_only=True)，它会自动包含用户数据

        data = {
            "message": "骑手注册成功",
            "data": serializer.data,
        }
        return Response(data, status=status.HTTP_201_CREATED)

{   
    "email": "faruq.mohammad@example.com",
    "first_name": "Faruq",
    "last_name": "Mohammad",
    "phone_number": "08137021976",
    "password": "#FaruqMohammad1234",
    "confirm_password": "#FaruqMohammad1234",
    "vehicle_registration_number": "ABJ145",
    "min_capacity": 20,
    "max_capacity": 50,
    "fragile_item_allowed": true,
    "charge_per_mile": 1000,
    "vehicle_type": "FOUR_WHEELER"
}

{
    "message": "骑手注册成功",
    "data": {
        "user": {
            "email": "faruq.mohammad@example.com",
            "first_name": "Faruq",
            "last_name": "Mohammad",
            "phone_number": "08137021976"
        },
        "is_available": true,
        "vehicle_type": "FOUR_WHEELER",
        "vehicle_registration_number": "ABJ145",
        "min_capacity": 20,
        "max_capacity": 50,
        "fragile_item_allowed": true,
        "ratings": null,
        "charge_per_mile": "1000.00"
    }
}