从入门到_精通_Django REST Framework-(二)

from rest_framework import serializers

# 示例模型
class User(models.Model):
    username = models.CharField(max_length=100)
    email = models.EmailField()
    is_active = models.BooleanField(default=True)

# 手动定义 Serializer
class UserSerializer(serializers.Serializer):
    username = serializers.CharField(max_length=100)
    email = serializers.EmailField()
    is_active = serializers.BooleanField()

# 单个对象序列化
user = User.objects.get(id=1)
serializer = UserSerializer(user)
serializer.data  # 输出：{'username': 'john', 'email': 'john@example.com', ...}

# 多个对象序列化
users = User.objects.all()
serializer = UserSerializer(users, many=True)
print(serializer.data)

data = {'username': 'alice', 'email': 'alice@example.com'}
serializer = UserSerializer(data=data)

if serializer.is_valid():
    validated_data = serializer.validated_data  # 获取验证后的数据
else:
    errors = serializer.errors  # 获取错误信息

from rest_framework import serializers

class RGBColorField(serializers.Field):
    """
    自定义字段：将 "#RRGGBB" 格式字符串转换为 RGB 元组
    """
    def to_representation(self, value):
        # 从数据库值转换为序列化输出
        return {
            'r': int(value[1:3], 16),
            'g': int(value[3:5], 16),
            'b': int(value[5:7], 16)
        }

    def to_internal_value(self, data):
        # 从客户端输入转换为数据库存储格式
        hex_color = "#{:02x}{:02x}{:02x}".format(data['r'], data['g'], data['b'])
        return hex_color

class ProductSerializer(serializers.Serializer):
    color = RGBColorField()

class UserSerializer(serializers.Serializer):
    id = IntegerField(read_only=True)          # 用户只能读取，无法提交json修改
    password = CharField(write_only=True)      # 用户只能写入，程序不会响应给用户password数据

class CommentSerializer(serializers.Serializer):
    content = CharField(
        allow_blank=False,     # 禁止空字符串
        trim_whitespace=True   # 自动去除首尾空格
    )

class ProductSerializer(serializers.Serializer):
    price = DecimalField(
        max_digits=10,
        decimal_places=2,
        min_value=0.01,        # 价格必须大于 0
        max_value=999999.99
    )

class UserSerializer(serializers.Serializer):
    username = CharField(
        min_length=3,
        error_messages={
            'min_length': '用户名至少需要 {min_length} 个字符',  # 支持格式化
            'required': '用户名不能为空'
        }
    )

from rest_framework import serializers
from django.utils import timezone

class ArticleSerializer(serializers.Serializer):
    # 基础参数
    title = serializers.CharField(
        max_length=100,
        label="标题",
        help_text="请输入文章标题",
        error_messages={'blank': '标题不能为空'}
    )
    
    # 时间字段
    created_at = serializers.DateTimeField(
        read_only=True,
        default=timezone.now
    )
    
    # 数值字段
    views = serializers.IntegerField(
        min_value=0,
        default=0,
        help_text="阅读次数"
    )
    
    # 关联字段
    author = serializers.PrimaryKeyRelatedField(
        queryset=User.objects.all(),
        write_only=True  # 只允许输入作者ID，输出时不显示
    )
    
    # 自定义验证
    def validate_title(self, value):
        if 'test' in value.lower():
            raise serializers.ValidationError("标题不能包含敏感词")
        return value

class OrderSerializer(serializers.Serializer):
    product_id = serializers.IntegerField()
    quantity = serializers.IntegerField(min_value=1)

    # 字段级验证
    def validate_quantity(self, value):
        if value > 100:
            raise serializers.ValidationError("单次购买不能超过100件")
        return value

    # 对象级验证
    def validate(self, data):
        if data['product'].stock < data['quantity']:
            raise serializers.ValidationError("库存不足")
        return data

    # 使用独立验证器
    discount_code = serializers.CharField(validators=[validate_discount_code])

class UserSerializer(serializers.Serializer):
    # ...字段定义...

    def create(self, validated_data):
        return User.objects.create(**validated_data)

    def update(self, instance, validated_data):
        instance.username = validated_data.get('username', instance.username)
        instance.email = validated_data.get('email', instance.email)
        instance.save()
        return instance

# 创建新对象
serializer = UserSerializer(data=data)
if serializer.is_valid():
    user = serializer.save()  # 调用 create()

# 更新对象
user = User.objects.get(id=1)
serializer = UserSerializer(user, data=data)
if serializer.is_valid():
    updated_user = serializer.save()  # 调用 update()

class DynamicUserSerializer(serializers.Serializer):
    def __init__(self, *args, **kwargs):
        # 根据上下文隐藏敏感字段
        fields = kwargs.pop('fields', None)
        super().__init__(*args, **kwargs)

        if fields is not None:
            allowed = set(fields)
            existing = set(self.fields)
            for field_name in existing - allowed:
                self.fields.pop(field_name)

class ProfileSerializer(serializers.Serializer):
    address = serializers.CharField()

class UserDetailSerializer(serializers.Serializer):
    username = serializers.CharField()
    profile = ProfileSerializer()  # 嵌套序列化器

# 使用 partial=True
serializer = UserSerializer(instance, data={'email': 'new@example.com'}, partial=True)

def to_representation(self, instance):
    data = super().to_representation(instance)
    data['status'] = 'active' if instance.is_active else 'inactive'
    return data