在Django REST框架中验证用户的更新请求

from rest_framework import serializers

class UserSerializer(serializers.Serializer):
    username = serializers.CharField(max_length=100)
    email = serializers.EmailField()

    def validate_username(self, value):
        # 自定义验证逻辑，例如检查用户名是否已存在
        if User.objects.filter(username=value).exists():
            raise serializers.ValidationError("Username already exists")
        return value

    def update(self, instance, validated_data):
        # 更新验证逻辑，例如检查是否有权限更新该用户
        if not instance.has_permission(self.context['request'].user):
            raise serializers.ValidationError("You don't have permission to update this user")

        instance.username = validated_data.get('username', instance.username)
        instance.email = validated_data.get('email', instance.email)
        instance.save()
        return instance