from rest_framework import serializers

class demoSerializer(serializers.Serializer):
    amount = serializers.IntegerField(max_value=100, min_value=0, error_messages={
        "min_value": "The Age Filed Must Be 0 <= amount",  # amount在反序列化必須是 0 <= amount <= 100
        "max_value": "The amount Filed Must Be amount <= 100",
    })

class DemoAPIView(APIView):
     def post(self, request, *args):
       try:
          serializer = demoSerializer(data=request.data)
          serializer.is_valid(raise_exception=True)
          # 拿出已驗(yàn)證的數(shù)據(jù)中的data
          validated_data = ser.validated_data.get('amount')
          #  返回信息
          return Response({"msg": "ok", "data":validated_data}, status=status.HTTP_201_CREATED)
       except ValidationError as e:
           return Response({"msg": "error", "error_message": e.detail}, status=status.HTTP_401_UNAUTHORIZED)

from rest_framework import serializers

def check_num(data):
        """外部驗(yàn)證函數(shù)"""
         if len(data) != 3:
         raise serializers.ValidationError(detail="num格式不正        確！必須是3個(gè)字符", code="check_num")
       # 驗(yàn)證完成以后，務(wù)必返回結(jié)果，否則最終的驗(yàn)證結(jié)果沒(méi)有該數(shù)據(jù)
         return data
      
class demoSerializer(serializers.Serializer):
   num = serializers.CharField(validators=[check_classmate])
     

class demoSerializer(serializers.Serializer):
   name = serializers.CharField(required=True)   # required=True , 反序列化階段必填
    sex = serializers.BooleanField(default=True)  # default=True，  反序列化階段，客戶端沒(méi)有提交，則默認(rèn)為True
   
   def validate(self, attrs):
        """
        驗(yàn)證來(lái)自客戶端的所有數(shù)據(jù)
        類似會(huì)員注冊(cè)的密碼和確認(rèn)密碼，就只能在validate方法中校驗(yàn)
        validate是固定方法名，
        參數(shù)：attrs，是在序列化器實(shí)例化時(shí)的data選項(xiàng)數(shù)據(jù)
        """
        if attrs.get("name") == "xxx" and attrs.get("sex"):
            raise serializers.ValidationError(detail="錯(cuò)誤信息xx", code="validate")

        return attrs

    def validate_name(self, data):
        """驗(yàn)證單個(gè)字段
        方法名的格式必須以 validate_<字段名> 為名稱，否則序列化器不識(shí)別！
        validate開(kāi)頭的方法，會(huì)自動(dòng)被is_valid調(diào)用的
        """
        if data in ["python", "django"]:
            # 在序列化器中，驗(yàn)證失敗可以通過(guò)拋出異常的方式來(lái)告知 is_valid
            raise serializers.ValidationError(detail="錯(cuò)誤信息", code="validate_name")
        # 驗(yàn)證成功以后，必須返回?cái)?shù)據(jù)，否則最終的驗(yàn)證結(jié)果中，就不會(huì)出現(xiàn)這個(gè)數(shù)據(jù)了。
        return data  

class demoSerializer(serializers.Serializer):
  name = serializers.CharField(required=True，
validators=[validate_name])   # required=True , 反序列化階段必填
   def validate_name(self, data):
       """驗(yàn)證單個(gè)字段
       方法名的格式必須以 validate_<字段名> 為名稱，否則序列化器不識(shí)別！
       validate開(kāi)頭的方法，會(huì)自動(dòng)被is_valid調(diào)用的
       """
       if data in ["python", "django"]:
           # 在序列化器中，驗(yàn)證失敗可以通過(guò)拋出異常的方式來(lái)告知 is_valid
           raise serializers.ValidationError(detail="錯(cuò)誤信息", code="validate_name")
       # 驗(yàn)證成功以后，必須返回?cái)?shù)據(jù)，否則最終的驗(yàn)證結(jié)果中，就不會(huì)出現(xiàn)這個(gè)數(shù)據(jù)了。
       return data  

from django.db import models
# Create your models here.
class DemoModel(models.Model):
    """信息"""
    price = models.IntegerField(verbose_name="價(jià)格")
    class Meta:
        db_table = "mysql_demo"
        verbose_name = "demotest"
        verbose_name_plural = verbose_name

from rest_framework import serializers
from .models import DemoModel  #一定要導(dǎo)入models,py里寫的model

class DemoModelSerializer(serializers.ModelSerializer):
    #...... 其他代碼
    class Meta:
        model = DemoModel
        fields = "__all__"
        extra_kwargs = {
            "age": {
                "max_value": 100,
                "error_messages": {
                    "max_value": "價(jià)格不能超過(guò)100！",
                }
            }
        }