一竖螃、restframework 序列化組件之 serializers

from rest_framework import serializers
from rest_framework.response import Response
from rest_framework.views import APIView

from app01.models import Book


class BookSerializer(serializers.Serializer): # 【自定義一個序列化類】
    title = serializers.CharField(max_length=32) # 【寫哪些字段就序列化哪些】
    price = serializers.DecimalField(max_digits=5, decimal_places=2)
    publish = serializers.CharField(max_length=32)  # 一本書對應(yīng)一個出版社
    publish_email = serializers.CharField(max_length=32, source='publish.email')  # 一本書對應(yīng)一個出版社
    publish_city = serializers.CharField(max_length=32, source='publish.city')  # 一本書對應(yīng)一個出版社

    # authors = serializers.CharField(max_length=32)
    # authors = serializers.CharField(max_length=32,source='authors.all')
    # "authors": "<QuerySet [<Author: 張三>, <Author: 王五>]>"
    authors = serializers.SerializerMethodField()

    def get_authors(self, obj):
        ret = []  # 這個數(shù)據(jù)類型可根據(jù)前端需求自己構(gòu)建
        for i in obj.authors.all():
            ret.append(i.name)
        return ret


class BookView(APIView):

    def get(self, request):
        book_list = Book.objects.all()
        bs = BookSerializer(book_list, many=True) # 【序列化接口】
        print(bs.data)  # 【有序字典】
        return Response(bs.data)

    def post(self,request): #  請求來了必須先校驗有效性啡邑，才能存入數(shù)據(jù)庫
        bs =BookSerializer(data=request.data)
        print(request.data)  # 【字典】
        print(bs.is_valid())  # 不符合規(guī)范就是False
        if bs.is_valid():  # 【校驗】
            Book.objects.create(**request.data) # 【存庫】
            return Response(bs.data)  # 【返回結(jié)果】
        else:
            return Response(bs.errors) # 【返回錯誤信息】

這樣寫非常多,每一個字段都得自己寫，所以就引出了ModelSerializer，【見 三】

• 運用 source='*'
• serializermethodfield
• read_only和write_only

二评凝、序列化過程（GET請求）

bs = BookSerializer(book_list,many = True)
bs.data
temp = []
for obj in book_list:
    temp.append({
        'title':obj.title,
        'price':obj.price,
        'publish':obj.publish 【此時坯钦，取出來的是個對象，顯示的是此對象中__str__方法的返回值】
                                所以益咬，設(shè)置外鍵關(guān)聯(lián)的字段也能序列化出來逮诲。
      })
1，另外：加上source幽告，就會找source里面的梅鹦。可用到外鍵的關(guān)聯(lián)字段里冗锁，點出來一個對象之后再找出對象的屬性齐唆。
      publish = serializers.CharField(max_length=32,source='publish.email')
2，所以：外鍵的關(guān)聯(lián)對象的任何字段都可以取出冻河。
      publish_email = serializers.CharField(max_length=32,source='publish.email')
      publish_city = serializers.CharField(max_length=32,source='publish.city')
3箍邮，多對多字段這樣寫會形成這樣的數(shù)據(jù)類型：
      authors = serializers.CharField(max_length=32,source='authors.all')
      "authors": "<QuerySet [<Author: 張三>, <Author: 王五>]>"
4，所以：多對多字段可以這樣寫：
      authors = serializers,SerializerMethodField()
      def get_authors(self,obj):
          ret = []
          for i in obj.authors.all()
              ret.append(i.name)
          return ret
5叨叙，序列化時锭弊，看見是SerializerMethodField類，就會執(zhí)行自定義的get_字段名的方法摔敛。即可解決多對多的顯示問題
      if 字段SerializerMethodField：
       "authors":get_authors(obj)

三廷蓉、ModelSerializer 的（get查看）和（post添加）

from rest_framework import serializers
from rest_framework.response import Response
from rest_framework.views import APIView

from app01.models import Book


class BookSerializer(serializers.ModelSerializer):
    publish_name = serializers.CharField(max_length=32, source="publish.name", read_only=True)
    publish_city = serializers.CharField(max_length=32, source='publish.city',read_only=True)
    publish_pk=serializers.CharField(max_length=32,source="publish.pk",read_only=True)

    author_list = serializers.SerializerMethodField(read_only=True)  # 【規(guī)定只讀】
    def get_author_list(self, obj):
        ret = []  # 這個數(shù)據(jù)類型可根據(jù)前端需求自己構(gòu)建
        for i in obj.authors.all():
            ret.append({'name':i.name,'pk':i.pk})
        return ret

    publish_info = serializers.SerializerMethodField(read_only=True)
    def get_publish_info(self, obj):
        return {"name": obj.publish.name, "publish_pk": obj.publish.pk,"publish_city":obj.publish.city}

    class Meta:
        model = Book
        # fields = ['title','price']
        fields = '__all__'
        extra_kwargs = {"publish": {"write_only": True}, "authors": {"write_only": True}}#【規(guī)定只寫】


class BookView(APIView):
    def get(self, request):
        book_list = Book.objects.all()
        bs = BookSerializer(book_list, many=True)
        return Response(bs.data)

    def post(self, request):
        bs = BookSerializer(data=request.data, many=False)
        if bs.is_valid():
            bs.save()  # 【create操作,用ModelSerializer就可直接save】
            return Response(bs.data)
        else:
            return Response(bs.errors)