serializer功能

序列化與反序列換

對(duì)象轉(zhuǎn)換成Dict

Dict轉(zhuǎn)換成對(duì)象

1.創(chuàng)建模型

from django.db import models


class Animal(models.Model):

    a_name = models.CharField(max_length=32)
    a_weight = models.FloatField(default=10)


class Spider(models.Model):

    s_host = models.CharField(max_length=200)


class People(models.Model):

    p_name = models.CharField(max_length=32)
    p_age = models.IntegerField(default=18)

2.創(chuàng)建序繼承serializers.Serializer的列化器，必須實(shí)現(xiàn)抽象方法

必須實(shí)現(xiàn)抽象的方

abstract.png

alt+enter

ewrwe.png

alt+enter

2342.png

序列化器寫法

Serializer

- 必須實(shí)現(xiàn)抽象方法
  - update
    - 更新
  - create
    - 創(chuàng)建
- 其余字段聲明
  - Field
    - 初始化屬性
      - read_only  只讀(id)
      - write_only  只寫 (密碼)
      - required
      - default
      - initial
      - source
        - 映射(單個(gè)時(shí)候用不到枉阵，級(jí)聯(lián)的時(shí)候會(huì)用到)
      - label
      - help_text
      - style
      - error_messages   錯(cuò)誤信息
      - validators 驗(yàn)證器

源碼

 
    @property
    def validators(self):
        if not hasattr(self, '_validators'):
            self._validators = self.get_validators()
        return self._validators

    @validators.setter
    def validators(self, validators):
        self._validators = validators
      - allow_null  允許為空
  - BooleanField
    - 繼承Field
      - 實(shí)現(xiàn)抽象方法
        - to_internal_value
        - to_representation
  - IntegerField
  - CharField
  - 和ORM聲明非常像
- ModelSerializer
  - 模型直接序列化
- HyperLinkedModelSerializer
  - 模型序列化薪贫，添加超鏈接

from rest_framework import serializers

from SerializerLearn.models import Animal, Spider, People

# 生成序列化器
class AnimalSerializer(serializers.Serializer):

# read_only 只能讀
# POST提交用的
    id = serializers.IntegerField(read_only=True)
    a_name = serializers.CharField()
    a_weight = serializers.FloatField()

    def update(self, instance, validated_data):

        instance.a_name = validated_data.get("a_name", instance.a_name)
        instance.a_weight = validated_data.get("a_weight", instance.a_weight)

        instance.save()
        return instance

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

serializers.ModelSerializer繼承自serializers

多了一個(gè)映射，將模型屬性映射到serializer屬性

已經(jīng)將create方法和update方法(抽象方法)寫好了

注意： 如果有級(jí)聯(lián)就會(huì)拋異常

class SpiderSerializer(serializers.ModelSerializer):

    class Meta:
        model = Spider
        fields = ("id", "s_host")


class PeopleSerializer(serializers.ModelSerializer):

    class Meta:
        model = People
        fields = ("id", "p_name", "p_age")

對(duì)象轉(zhuǎn)字典

>>> from SerializerLearn.serializern import AnimalSerializer
>>> from SerializerLearn.models import Animal
>>> from SerializerLearn.serializers import AnimalSerializer
>>> animal = Animal.objects.get(pk=2)
>>> animal.a_name
'sssdf'
>>> animal
<Animal: Animal object>
>>> seriallizer = AnimalSerializer(animal)
>>> seriallizer.data
{'id': 2, 'a_name': 'sssdf', 'a_weight': 23.0}
>>> type(seriallizer.data)
<class 'rest_framework.utils.serializer_helpers.ReturnDict'>
>>> 

對(duì)象轉(zhuǎn)字典.png

views.py

獲取單個(gè)數(shù)據(jù)
獲取全部數(shù)據(jù)
添加數(shù)據(jù)

from django.http import JsonResponse, HttpResponse
from django.views.decorators.csrf import csrf_exempt
from rest_framework.decorators import api_view
from rest_framework.response import Response
from rest_framework.views import APIView

from SerializerLearn.models import Animal, Spider, People
from SerializerLearn.serializers import AnimalSerializer, SpiderSerializer, PeopleSerializer

# 獲取全部和添加數(shù)據(jù)
@csrf_exempt
def animals(request):
    if request.method == "GET":

        animal_list = Animal.objects.all()

        serializer = AnimalSerializer(animal_list, many=True)

        return JsonResponse(serializer.data, safe=False)

    elif request.method == "POST":

        a_name = request.POST.get("a_name")
        a_weight = request.POST.get("a_weight")
        # 轉(zhuǎn)成字典
        animal_data = {
            "a_name": a_name,
            "a_weight": a_weight,
        }

        serializer = AnimalSerializer(data=animal_data)
        
        # 驗(yàn)證
        if serializer.is_valid():
            serializer.save()
            return JsonResponse(serializer.data)
        return JsonResponse({"msg": "create fial"})

# 獲取單個(gè)

def animal(request, pk):

    if request.method == "GET":
        animal_obj = Animal.objects.get(pk=pk)

        serializer = AnimalSerializer(animal_obj)

        return JsonResponse(serializer.data)

def spiders(request):
    if request.method == "GET":
        spider_list = Spider.objects.all()

        serializer = SpiderSerializer(spider_list, many=True)

        return JsonResponse(serializer.data, safe=False)

繼承自APIView會(huì)在下一章節(jié)
Response是RSTFul自己的功能很強(qiáng)大，下章節(jié)說(shuō)

class PeopleAPIView(APIView):

    def get(self, request):

        print(type(request))

        peoples = People.objects.all()

        serializer = PeopleSerializer(peoples, many=True)

        return Response(data=serializer.data)


@api_view(["GET"])
def HelloAPIView(request):

    print(type(request))

    # return HttpResponse("haha")

    data = {
        "msg": "ok"
    }

    return Response(data)