Django REST framework序列化

Django REST framework序列化

开发我们的Web API的第一件事是为我们的Web API提供一种将代码片段实例序列化和反序列化为诸如json之类的表示形式的方式

models部分

from django.db import models


class Book(models.Model):
    title = models.CharField(max_length=32)
    price = models.IntegerField()
    pub_date = models.DateField()
    publish = models.ForeignKey("Publish")
    authors = models.ManyToManyField("Author")

    def __str__(self):
        return self.title


class Publish(models.Model):
    name = models.CharField(max_length=32)
    email = models.EmailField()

    def __str__(self):
        return self.name


class Author(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()

    def __str__(self):
        return self.name

view部分

from django.views import View
from rest_framework.response import Response
from app01.serializer import *
from rest_framework.views import APIView


class PublishView(APIView):
    def get(self, request):

        # 序列化方式
        # 方式1:
        # publish_list=list(Publish.objects.all().values("name","email"))

        # 方式2:
        # model_to_dict就是把一个model对象转换成字典
        # from django.forms.models import model_to_dict
        # publish_list=Publish.objects.all()
        # temp=[]
        # for obj in publish_list:
        #     temp.append(model_to_dict(obj))

        # 方式3:
        # django的序列化组件,跟restful没关系,最简单的方式
        # from django.core import serializers
        # ret=serializers.serialize("json",publish_list)

        # 方式4:
        # DjangoRESTframework序列组件,详见serializer部分
        # 实例化一个序列化对象,传入要序列化的数据和many
        # many=True表示传入的是一个queryset,false是model对象
        publish_list = Publish.objects.all()
        ps = PublishModelSerializers(publish_list, many=True)
        # 取序列化后的数据
        return Response(ps.data)
 # restframework中get取数据
# print("request.data", request.data)
# print("request.data type", type(request.data))
# print(request._request.GET)
# print(request.GET)
 

serializer部分

from rest_framework import serializers
from app01.models import *


# 类1: 为queryset,model对象做序列化
# 对哪些字段做序列化name = serializers.CharField() 这个字段序列化成什么类型
class PublishSerializers(serializers.Serializer):
    name = serializers.CharField()
    email = serializers.CharField()


# 类2: 上面的方式需要自己定义字段,faramework组件也有一个类似modelform的组件 class PublishModelSerializers(serializers.ModelSerializer): class Meta: model = Publish fields = "__all__"
# 类1中只设置了一些简单的字段,下面是一对多,多对多的字段时的方法 # class BookSerializers(serializers.Serializer): # title = serializers.CharField(max_length=32) # price = serializers.IntegerField() # pub_date = serializers.DateField() # publish=serializers.CharField(source="publish.name") # #authors=serializers.CharField(source="authors.all") # authors = serializers.SerializerMethodField() # def get_authors(self,obj): # temp=[] # for obj in obj.authors.all(): # temp.append(obj.name) # return temp ''' 序列化BookSerializers(book_list,many=True)过程: temp=[] for obj in book_list: temp.append({ "title":obj.title, "price":obj.price, "pub_date":obj.pub_date, "publish":str(obj.publish), # obj.publish.name #"authors":obj.authors.all, "authors": get_authors(obj) }) '''

ModelSerializer

上面的类2就用的ModelSerializer

class BookSerializers(serializers.ModelSerializer):
      class Meta:
          model=Book
          fields="__all__"
          depth=1

处理POST请求

    def post(self, request):
        # 取数据,原生request支持的操作,如果contenttype其它的原生request不会帮你封装
        # print("POST",request.POST)
        # print("body",request.body)
        # # print(request)
        # print(type(request))
        # from django.core.handlers.wsgi import WSGIRequest
        #  新的request支持的操作
        # print("request.data",request.data)
        # print("request.data type",type(request.data))

                # post请求的数据
        ps = PublishModelSerializers(data=request.data, many=False)
        if ps.is_valid():
            print(ps.validated_data)
            ps.save()  # create方法
            return Response(ps.data)
        else:
            return Response(ps.errors)

重写save中的create方法

class BookModelSerializers(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = "__all__"
    # authors=serializers.CharField(source="authors.all")
    authors = serializers.SerializerMethodField()
    def get_authors(self,obj):
        temp=[]
        for obj in obj.authors.all():
            temp.append(obj.name)
        return temp
    
# 假如你上面自定义了字段的显示,就需要重写create方法了 def create(self, validated_data):

authors = validated_data.pop('authors') book =Book.objects.create(**validated_data)
book.authors.add(*authors)
return book

单条数据的get、put、delete请求

class PublishDetailView(APIView):
    def get(self, request, pk):

        publish = Publish.objects.filter(pk=pk).first()
        ps = PublishModelSerializers(publish)
        return Response(ps.data)

    def put(self, request, pk):
        publish = Publish.objects.filter(pk=pk).first()
        ps = PublishModelSerializers(publish, data=request.data)
        if ps.is_valid():
            ps.save()
            return Response(ps.data)
        else:
            return Response(ps.errors)

    def delete(self, request, pk):
        Publish.objects.filter(pk=pk).delete()

        return Response()

超链接API:Hyperlinked

很多时候,我们就想一个字段的值是另一个字段的超链接,如下book表的publish字段就是publish表的超链接

class BookModelSerializers(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = "__all__"

    publish = serializers.HyperlinkedIdentityField(
        # 你要找的url的别名
        view_name="detailpublish",
        # 含正则表达式如(\d+)的话,下两步是把什么字段的内容,赋值给哪个分组命名
        lookup_field="publish_id",
        # 赋给什么分组命名
        lookup_url_kwarg="pk"
    )

urls部分

urlpatterns = [

    # View:view(request)=====APIView:dispatch()
    url(r'^publishes/$', views.PublishView.as_view(), name="publish"),
    url(r'^publishes/(?P<pk>\d+)/$', views.PublishDetailView.as_view(), name="detailpublish"),

    # View:view(request)=====APIView:dispatch()
    url(r'^books/$', views.BookView.as_view(), name="books"),
    url(r'^books/(\d+)/$', views.BookDetailView.as_view(), name="detailbook"),

]

小结

# 需要会的:
restframework(Django) ----针对数据:json (1)Django的原生request: 浏览器 ------------- 服务器 "GET url?a=1&b=2 http/1.1\r\user_agent:Google\r\ncontentType:urlencoded\r\n\r\n" "POST url http/1.1\r\user_agent:Google\r\ncontentType:urlencoded\r\n\r\na=1&b=2"       
      
      # post请求才有请求体,get没有请求体 request.body: a=1&b=2 request.POST: if contentType:urlencoded: # 才会给你封装 a=1&b=2----->{"a":1,"b":2}

(2)restframework 下的APIView: (3) class PublishSerializers(serializers.Serializer): name=serializers.CharField() email=serializers.CharField() PublishSerializers(queryset,many=true) PublishSerializers(model_obj) 总结: 1 reuqest类----源码 2 restframework 下的APIView--源码 url(r'^books/$', views.BookView.as_view(),name="books")# View下的view books/一旦被访问: view(request) ------APIView: dispatch() 3 def dispatch(): 构建request对象 self.request=Request(request) self.request._request self.request.GET # get self.request.data # POST PUT 分发----if get请求: if request.method.lower() in self.http_method_names: handler = getattr(self, request.method.lower(), self.http_method_not_allowed) else: handler = self.http_method_not_allowed response = handler(request, *args, **kwargs) # self.get(request, *args, **kwargs) return response 4 序列化类 # from django.core import serializers # ret=serializers.serialize("json",publish_list) restframework下的序列类 BookModelSerializers 将queryset或者model对象序列成一json数据 bs=BookModelSerializers(book_list,many=True,context={'request': request}) bs=BookModelSerializers(book,context={'request': request}) 还可以做校验数据,json-------》queryset/model-->记录 bs=BookModelSerializers(data=request.data) if bs.is_valid(): print(bs.validated_data) bs.save() # 重写create方法 5 操作数据: 以Book表为例 class BookView(APIView): # 查看所有书籍 def get(self,request): book_list=Book.objects.all() bs=BookModelSerializers(book_list,many=True,context={'request': request}) return Response(bs.data) # 添加一本书籍 def post(self,request): # post请求的数据 bs=BookModelSerializers(data=request.data) if bs.is_valid(): print(bs.validated_data) bs.save()# create方法 return Response(bs.data) else: return Response(bs.errors) class BookDetailView(APIView): # 查看一本书籍 def get(self,request,id): book=Book.objects.filter(pk=id).first() bs=BookModelSerializers(book,context={'request': request}) return Response(bs.data) # 更新一本书籍 def put(self,request,id): book=Book.objects.filter(pk=id).first() bs=BookModelSerializers(book,data=request.data) if bs.is_valid(): bs.save() return Response(bs.data) else: return Response(bs.errors) # 删除某一本书籍 def delete(self,request,id): Book.objects.filter(pk=id).delete() return Response() restframework 1 APIView 2 序列组件 3 视图、 4 组件(认证权限频率) 5 数据解析器 6 分页和Response

 

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