Django Rest Framework(分页、视图、路由、渲染器)

一、分页

试问如果当数据量特别大的时候，你是怎么解决分页的？

• 方式a、记录当前访问页数的数据id
• 方式b、最多显示120页等
• 方式c、只显示上一页，下一页，不让选择页码，对页码进行加密

1、基于limit offset 做分页（如：在url后面加上？offset=0&limit=2,即代表从第0条开始，往后取2条(即1,2)）

from rest_framework.pagination import LimitOffsetPagination

 urlpatterns = [
     url(r'^admin/', admin.site.urls),
     url(r'^app01/(?P<version>[v1|v2]+)/', include('app01.urls'))

 ]

urls.py

 urlpatterns = [
     url(r'^index1/', views.IndexView1.as_view()),
     url(r'^index2/', views.IndexView2.as_view()),
     url(r'^index3/', views.IndexView3.as_view()),
     url(r'^index4/', views.IndexView4.as_view()),
     url(r'^index5/', views.IndexView5.as_view()),

 ]

app01.url

from rest_framework.views import APIView
from rest_framework.response import Response
from app01.serializes.myserializes import MySerializes
from rest_framework.pagination import LimitOffsetPagination
from app01 import models

# =========== 可以自己进行自定制分页，基于limitoffset===================
class P1(LimitOffsetPagination):
    max_limit = 3  # 最大显示3条数据，当取的条数超过3条时，只显示前3条，不会再显示后面的，这个值默认是None，即不做限制
    default_limit =2  # 设置每一页显示多少条
    limit_query_param = 'limit'  # 往后取几条
    offset_query_param = 'offset'  # 当前所在的位置

class IndexView2(APIView):
    #使用http://127.0.0.1:8080/app01/v1/index2/?offset=2&limit=4可进行判断
    def get(self,request,*args,**kwargs):
        user_list = models.UserInfo.objects.all()
        p1 = P1()#注册分页
        page_user_list = p1.paginate_queryset(queryset=user_list,request=request,view=self)
        print('打印的是分页的数据',page_user_list)
        ser = MySerializes(instance=page_user_list,many=True)  #可允许多个
        # return Response(ser.data) #不含上一页下一页
        return p1.get_paginated_response(ser.data)

=======================也可以用下面这种形式===========
class BaseResponse(object):
    def __init__(self,code=1000,data=None,error=None):
        self.code = code
        self.data = data
        self.error = error
class IndexView(views.APIView):
    '''第二种类表示的方式'''
    def get(self,request,*args,**kwargs):
        ret = BaseResponse()
        try:
            user_list = models.UserInfo.objects.all()
            p1 = P1()
            page_user_list = p1.paginate_queryset(queryset=user_list,request=request,view=self)
            ser = IndexSerializer(instance=page_user_list,many=True)
            ret.data = ser.data
            ret.next = p1.get_next_link() #下一页链接
        except Exception as e:
            ret.code= 1001
            ret.error = 'xxxx错误'
        return Response(ret.__dict__)

views.py

2、基于页码的分页

from rest_framework.pagination import PageNumberPagination

# ======================基于页码实现的分页==============
class P2(PageNumberPagination):
    #默认每页显示的数据条数
    page_size = 2
    #获取url参数中设置的每页显示数据条数
    page_size_query_param = 'size'
    #获取url中传入的页码key
    page_query_param = 'page'
    #最大支持的每页显示的数据条数
    max_page_size = 5

class IndexView3(APIView):
    #使用http://127.0.0.1:8080/app01/v1/index3/?page=1&page_size=1可进行判断
    def get(self,request,*args,**kwargs):
        user_list = models.UserInfo.objects.all()
        #实例化分页对象，获取数据库中的分页数据
        p2 = P2()
        print(p2.page_size_query_description)
        page_user_list = p2.paginate_queryset(queryset=user_list,request=request,view=self)
        print('打印的是分页的数据',page_user_list)

        #序列化对象
        ser = MySerializes(instance=page_user_list,many=True)  #可允许多个

        #生成分页和数据
        # return Response(ser.data) #不含上一页下一页
        return p2.get_paginated_response(ser.data) # 是Response对象，有上一页下一页

views.py

3、基于Cursor的分页

2可能存在性能问题，如果用户吧page给改的很大，查询速度就会很慢。还有一种页码加密的方式，

 # =====================基于Cursor的分页============
 class P3(CursorPagination):
     # URL传入的游标参数
     cursor_query_param = 'cursor'
     # 默认每页显示的数据条数
     page_size = 2
     # URL传入的每页显示条数的参数
     page_size_query_param = 'size'
     # 每页显示数据最大条数
     max_page_size = 3

     # 根据ID从大到小排列
     ordering = "id"

 class IndexView4(APIView):
     #使用http://127.0.0.1:8080/app01/v1/index4/?cursor=cj0xJnA9NA%3D%3D&size=3可进行判断
     def get(self,request,*args,**kwargs):
         user_list = models.UserInfo.objects.all().order_by('-id')
         p3 = P3()#注册分页
         page_user_list = p3.paginate_queryset(queryset=user_list,request=request,view=self)
         print('打印的是分页的数据',page_user_list)
         ser = MySerializes(instance=page_user_list,many=True)  #可允许多个
         # return Response(ser.data) #不含上一页下一页
         return p3.get_paginated_response(ser.data)

views.py

二、视图

写视图函数可继承的几个类，我们以前经常用到的是APIView，现在我们来了解一下其他的类，其中1、3、4用到的最多

需要导入的类

from rest_framework.views import APIView
from rest_framework.generics import GenericAPIView
from rest_framework.viewsets import GenericViewSet
from rest_framework.viewsets import ModelViewSet

1、APIView

 class IndexView2(APIView):
     def get(self,request,*args,**kwargs):
         user_list = models.UserInfo.objects.all()
         ser = MySerializes(instance=user_list,many=True)
         return Response(ser.data)

APIView

2、GenericAPIView(APIView)

 from rest_framework.response import Response
 from rest_framework.generics import GenericAPIView
 from app01 import models
 from app01.serializes.myserializes import MySerializes
 from rest_framework.pagination import LimitOffsetPagination
 class P1(LimitOffsetPagination):
     max_limit = 3  # 最大限制默认是None
     default_limit =2  # 设置每一页显示多少条
     limit_query_param = 'limit'  # 往后取几条
     offset_query_param = 'offset'  # 当前所在的位置

 class IndexView1(GenericAPIView):
     queryset = models.UserInfo.objects.all()
     serializer_class = MySerializes
     pagination_class = P1
     def get(self,request,*args,**kwargs):
         user_list = self.get_queryset()
         p1 = P1()  #注册分页
         data = p1.paginate_queryset(queryset=user_list,request=request,view=self)  #获取分页的数据
         ser = self.get_serializer(instance=data,many=True) #序列化
         return Response(ser.data)

GenericAPIView

3、 GenericViewSet(ViewSetMixin, generics.GenericAPIView)

增
    POST
    /users/
删
    DELETE
    /users/1/
改   #全部修改
    PUT
    /users/1/
    #局部修改
    patch
    /users/1/
查
    GET
    /users/
    GET
    /users/1/
在GET请求的时候如果带ID说明查一条，如果不带则查所有

原始的

 urlpatterns = [

     url(r'^index/$', views.IndexView.as_view()),
     url(r'^index/(?P<pk>\d+)$', views.IndexView.as_view()),
 ]

urls.py

 class IndexView(views.APIView):

     def get(self,request,*args,**kwargs):
         pk = kwargs.get('pk')
         if pk:
             pass # 获取单条信息
         else:
             pass # 获取列表信息

     def post(self,request,*args,**kwargs):
         pass

     def put(self,request,*args,**kwargs):
         pass

     def patch(self,request,*args,**kwargs):
         pass

     def delete(self,request,*args,**kwargs):
                 pass

views.py

用了GenericViewSet这种方式的时候注意url变了

urlpatterns = [
    url(r'^index3/$', views.IndexView3.as_view({'get': 'list','post':'create'})), #get方式执行list函数,post方式执行create函数
    url(r'^index3/(?P<pk>\d+)/$', views.IndexView3.as_view({'get': 'retrieve'})),    #get方式执行retrieve函数

]

urls.py

 class IndexView3(GenericViewSet):
     queryset = models.UserInfo.objects.all()
     serializer_class = MySerializes
     pagination_class = P1

     def list(self,request,*args,**kwargs):
         #获取列表信息
         return Response('...')

     def retrieve(self,request,*args,**kwargs):
         #获取单条数据
         return Response('xxx')

GenericViewSet

4、 ModelViewSet(mixins.CreateModelMixin,mixins.RetrieveModelMixin,mixins.UpdateModelMixin,mixins.DestroyModelMixin,mixins.ListModelMixin,GenericViewSet)

利用ModelViewSet增删改查不用自己写了，内部把增删改查都干了，当满足不了需求的时候我们也可以自定制

 urlpatterns = [

     url(r'^index4/', views.IndexView4.as_view({'get': 'list','post':'create'})),  #获取数据和添加数据
     url(r'^index4\.(?P<format>[a-z0-9]+)/', views.IndexView4.as_view({'get': 'list','post':'create'})), #.json想让页面上显示成json格式
     url(r'^index4/(?P<pk>\d+)/', views.IndexView4.as_view({'get': 'retrieve', 'delete': 'destroy','put':'partial_update'})), #查看单条，删除，修改数据
     url(r'^index4(?P<pk>\d+)\.(?P<format>[a-z0-9]+)/', views.IndexView4.as_view({'get': 'retrieve', 'delete': 'destroy','put':'partial_update'})),

 ]

urls.py

  注意啦：用ModelSerializer这种方法必须要用IndexSerializer(ModelSerializer)这种方式序列化
 class P2(PageNumberPagination):
     page_size = 3  #每一页显示的条数
     page_query_param = 'page' #获取参数中传入的页码
     page_size_query_param = 'size' #获取url参数中每页显示的数据条数

     max_page_size = 5

 class IndexSerializer(ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class IndexView4(ModelViewSet):
     queryset = models.UserInfo.objects.all()
     serializer_class = IndexSerializer
     pagination_class = P2

views.py

自定制

 class P2(PageNumberPagination):
     page_size = 3  #每一页显示的条数
     page_query_param = 'page' #获取参数中传入的页码
     page_size_query_param = 'size' #获取url参数中每页显示的数据条数

     max_page_size = 5

 class IndexSerializer(ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class IndexView4(ModelViewSet):
     queryset = models.UserInfo.objects.all()
     serializer_class = IndexSerializer
     pagination_class = P2

     def list(self, request, *args, **kwargs):
         '''获取get请求的所有'''
         pass

     def retrieve(self, request, *args, **kwargs):
         '''查看单条数据'''
         pass
     def destroy(self, request, *args, **kwargs):
         '''删除DELETE'''
         pass
     def create(self, request, *args, **kwargs):
         '''添加数据POST'''
         pass
     def update(self, request, *args, **kwargs):
         '''全部修改PUT'''
         pass
     def partial_update(self, request, *args, **kwargs):
         '''局部修改PATCH'''
         pass

基于ModelViewSet自定制

继承关系

三、路由

第一类：自定义路由

# http://127.0.0.1:8000/api/v1/auth/
url(r'^auth/$', views.AuthView.as_view()),
# http://127.0.0.1:8000/api/v1/auth.json # 想要让页面显示json格式
url(r'^auth\.(?P<format>[a-z0-9]+)$', views.AuthView.as_view()),
# http://127.0.0.1:8000/api/v1/auth/1/
url(r'^auth/(?P<pk>\d+)/$', views.AuthView.as_view()),
# http://127.0.0.1:8000/api/v1/auth/1.json
url(r'^auth/(?P<pk>\d+)\.(?P<format>[a-z0-9]+)$', views.AuthView.as_view()),
class AuthView(views.APIView):

    def get(self,request,*args,**kwargs):
        return Response('...')

第二类：半自动路由

url(r'^index/$', views.IndexView.as_view({'get':'list','post':'create'})),
url(r'^index\.(?P<format>[a-z0-9]+)$', views.IndexView.as_view({'get':'list','post':'create'})),
url(r'^index/(?P<pk>\d+)/$', views.IndexView.as_view({'get':'retrieve','delete':'destroy','put':'update','patch':'partial_update'})),
url(r'^index(?P<pk>\d+)\.(?P<format>[a-z0-9]+)$', views.IndexView.as_view({'get':'retrieve','delete':'destroy','put':'update','patch':'partial_update'})),

class IndexView(viewsets.ModelViewSet):
    queryset = models.UserInfo.objects.all()
    serializer_class = IndexSerializer
    pagination_class = P2

第三类：全自动路由，会自动生成四个url

router = DefaultRouter()
router.register('index',views.IndexViewSet)
urlpatterns = [
    url(r'^', include(router.urls)),
]

class IndexViewSet(viewsets.ModelViewSet):
    queryset = models.UserInfo.objects.all()
    serializer_class = IndexSerializer
    pagination_class = P2

class IndexSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.UserInfo
        fields = "__all__"

四、渲染器

根据 用户请求URL 或 用户可接受的类型，筛选出合适的 渲染组件。
用户请求URL：

• http://127.0.0.1:8000/test/?format=json
• http://127.0.0.1:8000/test.json

用户请求头：

• Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8

1、. json

访问URL：

• http://127.0.0.1:8000/test/?format=json
• http://127.0.0.1:8000/test.json
• http://127.0.0.1:8000/test/

 from django.conf.urls import url, include
 from web.views import s11_render

 urlpatterns = [
     url(r'^test/$', s11_render.TestView.as_view()),
     url(r'^test\.(?P<format>[a-z0-9]+)', s11_render.TestView.as_view()),
 ]

urls.py

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers

 from rest_framework.renderers import JSONRenderer

 from .. import models

 class TestSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class TestView(APIView):
     renderer_classes = [JSONRenderer, ]

     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all()
         ser = TestSerializer(instance=user_list, many=True)
         return Response(ser.data)

views.py

2、.表格

访问URL：

• http://127.0.0.1:8000/test/?format=admin
• http://127.0.0.1:8000/test.admin
• http://127.0.0.1:8000/test/

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers

 from rest_framework.renderers import AdminRenderer

 from .. import models

 class TestSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class TestView(APIView):
     renderer_classes = [AdminRenderer, ]

     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all()
         ser = TestSerializer(instance=user_list, many=True)
         return Response(ser.data)

views.py

3、 Form表单

访问URL：

• http://127.0.0.1:8000/test/?format=form
• http://127.0.0.1:8000/test.form
• http://127.0.0.1:8000/test/

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers

 from rest_framework.renderers import JSONRenderer
 from rest_framework.renderers import AdminRenderer
 from rest_framework.renderers import HTMLFormRenderer

 from .. import models

 class TestSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class TestView(APIView):
     renderer_classes = [HTMLFormRenderer, ]

     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all().first()
         ser = TestSerializer(instance=user_list, many=False)
         return Response(ser.data)

views.py

4、 自定义显示模板

访问URL：

• http://127.0.0.1:8000/test/?format=html
• http://127.0.0.1:8000/test.html
• http://127.0.0.1:8000/test/

 from django.conf.urls import url, include
 from web.views import s11_render

 urlpatterns = [
     url(r'^test/$', s11_render.TestView.as_view()),
     url(r'^test\.(?P<format>[a-z0-9]+)', s11_render.TestView.as_view()),
 ]

urls.py

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers
 from rest_framework.renderers import TemplateHTMLRenderer

 from .. import models

 class TestSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class TestView(APIView):
     renderer_classes = [TemplateHTMLRenderer, ]

     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all().first()
         ser = TestSerializer(instance=user_list, many=False)
         return Response(ser.data, template_name='user_detail.html')

views.py

 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <title>Title</title>
 </head>
 <body>
     {{ user }}
     {{ pwd }}
     {{ ut }}
 </body>
 </html>

userdetail.html

5、浏览器格式API+JSON

访问URL：

• http://127.0.0.1:8000/test/?format=api
• http://127.0.0.1:8000/test.api
• http://127.0.0.1:8000/test/

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers

 from rest_framework.renderers import JSONRenderer
 from rest_framework.renderers import BrowsableAPIRenderer

 from .. import models

 class TestSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"

 class CustomBrowsableAPIRenderer(BrowsableAPIRenderer):
     def get_default_renderer(self, view):
         return JSONRenderer()

 class TestView(APIView):
     renderer_classes = [CustomBrowsableAPIRenderer, ]

     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all().first()
         ser = TestSerializer(instance=user_list, many=False)
         return Response(ser.data, template_name='user_detail.html')

views.py

注意：如果同时多个存在时，自动根据URL后缀来选择渲染器。