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Code  ›  Django Rest Framework(分页、视图、路由、渲染器)开发者社区
数据库视图 分页 django rest
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Django Rest Framework(分页、视图、路由、渲染器)

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社区首页 > 专栏 > Python > Django Rest Framework(分页、视图、路由、渲染器)

Django Rest Framework(分页、视图、路由、渲染器)

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用户1214487
发布 于 2022-03-26 14:21:31
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发布 于 2022-03-26 14:21:31
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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
1 urlpatterns = [
2     url(r'^admin/', admin.site.urls),
3     url(r'^app01/(?P<version>[v1|v2]+)/', include('app01.urls'))
5 ]
1 urlpatterns = [
2     url(r'^index1/', views.IndexView1.as_view()),
3     url(r'^index2/', views.IndexView2.as_view()),
4     url(r'^index3/', views.IndexView3.as_view()),
5     url(r'^index4/', views.IndexView4.as_view()),
6     url(r'^index5/', views.IndexView5.as_view()),
8 ]
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()
            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__)

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

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,

 1 # =====================基于Cursor的分页============
 2 class P3(CursorPagination):
 3     # URL传入的游标参数
 4     cursor_query_param = 'cursor'
 5     # 默认每页显示的数据条数
 6     page_size = 2
 7     # URL传入的每页显示条数的参数
 8     page_size_query_param = 'size'
 9     # 每页显示数据最大条数
10     max_page_size = 3
12     # 根据ID从大到小排列
13     ordering = "id"
15 class IndexView4(APIView):
16     #使用http://127.0.0.1:8080/app01/v1/index4/?cursor=cj0xJnA9NA%3D%3D&size=3可进行判断
17     def get(self,request,*args,**kwargs):
18         user_list = models.UserInfo.objects.all().order_by('-id')
19         p3 = P3()#注册分页
20         page_user_list = p3.paginate_queryset(queryset=user_list,request=request,view=self)
21         print('打印的是分页的数据',page_user_list)
22         ser = MySerializes(instance=page_user_list,many=True)  #可允许多个
23         # return Response(ser.data) #不含上一页下一页
24         return p3.get_paginated_response(ser.data)

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

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

2、GenericAPIView(APIView)

 1 from rest_framework.response import Response
 2 from rest_framework.generics import GenericAPIView
 3 from app01 import models
 4 from app01.serializes.myserializes import MySerializes
 5 from rest_framework.pagination import LimitOffsetPagination
 6 class P1(LimitOffsetPagination):
 7     max_limit = 3  # 最大限制默认是None
 8     default_limit =2  # 设置每一页显示多少条
 9     limit_query_param = 'limit'  # 往后取几条
10     offset_query_param = 'offset'  # 当前所在的位置
12 class IndexView1(GenericAPIView):
13     queryset = models.UserInfo.objects.all()
14     serializer_class = MySerializes
15     pagination_class = P1
16     def get(self,request,*args,**kwargs):
17         user_list = self.get_queryset()
18         p1 = P1()  #注册分页
19         data = p1.paginate_queryset(queryset=user_list,request=request,view=self)  #获取分页的数据
20         ser = self.get_serializer(instance=data,many=True) #序列化
21         return Response(ser.data)

3、 GenericViewSet(ViewSetMixin, generics.GenericAPIView)

增
    /users/
    DELETE
    /users/1/
改   #全部修改
    /users/1/
    #局部修改
    patch
    /users/1/
    /users/ 
    /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

1 urlpatterns = [
3     url(r'^index/$', views.IndexView.as_view()),
4     url(r'^index/(?P<pk>\d+)$', views.IndexView.as_view()),
5 ]
 1 class IndexView(views.APIView):
 3     def get(self,request,*args,**kwargs):
 4         pk = kwargs.get('pk')
 5         if pk:
 6             pass # 获取单条信息
 7         else:
 8             pass # 获取列表信息
10     def post(self,request,*args,**kwargs):
11         pass
13     def put(self,request,*args,**kwargs):
14         pass
16     def patch(self,request,*args,**kwargs):
17         pass
19     def delete(self,request,*args,**kwargs):
20                 pass

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
]
 1 class IndexView3(GenericViewSet):
 2     queryset = models.UserInfo.objects.all()
 3     serializer_class = MySerializes
 4     pagination_class = P1
 6     def list(self,request,*args,**kwargs):
 7         #获取列表信息
 8         return Response('...')
10     def retrieve(self,request,*args,**kwargs):
11         #获取单条数据
12         return Response('xxx')

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

1 urlpatterns = [
3     url(r'^index4/', views.IndexView4.as_view({'get': 'list','post':'create'})),  #获取数据和添加数据
4     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
5     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
6     url(r'^index4(?P<pk>\d+)\.(?P<format>[a-z0-9]+)/', views.IndexView4.as_view({'get': 'retrieve', 'delete': 'destroy','put':'partial_update'})),
8 ]
 1  注意啦:用ModelSerializer这种方法必须要用IndexSerializer(ModelSerializer)这种方式序列化
 2 class P2(PageNumberPagination):
 3     page_size = 3  #每一页显示的条数
 4     page_query_param = 'page' #获取参数中传入的页码
 5     page_size_query_param = 'size' #获取url参数中每页显示的数据条数
 7     max_page_size = 5
 9 class IndexSerializer(ModelSerializer):
10     class Meta:
11         model = models.UserInfo
12         fields = "__all__"
14 class IndexView4(ModelViewSet):
15     queryset = models.UserInfo.objects.all()
16     serializer_class = IndexSerializer
17     pagination_class = P2

自定制

 1 class P2(PageNumberPagination):
 2     page_size = 3  #每一页显示的条数
 3     page_query_param = 'page' #获取参数中传入的页码
 4     page_size_query_param = 'size' #获取url参数中每页显示的数据条数
 6     max_page_size = 5
 8 class IndexSerializer(ModelSerializer):
 9     class Meta:
10         model = models.UserInfo
11         fields = "__all__"
13 class IndexView4(ModelViewSet):
14     queryset = models.UserInfo.objects.all()
15     serializer_class = IndexSerializer
16     pagination_class = P2
18     def list(self, request, *args, **kwargs):
19         '''获取get请求的所有'''
20         pass
22     def retrieve(self, request, *args, **kwargs):
23         '''查看单条数据'''
24         pass
25     def destroy(self, request, *args, **kwargs):
26         '''删除DELETE'''
27         pass
28     def create(self, request, *args, **kwargs):
29         '''添加数据POST'''
30         pass
31     def update(self, request, *args, **kwargs):
32         '''全部修改PUT'''
33         pass
34     def partial_update(self, request, *args, **kwargs):
35         '''局部修改PATCH'''
36         pass

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/
1 from django.conf.urls import url, include
2 from web.views import s11_render
4 urlpatterns = [
5     url(r'^test/$', s11_render.TestView.as_view()),
6     url(r'^test\.(?P<format>[a-z0-9]+)', s11_render.TestView.as_view()),
7 ]
 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 from rest_framework.views import APIView
 4 from rest_framework.response import Response
 5 from rest_framework import serializers
 7 from rest_framework.renderers import JSONRenderer
 9 from .. import models
12 class TestSerializer(serializers.ModelSerializer):
13     class Meta:
14         model = models.UserInfo
15         fields = "__all__"
18 class TestView(APIView):
19     renderer_classes = [JSONRenderer, ]
21     def get(self, request, *args, **kwargs):
22         user_list = models.UserInfo.objects.all()
23         ser = TestSerializer(instance=user_list, many=True)
24         return Response(ser.data)

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/
 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 from rest_framework.views import APIView
 4 from rest_framework.response import Response
 5 from rest_framework import serializers
 7 from rest_framework.renderers import AdminRenderer
 9 from .. import models
12 class TestSerializer(serializers.ModelSerializer):
13     class Meta:
14         model = models.UserInfo
15         fields = "__all__"
18 class TestView(APIView):
19     renderer_classes = [AdminRenderer, ]
21     def get(self, request, *args, **kwargs):
22         user_list = models.UserInfo.objects.all()
23         ser = TestSerializer(instance=user_list, many=True)
24         return Response(ser.data)

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/
 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 from rest_framework.views import APIView
 4 from rest_framework.response import Response
 5 from rest_framework import serializers
 7 from rest_framework.renderers import JSONRenderer
 8 from rest_framework.renderers import AdminRenderer
 9 from rest_framework.renderers import HTMLFormRenderer
11 from .. import models
14 class TestSerializer(serializers.ModelSerializer):
15     class Meta:
16         model = models.UserInfo
17         fields = "__all__"
20 class TestView(APIView):
21     renderer_classes = [HTMLFormRenderer, ]
23     def get(self, request, *args, **kwargs):
24         user_list = models.UserInfo.objects.all().first()
25         ser = TestSerializer(instance=user_list, many=False)
26         return Response(ser.data)

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/
1 from django.conf.urls import url, include
2 from web.views import s11_render
4 urlpatterns = [
5     url(r'^test/$', s11_render.TestView.as_view()),
6     url(r'^test\.(?P<format>[a-z0-9]+)', s11_render.TestView.as_view()),
7 ]
 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 from rest_framework.views import APIView
 4 from rest_framework.response import Response
 5 from rest_framework import serializers
 6 from rest_framework.renderers import TemplateHTMLRenderer
 8 from .. import models
11 class TestSerializer(serializers.ModelSerializer):
12     class Meta:
13         model = models.UserInfo
14         fields = "__all__"
17 class TestView(APIView):
18     renderer_classes = [TemplateHTMLRenderer, ]
20     def get(self, request, *args, **kwargs):
21         user_list = models.UserInfo.objects.all().first()
22         ser = TestSerializer(instance=user_list, many=False)
23         return Response(ser.data, template_name='user_detail.html')
 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     {{ user }}
 9     {{ pwd }}
10     {{ ut }}
11 </body>
12 </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/
 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 from rest_framework.views import APIView
 4 from rest_framework.response import Response
 5 from rest_framework import serializers
 7 from rest_framework.renderers import JSONRenderer
 8 from rest_framework.renderers import BrowsableAPIRenderer
10 from .. import models
13 class TestSerializer(serializers.ModelSerializer):
14     class Meta:
15         model = models.UserInfo
16         fields = "__all__"
19 class CustomBrowsableAPIRenderer(BrowsableAPIRenderer):
20     def get_default_renderer(self, view):
21         return JSONRenderer()
24 class TestView(APIView):
 
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