DRF（Django REST Framework）框架

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一.DRF中的Request

在Django REST Framework中内置的Request类扩展了Django中的Request类, 实现了很多方便的功能 -- 如请求数据解析和认证等.

比如, 区别于Django中的request: 从request.GET中获取URL参数, 从request.POST中去取某些情况下的POST数据(前端提交过来的数据).

在APIView中封装的request, 就实现了请求数据的解析:

• 对于GET请求的参数, APIView通过request.query_params来获取
• 对于POST请求、PUT请求的数据, APIView通过request.data来获取

二.前戏: 关于面向对象的继承

# 讲一个葫芦娃的故事class Wa1(object):
name = "红娃" def f1(self):
print("力大无穷！")class Wa2(object):
name = '橙娃' def f2(self):
print('千里眼顺风耳！')class Wa3(object):
name = '黄娃' def f3(self):
print('钢筋铁骨！')class Wa4(object):
name = '绿娃' def f4(self):
print("会喷火！")class Wa5(object):
name = '青蛙' def f5(self):
print("会喷水！")class Jishuwa(Wa1, Wa3, Wa5):
name = '奇数娃' def ff(self):
print("我是{}, 我会:".format(self.name))
self.f1()
self.f3()
self.f5()class Oushuwa(Wa2, Wa4):
name = '偶数娃' def ff(self):
print("我是{}, 我会:".format(self.name))
self.f2()
self.f4()jsw = Jishuwa()
jsw.ff()
osw = Oushuwa()
osw.ff()# 直接定义一个基数娃
class Taowa(Wa1, Wa3, Wa5):
name = '套娃' def ff(self):
print("我是{}, 我会:".format(self.name))
self.f1()
self.f3()
self.f5()class Wawa(Taowa):
passprint("=" * 120)
a = Wawa()
a.ff()


三.初级版本

1. settings.py文件 -- 注册app

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'bms.apps.BmsConfig',
'rest_framework', # 注册app
]


2. models.py文件 -- 创建表

from django.db import models# 出版社表
class Publisher(models.Model):
name = models.CharField(max_length=32) def __str__(self):
return self.name# 书籍表
class Book(models.Model):
title = models.CharField(max_length=32)
publisher = models.ForeignKey(to='Publisher', to_field='id', on_delete=models.CASCADE) def __str__(self):
return self.title
# cd到当前项目目录
# 执行数据库迁移指令
python manage.py makemigrations
python manage.py migrate


3. admin.py文件

from django.contrib import admin
from bms import models # bms是我们的appadmin.site.register(models.Publisher)
admin.site.register(models.Book)
# 创建超级用户
# cd到当前项目目录
python manage.py createsuperuser
# 启动Django项目
python manage.py runserver 127.0.0.1:8000
# 浏览器地址栏输入 127.0.0.1:8000
# 输入账号和密码,进入admin页面,对数据库中的表 添加或修改相关数据


4. 根目录下urls.py -- 路由匹配

from django.conf.urls import url
from django.contrib import admin
from bms import viewsurlpatterns = [
url(r'^admin/', admin.site.urls), url(r'^book/$', views.BookListView.as_view()),
url(r'^book/(?P<pk>\d+)$', views.BookDetailView.as_view()),
]


5. bms/views.py -- 视图函数

from rest_framework.response import Response
from rest_framework.views import APIView
from bms import models
from bms.modelserializers import BookModelSerializerclass BookListView(APIView):
def get(self, request):
# 1.从数据库查询出所有书籍对象
queryset = models.Book.objects.all()
# 2.使用modelserializer对获取的对象进行序列化
ser_obj = BookModelSerializer(queryset, many=True)
return Response(ser_obj.data) def post(self, request):
# 1.获取前端提交过来的数据 --> request.data
# 2.对数据进行有效性校验
ser_obj = BookModelSerializer(data=request.data)
if ser_obj.is_valid():
ser_obj.save()
return Response('添加成功!')
else:
return Response(ser_obj.errors)class BookDetailView(APIView):
def get(self, request, pk): # get获取具体某本书的信息
# 1.根据pk去数据库中查询具体的那本书籍对象
book_obj = models.Book.objects.filter(pk=pk).first()
if book_obj:
# 2.将书籍对象 序列化成 json格式的数据
ser_obj = BookModelSerializer(book_obj)
# 3.返回响应
return Response(ser_obj.data)
else:
return Response('无效的书籍id') def put(self, request, pk): # put修改具体某本书的信息
# 1.根据pk去查询具体的那本书籍对象
book_obj = models.Book.objects.filter(pk=pk).first()
if book_obj:
# 2.获取用户发送过来的数据并修改数据
ser_obj = BookModelSerializer(instance=book_obj, data=request.data, partial=True)
if ser_obj.is_valid():
# 3.保存并返回修改后的数据
ser_obj.save()
return Response(ser_obj.data)
else:
return Response(ser_obj.errors)
else:
return Response('无效的书籍id') def delete(self, request, pk): # delete删除具体某一本书籍对象
# 1.根据pk去查询具体的那本书籍对象
book_obj = models.Book.objects.filter(pk=pk).first()
if book_obj:
# 2.删除该书籍对象
book_obj.delete()
return Response('删除成功')
else:
return Response('无效的书籍id')


6. bms/modelserializers.py -- 自定义序列化工具

from rest_framework import serializers
from bms import modelsclass PublisherSerializer(serializers.Serializer):
id = serializers.IntegerField()
name = serializers.CharField()class BookModelSerializer(serializers.ModelSerializer):
publisher_info = serializers.SerializerMethodField(read_only=True) def get_publisher_info(self, book_obj):
return PublisherSerializer(book_obj.publisher).data class Meta:
model = models.Book
fields = '__all__'
extra_kwargs = {
'publisher': {'write_only': True},
}class PublisherModelSerializer(serializers.ModelSerializer):
class Meta:
model = models.Publisher
fields = '__all__'


四.进化版: 使用自定义混合类和自定义通用类

提取出views.py文件中函数BookListView和BookDetailView代码中的重复部分, 并将这些重复部分封装为通用类(Generic)和混合类(Mixin), 利用Python强大的多继承功能, 将代码进一步优化. 充分体现Python语言的"优雅"和"简洁".

注意: 混合类Mixin不能单独实例化, 需要与其他的类搭配使用.

bms/views.py:

from rest_framework.response import Response
from rest_framework.views import APIView
from bms import models
from bms.modelserializers import BookModelSerializer, PublisherModelSerializer# 通用功能
class GenericView(APIView):
queryset = None
serializer_class = None def get_queryset(self, request, *args, **kwargs):
# 再一次调用all()方法: 让每次请求来的时候都重新查一次数据
return self.queryset.all() def get_obj(self, request, pk, *args, **kwargs):
return self.get_queryset(request, *args, **kwargs).filter(pk=pk).first()# get展示(全部)资源
class ListMixin(object):
def get(self, request):
queryset = self.get_queryset(request)
ser_obj = self.serializer_class(queryset, many=True)
return Response(ser_obj.data)# post添加资源
class CreateMixin(object):
def post(self, request):
ser_obj = self.serializer_class(data=request.data)
if ser_obj.is_valid():
ser_obj.save()
return Response('添加成功!')
else:
return Response(ser_obj.errors)# get展示(部分)资源
class RetrieveMixin(object):
def get(self, request, pk, *args, **kwargs):
obj = self.get_obj(request, pk, *args, **kwargs)
if obj:
ser_obj = self.serializer_class(obj)
return Response(ser_obj.data)
else:
return Response('无效的id!')# put更新(修改)资源
class UpdateMixin(object):
def put(self, request, pk, *args, **kwargs):
obj = self.get_obj(request, pk, *args, **kwargs)
if obj:
ser_obj = self.serializer_class(instance=obj, data=request.data, partial=True)
if ser_obj.is_valid():
ser_obj.save()
return Response(ser_obj.data)
else:
return Response(ser_obj.errors)
else:
return Response('无效的id!')# delete删除资源
class DestroyMixin(object):
def delete(self, request, pk, *args, **kwargs):
obj = self.get_obj(request, pk, *args, **kwargs)
if obj:
obj.delete()
return Response('删除成功!')
else:
return Response('无效的id!')class BookListView(GenericView, ListMixin, CreateMixin):
queryset = models.Book.objects.all()
serializer_class = BookModelSerializerclass BookDetailView(GenericView, RetrieveMixin, UpdateMixin, DestroyMixin):
queryset = models.Book.objects.all()
serializer_class = BookModelSerializerclass PublisherListView(GenericView, ListMixin, CreateMixin):
queryset = models.Publisher.objects.all()
serializer_class = PublisherModelSerializerclass PublisherDetailView(GenericView, RetrieveMixin, UpdateMixin, DestroyMixin):
queryset = models.Publisher.objects.all()
serializer_class = PublisherModelSerializer


urls.py:

from django.conf.urls import url
from django.contrib import admin
from bms import viewsurlpatterns = [
url(r'^admin/', admin.site.urls), url(r'^book/$', views.BookListView.as_view()),
url(r'^book/(?P<pk>\d+)$', views.BookDetailView.as_view()),
url(r'^publisher/$', views.PublisherListView.as_view()),
url(r'^publisher/(?P<pk>\d+)$', views.PublisherDetailView.as_view()),
]


五.超级进化版: 使用GenericViewSet通用类

GenericViewSet是rest_framework这个app中已经封装好了的一个类:

from rest_framework.viewsets import GenericViewSet


需要注意的是, 继承了GenericViewSet以后, GenericViewSet这个类已经帮我们封装好了get_queryset()和get_object()这两个方法, 它们不需要接收参数, 我们直接调用即可.

bms/views.py:

from rest_framework.response import Response
from bms import models
from bms.modelserializers import BookModelSerializer, PublisherModelSerializer
from rest_framework.viewsets import GenericViewSet # 引入GenericViewSet通用类# get展示(全部)资源
class ListMixin(object):
def list(self, request, *args, **kwargs):
queryset = self.get_queryset()
ser_obj = self.serializer_class(queryset, many=True)
return Response(ser_obj.data)# post添加资源
class CreateMixin(object):
def create(self, request, *args, **kwargs):
ser_obj = self.serializer_class(data=request.data)
if ser_obj.is_valid():
ser_obj.save()
return Response('添加成功!')
else:
return Response(ser_obj.errors)# get展示(部分)资源
class RetrieveMixin(object):
def retrieve(self, request, pk, *args, **kwargs):
obj = self.get_object()
if obj:
ser_obj = self.serializer_class(obj)
return Response(ser_obj.data)
else:
return Response('无效的id!')# put更新(修改)资源
class UpdateMixin(object):
def update(self, request, pk, *args, **kwargs):
obj = self.get_object()
if obj:
ser_obj = self.serializer_class(instance=obj, data=request.data, partial=True)
if ser_obj.is_valid():
ser_obj.save()
return Response(ser_obj.data)
else:
return Response(ser_obj.errors)
else:
return Response('无效的id!')# delete删除资源
class DestroyMixin(object):
def destroy(self, request, pk, *args, **kwargs):
obj = self.get_object()
if obj:
obj.delete()
return Response('删除成功!')
else:
return Response('无效的id!')class BookViewSet(GenericViewSet, ListMixin, CreateMixin, RetrieveMixin, UpdateMixin, DestroyMixin):
queryset = models.Book.objects.all()
serializer_class = BookModelSerializerclass PublisherViewSet(GenericViewSet, ListMixin, CreateMixin, RetrieveMixin, UpdateMixin, DestroyMixin):
queryset = models.Publisher.objects.all()
serializer_class = PublisherModelSerializer


urls.py:

from django.conf.urls import url
from django.contrib import admin
from bms import viewsurlpatterns = [
url(r'^admin/', admin.site.urls), url(r'^book/$', views.BookViewSet.as_view(actions={'get': 'list', 'post': 'create'})),
url(r'^book/(?P<pk>\d+)$', views.BookViewSet.as_view(actions={'get': 'retrieve', 'put': 'update', 'delete': 'destroy'})),
url(r'^publisher/$', views.PublisherViewSet.as_view(actions={'get': 'list', 'post': 'create'})),
url(r'^publisher/(?P<pk>\d+)$', views.PublisherViewSet.as_view(actions={'get': 'retrieve', 'put': 'update', 'delete': 'destroy'})),
]


六.究极进化版: 使用rest_framework帮我们封装好的通用类和混合类

bms/views.py:

from bms import models
from bms.modelserializers import BookModelSerializer, PublisherModelSerializer
from rest_framework.viewsets import ModelViewSetclass BookViewSet(ModelViewSet):
queryset = models.Book.objects.all()
serializer_class = BookModelSerializerclass PublisherViewSet(ModelViewSet):
queryset = models.Publisher.objects.all()
serializer_class = PublisherModelSerializer


七.终极进化版: 使用rest_framework帮我们封装好的路由DefaultRouter

from rest_framework.routers import DefaultRouter
from bms import viewsurlpatterns = []router = DefaultRouter()
router.register('book', views.BookViewSet)
router.register('publisher', views.PublisherViewSet)# 重写urlpatterns
urlpatterns += router.urls