DAY101 - Rest Framework(六）- 视图组件、路由控制和响应器初识

一、视图组件
1.基本视图

class Books(APIView):
def get(self, request, *args, **kwargs):
books = models.Book.objects.all()
response = {'status': 200, 'msg': '查询成功', 'data': None}
ret = BooksSerializer(books, many=True)
response['data'] = ret.data
return JsonResponse(response, safe=False)
​
def post(self, request, *args, **kwargs):
response = {'status': 200, 'msg': '创建成功', 'data': None, 'error': None}
ret = BooksSerializer(data=request.data)
if ret.is_valid():
ret.save()
response['data'] = ret.data
else:
response['error'] = ret.errors
return JsonResponse(ret.data, safe=False)
​
​
class BooksDetail(APIView):
def get(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '查询成功', 'data': None}
if books:
ret = BooksSerializer(books, many=False)
response['data'] = ret.data
else:
response['msg'] = '查无此信息'
return JsonResponse(response, safe=False)
​
def put(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '更新成功', 'data': None, 'error': None}
ret = BooksSerializer(data=request.data, instance=books)
if ret.is_valid():
ret.save()
response['data'] = ret.data
else:
response['error'] = ret.errors
return JsonResponse(ret.data, safe=False)
​
def delete(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '删除成功', 'data': None}
ret = BooksSerializer(books, many=False)
response['data'] = ret.data
books.delete()
return JsonResponse(response, safe=False)
2.利用mixin类简化视图
基本视图中的有些代码可以进一步简化，比如说表名和序列化对象可以用一个

from rest_framework.mixins import ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin,DestroyModelMixin
from rest_framework.generics import GenericAPIView
​
​
class Books(GenericAPIView, ListModelMixin, CreateModelMixin):
# queryset和serializer_class是GenericAPIView定义必须要写的
queryset = models.Book.objects.all()
serializer_class = BooksSerializer
​
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
​
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
​
​
class BooksDetail(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
queryset = models.Book.objects.all()
serializer_class = BooksSerializer
# 必须传pk，因为这是RetrieveModelMixin等调用的GenericAPIView方法规定的
def get(self, request, pk):
return self.retrieve(request, pk)
​
def put(self, request, pk):
return self.update(request, pk)
​
def delete(self, request, pk):
return self.destroy(request, pk)
2.1 mixin类源码分析

类，并且引用就行了

ListModelMixin

以ListModelMixin举例，它实际上是，把我们写的基本视图中的代码进行了封装，而对于用户只要继承该类，并且引用就行了

class ListModelMixin(object):
"""
List a queryset.
"""
def list(self, request, *args, **kwargs):
queryset = self.filter_queryset(self.get_queryset())
​
page = self.paginate_queryset(queryset)
if page is not None:
serializer = self.get_serializer(page, many=True)
return self.get_paginated_response(serializer.data)
​
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
2.2 GenericAPIView源码分析

GenericAPIView

GenericAPIView

mixin类中的一些方法是调用GenericAPIView中的方法，所以视图类如果继承mixin类，就必须也继承GenericAPIView

由于GenericAPIView已经继承了APIView，所以视图不必再继承APIView了

class GenericAPIView(views.APIView):
queryset = None
serializer_class = None
​
lookup_field = 'pk'
lookup_url_kwarg = None
​
filter_backends = api_settings.DEFAULT_FILTER_BACKENDS
​
pagination_class = api_settings.DEFAULT_PAGINATION_CLASS
​
# get_queryset：获得视图类里的queryset表格的所有数据
def get_queryset(self):
queryset = self.queryset
# 判断queryset是否是QuerySet实例化后的对象
if isinstance(queryset, QuerySet):
# 如果是QuerySet对象，就再次all()
queryset = queryset.all()
return queryset

# get_object：获得单条数据
def get_object(self):
    # 对所及数据进行过滤
    queryset = self.filter_queryset(self.get_queryset())
    
    ........
    
    filter_kwargs = {self.lookup_field: self.kwargs[lookup_url_kwarg]}
    obj = get_object_or_404(queryset, **filter_kwargs)

​
self.check_object_permissions(self.request, obj)
​
return obj

# get_serializer:返回序列化对象
def get_serializer(self, *args, **kwargs):
    serializer_class = self.get_serializer_class()
    kwargs['context'] = self.get_serializer_context()
    return serializer_class(*args, **kwargs)

​
# get_serializer_class:获得视图里的序列化对象
def get_serializer_class(self):

    ........

​
return self.serializer_class
​
def get_serializer_context(self):
........
​
def filter_queryset(self, queryset):
........
​
@property
def paginator(self):
........
​
def paginate_queryset(self, queryset):
........
​
def get_paginated_response(self, data):
........
3.利用generice类简化代码
虽然已经简化了代码，但是get和post等方法的代码还是重复了，都是一条代码，还可以再一步简略

from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView
​
​
class Books(ListCreateAPIView):
queryset = models.Book.objects.all()
serializer_class = BooksSerializer
​
​
class BooksDetail(RetrieveUpdateDestroyAPIView):
queryset = models.Book.objects.all()
serializer_class = BooksSerializer
3.1 ListCreateAPIView源码分析

也是一样的

ListCreateAPIView：其实是对mixins类的进一步封装，这样视图里就不需用写get和post了，只要继承ListCreateAPIView就可以，RetrieveUpdateDestroyAPIView也是一样的

class ListCreateAPIView(mixins.ListModelMixin,
mixins.CreateModelMixin,
GenericAPIView):
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
​
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
4.使用ModelViewSet
进一步简化代码后，我们发现，两个视图的代码变得一样了，那么可不可以更进一步封装，drf提供了一个方法可以把两个视图合并。

url(r'^books/',views.Books.as_view({'get':'list','post':'create'})),
url(r'^booksdetail/(?P

from rest_framework.viewsets import ModelViewSet
​
class Books(ModelViewSet):
queryset = models.Book.objects.all()
serialzizer_class = BooksSerializer
4.1ModelViewSet源码分析

第一步

ModelViewSet

其实是对所有的mixins类继承

GenericViewSet才是关键

class ModelViewSet(mixins.CreateModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
mixins.ListModelMixin,
GenericViewSet):
pass
​

第二步

GenericViewSet

是对ViewSetMixin和GenericAPIView的继承

由于继承了GenericAPIView，而GenericAPIView已经继承了APIView，所以视图不必再继承APIView

class GenericViewSet(ViewSetMixin, generics.GenericAPIView):
pass

第三步

ViewSetMixin

ViewSetMixin是对as_view的重写

class ViewSetMixin(object):
@classonlymethod
def as_view(cls, actions=None, **initkwargs):
# actions={'get':'retrieve','put':'update','delete':'destroy'}
# 是路由层传来的参数
cls.name = None
cls.description = None
cls.suffix = None
cls.detail = None
cls.basename = None

    .......
    
    def view(request, *args, **kwargs):
        self = cls(**initkwargs)

​
self.action_map = actions
# 对action循环
# 请求方式：method='get' 对应方法：action='list'
for method, action in actions.items():
# 把action的，也就是list的内存地址赋给了handler
handler = getattr(self, action)
# 把handler的，也就是list的内存地址赋给了method
# 也就是说，执行get方法就是执行list方法
setattr(self, method, handler)
​
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
​
self.request = request
self.args = args
self.kwargs = kwargs
​
return self.dispatch(request, *args, **kwargs)
​
update_wrapper(view, cls, updated=())
​
update_wrapper(view, cls.dispatch, assigned=())
​
view.cls = cls
view.initkwargs = initkwargs
view.actions = actions
return csrf_exempt(view)
二、路由控制
1.自定义路由

url(r'^books/', views.Books.as_view()),
url(r'^booksdetail/(?P

class Books(APIView):
def get(self, request, *args, **kwargs):
books = models.Book.objects.all()
response = {'status': 200, 'msg': '查询成功', 'data': None}
ret = BooksSerializer(books, many=True)
response['data'] = ret.data
return JsonResponse(response, safe=False)
​
def post(self, request, *args, **kwargs):
response = {'status': 200, 'msg': '创建成功', 'data': None, 'error': None}
ret = BooksSerializer(data=request.data)
if ret.is_valid():
ret.save()
response['data'] = ret.data
else:
response['error'] = ret.errors
return JsonResponse(ret.data, safe=False)
​
​
class BooksDetail(APIView):
def get(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '查询成功', 'data': None}
if books:
ret = BooksSerializer(books, many=False)
response['data'] = ret.data
else:
response['msg'] = '查无此信息'
return JsonResponse(response, safe=False)
​
def put(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '更新成功', 'data': None, 'error': None}
ret = BooksSerializer(data=request.data, instance=books)
if ret.is_valid():
ret.save()
response['data'] = ret.data
else:
response['error'] = ret.errors
return JsonResponse(ret.data, safe=False)
​
def delete(self, request, id, *args, **kwargs):
books = models.Book.objects.filter(pk=id).first()
response = {'status': 200, 'msg': '删除成功', 'data': None}
ret = BooksSerializer(books, many=False)
response['data'] = ret.data
books.delete()
return JsonResponse(response, safe=False)
2.半自动路由(需继承ModelViewSet)

url(r'^books/',views.Books.as_view({'get':'list','post':'create'})),
url(r'^booksdetail/(?P

ModelViewSet
from rest_framework.viewsets import ModelViewSet
​
class Books(ModelViewSet):
queryset = models.Book.objects.all()
serialzizer_class = BooksSerializer
3.全自动路由

from django.conf.urls import url,include
from django.contrib import admin
from app01 import views
from rest_framework import routers

生成一个router对象

router = routers.DefaultRouter()

需要传两个参数,第一个参数就是匹配的路径,第二个参数,是视图类

router.register('books',views.Books)
urlpatterns = [
url(r'^admin/', admin.site.urls),
# 不用匹配正则，空字符串就行
url('',include(router.urls))]
​

url('',include(router.urls))会自动创建以下6个URL

'^books/$ [name='book-list']'

'^books.(?P

'^books/(?P

'^books/(?P

'^$ [name='api-root']'

'^.(?P

继承的
from rest_framework.viewsets import ModelViewSet
​

视图一定要是继承ModelViewSet的

class Books(ModelViewSet):
queryset = models.Book.objects.all()
serializer_class = BooksSerializer
​
三、响应器
1.基本使用

from rest_framework.renderers import HTMLFormRenderer,BrowsableAPIRenderer,AdminRenderer,JSONRenderer
​
class Books(APIView):
# 局部指定使用
renderer_classes = [AdminRenderer,]

setting.py

全局使用

REST_FRAMEWORK = {
'DEFAULT_RENDERER_CLASSES':['rest_framework.renderers.JSONRenderer']
}

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

显示json格式：JSONRenderer
​
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/

默认显示格式：BrowsableAPIRenderer（可以修改它的html文件）
​
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/

​
表格方式：AdminRenderer
​
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/

​
form表单方式：HTMLFormRenderer
​
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/