django Rest Framework 系列3 - Class-based Views

你的名字 2022-06-17 04:08 139阅读 0赞

官方地址：[http://www.django-rest-framework.org/tutorial/3-class-based-views/\#rewriting-our-api-using-class-based-views][http_www.django-rest-framework.org_tutorial_3-class-based-views_rewriting-our-api-using-class-based-views]  
我们也可以使用基于类的视图来编写API视图，而不是基于函数的视图。我们将会看到,这是一种可以允许我们重用通用功能的强大模式，可以帮助我们保持我们的代码DRY（Don’t repeat yourself）

**1. 使用基于类的View来重写API**  
我们从重写一个基于基类视图(class-based view)的根视图开始，所有涉及到的只需要一点点重构 views.py

from snippets.models import Snippet
    from snippets.serializers import SnippetSerializer
    from django.http import Http404
    from rest_framework.views import APIView
    from rest_framework.response import Response
    from rest_framework import status
    
    
    class SnippetList(APIView):
        """ List all snippets, or create a new snippet. """
        def get(self, request, format=None):
            snippets = Snippet.objects.all()
            serializer = SnippetSerializer(snippets, many=True)
            return Response(serializer.data)
    
        def post(self, request, format=None):
            serializer = SnippetSerializer(data=request.data)
            if serializer.is_valid():
                serializer.save()
                return Response(serializer.data, status=status.HTTP_201_CREATED)
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

到目前都不错, 看起来和之前的例子很相似,但对不同的HTTP方法有了更好的分离。 我们还需要 更新 views.py 实例视图。

class SnippetDetail(APIView):
        """ Retrieve, update or delete a snippet instance. """
        def get_object(self, pk):
            try:
                return Snippet.objects.get(pk=pk)
            except Snippet.DoesNotExist:
                raise Http404
    
        def get(self, request, pk, format=None):
            snippet = self.get_object(pk)
            serializer = SnippetSerializer(snippet)
            return Response(serializer.data)
    
        def put(self, request, pk, format=None):
            snippet = self.get_object(pk)
            serializer = SnippetSerializer(snippet, data=request.data)
            if serializer.is_valid():
                serializer.save()
                return Response(serializer.data)
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
    
        def delete(self, request, pk, format=None):
            snippet = self.get_object(pk)
            snippet.delete()
            return Response(status=status.HTTP_204_NO_CONTENT)

这样看起来很好了,但它仍然非常类似于基于函数的视图。  
我们也需要基于类的视图来重构我们的urls.py

from django.conf.urls import url
    from rest_framework.urlpatterns import format_suffix_patterns
    from snippets import views
    
    urlpatterns = [
        url(r'^snippets/$', views.SnippetList.as_view()),
        url(r'^snippets/(?P<pk>[0-9]+)/$', views.SnippetDetail.as_view()),
    ]
    
    urlpatterns = format_suffix_patterns(urlpatterns)

好了，我们完成了。如果运行开发服务器，一切都应该像以前一样工作

**2 . 使用混合 （Mixins）类**  
使用基于类的视图的最大优点之一是它可以很方便的重用代码。  
我们使用很多相似支持 API view 的create/retrieve/update/delete操作。这些常用的操作都封装到了 REST框架中mixin类中。  
让我们来看看怎样通过mixin类来构建这些视图,以下是 views.py的模块：

from snippets.models import Snippet
    from snippets.serializers import SnippetSerializer
    from rest_framework import mixins
    from rest_framework import generics
    
    class SnippetList(mixins.ListModelMixin, mixins.CreateModelMixin, generics.GenericAPIView):
        queryset = Snippet.objects.all()
        serializer_class = SnippetSerializer
    
        def get(self, request, *args, **kwargs):
            return self.list(request, *args, **kwargs)
    
        def post(self, request, *args, **kwargs):
            return self.create(request, *args, **kwargs)

我们将花一点时间来检查到底发生了什么。 我们通过`GenericAPIView`来创建我们的视图,并加入 `ListModelMixin` 和 `CreateModelMixin`。基类提供了核心的功能, mixin 类提供了 `.list()` 和 `.create()` 行为, 然后我们显示的绑定了 `get` 和 `post` 方法对应的功能， 足够简单的东西：

class SnippetDetail(mixins.RetrieveModelMixin, mixins.UpdateModelMixin, mixins.DestroyModelMixin, generics.GenericAPIView):
        queryset = Snippet.objects.all()
        serializer_class = SnippetSerializer
    
        def get(self, request, *args, **kwargs):
            return self.retrieve(request, *args, **kwargs)
    
        def put(self, request, *args, **kwargs):
            return self.update(request, *args, **kwargs)
    
        def delete(self, request, *args, **kwargs):
            return self.destroy(request, *args, **kwargs)

类似的, 我们再次使用 `GenericAPIView` 类来提供核心功能, 并加入mixins 来提供 `.retrieve()`,`.update()`, `.destory()` 动作

**3. 使用通用类视图(generic class-based views)**  
与之前的代码相比，通过混合（mixin）类我们用了较少的代码重新了视图,但我们可以更进一步。REST框架提供了一套混合通用视图更好的削减我们的views.py 模块。

from snippets.models import Snippet
    from snippets.serializers import SnippetSerializer
    from rest_framework import generics
    
    
    class SnippetList(generics.ListCreateAPIView):
        queryset = Snippet.objects.all()
        serializer_class = SnippetSerializer
    
    
    class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
        queryset = Snippet.objects.all()
        serializer_class = SnippetSerializer

哇，这很简洁。

[http_www.django-rest-framework.org_tutorial_3-class-based-views_rewriting-our-api-using-class-based-views]: http://www.django-rest-framework.org/tutorial/3-class-based-views/#rewriting-our-api-using-class-based-views