DRF--view

在学django的时候，我们写视图是这样的

from django.http import HttpResponse, JsonResponse
from django.views.decorators.csrf import csrf_exempt
from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


@csrf_exempt  # 这个函数可以跨域访问
def snippet_list(request):
    if request.method == 'GET':  # get请求
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)  # 序列化
        return JsonResponse(serializer.data, safe=False)

    if request.method == 'POST':  # post请求
        data = JSONParser().parse(request)
        serializer = SnippetSerializer(data=data)  # 序列化
        if serializer.is_valid():  # 验证序列化
            serializer.save()  # 保持数据
            return JsonResponse(serializer.data, status=201)
        return JsonResponse(serializer.errors, status=400)


@csrf_exempt
def snippet_detail(request, pk):  # 获取单个数据
    try:
        snippet = Snippet.objects.get(pk=pk)  # ORM的模型的对象，一个
    except Snippet.DoesNotExist:
        return HttpResponse(status=404)

    if request.method == 'GET':  # 获取单个数据
        serializer = SnippetSerializer(snippet)
        return JsonResponse(serializer.data)

    if request.method == 'PUT':  # 修改单个数据
        data = JSONParser().parse(request)
        serializer = SnippetSerializer(snippet, data=data)
        if serializer.is_valid():
            serializer.save()
            return JsonResponse(serializer.data)
        return JsonResponse(serializer.errors, status=400)

    if request.method == 'DELETE':  # 删除单个数据
        snippet.delete()
        return HttpResponse(status=204)

第二版

from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


@api_view(['GET', "POST"])  # get和post可以访问
def snippet_list(request, format=None):
    if request.method == 'GET':  # get对应的方法，获取全部数据
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return Response(serializer.data)

    if request.method == 'POST':  # post对应的方法
        serializer = SnippetSerializer(data=request.data)
        if serializer.is_valid():  # validated_data
            serializer.save()  # ORM,保存到数据库中
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


@api_view(['GET', 'PUT', 'DELETE'])  # 获取单个数据，put，delete对应的方法
def snippet_detail(request, pk, format=None):
    try:
        snippet = Snippet.objects.get(pk=pk)  # ORM的模型的对象，一个
    except Snippet.DoesNotExist:
        return Response(status=status.HTTP_404_NOT_FOUND)

    if request.method == 'GET':  # 获取单条数据
        serializer = SnippetSerializer(snippet)
        return Response(serializer.data)

    if request.method == 'PUT':  # 修改数据
        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)

    if request.method == 'DELETE':  # 删除数据
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

第三版，使用APIView

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):  # 继承APIView

    def get(self, request, format=None):  # get请求获取所有数据
        snippets = Snippet.objects.all()  # 查询数据
        serializer = SnippetSerializer(snippets, many=True)  # 序列化
        return Response(serializer.data)

    def post(self, request, format=None):  # post请求
        serializer = SnippetSerializer(data=request.data)  # 序列化
        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)


class SnippetDetail(APIView):

    def get_object(self, pk):
        try:
            snippet = Snippet.objects.get(pk=pk)  # ORM的模型的对象，一个
            return snippet
        except Snippet.DoesNotExist:
            raise Http404

    def get(self, request, pk, format=None):  # 获取单条数据
        snippet = self.get_object(pk)
        serializer = SnippetSerializer(snippet)
        return Response(serializer.data)

    def put(self, request, pk, format=None):  # 修改数据
        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):  # 删除数据
        snippet = self.get_object(pk)
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

第四版，混入mixin

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import mixins  # 导入mixins
from rest_framework import generics  # 导入generics


# ListModelMixin获取所有数据，CreateModelMixin创建数据
class SnippetList(mixins.ListModelMixin, mixins.CreateModelMixin, generics.GenericAPIView):
    queryset = Snippet.objects.all()  # filter()
    serializer_class = SnippetSerializer  # 序列化对象

    def get(self, request, *args, **kwargs):
        # 调用ListModelMixin下的list方法，获取所有数据
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        # 调用CreateModelMixin下的create方法，添加数据
        return self.create(request, *args, **kwargs)



# RetrieveModelMixin获取单条数据，UpdateModelMixin修改数据，DestroyModelMixin删除数据
class SnippetDetail(mixins.RetrieveModelMixin,
                    mixins.UpdateModelMixin,
                    mixins.DestroyModelMixin,
                    generics.GenericAPIView):
    queryset = Snippet.objects.all()  # filter()
    serializer_class = SnippetSerializer

    def get(self, request, *args, **kwargs):
        # 调用RetrieveModelMixin下的retrieve方法，获取单条数据
        return self.retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):
        # 调用UpdateModelMixin下的update方法，修改数据
        return self.update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):
        # 调用DestroyModelMixin下的destroy方法，删除数据
        return self.destroy(request, *args, **kwargs)

第五版，上面的在简化

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import generics
from rest_framework import permissions
from snippets.permissions import IsOwnerOrReadOnly



# generics.ListCreateAPIView继承了mixins.ListModelMixin, mixins.CreateModelMixin, GenericAPIView
# 获取所有数据（List），添加数据（Create）
class SnippetList(generics.ListCreateAPIView):
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer

    def perform_create(self, serializer):
        serializer.save(owner=self.request.user)


# generics.RetrieveUpdateDestroyAPIView继承了mixins.RetrieveModelMixin，mixins.UpdateModelMixin,mixins.DestroyModelMixin
# 获取单个数据（Retrieve），修改数据（Update），删除数据（Destroy）
class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
    # 当获取单个数据，修改数据，删除数据的时候，就去父类RetrieveUpdateDestroyAPIView找
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer