前言

在了解了REST farmwork封裝的視圖類之后，我對python的面向對象有了更深刻的理解。

Django RESR framework框架內置的視圖類充分發揮了面向對象封裝與繼承的特性。

自己寫一個類似于DRF內置視圖類的功能

實現一個圖書出版社的增、刪、改、查、查功能，兩個查一個是查所有出版社，一個是查具體的某一個出版社。

首先是一個簡略的表結構設計models.py：

from django.db import modelsclass Publisher(models.Model):  name = models.CharField(max_length=16)  def __str__(self):    return self.nameclass Author(models.Model):  name = models.CharField(max_length=16)  def __str__(self):    return self.nameclass Book(models.Model):  title = models.CharField(max_length=32)  CHOICES = ((1, 'Python'), (2, 'Go'), (3, 'Linux'))  category = models.IntegerField(choices=CHOICES)  pub_date = models.DateField()  publisher = models.ForeignKey(to='Publisher', on_delete=models.CASCADE)  authors = models.ManyToManyField(to='Author')  def __str__(self):    return self.title

然后是路由url：

將用到pk,與不用到pk的路由業務區分開

from django.contrib import adminfrom django.urls import path, re_pathfrom bms import viewsurlpatterns = [  path('admin/', admin.site.urls),  # 查所有對象，與添加對象  re_path(r'publishers/$', views.PublisherView.as_view()),  # 帶pk查詢具體某一條數據  re_path(r'publishers/(?P<pk>/d+)/$', views.PublisherDetailView.as_view()), # 出版社詳情]

再到序列化類，自創建的serializers.py

這里我省略了新增需要重寫的create方法和更新需要重寫的update方法。

from bms import modelsfrom rest_framework import serializersclass PublisherModelSerializer(serializers.ModelSerializer):  class Meta:    model = models.Publisher    fields = "__all__"class AuthorModelSerializer(serializers.ModelSerializer):  class Meta:    model = models.Author    fields = "__all__"

最后視圖views.py

from bms import modelsfrom rest_framework.views import APIViewfrom rest_framework.response import Responsefrom bms.serializers import PublisherModelSerializer##################### 面向對象，手動實現REST framework視圖功能##################class GenericView(APIView):  '''公用類'''  queryset = None  serializer_class = None  def get_queryset(self):    # 讓每一次請求來的時候都現查一次數據    print('GeneriView------',self)    return self.queryset.all()  def get_object(self, request, pk):    # 獲取具體queryset    return self.get_queryset().filter(pk=pk)class ListMixin(object):  # mixi.n 混合類，不能單獨使用，利用python支持多繼承  def get(self, request):    print('ListMixin------------', self)    queryset = self.get_queryset()    ser_obj = self.serializer_class(queryset, many=True)    return Response(ser_obj.data)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("ok")    else:      return Response(ser_obj.errors)class RetrieveMixin(object):  """ 獲取具體某一條記錄"""  def retrieve(self, request, pk):    '''將此get方法與ListMixin中的get方法區分'''    obj = self.get_object(request, pk).first()    if obj:      ser_obj = self.serializer_class(obj)      return Response(ser_obj.data)    else:      return Response("無效的id")class UpdateMixin(object):  def put(self, request, pk):    obj = self.get_object(request, pk).first()    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("無效的id")class DestroyMixin(object):  def delete(self, request, pk):    obj = self.get_object(request, pk)    if obj:      obj.delete()      return Response("刪除成功")    else:      return Response("無效的id")class RetrieveView(GenericView, RetrieveMixin):  '''因兩個get方法相沖圖，在此曲線訪問查詢具體對象的get方法'''  def get(self, request, pk):    return self.retrieve(request, pk)# 出版社class PublisherView(GenericView, ListMixin, CreateMixin):  '''查所有出版社，增加出版社'''  # 只用寫配置項  queryset = models.Publisher.objects.all()  serializer_class = PublisherModelSerializerclass PublisherDetailView(RetrieveView, UpdateMixin, DestroyMixin):  '''查詢具體某一出版社，編輯，刪除'''  queryset = models.Publisher.objects.all()  serializer_class = PublisherModelSerializer