01.Django rest framework的视图(APTV

一、Django的View和Django rest framework的APIView

1.View

Django中的View是所有基于类的view的父类，它负责将视图连接到URL、HTTP 方法调度(GET,POST等)和其它简单的功能。

2.APIView

APIView是drf中所有view的父类，本身继承于Django的VIew，只有简单的调度方法和健壮检查。
和View的不同请求和返回使用的drf的Request Response而不是django的HttpRequest HttpResponse。请求传入时进行身份验证，并在传给处理方法前进行权限检验。
任何APIException都会被捕捉并放入合适的想要中。

3.使用

3.1Django 项目搭建

项目搭建.png

3.2数据模型model.py

首先在models.py添加如下代码：

from django.db import models


# Create your models here.
class Author(models.Model):
    name = models.CharField(max_length=50, verbose_name='姓名')
    age = models.IntegerField(verbose_name='年龄')
    sex = models.BooleanField(max_length=1, choices=((0, '女'), (1, '男')), verbose_name='性别', default=1)
    birthday = models.DateField(auto_created=True, verbose_name='出生日期')
    address = models.CharField(verbose_name='地址', max_length=200)
    email = models.EmailField(verbose_name='邮箱')

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = '作者'
        verbose_name_plural = verbose_name


class Publisher(models.Model):
    name = models.CharField(max_length=50, verbose_name='名字')
    address = models.CharField(max_length=120, verbose_name='地址')
    website = models.URLField(verbose_name='网址')

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = '出版社'
        verbose_name_plural = verbose_name


class Book(models.Model):
    title = models.CharField(max_length=120, verbose_name='书名')
    author = models.ManyToManyField(Author, verbose_name='作者')
    publisher = models.ForeignKey(Publisher, verbose_name='出版社', related_name='book_publisher', on_delete=models.DO_NOTHING)
    publication_date = models.DateField(verbose_name='出版日期')

    def __str__(self):
        return self.title

    class Meta:
        verbose_name = '书籍'
        verbose_name_plural = verbose_name

3.3序列化

在bookApp下新建serializers.py,对模型进行序列化操作

from rest_framework import serializers
from bookApp.models import Book, Author, Publisher


class AuthorSerializer(serializers.ModelSerializer):
    class Meta:
        model = Author
        fields = ('name', 'address', 'email')


class PublisherSerializer(serializers.ModelSerializer):
    class Meta:
        model = Publisher
        fields = ('name', 'address', 'website')


class BookSerializer(serializers.ModelSerializer):
    author = AuthorSerializer(many=True)
    publisher = PublisherSerializer()

    class Meta:
        model = Book
        fields = (
            "title", "author", "publisher", "publication_date"
        )

某字段结果可能有多条时，记得加many=True！否则无法正确显示。

3.4编写视图views.py,实现出版社的增删改查

因为一本书可以有多个作者，所以要加many=True

from django.shortcuts import render
from rest_framework.views import APIView
from .models import Book, Author, Publisher
from .serializers import BookSerializer, AuthorSerializer, PublisherSerializer
from rest_framework.response import Response


# Create your views here.
class BookListsViews(APIView):
    def get(self, request):
        books = Book.objects.all()

        books_list = BookSerializer(books, many=True)

        return Response(books_list.data)


class AuthorListsViews(APIView):
    def get(self, request):
        authors = Author.objects.all()

        author_list = AuthorSerializer(authors, many=True)

        return Response(author_list.data)


class PublisherListView(APIView):
    def get(self, request):
        publisher = Publisher.objects.all()
        publisher_list = PublisherSerializer(publisher, many=True)
        return Response(publisher_list.data)

    def post(self, request):
        data = request.data
        serializer = PublisherSerializer(data=data)
        serializer.is_valid()
        serializer.save()
        return Response(serializer.data)

    def put(self, request, pk):
        data = request.data
        publisher = Publisher.objects.get(id=pk)
        serializer = PublisherSerializer(publisher, data)
        serializer.is_valid()
        serializer.save()
        return Response(serializer.data)

    def delete(self, request, pk):
        publisher = Publisher.objects.get(id=pk)
        serializer = PublisherSerializer(data=Publisher)
        serializer.is_valid()
        publisher.delete()
        return Response(serializer.data)

3.5配置urls.py

在bookApp下新建url.py

from django.urls import path, re_path
from .views import BookListsViews, AuthorListsViews, PublisherListView

urlpatterns = [
    path('book/list/', BookListsViews.as_view()),
    path('author/list/', AuthorListsViews.as_view()),
    path('publisher/list/', PublisherListView.as_view()),
    path('publisher/add/', PublisherListView.as_view()),
    re_path('publisher/update/(?P<pk>[0-9])/', PublisherListView.as_view()),
    re_path('publisher/delete/(?P<pk>[0-9])/', PublisherListView.as_view())
]

修改urls.py

"""DjangoDemo URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/3.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path, include
from bookApp import url as books_urls

urlpatterns = [
    path('admin/', admin.site.urls),
    path('api/', include(books_urls))
]

启动项目后在浏览器访问：

http://127.0.0.1:8000/api/book/booklist/

返回结果

二、GenericAPIView

作用： 通常结合一个或多个Mixin扩展类使用，用来快速地实现列表视图或详情视图，即标准的增删改查功能。
与APIView的不同点：主要增加了 操作序列化器 和 数据库查询的属性或方法，为Mixin扩展类的执行提供支持
1.属性：serializer_class 指明视图使用的序列化器
方法：get_serializer_class()返回序列化器类，默认返回serializer_class
方法：get_serializer()返回序列化器对象，主要用来提供给Mixin扩展类使用，如果我们在视图中想要获取序列化器对象，也可以直接调用此方法
2.属性：queryset 指明使用的数据查询集
方法：get_queryset()返回视图使用的查询集，主要用来提供给Mixin扩展类使用，是列表视图与详情视图获取数据的基础，默认返回queryset属性，可以重写。
方法：get_object()
返回详情视图所需的模型类数据对象，主要用来提供给Mixin扩展类使用。
在试图中可以调用该方法获取详情信息的模型类对象。
若详情访问的模型类对象不存在，会返回404。
该方法会默认使用APIView提供的check_object_permissions方法检查当前对象是否有权限被访问。
3.属性：lookup_field 查找单个model实例时的字段，默认为pk(主键)
4.属性：pagination_class:分页
5.属性：filter_backend
6.属性：lookup_url_kwarg 查询单一数据时URL中的参数关键字名称，默认与look_field相同
示例代码：GenericAPIView实现出版商实现增删改查

from django.shortcuts import render
from rest_framework.generics import GenericAPIView
from .models import Publisher
from .serializers import PublisherSerializer
from rest_framework.response import Response


# Create your views here.
class PublisherListView(GenericAPIView):
    lookup_field = 'pk'
    serializer_class = PublisherSerializer
    queryset = Publisher.objects.all()

    def get(self, request):
        publisher = self.get_queryset()
        publisher_list = self.get_serializer(publisher, many=True)
        return Response(publisher_list.data)

    def post(self, request):
        data = request.data
        serializer = self.get_serializer(data=data)
        serializer.is_valid()
        serializer.save()
        return Response(serializer.data)

    def put(self, request, pk):
        data = request.data
        publisher = self.get_object()  # Publisher.objects.get(id=pk)
        serializer = self.get_serializer(publisher, data)
        serializer.is_valid()
        serializer.save()
        return Response(serializer.data)

    def delete(self, request, pk):
        publisher = self.get_object()  # Publisher.objects.get(id=pk)
        serializer = self.get_serializer(data=Publisher)
        serializer.is_valid()
        publisher.delete()
        return Response(serializer.data)

三、总结
APIView和GenericAPIvIEW两个类的关系如下：

关系图.png