Drf01 /restful规范、drf初识

Drf01 /restful规范、drf初识/django rest framewok

第一部分 问题

1. 前后端分离？

   • vue.js
   • 后端给前段返回json数据

2. 移动端盛行。

   • app
   • 后端给app返回json数据

3. PC端应用？

   crm项目，前段后端一起写，运行在浏览器上。 一般情况下都是PC端使用。 

第二部分 任务

以前的我们 ：

http://127.0.0.1:8000/info/get/
http://127.0.0.1:8000/info/add/
http://127.0.0.1:8000/info/update/
http://127.0.0.1:8000/info/delete/

现在的我们：要遵循restful规范

http://127.0.0.1:8000/info/
    get,获取数据
    post，添加
    put，更新
    delete，删除

基于django可以实现遵循restful规范的接口开发：

• FBV，可以实现比较麻烦。
• CBV，相比较简答根据method做的了不同的区分。

第三部分 初识drf

3.1 安装

pip3 install djangorestframework

3.2 使用

• 注册app

  INSTALLED_APPS = [
      'django.contrib.admin',
      'django.contrib.auth',
      'django.contrib.contenttypes',
      'django.contrib.sessions',
      'django.contrib.messages',
      'django.contrib.staticfiles',
      'rest_framework'
  ]

• 写路由

  from django.conf.urls import url
  from django.contrib import admin
  from api import views
  
  urlpatterns = [
      url(r'^drf/info/', views.DrfInfoView.as_view()),
  ]
  

• 写视图

  from rest_framework.views import APIView
  from rest_framework.response import Response
  
  class DrfInfoView(APIView):
  
      def get(self,request,*args,**kwargs):
          data = [
              {'id': 1, 'title': '震惊了...王阳居然...', 'content': '...'},
              {'id': 2, 'title': '震惊了...王阳居然...', 'content': '...'},
              {'id': 3, 'title': '震惊了...王阳居然...', 'content': '...'},
              {'id': 4, 'title': '震惊了...王阳居然...', 'content': '...'},
          ]
          return Response(data)

DRF的应用场景

以后在公司参与前后端分离项目、参与为app写接口时，用drf会比较方便。

总结

• restful规范

  1.给别人提供一个URL，根据URL请求方式的不同，做不同操作。
    get,获取
    post,增加
    put，全部更新
    patch,局部更新
    delete,删除
  2.数据传输基于json格式。
  

• drf框架

  不基于drf也可以实现restful规范来开发接口程序。
  
  使用了drf之后，可以快速帮我们开发restful规范来开发接口。
  

第四部分

4.1 创建程序并初始化数据库

4.2 接口：实现访问接口时，创建一个文章类型

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^drf/category/', views.DrfCategoryView.as_view()),
]

from rest_framework.views import APIView
from rest_framework.response import Response
class DrfCategoryView(APIView):
    pass

假设：我是前段，你是后端。

开发完毕之后告诉前端：

http://127.0.0.1:8000/drf/category/

用工具模拟前端发请求：postman

x-www-urlencoded

request.body: name=alex&age=19&gender=12
request.POST: {'name': ['alex'], 'age': ['19'], 'gender': ['12']}

json

request.body: b'{"ID":1,"name":"Alex","age":19}'
request.POST: 没有值

参考答案

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^info/', views.InfoView.as_view()),
    url(r'^drf/info/', views.DrfInfoView.as_view()),
    url(r'^drf/category/', views.DrfCategoryView.as_view()),
]

from api import models
class DrfCategoryView(APIView):

    def post(self,request,*args,**kwargs):
        """增加一条分类信息"""
        models.Category.objects.create(**request.data)
        return Response('成功')

4.3 接口：获取所有文章类型

from api import models
class DrfCategoryView(APIView):
    def get(self,request,*args,**kwargs):
        """获取所有文章分类"""
        queryset = models.Category.objects.all().values('id','name')
        data_list = list(queryset)
        return Response(data_list)

    def post(self,request,*args,**kwargs):
        """增加一条分类信息"""
        models.Category.objects.create(**request.data)
        return Response('成功')

4.4 接口：获取一条文章类型的详细信息

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^drf/category/$', views.DrfCategoryView.as_view()),
    url(r'^drf/category/(?P<pk>\d+)/$', views.DrfCategoryView.as_view()),
]

from api import models
from django.forms.models import model_to_dict
class DrfCategoryView(APIView):
    def get(self,request,*args,**kwargs):
        """获取所有文章分类/单个文章分类"""
        pk = kwargs.get('pk')
        if not pk:
            queryset = models.Category.objects.all().values('id','name')
            data_list = list(queryset)
            return Response(data_list)
        else:
            category_object = models.Category.objects.filter(id=pk).first()
            data = model_to_dict(category_object)
            return Response(data)

    def post(self,request,*args,**kwargs):
        """增加一条分类信息"""
        models.Category.objects.create(**request.data)
        return Response('成功')

4.5 接口：文章分类的更新和删除

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^drf/category/$', views.DrfCategoryView.as_view()),
    url(r'^drf/category/(?P<pk>\d+)/$', views.DrfCategoryView.as_view()),
]

from api import models
from django.forms.models import model_to_dict
class DrfCategoryView(APIView):
    def get(self,request,*args,**kwargs):
        """获取所有文章分类/单个文章分类"""
        pk = kwargs.get('pk')
        if not pk:
            queryset = models.Category.objects.all().values('id','name')
            data_list = list(queryset)
            return Response(data_list)
        else:
            category_object = models.Category.objects.filter(id=pk).first()
            data = model_to_dict(category_object)
            return Response(data)

    def post(self,request,*args,**kwargs):
        """增加一条分类信息"""
        models.Category.objects.create(**request.data)
        return Response('成功')

    def delete(self,request,*args,**kwargs):
        """删除"""
        pk = kwargs.get('pk')
        models.Category.objects.filter(id=pk).delete()
        return Response('删除成功')

    def put(self,request,*args,**kwargs):
        """更新"""
        pk = kwargs.get('pk')
        models.Category.objects.filter(id=pk).update(**request.data)
        return Response('更新成功')

第五部分 drf的序列化

drf的 serializers帮助我们提供了

• 数据校验
• 序列化

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^info/$', views.InfoView.as_view()),
    url(r'^drf/info/$', views.DrfInfoView.as_view()),
    url(r'^drf/category/$', views.DrfCategoryView.as_view()),
    url(r'^drf/category/(?P<pk>\d+)/$', views.DrfCategoryView.as_view()),


    url(r'^new/category/$', views.NewCategoryView.as_view()),
    url(r'^new/category/(?P<pk>\d+)/$', views.NewCategoryView.as_view()),
]

from rest_framework import serializers

class NewCategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Category
        # fields = "__all__"
        fields = ['id','name']

class NewCategoryView(APIView):
    def get(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        if not pk:
            queryset = models.Category.objects.all()
            ser = NewCategorySerializer(instance=queryset,many=True)
            return Response(ser.data)
        else:
            model_object = models.Category.objects.filter(id=pk).first()
            ser = NewCategorySerializer(instance=model_object, many=False)
            return Response(ser.data)

    def post(self,request,*args,**kwargs):
        ser = NewCategorySerializer(data=request.data)
        if ser.is_valid():
            ser.save()
            return Response(ser.data)
        return Response(ser.errors)

    def put(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        category_object = models.Category.objects.filter(id=pk).first()
        ser = NewCategorySerializer(instance=category_object,data=request.data)
        if ser.is_valid():
            ser.save()
            return Response(ser.data)
        return Response(ser.errors)

    def delete(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        models.Category.objects.filter(id=pk).delete()
        return Response('删除成功')

总结

1. 什么是前后端分离？

   前端所有用到的数据都是后端通过异步接口的方式提供的，前端只管页面的展示及效果。

2. drf组件

   帮助我们在django框架基础上快速搭建遵循restful规范接口的程序。
   

3. drf组件的功能

   • 解析器，解析请求体中的数据，将其变成我们想要的格式。request.data
   • 序列化，对对象或对象列表（queryset）进行序列化操作以及表单验证的功能。
   • 视图，继承APIView（在内部apiview继承了django的View）

4. postman

   模拟浏览器进行发送请求
   

5. 查找模板的顺序

   优先根目录下：templates
   根据app的注册顺序去每个app的templates目录中找。
   

6. 在URL的最后添加终止符

作业：对文章表做增删改查

from django.conf.urls import url
from django.contrib import admin
from api import views
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^info/$', views.InfoView.as_view()),
    url(r'^drf/info/$', views.DrfInfoView.as_view()),
    url(r'^drf/category/$', views.DrfCategoryView.as_view()),
    url(r'^drf/category/(?P<pk>\d+)/$', views.DrfCategoryView.as_view()),


    url(r'^new/category/$', views.NewCategoryView.as_view()),
    url(r'^new/category/(?P<pk>\d+)/$', views.NewCategoryView.as_view()),

    # get获取列表
    # post增加数据
    url(r'^drf/article/$', views.ArticleView.as_view()),
    url(r'^drf/article/(?P<pk>\d+)/$', views.ArticleView.as_view()),
]

class ArticleView(APIView):
    def get(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        if not pk:
            queryset = models.Article.objects.all()
            ser = serializer.ArticleSerializer(instance=queryset,many=True)
            return Response(ser.data)
        article_object = models.Article.objects.filter(id=pk).first()
        ser = serializer.ArticleSerializer(instance=article_object, many=False)
        return Response(ser.data)

    def post(self,request,*args,**kwargs):
        ser = serializer.ArticleSerializer(data=request.data)
        if ser.is_valid():
            ser.save()
            return Response(ser.data)
        return Response(ser.errors)

    def put(self,request,*args,**kwargs):
        """全部更新"""
        pk = kwargs.get('pk')
        article_object = models.Article.objects.filter(id=pk).first()
        ser = serializer.ArticleSerializer(instance=article_object,data=request.data)
        if ser.is_valid():
            ser.save()
            return Response(ser.data)
        return Response(ser.errors)

    def patch(self,request,*args,**kwargs):
        """局部"""
        pk = kwargs.get('pk')
        article_object = models.Article.objects.filter(id=pk).first()
        ser = serializer.ArticleSerializer(instance=article_object, data=request.data,partial=True)
        if ser.is_valid():
            ser.save()
            return Response(ser.data)
        return Response(ser.errors)

    def delete(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        models.Article.objects.filter(id=pk).delete()
        return Response('删除成功')

from rest_framework import serializers
from api import models
class ArticleSerializer(serializers.ModelSerializer):
    category_txt = serializers.CharField(source='category.name',required=False)
    x1 = serializers.SerializerMethodField()

    status_txt = serializers.CharField(source='get_status_display',required=False)

    x2 = serializers.SerializerMethodField()
    class Meta:
        model = models.Article
        # fields = "__all__"
        fields = ['id','title','summary','content','category','category_txt','x1','status','status_txt','x2']
        # depth = 1

    def get_x1(self,obj):
        return obj.category.name

    def get_x2(self,obj):
        return obj.get_status_display()