Django——REST framework

1. 什么是REST

• REST与技术无关，代表的是一种软件架构风格，REST是Representational State Transfer的简称，中文翻译为“表征状态转移”
• REST从资源的角度类审视整个网络，它将分布在网络中某个节点的资源通过URL进行标识，客户端应用通过URL来获取资源的表征，获得这些表征致使这些应用转变状态
• 所有的数据，不过是通过网络获取的还是操作（增删改查）的数据，都是资源，将一切数据视为资源是REST区别与其他架构风格的最本质属性
• 对于REST这种面向资源的架构风格，有人提出一种全新的结构理念，即：面向资源架构（ROA：Resource Oriented Architecture）

设计参考：http://www.ruanyifeng.com/blog/2014/05/restful_api.html

2. 目前如何实现 REST API ？

按照规则，根据不同的请求方式做出不同的处理，并且返回内容以及相应状态码

3. 什么是 Django REST framework？

Django REST framework是一个基于Django开发的app，用于快速搭建REST API。

安装：

pip3 install djangorestframework

a. 快速使用

1. 注册APP

 from rest_framework import routers
 from . import views

 router = routers.DefaultRouter()
 router.register(r'users', views.UserInfoViewSet)

 urlpatterns = [
     url(r'^', include(router.urls)),
 ]

2. 注册路由

 from rest_framework import viewsets
 from . import models
 from . import serializers

 # ########### 1. 基本处理方式 ###########

 class UserInfoViewSet(viewsets.ModelViewSet):
     """
     API endpoint that allows users to be viewed or edited.
     """
     queryset = models.UserInfo.objects.all().order_by('-id')
     serializer_class = serializers.UserInfoSerializer

3. 编写ViewSet，视图函数

 from rest_framework import serializers
 from . import models

 class UserInfoSerializer(serializers.HyperlinkedModelSerializer):
     class Meta:
         model = models.UserInfo
         # fields = ('id', 'username', 'pwd','ug') # fields = '__all__'
         exclude = ('ug',)
         depth = 1  # 0<=depth<=10

4. 编写serializers，form验证以及数据库操作

PS：最终访问路径

 [GET]          http://127.0.0.1:8000/api/users/
 [POST]         http://127.0.0.1:8000/api/users/
 [GET]          http://127.0.0.1:8000/api/users/7/
 [PUT]          http://127.0.0.1:8000/api/users/7/
 [DELETE]       http://127.0.0.1:8000/api/users/7/

b. 基于CBV

 from django.conf.urls import url,include
 from django.contrib import admin
 from . import views

 urlpatterns = [
     url(r'^users/$', views.UserList.as_view()),
     url(r'^users/(?P<pk>[0-9]+)/$', views.UserDetail.as_view()),
 ]

1. URL

 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework.request import Request
 from rest_framework.parsers import JSONParser
 from . import models
 from . import serializers

 class UserList(APIView):
     def get(self, request, *args, **kwargs):
         user_list = models.UserInfo.objects.all()
         serializer = serializers.MySerializer(instance=user_list, many=True)
         return Response(serializer.data)

     def post(self, request, *args, **kwargs):
         data = JSONParser().parse(request)
         serializer = serializers.MySerializer(data=data)
         if serializer.is_valid():
             # print(serializer.data)
             # print(serializer.errors)
             # print(serializer.validated_data)
             # 如果有instance，则执行update方法；否则，执行create
             serializer.save()
             return Response(serializer.data, status=201)
         return Response(serializer.errors, status=400)

 class UserDetail(APIView):
     def get(self, request, *args, **kwargs):
         obj = models.UserInfo.objects.filter(pk=kwargs.get('pk')).first()
         serializer = serializers.MySerializer(obj)
         return Response(serializer.data)

     def delete(self, request, *args, **kwargs):
         obj = models.UserInfo.objects.filter(pk=kwargs.get('pk')).first()
         obj.delete()
         return Response(status=204)

     def put(self, request, *args, **kwargs):
         data = JSONParser().parse(request)
         obj = models.UserInfo.objects.filter(pk=kwargs.get('pk')).first()
         serializer = serializers.MySerializer(obj, data=data)
         if serializer.is_valid():
             serializer.save()
             return Response(serializer.data)
         return Response(serializer.errors, status=400)

2. 编写视图函数

 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
 from . import models

 class MySerializer(serializers.Serializer):
     id = serializers.IntegerField(read_only=True)
     username = serializers.CharField(required=False, allow_blank=True, max_length=100)
     pwd = serializers.CharField()

     def validate_username(self, value):
         if value == '中国':
             raise ValidationError('用户名中存在敏感字符')
         return value

     def validate_pwd(self, value):
         print(value)
         return value

     def validate(self, attrs):
         print(attrs)
         return attrs

     def create(self, validated_data):
         """
         当执行save方法时，自动调用。instance未传值
         :param validated_data:
         :return:
         """
         print(validated_data)
         return models.UserInfo.objects.create(**validated_data)

     def update(self, instance, validated_data):
         """
         当执行save方法时，自动调用。instance传值
         :param instance:
         :param validated_data:
         :return:
         """
         instance.username = validated_data.get('username', instance.username)
         instance.save()
         return instance

3. 编写serializer

c. 基于FBV

 from django.conf.urls import url,include
 from django.contrib import admin
 from . import views

 urlpatterns = [
     url(r'^users/$', views.user_list),
     url(r'^users/(?P<pk>[0-9]+)/$', views.user_detail),
 ]

1. URL

 from django.http import JsonResponse,HttpResponse
 from rest_framework.response import Response
 from rest_framework.parsers import JSONParser
 from rest_framework.decorators import api_view
 from .serializers import MySerializer
 from . import models

 @api_view(['GET',"POST"])
 def user_list(request):
     """
     List all code snippets, or create a new snippet.
     """
     if request.method == 'GET':
         user_list = models.UserInfo.objects.all()
         serializer = MySerializer(user_list,many=True)
         return Response(serializer.data)

     elif request.method == 'POST':
         data = JSONParser().parse(request)
         serializer = MySerializer(data=data)
         if serializer.is_valid():
             print(serializer.data)
             print(serializer.errors)
             print(serializer.validated_data)
             # 如果有instance，则执行update方法；否则，执行create
             serializer.save()
             return Response(serializer.data, status=201)
         return Response(serializer.errors, status=400)

 @api_view(['GET',"POST","PUT"])
 def user_detail(request, pk):
     """
     Retrieve, update or delete a code snippet.
     """

     obj = models.UserInfo.objects.filter(pk=pk).first()
     if not obj:
         return HttpResponse(status=404)

     if request.method == 'GET':
         serializer = MySerializer(obj)
         # return JsonResponse(serializer.data,json_dumps_params={'ensure_ascii':False},content_type='application/json;charset=utf-8')
         return Response(serializer.data)

     elif request.method == 'PUT':
         data = JSONParser().parse(request)
         serializer = MySerializer(obj, data=data)
         if serializer.is_valid():
             serializer.save()
             return Response(serializer.data)
         return Response(serializer.errors, status=400)

     elif request.method == 'DELETE':
         obj.delete()
         return Response(status=204)

2. 视图函数

 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
 from . import models

 class MySerializer(serializers.Serializer):
     id = serializers.IntegerField(read_only=True)
     username = serializers.CharField(required=False, allow_blank=True, max_length=100)
     pwd = serializers.CharField()

     def validate_username(self, value):
         if value == '中国':
             raise ValidationError('用户名中存在敏感字符')
         return value

     def validate_pwd(self, value):
         print(value)
         return value

     def validate(self, attrs):
         print(attrs)
         return attrs

     def create(self, validated_data):
         """
         当执行save方法时，自动调用。instance未传值
         :param validated_data:
         :return:
         """
         print(validated_data)
         return models.UserInfo.objects.create(**validated_data)

     def update(self, instance, validated_data):
         """
         当执行save方法时，自动调用。instance传值
         :param instance:
         :param validated_data:
         :return:
         """
         instance.username = validated_data.get('username', instance.username)
         instance.save()
         return instance

3. 编写serializer

d. 权限控制

 REST_FRAMEWORK = {
     'DEFAULT_PERMISSION_CLASSES': [
         'permissi.MyPermission',
     ]
 }

1. settings配置文件

 class MyPermission(object):
     """
     A base class from which all permission classes should inherit.
     """

     def has_permission(self, request, view):
         """
         Return `True` if permission is granted, `False` otherwise.
         """

         return True

     def has_object_permission(self, request, view, obj):
         return True

2. 权限控制

转载自银角大王：

Django REST framework