Django后端项目---- rest framework（3）

一、版本

程序也来越大时，可能通过版本不同做不同的处理

没用rest_framework之前，我们可以通过以下这样的方式去获取。

 class UserView(APIView):
     def get(self,request,*args,**kwargs):
         version = request.query_params.get('version')
         print(version)
         if version=='v1':
             #如果版本是v1
             ret = {
                 'code':111,
                 'msg':'版本一的内容'
             }
 
         elif version=='v2':
             # 如果是v2
             ret = {
                 'code': 112,
                 'msg': '版本二的内容'
             }
         else:
             ret = {
                 'code': 0,
                 'msg': '不支持其他版本'
             }
         return Response(ret)

现在我们来用rest_framework实现一下，有两种方式

1、基于url的方式

 #基于url传参的形式
     versioning_class = QueryParameterVersioning
    #http://127.0.0.1:8080/api/users/?version=v2
 
#基于url的形式
　　versioning_class = URLPathVersioning
　　#http://127.0.0.1:8080/api/v1/users/

具体步骤

 REST_FRAMEWORK = {
     'DEFAULT_VERSION': 'v1',  #默认的版本
     'ALLOWED_VERSIONS': ['v1','v2'],  #允许的版本
     'VERSION_PARAM': 'version',
 }

1、配置

 from django.conf.urls import url,include
 from django.contrib import admin
 
 urlpatterns = [
     url(r'^admin/', admin.site.urls),
     url(r'^api/(?P<version>[v1|v2]+)/', include('api.urls'), name='users-list'),
 ]

urls.py

 from api import views
 urlpatterns = [
     # url(r'^users/', views.UserView.as_view()),
     url(r'^users/', views.UserView1.as_view()),
 
 ]

urls.py

 class UserView1(APIView):
     #基于url传参的形式
     # versioning_class = QueryParameterVersioning
     #http://127.0.0.1:8080/api/users/?version=v2
 
     #基于url的形式
     #http://127.0.0.1:8080/api/v1/users/
     versioning_class = URLPathVersioning
     def get(self,request,*args,**kwargs):
         # self.dispatch
         print(request.version)  #打印的是版本
         print(request.versioning_scheme)  #打印的是对象
         if request.version=='v2':
             return Response('我是版本二')
         elif request.version=='v1':
             return Response('我是版本一')
         else:
             return Response('去去去')

views.py

注：在配置的时候

REST_FRAMEWORK = {
                'VERSION_PARAM':'version',
                'DEFAULT_VERSION':'v1',
                'ALLOWED_VERSIONS':['v1','v2'],
                # 'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.HostNameVersioning" 
 　　　　　　　　　　#如果加上这个配置就不用versioning_class = QueryParameterVersioning这样在指定了，

　　　　　　　　　　 'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.URLPathVersioning" }

附加：restful提供的反向生成

#http://127.0.0.1:8080/api/v1/users/

 #urls.py
 #分发路由
 urlpatterns = [
     url(r'^admin/', admin.site.urls),
     url(r'^api/(?P<version>[v1|v2]+)/', include('api.urls')),
 ]
 
 #api.urls.py
 urlpatterns = [
     url(r'^users/', views.UserView1.as_view(), name='users-list'),
 ]
 
 #views.py
 导入类
 from rest_framework.reverse import reverse
 url = request.versioning_scheme.reverse(viewname='users-list',request=request)
         print(url)

restfoamework反向解析

我们自己用django实现的，当前版本不一样的时候可以用这种方式

 from django.urls import reverse
        url = reverse(viewname='users-list',kwargs={'version':'v2'}) #指定的是v2就是v2，当你路径中输入v1的时候还是v2的路径
        print(url) #/api/v2/users/

2、基于子域名传参

 #分发url
             urlpatterns = [
                 #url(r'^admin/', admin.site.urls),
                 url(r'^api/', include('api.urls')),
             ]
 
             urlpatterns = [
                 url(r'^users/', views.UsersView.as_view(),name='u'),
             ]
 
             class UsersView(APIView):
 
                 def get(self,request,*args,**kwargs):
                     self.dispatch
                     print(request.version) # QueryParameterVersioning().detemiin_version()
                     print(request.versioning_scheme) # QueryParameterVersioning()
 
             REST_FRAMEWORK = {
                 'VERSION_PARAM':'version',
                 'DEFAULT_VERSION':'v1',
                 'ALLOWED_VERSIONS':['v1','v2'],
                 'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.HostNameVersioning"
             }
 
             # C:\Windows\System32\drivers\etc
             # vim /etc/hosts
             127.0.0.1    v1.luffy.com
             127.0.0.1    v2.luffy.com
 
             #配置ALLOWED_HOSTS = ['*']

基于子域名传参

如果遇到这样的错误

这是由于没有允许，解决办法，在settings里面配置一下

ALLOWED_HOSTS = ['*']

二、解析器：reqest.data取值的时候才执行

对请求的数据进行解析：是针对请求体进行解析的。表示服务器可以解析的数据格式的种类

django中的发送请求

#如果是这样的格式发送的数据，在POST里面有值
Content-Type: application/url-encoding.....
    request.body
    request.POST
 
#如果是发送的json的格式，在POST里面是没有值的，在body里面有值，可通过decode,然后loads取值
Content-Type: application/json.....
    request.body
    request.POST

为了这种情况下每次都要decode，loads，显得麻烦，所以才有的解析器。弥补了django的缺点

 客户端：
             Content-Type: application/json
             '{"name":"alex","age":123}'
 
         服务端接收：
             读取客户端发送的Content-Type的值 application/json
 
             parser_classes = [JSONParser,FormParser]  #表示服务器可以解析的数据格式的种类
             media_type_list = ['application/json','application/x-www-form-urlencoded']
 
             如果客户端的Content-Type的值和 application/json 匹配：JSONParser处理数据
             如果客户端的Content-Type的值和 application/x-www-form-urlencoded 匹配：FormParser处理数据
 
         配置：
             单视图：
             class UsersView(APIView):
                 parser_classes = [JSONParser,]
 
             全局配置：
                 REST_FRAMEWORK = {
                     'VERSION_PARAM':'version',
                     'DEFAULT_VERSION':'v1',
                     'ALLOWED_VERSIONS':['v1','v2'],
                     # 'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.HostNameVersioning"
                     'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.URLPathVersioning",
                     'DEFAULT_PARSER_CLASSES':[
                         'rest_framework.parsers.JSONParser',
                         'rest_framework.parsers.FormParser',
                     ]
                 }
 
                 class UserView(APIView):
                     def get(self,request,*args,**kwargs):
                         return Response('ok')
                     def post(self,request,*args,**kwargs):
                         print(request.data)  #以后取值就在这里面去取值
                         return Response('...')

具体讲解

传上传文件

 from django.conf.urls import url, include
 from web.views import TestView
 
 urlpatterns = [
     url(r'test/(?P<filename>[^/]+)', TestView.as_view(), name='test'),
 ]

urls.py

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework.request import Request
 from rest_framework.parsers import FileUploadParser
 
 class TestView(APIView):
     parser_classes = [FileUploadParser, ]
 
     def post(self, request, filename, *args, **kwargs):
         print(filename)
         print(request.content_type)
 
         # 获取请求的值，并使用对应的JSONParser进行处理
         print(request.data)
         # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值
         print(request.POST)
         print(request.FILES)
         return Response('POST请求，响应内容')
 
     def put(self, request, *args, **kwargs):
         return Response('PUT请求，响应内容')

views.py

 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <title>Title</title>
 </head>
 <body>
 <form action="http://127.0.0.1:8000/test/f1.numbers" method="post" enctype="multipart/form-data">
     <input type="text" name="user" />
     <input type="file" name="img">
 
     <input type="submit" value="提交">
 
 </form>
 </body>
 </html>

upload.html

全局使用

 REST_FRAMEWORK = {
     'DEFAULT_PARSER_CLASSES':[
         'rest_framework.parsers.JSONParser'
         'rest_framework.parsers.FormParser'
         'rest_framework.parsers.MultiPartParser'
     ]
 
 }

settings.py

三、序列化

序列化用于对用户请求数据进行验证和数据进行序列化（为了解决queryset序列化问题）。

那什么是序列化呢？序列化就是把对象转换成字符串，反序列化就是把字符串转换成对象

models.py

from django.db import models
 
# Create your models here.
class Group(models.Model):
    title = models.CharField(max_length=32)
    mu = models.ForeignKey(to='Menu',default=1)
 
class UserInfo(models.Model):
    name = models.CharField(max_length=32)
    pwd = models.CharField(max_length=32)
    group = models.ForeignKey(to="Group")
 
    roles = models.ManyToManyField(to="Role")
class Menu(models.Model):
    name = models.CharField(max_length=21)
 
class Role(models.Model):
    name = models.CharField(max_length=32)

1、基本操作

 from django.shortcuts import render,HttpResponse
 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework.versioning import BaseVersioning
 from rest_framework.versioning import QueryParameterVersioning  #获取version的值
 from rest_framework.versioning import URLPathVersioning #支持版本
 from rest_framework.versioning import HostNameVersioning
 from rest_framework.parsers import JSONParser  #解析器
 from rest_framework import serializers
 from app03 import models
 class UsersSerializer(serializers.Serializer):
     name = serializers.CharField()  #字段名字
     pwd = serializers.CharField()
 
 class UserView(APIView):
     def get(self,request,*args,**kwargs):
         # 方式一实现
         # user_list = models.UserInfo.objects.values('name','pwd','group__mu','group__title')
         # print(type(user_list))
         # return Response(user_list)
 
         # 方式二之多对象
         # user_list = models.UserInfo.objects.all()  #直接这样查会报错，借助他提供的系列化
         # ser = UsersSerializer(instance=user_list,many=True) #可允许多个
         # # print(type(ser))  #<class 'rest_framework.serializers.ListSerializer'>
         # print(ser.data)  #返回的是一个有序字典
 
         #方式三之单对象
         user = models.UserInfo.objects.all().first()
         ser = UsersSerializer(instance=user,many=False)
 
         return Response(ser.data)

views.py

2、跨表

 x1 = serializers.CharField(source='group.mu.name') 

   如果你想跨表拿你任何需要的数据，都可以用上面的这种操作，内部做判断，如果可用内部就加括号调用了

 from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import serializers
 from app03 import models
 class UsersSerializer(serializers.Serializer):
     name = serializers.CharField()  #字段名字
     pwd = serializers.CharField()
     # group = serializers.CharField()  #会显示对象
     # group_id = serializers.CharField()  #会显示id
     x1 = serializers.CharField(source='group.mu.name')
     roles = serializers.CharField(source='roles.all') #多对多关系的这样查出的是queryset对象
 
 class UserView2(APIView):
     '''跨表操作'''
     def get(self,request,*args,**kwargs):
 
         user = models.UserInfo.objects.all()
         ser = UsersSerializer(instance=user,many=True)
 
         return Response(ser.data)

Views.py

3、复杂序列化

解决方案一：

 class MyCharField(serializers.CharField):
 
     def to_representation(self, value): ##打印的是所有的数据
         data_list = []
         for row in value:
             data_list.append(row.name)
         return data_list
 
 class UsersSerializer(serializers.Serializer):
     name = serializers.CharField() # obj.name
     pwd = serializers.CharField()  # obj.pwd
     group_id = serializers.CharField() # obj.group_id
     xxxx = serializers.CharField(source="group.title") # obj.group.title
     x1 = serializers.CharField(source="group.mu.name") # obj.mu.name
     # x2 = serializers.CharField(source="roles.all") #  多对多关系的这样查出的是queryset对象
     x2 = MyCharField(source="roles.all") # obj.mu.name

Views.py

解决方案二：

 class MyCharField(serializers.CharField):
     def to_representation(self, value):
         return {'id':value.pk, 'name':value.name}
 
 class UsersSerializer(serializers.Serializer):
     name = serializers.CharField() # obj.name
     pwd = serializers.CharField()  # obj.pwd
     group_id = serializers.CharField() # obj.group_id
     xxxx = serializers.CharField(source="group.title") # obj.group.title
     x1 = serializers.CharField(source="group.mu.name") # obj.mu.name
     # x2 = serializers.CharField(source="roles.all") # obj.mu.name
     x2 = serializers.ListField(child=MyCharField(),source="roles.all") # obj.mu.name

Views.py

解决方案三（推荐使用）

 class UsersSerializer(serializers.Serializer):
     name = serializers.CharField() # obj.name
     pwd = serializers.CharField()  # obj.pwd
     group_id = serializers.CharField() # obj.group_id
     xxxx = serializers.CharField(source="group.title") # obj.group.title
     x1 = serializers.CharField(source="group.mu.name") # obj.mu.name
     # x2 = serializers.CharField(source="roles.all") # obj.mu.name
     # x2 = serializers.ListField(child=MyCharField(),source="roles.all") # obj.mu.name
     x2 = serializers.SerializerMethodField()
 
     def get_x2(self,obj):  #get_字段名
         print(obj)   ##UserInfo object
         obj.roles.all()
         role_list = obj.roles.filter(id__gt=1)
         data_list = []
         for row in role_list:
             data_list.append({'pk':row.pk,'name':row.name})
         return data_list
     

Views.py

4、基于Model

 class UsersSerializer(serializers.ModelSerializer):
 x1 = serializers.CharField(source='name')
 group = serializers.HyperlinkedIdentityField(view_name='detail')
 class Meta:
 
     model = models.UserInfo
     # fields = "__all__"
     fields = ['name','pwd','group','x1']  #自定义字段的时候注意要指定source,scource里面的数据必须是数据库有的数据
     depth = 1 #表示深度
 
 class UsersView(APIView):
     def get(self,request,*args,**kwargs):
         self.dispatch
         # 方式一：
         # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title")
         # return Response(user_list)
 
         # 方式二之多对象
         user_list = models.UserInfo.objects.all()
         # [obj1,obj2,obj3]
         ser = UsersSerializer(instance=user_list,many=True)
         return Response(ser.data)

Views.py

5、生成URL

 class UsersSerializer(serializers.ModelSerializer):  #
     group = serializers.HyperlinkedIdentityField(view_name='detail')
     class Meta:
         model = models.UserInfo
         fields = "__all__"
         fields = ['name', 'pwd','group']
         depth = 1
 
 class UsersView(APIView):
     def get(self,request,*args,**kwargs):
         self.dispatch
         # 方式一：
         # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title")
         # return Response(user_list)
 
         # 方式二之多对象
         user_list = models.UserInfo.objects.all()
         # [obj1,obj2,obj3]
         ser = UsersSerializer(instance=user_list,many=True,context={'request':request})
         return Response(ser.data)

views.py

from django.conf.urls import url,include
from django.contrib import admin
from app03 import views
urlpatterns = [
 
    url(r'^users4/', views.UserView4.as_view(), name='xxx'), #吧users4的group的值反向生成users5的url
    url(r'^users5/(?P<pk>.*)', views.UserView5.as_view(), name='detail'),  #必须叫pk
    # url(r'^users4/(?P<pk>.*)', views.UserView4.as_view(), name='detail'),
]

6、全局生成URL

 class UsersSerializer(serializers.HyperlinkedModelSerializer): #继承他自动生成
     class Meta:
         model = models.UserInfo
         fields = "__all__"
 
         # fields = ['id','name','pwd']  
 
 class UsersView(APIView):
     def get(self,request,*args,**kwargs):
         self.dispatch
         # 方式一：
         # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title")
         # return Response(user_list)
 
         # 方式二之多对象
         user_list = models.UserInfo.objects.all()
         # [obj1,obj2,obj3]
         ser = UsersSerializer(instance=user_list,many=True,context={'request':request})
         return Response(ser.data)

views.py

四、请求数据验证：

a、自己手写

 class PasswordValidator(object):
     def __init__(self, base):
         self.base = base
 
     def __call__(self, value):
         if value != self.base:
             message = '用户输入的值必须是 %s.' % self.base
             raise serializers.ValidationError(message)
 
     def set_context(self, serializer_field):
         """
         This hook is called by the serializer instance,
         prior to the validation call being made.
         """
         # 执行验证之前调用,serializer_fields是当前字段对象
         pass
 
 class UsersSerializer(serializers.Serializer):
         name = serializers.CharField(min_length=6)
         pwd = serializers.CharField(error_messages={'required': '密码不能为空'}, validators=[PasswordValidator('')])

views.py

b、基于model

 class PasswordValidator(object):
     def __init__(self, base):
         self.base = base
 
     def __call__(self, value):
         if value != self.base:
             message = '用户输入的值必须是 %s.' % self.base
             raise serializers.ValidationError(message)
 
     def set_context(self, serializer_field):
         """
         This hook is called by the serializer instance,
         prior to the validation call being made.
         """
         # 执行验证之前调用,serializer_fields是当前字段对象
         pass
 
 class UsersSerializer(serializers.ModelSerializer):
     class Meta:
         model = models.UserInfo
         fields = "__all__"
         #自定义验证规则
         extra_kwargs = {
             'name': {'min_length': 6},
             'pwd': {'validators': [PasswordValidator(666), ]}
         }

views.py

使用

 class UsersView(APIView):
     def get(self,request,*args,**kwargs):
         self.dispatch
         # 方式一：
         # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title")
         # return Response(user_list)
 
         # 方式二之多对象
         user_list = models.UserInfo.objects.all()
         # [obj1,obj2,obj3]
         ser = UsersSerializer(instance=user_list,many=True,context={'request':request})
         return Response(ser.data)
 
     def post(self,request,*args,**kwargs):
         ser = UsersSerializer(data=request.data)
         if ser.is_valid():
             print(ser.validated_data)
         else:
             print(ser.errors)
         return Response('...')

viewS.py

钩子函数

def validate_字段(self,validated_value):
       raise ValidationError(detail='xxxxxx')
       return validated_value