REST framework框架的基本组件

restful规范

1.根据method不同，进行不同操作
2.面向资源编程
3.体现版本
4.体现是API
5.最好用https
6.响应式设置状态码
7.条件 ?id=1
8.返回值
9.返回错误信息
10.Hypermedia API

REST framework框架

1.路由
2.视图
3.权限
4.认证
5.访问频率限制
6.序列化
7.分页
8.解析器
9.渲染器
10.版本

我对 django rest framework框架的认识！

- 路由，

- 可以通过as_view传参数，根据请求方式不同执行相应的方法
- 可以在url中设置一个结尾，类似于： .json

- 视图，

- 帮助开发者提供了一些类，并在类中提供了多个方法以供我们使用。

- 版本，

- 在url中设置version参数，用户请求时候传入参数。在request.version中获取版本，根据版本不同做不同处理

- 认证，

- 写一个类并注册到认证类，在类的的authticate方法中编写认证逻辑。
- 认证成功（user,auth）
- raise AuthticateFaild(....)
- None

- 权限

- 写一个类并注册到权限类，在类的的has_permission方法中编写认证逻辑。
- True
- False

- 频率限制

- 写一个类并注册到频率类，在类的的 allow_request/wait 方法中编写认证逻辑。

allow_request
- True
- False 如果返回False，那么就要执行wait

- 解析器，

- 根据ContentType请求头，选择不同解析器对 请求体中的数据进行解析。

POST /index/ http1.1. host:11.11.11.11 Content-Type:url-formendo.... user=alex&age=123
POST /index/ http1.1. host:11.11.11.11 Content-Type:application/json {....}

- 分页

- 对从数据库中获取到的数据进行分页处理: SQL -> limit offset
- 根据页码：http://www.luffycity.com/api/v1/student/?page=1&size=10
- 根据索引：http://www.luffycity.com/api/v1/student/?offset=60&limit=10
- 根据加密：http://www.luffycity.com/api/v1/student/?page=erd8

页码越大速度越慢，为什么以及如何解决？
原因：页码越大向后需要扫描的行数越多，因为每次都是从0开始扫描。
解决：
- 限制显示的页数
- 记录当前页数据ID最大值和最小值，再次分页时，根据ID现行筛选，然后再分页。

- 序列化

- 对queryset序列化以及对请求数据格式校验。

- 渲染器

- 根据URL中传入的后缀，决定在数据如何渲染到到页面上。

视图三部曲

使用混合（mixins）

from rest_framework.views import APIView
from rest_framework.response import Response
from .models import *
from django.shortcuts import HttpResponse
from django.core import serializers


from rest_framework import serializers


class BookSerializers(serializers.ModelSerializer):
      class Meta:
          model=Book
          fields="__all__"
          #depth=1


class PublshSerializers(serializers.ModelSerializer):

      class Meta:
          model=Publish
          fields="__all__"
          depth=1


class BookViewSet(APIView):

    def get(self,request,*args,**kwargs):
        book_list=Book.objects.all()
        bs=BookSerializers(book_list,many=True,context={'request': request})
        return Response(bs.data)


    def post(self,request,*args,**kwargs):
        print(request.data)
        bs=BookSerializers(data=request.data,many=False)
        if bs.is_valid():
            print(bs.validated_data)
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)


class BookDetailViewSet(APIView):

    def get(self,request,pk):
        book_obj=Book.objects.filter(pk=pk).first()
        bs=BookSerializers(book_obj,context={'request': request})
        return Response(bs.data)

    def put(self,request,pk):
        book_obj=Book.objects.filter(pk=pk).first()
        bs=BookSerializers(book_obj,data=request.data,context={'request': request})
        if bs.is_valid():
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)


class PublishViewSet(APIView):

    def get(self,request,*args,**kwargs):
        publish_list=Publish.objects.all()
        bs=PublshSerializers(publish_list,many=True,context={'request': request})
        return Response(bs.data)


    def post(self,request,*args,**kwargs):

        bs=PublshSerializers(data=request.data,many=False)
        if bs.is_valid():
            # print(bs.validated_data)
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)


class PublishDetailViewSet(APIView):

    def get(self,request,pk):

        publish_obj=Publish.objects.filter(pk=pk).first()
        bs=PublshSerializers(publish_obj,context={'request': request})
        return Response(bs.data)

    def put(self,request,pk):
        publish_obj=Publish.objects.filter(pk=pk).first()
        bs=PublshSerializers(publish_obj,data=request.data,context={'request': request})
        if bs.is_valid():
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)

mixin类编写视图

from rest_framework import mixins
from rest_framework import generics

class BookViewSet(mixins.ListModelMixin,
                  mixins.CreateModelMixin,
                  generics.GenericAPIView):

    queryset = Book.objects.all()
    serializer_class = BookSerializers

    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)



class BookDetailViewSet(mixins.RetrieveModelMixin,
                    mixins.UpdateModelMixin,
                    mixins.DestroyModelMixin,
                    generics.GenericAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializers

    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):
        return self.update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):
        return self.destroy(request, *args, **kwargs)

使用通用的基于类的视图

通过使用mixin类，我们使用更少的代码重写了这些视图，但我们还可以再进一步。REST框架提供了一组已经混合好（mixed-in）的通用视图，我们可以使用它来简化我们的views.py模块。

from rest_framework import mixins
from rest_framework import generics

class BookViewSet(generics.ListCreateAPIView):

    queryset = Book.objects.all()
    serializer_class = BookSerializers

class BookDetailViewSet(generics.RetrieveUpdateDestroyAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializers

class PublishViewSet(generics.ListCreateAPIView):

    queryset = Publish.objects.all()
    serializer_class = PublshSerializers

class PublishDetailViewSet(generics.RetrieveUpdateDestroyAPIView):
    queryset = Publish.objects.all()
    serializer_class = PublshSerializers

使用viewsets.ModelViewSet

urls.py:

url(r'^books/$', views.BookViewSet.as_view({"get":"list","post":"create"}),name="book_list"),
    url(r'^books/(?P<pk>d+)$', views.BookViewSet.as_view({
                'get': 'retrieve',
                'put': 'update',
                'patch': 'partial_update',
                'delete': 'destroy'
            }),name="book_detail"),

views.py:

class BookViewSet(viewsets.ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookSerializers

认证与权限组件

认证组件

局部视图认证

在app01.service.auth.py:

通过用户的token值做认证

class Authentication(BaseAuthentication):

    def authenticate(self,request):
        token=request._request.GET.get("token")
        token_obj=UserToken.objects.filter(token=token).first()
        if not token_obj:
            raise exceptions.AuthenticationFailed("验证失败!")
        return (token_obj.user,token_obj)

在views.py：

def get_random_str(user):
    import hashlib,time
    ctime=str(time.time())

    md5=hashlib.md5(bytes(user,encoding="utf8"))
    md5.update(bytes(ctime,encoding="utf8"))

    return md5.hexdigest()


from app01.service.auth import *

from django.http import JsonResponse
class LoginViewSet(APIView):
    authentication_classes = [Authentication,]
    def post(self,request,*args,**kwargs):
        res={"code":1000,"msg":None}
        try:
            user=request._request.POST.get("user")
            pwd=request._request.POST.get("pwd")
            user_obj=UserInfo.objects.filter(user=user,pwd=pwd).first()
            print(user,pwd,user_obj)
            if not user_obj:
                res["code"]=1001
                res["msg"]="用户名或者密码错误"
            else:
                token=get_random_str(user)
                UserToken.objects.update_or_create(user=user_obj,defaults={"token":token})
                res["token"]=token

        except Exception as e:
            res["code"]=1002
            res["msg"]=e

        return JsonResponse(res,json_dumps_params={"ensure_ascii":False})

全局视图认证组件

settings.py配置如下：

REST_FRAMEWORK={
    "DEFAULT_AUTHENTICATION_CLASSES":["app01.service.auth.Authentication",]
}

权限组件

局部视图权限

在app01.service.permissions.py中：

from rest_framework.permissions import BasePermission
class SVIPPermission(BasePermission):
    message="SVIP才能访问!"
    def has_permission(self, request, view):
        if request.user.user_type==3:
            return True
        return False

在views.py：

from app01.service.permissions import *

class BookViewSet(generics.ListCreateAPIView):
    permission_classes = [SVIPPermission,]
    queryset = Book.objects.all()
    serializer_class = BookSerializers

全局视图权限

settings.py配置如下：

REST_FRAMEWORK={
    "DEFAULT_AUTHENTICATION_CLASSES":["app01.service.auth.Authentication",],
    "DEFAULT_PERMISSION_CLASSES":["app01.service.permissions.SVIPPermission",]
}

 

throttle(访问频率)组件

局部视图throttle

在app01.service.throttles.py中：

from rest_framework.throttling import BaseThrottle

VISIT_RECORD={}
class VisitThrottle(BaseThrottle):

    def __init__(self):
        self.history=None

    def allow_request(self,request,view):
        remote_addr = request.META.get('REMOTE_ADDR')
        print(remote_addr)
        import time
        ctime=time.time()

        if remote_addr not in VISIT_RECORD:
            VISIT_RECORD[remote_addr]=[ctime,]
            return True

        history=VISIT_RECORD.get(remote_addr)
        self.history=history

        while history and history[-1]<ctime-60:
            history.pop()

        if len(history)<3:
            history.insert(0,ctime)
            return True
        else:
            return False

    def wait(self):
        import time
        ctime=time.time()
        return 60-(ctime-self.history[-1])

在views.py中：

from app01.service.throttles import *

class BookViewSet(generics.ListCreateAPIView):
    throttle_classes = [VisitThrottle,]
    queryset = Book.objects.all()
    serializer_class = BookSerializers

全局视图throttle

REST_FRAMEWORK={
    "DEFAULT_AUTHENTICATION_CLASSES":["app01.service.auth.Authentication",],
    "DEFAULT_PERMISSION_CLASSES":["app01.service.permissions.SVIPPermission",],
    "DEFAULT_THROTTLE_CLASSES":["app01.service.throttles.VisitThrottle",]
}

内置throttle类

在app01.service.throttles.py修改为：

class VisitThrottle(SimpleRateThrottle):

    scope="visit_rate"
    def get_cache_key(self, request, view):

        return self.get_ident(request)

settings.py设置：

REST_FRAMEWORK={
    "DEFAULT_AUTHENTICATION_CLASSES":["app01.service.auth.Authentication",],
    "DEFAULT_PERMISSION_CLASSES":["app01.service.permissions.SVIPPermission",],
    "DEFAULT_THROTTLE_CLASSES":["app01.service.throttles.VisitThrottle",],
    "DEFAULT_THROTTLE_RATES":{
        "visit_rate":"5/m",
    }
}

解析器

request类

django的request类和rest-framework的request类的源码解析

局部视图

from rest_framework.parsers import JSONParser,FormParser
class PublishViewSet(generics.ListCreateAPIView):
    parser_classes = [FormParser,JSONParser]
    queryset = Publish.objects.all()
    serializer_class = PublshSerializers
    def post(self, request, *args, **kwargs):
        print("request.data",request.data)
        return self.create(request, *args, **kwargs)

全局视图

REST_FRAMEWORK={
    "DEFAULT_AUTHENTICATION_CLASSES":["app01.service.auth.Authentication",],
    "DEFAULT_PERMISSION_CLASSES":["app01.service.permissions.SVIPPermission",],
    "DEFAULT_THROTTLE_CLASSES":["app01.service.throttles.VisitThrottle",],
    "DEFAULT_THROTTLE_RATES":{
        "visit_rate":"5/m",
    },
    "DEFAULT_PARSER_CLASSES":['rest_framework.parsers.FormParser',]
}

序列化

ser = ServerSerializer(instance=queryset, many=True)
#instance接受queryset对象或者单个model对象，当有多条数据时候，使用many=True,单个对象many=False

看序列化代码

from django.shortcuts import render,HttpResponse,redirect
from django.views import View
from app01 import models

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers


class BookSerializers(serializers.Serializer):
    #我们先序列化写两个字段的数据，别忘了这里面的字段和model表中的字段变量名要一样
    title = serializers.CharField(max_length=32)
    price = serializers.DecimalField(max_digits=5, decimal_places=2)

    #一对多的处理
    # publish = serializers.CharField(max_length=32)  #返回对象
    publish_email = serializers.CharField(max_length=32, source='publish.email')  # source指定返回的多对一的那个publish对象的email数据，并且我们现在找到书籍的email，所以前面的字段名称就可以不和你的publish对应好了，随便取名字
    publish_name = serializers.CharField(max_length=32, source='publish.name')  # source指定返回的多对一的那个publish对象的其他字段数据，可以接着写字段,也就是说关联的所有的字段的数据都可以写在这里进行序列化

    #对多对的处理
    # authors = serializers.CharField(max_length=32) #bookobj.authors拿到的类似于一个models.Authors.object，打印的时候这是个None
    # authors = serializers.CharField(max_length=32,source="authors.all") #这样写返回的是queryset类型的数据，这样给前端肯定是不行的，所以按照下面的方法写
    authors = serializers.SerializerMethodField() #序列化方法字段，专门给多对多字段用的，然后下面定义一个方法，方法名称写法是这样的get_字段名,名字必须是这样
    def get_authors(self,obj): #参数写一个obj，这个obj是一个一个的书籍对象，然后我们通过书籍对象来返回对应的数据
        # author_list_values = obj.authors.all().values() #返回这样类型的数据也行,那么具体你要返回什么结构的数据，需要和前端人员沟通清楚，然后这里对数据进行加工
        #假如加工成的数据是这种类型的[ {},{} ],就可以按照下面的逻辑来写，我简单写的，肯定有更好的逻辑来加工这些数据
        author_list_values = []
        author_dict = {}
        author_list = obj.authors.all()
        for i in author_list:
            author_dict['name'] = i.name
            author_list_values.append(author_dict)
        return author_list_values


class BookView(APIView):
    def get(self,request):
        book_obj_list = models.Book.objects.all()
        s_books = BookSerializers(book_obj_list,many=True)
        return Response(s_books.data)

    def post(self,request):
        pass

serializer在内部就做了这点事儿，伪代码昂

创建一个序列化类

简单使用

开发我们的Web API的第一件事是为我们的Web API提供一种将代码片段实例序列化和反序列化为诸如json之类的表示形式的方式。我们可以通过声明与Django forms非常相似的序列化器（serializers）来实现。

models部分:

from django.db import models

# Create your models here.


class Book(models.Model):
    title=models.CharField(max_length=32)
    price=models.IntegerField()
    pub_date=models.DateField()
    publish=models.ForeignKey("Publish")
    authors=models.ManyToManyField("Author")
    def __str__(self):
        return self.title

class Publish(models.Model):
    name=models.CharField(max_length=32)
    email=models.EmailField()
    def __str__(self):
        return self.name

class Author(models.Model):
    name=models.CharField(max_length=32)
    age=models.IntegerField()
    def __str__(self):
        return self.name

 

views部分：

from rest_framework.views import APIView
from rest_framework.response import Response
from .models import *
from django.shortcuts import HttpResponse
from django.core import serializers


from rest_framework import serializers

class BookSerializers(serializers.Serializer):
    title=serializers.CharField(max_length=32)
    price=serializers.IntegerField()
    pub_date=serializers.DateField()
    publish=serializers.CharField(source="publish.name")
    #authors=serializers.CharField(source="authors.all")
    authors=serializers.SerializerMethodField()
    def get_authors(self,obj):
        temp=[]
        for author in obj.authors.all():
            temp.append(author.name)
        return temp


class BookViewSet(APIView):

    def get(self,request,*args,**kwargs):
        book_list=Book.objects.all()
        # 序列化方式1:
        # from django.forms.models import model_to_dict
        # import json
        # data=[]
        # for obj in book_list:
        #     data.append(model_to_dict(obj))
        # print(data)
        # return HttpResponse("ok")

        # 序列化方式2:
        # data=serializers.serialize("json",book_list)
        # return HttpResponse(data)

        # 序列化方式3:
        bs=BookSerializers(book_list,many=True)
        return Response(bs.data)

ModelSerializer

class BookSerializers(serializers.ModelSerializer):
      class Meta:
          model=Book
          fields="__all__"
          depth=1

提交post请求

  def post(self,request,*args,**kwargs):
       
        bs=BookSerializers(data=request.data,many=False)
        if bs.is_valid():
            # print(bs.validated_data)
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)

重写save中的create方法

class BookSerializers(serializers.ModelSerializer):

      class Meta:
          model=Book
          fields="__all__"
          # exclude = ['authors',]
          # depth=1

      def create(self, validated_data):
        
          authors = validated_data.pop('authors')
          obj = Book.objects.create(**validated_data)
          obj.authors.add(*authors)
          return obj

单条数据的get和put请求

class BookDetailViewSet(APIView):

    def get(self,request,pk):
        book_obj=Book.objects.filter(pk=pk).first()
        bs=BookSerializers(book_obj)
        return Response(bs.data)

    def put(self,request,pk):
        book_obj=Book.objects.filter(pk=pk).first()
        bs=BookSerializers(book_obj,data=request.data)
        if bs.is_valid():
            bs.save()
            return Response(bs.data)
        else:
            return HttpResponse(bs.errors)

超链接API：Hyperlinked

class BookSerializers(serializers.ModelSerializer):
      publish= serializers.HyperlinkedIdentityField(
                     view_name='publish_detail',
                     lookup_field="publish_id",
                     lookup_url_kwarg="pk")
      class Meta:
          model=Book
          fields="__all__"
          #depth=1

urls部分：

urlpatterns = [
    url(r'^books/$', views.BookViewSet.as_view(),name="book_list"),
    url(r'^books/(?P<pk>d+)$', views.BookDetailViewSet.as_view(),name="book_detail"),
    url(r'^publishers/$', views.PublishViewSet.as_view(),name="publish_list"),
    url(r'^publishers/(?P<pk>d+)$', views.PublishDetailViewSet.as_view(),name="publish_detail"),
]

分页

简单分页

from rest_framework.pagination import PageNumberPagination,LimitOffsetPagination

class PNPagination(PageNumberPagination):
        page_size = 1
        page_query_param = 'page'
        page_size_query_param = "size"
        max_page_size = 5

class BookViewSet(viewsets.ModelViewSet):

    queryset = Book.objects.all()
    serializer_class = BookSerializers
    def list(self,request,*args,**kwargs):

        book_list=Book.objects.all()
        pp=LimitOffsetPagination()
        pager_books=pp.paginate_queryset(queryset=book_list,request=request,view=self)
        print(pager_books)
        bs=BookSerializers(pager_books,many=True)

        #return Response(bs.data)
        return pp.get_paginated_response(bs.data)

偏移分页

from rest_framework.pagination import LimitOffsetPagination