Django 之RestFramework

1. 从request先说起

在Django原生的request里，请求的数据可以从request.GET或者request.POST里面取到。

需要注意的是，如果是POST请求，request.POST里面只能取到Content-Type=application/x-www-form-urlencoded 的数据，我们常用的json数据就只能从报文request.body里取。  b'{"a": 1,"b": "2"}'

So。。。

RestFramework的APIView 封装的新request就解决了这个问题，post请求的任何数据都可以从request.data里面拿到 ，而get请求需要在request.GET里面取。

并且它还保留了原生request的接口：request._request

2. 序列化

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。

准备models部分:

class Book(models.Model):
    title=models.CharField(max_length=32)
    price=models.IntegerField()
    pub_date=models.DateField()
    CHOICES = ((1, "Python"), (2, "Go"), (3, "Linux"))
    category = models.IntegerField(choices=CHOICES, verbose_name="图书的类别")
    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

序列化类：

from rest_framework import serializers
from .models import Book

class BookSerializer(serializers.Serializer):
    id = serializers.IntegerField(required=False)
    title = serializers.CharField(max_length=32, validators=[my_validate])  # 自定义验证方法，校验优先级高于下面的validate_title方法

    CHOICES = ((1, "Python"), (2, "Go"), (3, "Linux"))
    category = serializers.ChoiceField(choices=CHOICES, source="get_category_display",
                                       read_only=True)  # read_only表示get方法拿到的值
    w_category = serializers.ChoiceField(choices=CHOICES, write_only=True)  # write_only 表示只进行操作不进行展示
    pub_time = serializers.DateField()

    publisher = PublisherSerializer(
        read_only=True)  # 如若只想展示关键信息不想全部展示，只需要指定 publish = serializers.CharField(source="publish.name")
    publisher_id = serializers.IntegerField(write_only=True)

    # authors = serializers.SerializerMethodField()  # 所以处理多对多关系使用SerializerMethodField 方法
    # def get_authors(self, obj):  # get_字段 可以返回任何类型你想返回的值
    #     temp = []
    #     for author in obj.authors.all():
    #         temp.append(author.name)
    #     return temp

    # 处理多对多的get请求时有两种方法：1、如上，想展示什么字段都可以。2、如下，嵌套定义的序列化类，这里想展示的数量不能自己定制
    author = AuthorSerializer(many=True, read_only=True)  # many=True 表示有多个值

    author_list = serializers.ListField(write_only=True)

    def create(self, validated_data):  # post请求重新create方法
        book = Book.objects.create(title=validated_data["title"], category=validated_data["w_category"],
                                   pub_time=validated_data["pub_time"], publisher_id=validated_data["publisher_id"])
        book.author.add(*validated_data["author_list"])
        return book

    def update(self, instance, validated_data):  # 更新重写update
        instance.title = validated_data.get("title", instance.title)
        instance.category = validated_data.get("category", instance.category)
        instance.pub_time = validated_data.get("pub_time", instance.pub_time)
        instance.publisher_id = validated_data.get("publisher_id", instance.publisher_id)
        if validated_data.get("author_list"):
            instance.author.set(validated_data["author_list"])
        instance.save()
        return instance

    def validate_title(self, value):  # 指定某个字段的验证
        if "python" not in value.lower():
            raise serializers.ValidationError("标题必须含有python")
        return value

    def validate(self, attrs):  # 联合验证
        if attrs["w_category"] == 1 and attrs["publisher_id"] == 1:
            return attrs
        else:
            raise serializers.ValidationError("分类以及标题不符合要求")

def my_validate(value):  # 额外为字段定制的校验
    if "敏感信息" in value.lower():
        raise serializers.ValidationError("不能含有敏感信息")
    else:
        return value

views部分：

from rest_framework.views import APIView
from rest_framework.response import Response  # 可以用Django原生的Response,但是rest_framework的response做了一些封装。可以格式化你的json数据，并且浏览器访问会返回一个api页面
from .models import *
from django.shortcuts import HttpResponse
# from django.core import serializers

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)  # many=true 代表了返回的是一个queryset列表，返回一个对象就不用加
        return Response(bs.data)

ModelSerializer

class BookSerializer(serializers.ModelSerializer):
    category_display = serializers.SerializerMethodField(read_only=True)  # 自定义要获取的字段内容，在下面用get_<field-name>钩子来自定义内容
    publisher_info = serializers.SerializerMethodField(read_only=True)  # 此方法
    authors = serializers.SerializerMethodField(read_only=True)

    def get_category_display(self, obj):
        return obj.get_category_display()  # orm中Choice_field显示中文的方式

    def get_authors(self, obj):  # get_字段：可以返回你想要返回的值
        authors_query_set = obj.author.all()
        return [{"id": author_obj.id, "name": author_obj.name} for author_obj in authors_query_set]

    def get_publisher_info(self, obj):
        # obj 是我们序列化的每个Book对象
        publisher_obj = obj.publisher
        return {"id": publisher_obj.id, "title": publisher_obj.title}

    class Meta:
        model = Book
        # fields = ["id", "title", "pub_time"]
        fields = "__all__"  # 遇到一对多或多对多默认取主键，所以需要自己定义取得数据
        # depth = 1 #外键嵌套的层级数量

        extra_kwargs = {"category": {"write_only": True}, "publisher": {"write_only": True},
                        "author": {"write_only": True}}  # 使用extra_kwargs参数为ModelSerializer添加或修改原有的选项参数

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

post请求需要重写create()方法，put请求需要重写update()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"),
]

3. 视图优化

上一节的视图部分：

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.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)

上一节实现的逻辑代码

3.1 使用混合（mixins）

from web.models import *
from web.serializer import BookSerializer
from rest_framework.mixins import \
    (ListModelMixin, CreateModelMixin, DestroyModelMixin, UpdateModelMixin, RetrieveModelMixin)
from rest_framework.generics import GenericAPIView

class BookViewSet(ListModelMixin,
                  CreateModelMixin,
                  GenericAPIView):
    queryset = Book.objects.all()  # 必须要指定一个quetyset
    serializer_class = BookSerializer  # 必须要指定一个序列化类

    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(RetrieveModelMixin,  # 单条数据操作视图
                        UpdateModelMixin,
                        DestroyModelMixin,
                        GenericAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

    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)

3.2 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

3.3 viewsets.ModelViewSet

urls.py:

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

views.py:

from rest_framework.viewsets import ModelViewSet

class BookViewSet(ModelViewSet):
    queryset = Book.objects.all()  # 指定一个RetrieveModelMixin
    serializer_class = BookSerializer  # 指定一个序列化类

4. 认证与权限组件

4.1 认证组件

局部视图认证

先定义一个认证类:

from rest_framework.authentication import BaseAuthentication
from rest_framework.exceptions import AuthenticationFailed

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",]
}

4.2 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",]
}

5. 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",  # 5：5次 m：分
    }
}

6. 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',]
}

回到顶部

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