Django-rest Framework(五)

把十大接口做完了才能更好的了解后面的视图类

1.(重点)二次封装Response;自定义APIResponse继承Response,重写 ____init____方法

from rest_framework.response import Response  #导入Response类

class APIResponse(Response):  #继承Response类
    def __init__(self,status=0,msg='ok',results=None,http_status=None,headers=None,exception=None,**kwargs): #重写__init__方法
        data = {
            'status':status,
            'msg':msg
        }
        if results is not None:
            data['result'] = results

        data.update(**kwargs)   #接收其他多余参数
        # 再使用父类的__init__方法
        super().__i

2.(正常)在orm的模型表中,设置了abstract为True的模型类,称之为基类,这样的模型类是专门作为基类来提供公有属性的(基类不会参与数据迁移)

class BaseModel(models.Model):   #继承基础模型类
    is_delete = models.BooleanField()  #创建公共属性
    create_time = models.DateTimeField(auto_now_add=True)  #创建公共属性
    class Meta:
        abstract:True   # 声明为基类
        
class xxx(BaseModel)  # 其他类继承基类
    

3.(重点)ORM多表关联操作(以书籍表 作者表 出版社表 作者详情表为例):

1. 外键所放的位置

   1. 一对多 : 外键放在多的那一方(出版社,书籍)

      class Book(BaseModel):
          name = models.CharField(max_length=32)
          price = models.DecimalField(max_digits=9,decimal_places=2)
          '''
               related_name='books' : 设置反向查询为books
               db_constraint=False : 断开外键约束
               on_delete=models.DO_NOTHING(在外键数据没有的情况下,任然保持数据 出版社没了，书还是		  那个出版社出版)
          ''' publish=models.ForeignKey(to='Publish',related_name='books',db_constraint=False,on_delete=models.DO_NOTHING)
          # 多对多字段 断约束  设置反向查询名字
          author = models.ManyToManyField(to='Author',db_constraint=False,related_name='books')
          
      class Publish(BaseModel):
          name = models.CharField(max_length=32)
          addres = models.CharField(max_length=32)
      

   2. 多对多:外键放在常用的一方(书 ,作者)

      class Book(BaseModel):
          name = models.CharField(max_length=32)
          price = models.DecimalField(max_digits=9,decimal_places=2)
          '''
               related_name='books' : 设置反向查询为books
               db_constraint=False : 断开外键约束
               on_delete=models.DO_NOTHING(在外键数据没有的情况下,任然保持数据 出版社没了，书还是那个出版社出版)
          '''
          publish = 									models.ForeignKey(to='Publish',related_name='books',db_constraint=False,on_delete=models.DO_NOTHING)
          # 多对多字段 断约束  设置反向查询名字
      author=models.ManyToManyField(to='Author',db_constraint=False,related_name='books')
      
      

   3.一对一 : 外键放在不长用的那一方

   class Book(BaseModel):
       name = models.CharField(max_length=32)
       price = models.DecimalField(max_digits=9,decimal_places=2)
       '''
            related_name='books' : 设置反向查询为books
            db_constraint=False : 断开外键约束
            on_delete=models.DO_NOTHING(在外键数据没有的情况下,任然保持数据 出版社没了，书还是那个			出版社出版)
       '''
       publish = models.ForeignKey(to='Publish',related_name='books',db_constraint=False,on_delete=models.DO_NOTHING)
       # 多对多字段 断约束  设置反向查询名字
       author = models.ManyToManyField(to='Author',db_constraint=False,related_name='books')
   
   
   

   外键字段为正向查询字段,related_name是反向查询字段

2.如何断外键关联

​ 设置外键字段db_constraint=False

3.外键之间的级联关系

1. 一对一 : 作者没了,详情也没了 : on_delete=models.CASEADE
2. 一对多 : 出版社没了,书还是那个出版社出版:on_delete=models.DO_ONTHING
3. 一对多 : 部门没了 ,员工没有部门(空部门) :null=True ,on_delete=models.SET_NULL
4. 一对多 : 部门没了,员工进入默认部门(默认值) : default=0, on_delete=models.SET_DEFAULT
5. 多对多 : 不能设置 on_delete

4.(重点)连表序列化,在model类中定义插拔序列化方法属性,完成连表查询

    @property
    def author_detail(self):
        author_queryset = self.authors.all()   #查询出所有的作者
        author_detail = []
        for author_obj in author_queryset:
            author_detail.append(
                {
                    'name': author_obj.name,
                    'sex':author_obj.get_sex_display(),
                    'mobile':author_obj.detail.mobile

                }
            )
        return author_detail  #返回作者列表信息

5.(正常) 子序列化可以辅助快速实现自定义外键深度的序列化,但是不能完成反序列化

# 前提 : 如果只有查需求的接口,自定义深度还可以用子序列化方式完成
class PublishSerilizer(ModelSerializer):
    # 子序列化都是提供外键(正方向)完成深度查询的,外键数据是唯一:many=Falise 不唯一 many=True
    #注 : 只能参与序列化,且反序列化不能写(反序列化外键字段会抛异常)
    books = BookSerializer(many=True)
    class Meta:
        model = models.Publish
        fields = ['name','address','books']

6.(重要) 单查 群查接口,序列化类提供序列化对象,many参数控制着操作的数据是一条还是多条

7.(正常)单删 群删接口,后台操作删除字段即可,前端提供pk为单删,提供pks就是群删

# 单删 群删
    def delete(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        if pk:
            pks = [pk]
        else:
            pks = request.data.get('pks')
        row = models.Book.objects.filter(is_delete=False,pk__in=pks).update(is_delete=True)
        if row:
            return APIResponse.APIResponse(msg='delete ok')
        return APIResponse.APIResponse(status=1,msg='delete error')

8.(重点) 单增群增接口,根据数据判断是单增还是群增,对应序列化类要设置many,而序列化只需要通过data即可

# 单增 群增
    def post(self,request,*args,**kwargs):
        request_data = request.data
        if isinstance(request_data,dict)  and len(request_data) !=0:
            book_ser = Serializers.BookSerializer(data=request_data,many=False)
            if book_ser.is_valid(raise_exception=True):
                book_obj = book_ser.save()
                return APIResponse.APIResponse(results=Serializers.BookSerializer(book_obj,many=False).data)
            else:
                return APIResponse.APIResponse(results=book_ser.errors)

        elif isinstance(request_data,list) and len(request_data) !=0:
            book_ser = Serializers.BookSerializer(data=request_data, many=True)
            if book_ser.is_valid(raise_exception=True):
                book_obj_list = book_ser.save()
                return APIResponse.APIResponse(results=Serializers.BookSerializer(book_obj_list,many=True).data)
            else:
                return APIResponse.APIResponse(results=book_ser.errors)
        else:
            return APIResponse.APIResponse(1,'add error')

9.(正常)单整体改群整体改,前端提供的数据,后台要转化成要修改的对象们和用来更新的数据们,ModelSerializser设置 list_serializesr_class关联自己的ListSerializer,重新update()方法,完成群该

# 单整体改  群整体改
    def put(self,request,*args,**kwargs):
        request_data = request.data
        pk = kwargs.get('pk')
        if pk:
            try:
                book_obj = models.Book.objects.get(pk=pk)
                print(pk)
                print(book_obj)
            except:
                return APIResponse.APIResponse(1,'update error')
            book_ser = Serializers.BookSerializer(instance=book_obj,data=request_data)
            book_ser.is_valid(raise_exception=True)
            res_obj = book_ser.save()
            return APIResponse.APIResponse(results=Serializers.BookSerializer(res_obj).data)
        elif isinstance(request_data,list) and len(request_data) !=0:
            obj_list = []
            data_list = []
            for dic in request_data:
                try:
                    pk = dic.pop('pk')
                    try:
                        obj = models.Book.objects.filter(pk=pk).first()
                        obj_list.append(obj)
                        data_list.append(dic)
                    except:
                        pass
                except:
                    return APIResponse.APIResponse(1,'update error')

            book_ser_list = Serializers.BookSerializer(instance=obj_list,data=data_list,many=True)
            book_ser_list.is_valid(raise_exception=True)
            book_res_list = book_ser_list.save()
            return APIResponse.APIResponse(results=Serializers.BookSerializer(book_res_list,many=True).data)
        else:
            return APIResponse.APIResponse(http_status=400,status=1,msg='update error')

10.(正常) 单局部改,序列化参数instance=修改的对象,data=修改的数据,partial=能否能局部修改,单整体改就是partial=False (默认就是False)

# 单局部改  群局部改
    def patch(self, request, *args, **kwargs):
        request_data = request.data
        pk = kwargs.get('pk')
        if pk:
            try:
                book_obj = models.Book.objects.get(pk=pk)
            except:
                return APIResponse.APIResponse(1, 'update error')
            book_ser = Serializers.BookSerializer(instance=book_obj, data=request_data,partial=True)
            book_ser.is_valid(raise_exception=True)
            res_obj = book_ser.save()
            return APIResponse.APIResponse(results=Serializers.BookSerializer(res_obj).data)
        elif isinstance(request_data, list) and len(request_data) != 0:
            obj_list = []
            data_list = []
            for dic in request_data:
                try:
                    pk = dic.pop('pk')
                    try:
                        obj = models.Book.objects.filter(pk=pk).first()
                        obj_list.append(obj)
                        data_list.append(dic)
                    except:
                        pass
                except:
                    return APIResponse.APIResponse(1, 'update error')

            book_ser_list = Serializers.BookSerializer(instance=obj_list, data=data_list, many=True,partial=True)
            book_ser_list.is_valid(raise_exception=True)
            book_res_list = book_ser_list.save()
            return APIResponse.APIResponse(results=Serializers.BookSerializer(book_res_list, many=True).data)
        else:
            return APIResponse.APIResponse(http_status=400, status=1, msg='update error')

异常模块代码:

from rest_framework.response import Response  #导入Response类

class APIResponse(Response):  #继承Response类
    def __init__(self,status=0,msg='ok',results=None,http_status=None,headers=None,exception=None,**kwargs): #重写__init__方法
        data = {
            'status':status,
            'msg':msg
        }
        if results is not None:
            data['result'] = results

        data.update(**kwargs)   #接收其他多余参数
        # 再使用父类的__init__方法
        super().__init__(data=data,status=http_status,headers=headers,exception=exception)

orm models代码:

from django.db import models
from django.conf import settings


# 一、基表
# Model类的内部配置Meta类要设置abstract=True，这样的Model类就是用来作为基表
# 多表：Book，Publish，Author，AuthorDetail
class BaseModel(models.Model):
    is_delete = models.BooleanField(default=False)
    create_time = models.DateTimeField(auto_now_add=True)
    class Meta:
        # 基表必须设置abstract，基表就是给普通Model类继承使用的，设置了abstract就不会完成数据库迁移完成建表
        abstract = True

class Book(BaseModel):
    name = models.CharField(max_length=16)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    publish = models.ForeignKey(to='Publish', related_name='books', db_constraint=False, on_delete=models.DO_NOTHING)

    # 重点：多对多外键实际在关系表中，ORM默认关系表中两个外键都是级联
    # ManyToManyField字段不提供设置on_delete，如果想设置关系表级联，只能手动定义关系表
    authors = models.ManyToManyField(to='Author', related_name='books', db_constraint=False)
    @property
    def author_detail(self):
        author_queryset = self.authors.all()
        author_detail = []
        for author_obj in author_queryset:
            author_detail.append(
                {
                    'name': author_obj.name,
                    'sex':author_obj.get_sex_display(),
                    'mobile':author_obj.detail.mobile

                }
            )
        return author_detail
    class Meta:
        verbose_name_plural = '书籍表'

    def __str__(self):
        return self.name


class Publish(BaseModel):
    name = models.CharField(max_length=16)
    address = models.CharField(max_length=64)

    class Meta:
        verbose_name_plural = '出版社表'

    def __str__(self):
        return self.name

class Author(BaseModel):
    name = models.CharField(max_length=16)
    sex = models.IntegerField(choices=[(0, '男'),(1, '女')], default=0)

    class Meta:
        verbose_name_plural='作者表'

    def __str__(self):
        return self.name

class AuthorDetail(BaseModel):
    mobile = models.CharField(max_length=11)
    # 有作者可以没有详情，删除作者，详情一定会被级联删除
    # 外键字段为正向查询字段，related_name是反向查询字段
    author = models.OneToOneField(to='Author', related_name='detail', db_constraint=False, on_delete=models.CASCADE)

序列化代码:

from rest_framework import serializers
from rest_framework.serializers import ModelSerializer
from . import models

class BookListSerializer(serializers.ListSerializer):

    def update(self, instance, validated_data):
        return [
            self.child.update(instance[i],attrs) for i,attrs in validated_data
        ]

class BookSerializer(ModelSerializer):
    class Meta:
        model = models.Book
        list_serializes_class = BookListSerializer
        fields = ['name','price','author_detail','publish','authors']
        extra_kwargs = {
            'publish':{
                'write_only':True
            },
            'authors':{
                'write_only':True
            }
        }

class PublishSerilizer(ModelSerializer):
    books = BookSerializer(many=True)
    class Meta:
        model = models.Publish
        fields = ['name','address','books']