序列化组件

时间 2019-12-02

标签序列组件繁體版

原文原文链接

1、Serializer

1.序列化准备：

模型层：models.py

class User(models.Model):
    SEX_CHOICES = [
        [0, '男'],
        [1, '女'],
    ]
    name = models.CharField(max_length=64)
    pwd = models.CharField(max_length=32)
    phone = models.CharField(max_length=11, null=True, default=None)
    sex = models.IntegerField(choices=SEX_CHOICES, default=0)
    icon = models.ImageField(upload_to='icon', default='icon/default.jpg')

    class Meta:
        db_table = 'old_boy_user'
        verbose_name = '用户'
        verbose_name_plural = verbose_name

    def __str__(self):
        return '%s' % self.name

后台管理层：admin.py

from django.contrib import admin
from . import models

admin.site.register(models.User)

配置层：settings.py

# 注册rest_framework
INSTALLED_APPS = [
    # ...
    'rest_framework',
]

# 配置数据库
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'day70',
        'USER': 'root',
        'PASSWORD': '123'
    }
}

# media资源
MEDIA_URL = '/media/'  # 后期高级序列化类与视图类，会使用该配置
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')  # media资源路径

# 国际化配置
LANGUAGE_CODE = 'zh-hans'
TIME_ZONE = 'Asia/Shanghai'
USE_I18N = True
USE_L10N = True
USE_TZ = False

主路由：项目下urls.py

urlpatterns = [
    # ...
    url(r'^api/', include('api.urls')),

    url(r'^media/(?P<path>.*)', serve, {'document_root': settings.MEDIA_ROOT}),
]

子路由：应用下urls.py

urlpatterns = [
    url(r'^users/$', views.User.as_view()),
    url(r'^users/(?P<pk>.*)/$', views.User.as_view()),
]

2.序列化使用

序列化层：api/serializers.py

"""
1）设置须要返回给前台 那些model类有对应的 字段，不须要返回的就不用设置了
2）设置方法字段，字段名能够随意，字段值有 get_字段名 提供，来完成一些须要处理在返回的数据
"""

# 序列化组件 - 为每个model类经过一套序列化工具类
# 序列化组件的工做方式与django froms组件很是类似
from rest_framework import serializers, exceptions
from django.conf import settings

from . import models

class UserSerializer(serializers.Serializer):
    name = serializers.CharField()
    phone = serializers.CharField()
    # 序列化提供给前台的字段个数由后台决定，能够少提供，
    # 可是提供的数据库对应的字段，名字必定要与数据库字段相同
    # sex = serializers.IntegerField()
    # icon = serializers.ImageField()

    # 自定义序列化属性
    # 属性名随意，值由固定的命名规范方法提供:
    #       get_属性名(self, 参与序列化的model对象)
    #       返回值就是自定义序列化属性的值
    gender = serializers.SerializerMethodField()
    def get_gender(self, obj):
        # choice类型的解释型值 get_字段_display() 来访问
        return obj.get_sex_display()


    icon = serializers.SerializerMethodField()
    def get_icon(self, obj):
        # settings.MEDIA_URL: 本身配置的 /media/，给后面高级序列化与视图类准备的
        # obj.icon不能直接做为数据返回，由于内容虽然是字符串，可是类型是ImageFieldFile类型
        return '%s%s%s' % (r'http://127.0.0.1:8000', settings.MEDIA_URL, str(obj.icon))

视图层

"""
1）从数据库中将要序列化给前台的model对象，或是对个model对象查询出来
    user_obj = models.User.objects.get(pk=pk) 或者
    user_obj_list = models.User.objects.all()
2）将对象交给序列化处理，产生序列化对象，若是序列化的是多个数据，要设置many=True
    user_ser = serializers.UserSerializer(user_obj) 或者
    user_ser = serializers.UserSerializer(user_obj_list, many=True)
3）序列化 对象.data 就是能够返回给前台的序列化数据
    return Response({
        'status': 0,
        'msg': 0,
        'results': user_ser.data
    })
"""

class User(APIView):
    def get(self, request, *args, **kwargs):
        pk = kwargs.get('pk')
        if pk:
            try:
                # 用户对象不能直接做为数据返回给前台
                user_obj = models.User.objects.get(pk=pk)
                # 序列化一下用户对象
                user_ser = serializers.UserSerializer(user_obj)
                # print(user_ser, type(user_ser))
                return Response({
                    'status': 0,
                    'msg': 0,
                    'results': user_ser.data
                })
            except:
                return Response({
                    'status': 2,
                    'msg': '用户不存在',
                })
        else:
            # 用户对象列表(queryset)不能直接做为数据返回给前台
            user_obj_list = models.User.objects.all()
            # 序列化一下用户对象
            user_ser_data = serializers.UserSerializer(user_obj_list, many=True).data
            return Response({
                'status': 0,
                'msg': 0,
                'results': user_ser_data
            })

2、ModelSerializer

配置：settings.py

INSTALLED_APPS = [
    # ...
    'rest_framework',
]

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'dg_proj',
        'USER': 'root',
        'PASSWORD': '123',
    }
}
"""
任何__init__文件
import pymysql
pymysql.install_as_MySQLdb()
"""

LANGUAGE_CODE = 'zh-hans'
TIME_ZONE = 'Asia/Shanghai'
USE_I18N = True
USE_L10N = True
USE_TZ = False

MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

View Code

路由

# 主
from django.conf.urls import url, include
from django.contrib import admin
from django.views.static import serve
from django.conf import settings
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^api/', include('api.urls')),
    url(r'^media/(?P<path>.*)', serve, {'document_root': settings.MEDIA_ROOT}),
]


# 子
from django.conf.urls import url
from . import views
urlpatterns = [
    
]

View Code

多表设计

""" Book表：name、price、img、authors、publish、is_delete、create_time

Publish表：name、address、is_delete、create_time Author表：name、age、is_delete、create_time

AuthorDetail表：mobile, author、is_delete、create_time BaseModel基表 is_delete、create_time 上面四表继承基表，能够继承两个字段 """

基表

class BaseModel(models.Model): is_delete = models.BooleanField(default=False) create_time = models.DateTimeField(auto_now_add=True)

# 设置 abstract = True 来声明基表，做为基表的Model不能在数据库中造成对应的表
class Meta:
    abstract = True

断关联多表关系

""" 一、外键位置： 一对多 - 外键放多的一方
       一对一 - 从逻辑正反向考虑，如做者表与做者详情表，做者删除级联删除详情，详情删除做者依旧存在，因此建议外键在详情表中 
      多对多 - 外键在关系表中
   二、ORM正向方向连表查找：
      正向：经过外键字段 eg: author_detial_obj.author
      反向：经过related_name的值 eg：author_obj.detail 
                                     注：依赖代码见下方 
   三、连表操做关系：
     1）做者删除，详情级联 - on_delete=models.CASCADE
     2）做者删除，详情置空 - null=True, on_delete=models.SET_NULL 
     3）做者删除，详情重置 - default=0, on_delete=models.SET_DEFAULT 
     4）做者删除，详情不动 - on_delete=models.DO_NOTHING
                               注：拿做者与做者详情表举例 
   四、外键关联字段的参数 - 如何实现 断关联、目前表间操做关系、方向查询字段 
     i）做者详情表中的 author = models.OneToOneField( to='Author', related_name='detail', db_constraint=False, on_delete=models.CASCADE )
    ii）图书表中的
 publish = models.ForeignKey(
    to='Publish',
    related_name='books',
    db_constraint=False,
    on_delete=models.DO_NOTHING,
)
authors = models.ManyToManyField(
    to='Author'
    related_name='books',
    db_constraint=False,
)
注：ManyToManyField不能设置on_delete，OneToOneField、ForeignKey必须设置on_delete（django1.x系统默认级联，可是django2.x必须手动明确）
"""

model类

from django.db import models

图书管理系统：Book、Author、AuthorDetail、Publish

""" Book表: name、price、img、authors、publish、is_delete、create_time Publish表: name、address、is_delete、create_time Author表: name、age、is_delete、create_time AuthorDetail表: mobile, author、is_delete、create_time """

class BaseModel(models.Model): is_delete = models.BooleanField(default=False) create_time = models.DateTimeField(auto_now_add=True)

# 做为基表的Model不能在数据库中造成对应的表，设置 abstract = True
class Meta:
    abstract = True
class Book(BaseModel): """name、price、img、authors、publish、is_delete、create_time""" name = models.CharField(max_length=64) price = models.DecimalField(max_digits=5, decimal_places=2) img = models.ImageField(upload_to='img', default='img/default.jpg') publish = models.ForeignKey( to='Publish', db_constraint=False, # 断关联 related_name='books', # 反向查询字段：publish_obj.books 就能访问全部出版的书 on_delete=models.DO_NOTHING, # 设置连表操做关系 ) authors = models.ManyToManyField( to='Author', db_constraint=False, related_name='books' )

# 序列化插拔式属性 - 完成自定义字段名完成连表查询
@property
def publish_name(self):
    return self.publish.name

@property
def author_list(self):
    return self.authors.values('name', 'age', 'detail__mobile').all()

class Meta:
    db_table = 'book'
    verbose_name = '书籍'
    verbose_name_plural = verbose_name
def __str__(self):
    return self.name
class Publish(BaseModel): """name、address、is_delete、create_time""" name = models.CharField(max_length=64) address = models.CharField(max_length=64)

class Meta:
    db_table = 'publish'
    verbose_name = '出版社'
    verbose_name_plural = verbose_name
def __str__(self):
    return self.name
class Author(BaseModel): """name、age、is_delete、create_time""" name = models.CharField(max_length=64) age = models.IntegerField()

class Meta:
    db_table = 'author'
    verbose_name = '做者'
    verbose_name_plural = verbose_name
def __str__(self):
    return self.name
class AuthorDetail(BaseModel): """mobile, author、is_delete、create_time""" mobile = models.CharField(max_length=11) author = models.OneToOneField( to='Author', db_constraint=False, related_name='detail', on_delete=models.CASCADE, )

class Meta:
    db_table = 'author_detail'
    verbose_name = '做者详情'
    verbose_name_plural = verbose_name
def __str__(self):
    return '%s的详情' % self.author.name

View Code

序列化

序列化层：api/serializers.py

from rest_framework.serializers import ModelSerializer, SerializerMethodField from rest_framework.exceptions import ValidationError from . import models

class PublishModelSerializer(ModelSerializer): class Meta: model = models.Publish fields = ('name', 'address')

class BookModelSerializer(ModelSerializer): # 了解: 该方式设置的序列化字段，必须在fields中声明 # publish_address = SerializerMethodField() # def get_publish_address(self, obj): # return obj.publish.address

# 自定义连表深度 - 子序列化方式 - 该方式不能参与反序列化，使用在序列化反序列化共存时，不能书写
publish = PublishModelSerializer()

class Meta:
    # 序列化类关联的model类
    model = models.Book
    # 参与序列化的字段
    fields = ('name', 'price', 'img', 'author_list', 'publish')

    # 了解知识点
    # 全部字段
    # fields = '__all__'
    # 与fields不共存，exclude排除哪些字段
    # exclude = ('id', 'is_delete', 'create_time')
    # 自动连表深度
    # depth = 1

视图层：api/views.py

# 序列化
class Book(APIView):
    def get(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        if pk:
            try:
                book_obj = models.Book.objects.get(pk=pk,is_delete=False)
                book_data = serializers.BookModelSerializer(book_obj).data
            except:
                return Response({
                    'status':1,
                    'msg':'书籍不存在'
                })
        else:
            book_query = models.Book.objects.filter(is_delete=False).all()
            book_data = serializers.BookModelSerializer(book_query,many=True).data
        return Response({
            'status':0,
            'msg':'ok',
            'results':book_data
        })

路由层：api/urls.py

urlpatterns = [ url(r'^books/$', views.Book.as_view()), url(r'^books/(?P<pk>.*)/$', views.Book.as_view()), ]

反序列化

序列化层：api/serializers.py

# 反序列化
class BookModelDeserializer(ModelSerializer):
    class Meta:
        fields = ('name','price','publish','authors')
        # extra_kwargs 用来完成反序列化字段 系统检测规则
        extra_kwargs = {
            'name':{
                'required':True,
                'min_length':1,
                'error_messages':{
                    'required':'必填项',
                    'min_length':'过短',
                }
            }
        }
        # 局部钩子
        def validate_name(self,value):
            if 'g' in value.lower():
                raise ValidationError('该书不能出版')
            return value
        # 全局钩子
        def validate(self,attrs):
            publish = attrs.get('publish')
            name = attrs.get('name')
            if models.Book.objects.filter(name=name,publish=publish):
                raise ValidationError({'book':'该书已存在'})
            return attrs

视图层：api/views.py

    # 反序列化
    def post(self,request,*args,**kwargs):
        request_data = request.data
        book_ser = serializers.BookModelDeserializer(data=request_data)
        # raise_exception=True 当校验失败，立刻终止当前视图方法
        book_ser.is_valid(raise_exception=True)
        book_obj = book_ser.save()
        return Response({
            'status':0,
            'msg':'ok',
            'results':serializers.BookModelSerializer(book_obj).data
        })

路由层：api/urls.py

urlpatterns = [ url(r'^books/$', views.Book.as_view()), url(r'^books/(?P<pk>.*)/$', views.Book.as_view()), ]

序列化与反序列化整合（重点）

"""
1) fields中设置全部序列化与反序列化字段
2) extra_kwargs划分只序列化或只反序列化字段
    write_only：只反序列化
    read_only：只序列化
    自定义字段默认只序列化(read_only)
3) 设置反序列化所需的 系统、局部钩子、全局钩子 等校验规则
"""

序列化层：api/serializers.py

class V2BookModelSerializer(ModelSerializer):
    class Meta:
        model = models.Book
        fields = ('name', 'price', 'img', 'author_list', 'publish_name', 'publish', 'authors')
        extra_kwargs = {
            'name': {
                'required': True,
                'min_length': 1,
                'error_messages': {
                    'required': '必填项',
                    'min_length': '过短',
                }
            },
            'publish': {
                'write_only': True
            },
            'authors': {
                'write_only': True
            },
            'img': {
                'read_only': True,
            },
            'author_list': {
                'read_only': True,
            },
            'publish_name': {
                'read_only': True,
            }
        }

    def validate_name(self, value):
        # 书名不能包含 g 字符
        if 'g' in value.lower():
            raise ValidationError('该g书不能出版')
        return value

    def validate(self, attrs):
        publish = attrs.get('publish')
        name = attrs.get('name')
        if models.Book.objects.filter(name=name, publish=publish):
            raise ValidationError({'book': '该书已存在'})
        return attrs

视图层：api/views.py

    # 单增：传的数据是与model对应的字典
    # 群增：传的数据是 装多个 model对应字典 的列表
    def post(self,request,*args,**kwargs):
        request_data = request.data
        if isinstance(request_data,dict):
            many = False
        elif isinstance(request_data,list):
            many = True
        else:
            return Response({
                'status':1,
                'msg':'数据有误',
            })
        book_ser = serializers.V2BookModelSerializer(data=request_data,many=many)

        book_ser.is_valid(raise_exception=True)
        book_result = book_ser.save()
        return Response({
            'status':0,
            'msg':'ok',
            'results':serializers.V2BookModelSerializer(book_result,many=many).data
        })

    # 单删：有pk
    # 群删：有pks   |  {"pks": [1, 2, 3]}

    def delete(self,request,*args,**kwargs):
        pk = kwargs.get('pk')
        if pk:
            pks = [pk]
        else:
            pks = request.data.get('pks')
        if models.Book.objects.filter(pk__in=pks,is_delete=False).update(is_delete=True):
            return Response({
            'status':0,
            'msg':'删除成功'
        })
        return Response({
            'status':1,
            'msg':'删除失败'
        })

路由层：api/urls.py

urlpatterns = [ url(r'^v2/books/$', views.V2Book.as_view()), url(r'^v2/books/(?P<pk>.*)/$', views.V2Book.as_view()), ]

3、ListModelSerializer

总体单改

路由层、模型层、序列化层不须要作修改，只须要处理视图层：views.py

"""
1) 单总体改，说明前台要提供修改的数据，那么数据就须要校验，校验的数据应该在实例化“序列化类对象”时，赋值给data
2）修改，就必须明确被修改的模型类对象，并在实例化“序列化类对象”时，赋值给instance
3）总体修改，全部校验规则有required=True的字段，都必须提供，由于在实例化“序列化类对象”时，参数partial默认为False


注：若是partial值设置为True，就是能够局部改

1）单总体修改，通常用put请求：
V2BookModelSerializer(
    instance=要被更新的对象, 
    data=用来更新的数据,
    partial=默认False，必须的字段所有参与校验
)

2）单局部修改，通常用patch请求：
V2BookModelSerializer(
    instance=要被更新的对象, 
    data=用来更新的数据,
    partial=设置True，必须的字段都变为选填字段
)
    注：partial设置True的本质就是使字段 required=True 校验规则失效
"""

class V2Book(APIView):
    # 单总体改: 对 v2/books/(pk)/ 传的数据是与model对应的字典{name|price|publish|authors}
    def put(self, request, *args, **kwargs):
        request_data = request.data
        pk = kwargs.get('pk')
        old_book_obj = models.Book.objects.filter(pk=pk).first()
        # 目的：将众多数据的校验交给序列化类来处理 - 让序列化类扮演反序列化角色，校验成功后，序列化类来帮你入库
        book_ser = serializers.V2BookModelSerializer(instance=old_book_obj, data=request_data, partial=False)
        book_ser.is_valid(raise_exception=True)
        # 校验经过，完成数据的更新：要更新的目标，用来更新的新数据
        book_obj = book_ser.save()

        return Response({
            'status': 0,
            'msg': 'ok',
            'results': serializers.V2BookModelSerializer(book_obj).data
        })

单与总体局部修改

序列化层：serializers.py

# 重点：ListSerializer与ModelSerializer创建关联的是：
# ModelSerializer的Meta类的 - list_serializer_class
class V2BookListSerializer(ListSerializer):
    def update(self, instance, validated_data):
        # print(instance)  # 要更新的对象们
        # print(validated_data)  # 更新的对象对应的数据们
        # print(self.child)  # 服务的模型序列化类 - V2BookModelSerializer
        for index, obj in enumerate(instance):
            self.child.update(obj, validated_data[index])
        return instance
    
# 原模型序列化类变化
class V2BookModelSerializer(ModelSerializer):
    class Meta:
        # ...
        # 群改，须要设置 自定义ListSerializer，重写群改的 update 方法
        list_serializer_class = V2BookListSerializer
    # ...

视图层：views.py

class V2Book(APIView):
    # 单局部改：对 v2/books/(pk)/ 传的数据，数据字段key都是选填
    # 群局部改：对 v2/books/ 
    # 请求数据 - [{pk:1, name:123}, {pk:3, price:7}, {pk:7, publish:2}]
    def patch(self, request, *args, **kwargs):
        request_data = request.data
        pk = kwargs.get('pk')

        # 将单改，群改的数据都格式化成 pks=[要须要的对象主键标识] | request_data=[每一个要修改的对象对应的修改数据]
        if pk and isinstance(request_data, dict):  # 单改
            pks = [pk, ]
            request_data = [request_data, ]
        elif not pk and isinstance(request_data, list): # 群改
            pks = []
            for dic in request_data:  # 遍历前台数据[{pk:1, name:123}, {pk:3, price:7}, {pk:7, publish:2}]，拿一个个字典
                pk = dic.pop('pk', None)
                if pk:
                    pks.append(pk)
                else:
                    return Response({
                        'status': 1,
                        'msg': '数据有误',
                    })
        else:
            return Response({
                'status': 1,
                'msg': '数据有误',
            })

        # pks与request_data数据筛选，
        # 1）将pks中的没有对应数据的pk与数据已删除的pk移除，request_data对应索引位上的数据也移除
        # 2）将合理的pks转换为 objs
        objs = []
        new_request_data = []
        for index, pk in enumerate(pks):
            try:
                # pk对应的数据合理，将合理的对象存储
                obj = models.Book.objects.get(pk=pk)
                objs.append(obj)
                # 对应索引的数据就须要保存下来
                new_request_data.append(request_data[index])
            except:
                # 重点：反面教程 - pk对应的数据有误，将对应索引的data中request_data中移除
                # index = pks.index(pk)
                # request_data.pop(index)
                continue

        book_ser = serializers.V2BookModelSerializer(instance=objs, data=new_request_data, partial=True, many=True)
        book_ser.is_valid(raise_exception=True)
        book_objs = book_ser.save()

        return Response({
            'status': 0,
            'msg': 'ok',
            'results': serializers.V2BookModelSerializer(book_objs, many=True).data
        })

4、视图类传递参数给序列化类

 1）在视图类中实例化序列化对象时，能够设置context内容
 2）在序列化类中的局部钩子、全局钩子、create、update方法中，均可以用self.context访问视图类传递过来的内容


 需求：
 1) 在视图类中，能够经过request获得登录用户request.user
 2) 在序列化类中，要完成数据库数据的校验与入库操做，可能会须要知道当前的登录用户，但序列化类没法访问request
 3) 在视图类中实例化序列化对象时，将request对象传递进去

视图层：views.py

class Book(APIView):
    def post(self, request, *args, **kwargs):
        book_ser = serializers.BookModelSerializer(data=request_data,context={'request':request})
        book_ser.is_valid(raise_exception=True)
        book_result = book_ser.save()
        return Response({
            'status': 0,
            'msg': 'ok',
            'results': serializers.BookModelSerializer(book_result).data
        })

序列化层：serializers.py

class BookModelSerializer(ModelSerializer):
    class Meta:
        model = models.Book
        fields = ('name', 'price')
    def validate_name(self, value):
        print(self.context.get('request').method)
        return value