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drf 序列化

时间:2019-10-18 19:47:50      阅读:44      评论:0      收藏:0      [点我收藏+]

 

序列化组件:

知识点:Serializer(偏底层)、ModelSerializer(重点)、ListModelSerializer(辅助群改)

Serializer

序列化准备:

  • 模型层:models.py

    class User(models.Model):
        SEX_CHOICES = [
            [0, ],
            [1, ],
        ] # 自定义的数据
        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             #数据库表名
            verbose_name = 用户               #表名中文
            verbose_name_plural = verbose_name   #表名祛除s
    
        def __str__(self):
            return %s % self.name

     

  • 后台管理层:admin.py
  • # 在admin.py中进行注册
    
    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()),
]

序列化使用


  • 序列化层:api/serializers.py

"""
1)设置需要返回给前台 那些model类有对应的 字段,不需要返回的就不用设置了
2)设置方法字段,字段名可以随意,字段值有 get_字段名 提供,来完成一些需要处理在返回的数据
"""





#
序列化组件 - 为每一个model类通过一套序列化工具类 # 序列化组件的工作方式与django froms组件非常相似 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,可以少提供, # 但是提供的数据库对应的字段,名字一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: 自己配置的 /media/,给后面高级序列化与视图类准备的 # obj.icon不能直接作为数据返回,因为内容虽然是字符串,但是类型是ImageFieldFile类型 return %s%s%s % (rhttp://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,如果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 就是可以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:
                # 用户对象不能直接作为数据返回给前台
                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)不能直接作为数据返回给前台
            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
            })
Serializer序列化模块   总结
	序列化
	 ser:
		1)设置需要返回给前台 那些model类有对应的 字段,不需要返回的就不用设置了
		2)设置方法字段,字段名可以随意,字段值有 get_字段名 提供,来完成一些需要处理在返回的数据
	 view:
		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,如果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 就是可以返回给前台的序列化数据
            return Response({
                ‘status‘: 0,
                ‘msg‘: 0,
                ‘results‘: user_ser.data
            })
	反序列化
	 ser:
	 	1)设置必填与选填序列化字段,设置校验规则
        2)为需要额外校验的字段提供局部钩子函数,如果该字段不入库,且不参与全局钩子校验,可以将值取出校验
        3)为有联合关系的字段们提供全局钩子函数,如果某些字段不入库,可以将值取出校验
        4)重写create方法,完成校验通过的数据入库工作,得到新增的对象
	 view:

项目序列化准备: 

  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)
  路由
#
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}),
]

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

  多表设计

技术分享图片
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,可以继承两个字段
View Code

  基表

 

技术分享图片
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,作为基表的Model不能在数据库中形成对应的表
    class Meta:
        abstract = True
View Code

 

  断关联多表关系

1、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,如作者表与作者详情表,作者删除级联删除详情,详情删除作者依旧存在,所以建议外键在详情表中
    多对多 - 外键在关系表中
    
2、ORM正向方向连表查找:
    正向:通过外键字段 eg: author_detial_obj.author 
    反向:通过related_name的值 eg:author_obj.detail
    注:依赖代码见下方
    
3、连表操作关系:
    1)作者删除,详情级联 - on_delete=models.CASCADE
    2)作者删除,详情置空 - null=True, on_delete=models.SET_NULL
    3)作者删除,详情重置 - default=0, on_delete=models.SET_DEFAULT
    4)作者删除,详情不动 - on_delete=models.DO_NOTHING
    注:拿作者与作者详情表举例
    
4、外键关联字段的参数 - 如何实现 断关联、目前表间操作关系、方向查询字段
    i)作者详情表中的
    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,但是django2.x必须手动明确)
  model类
技术分享图片
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
"""

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

    # 作为基表的Model不能在数据库中形成对应的表,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 就能访问所有出版的书
        on_delete=models.DO_NOTHING,  # 设置连表操作关系
    )
    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 = 作者
        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 = 作者详情
        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

# 可以单独作为Publish接口的序列化类,也可以作为Book序列化外键publish辅助的序列化组件
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
        # 所有字段
        # 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
技术分享图片
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
        })
View Code
  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
技术分享图片
 1 class BookModelDeserializer(ModelSerializer):
 2     class Meta:
 3         model = models.Book
 4         fields = (name, price, publish, authors)
 5         # extra_kwargs 用来完成反序列化字段的 系统校验规则
 6         extra_kwargs = {
 7             name: {
 8                 required: True,
 9                 min_length: 1,
10                 error_messages: {
11                     required: 必填项,
12                     min_length: 太短,
13                 }
14             }
15         }
16     
17     # 局部钩子
18     def validate_name(self, value):
19         # 书名不能包含 g 字符
20         if g in value.lower():
21             raise ValidationError(该g书不能出版)
22         return value
23     # 全局钩子
24     def validate(self, attrs):
25         publish = attrs.get(publish)
26         name = attrs.get(name)
27         if models.Book.objects.filter(name=name, publish=publish):
28             raise ValidationError({book: 该书已存在})
29         return attrs
30 
31     # ModelSerializer类已经帮我们实现了 create 与 update 方法
钩子

  视图层:api/views.py

class Book(APIView):
    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,马上终止当前视图方法,抛异常返回给前台
        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)

  序列化层:api/serializers.py
"""
1) fields中设置所有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
"""
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: 太短,
                }
            },
            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
class V2Book(APIView):
    # 单查:有pk
    # 群查:无pk
    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.V2BookModelSerializer(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.V2BookModelSerializer(book_query, many=True).data
        return Response({
            status: 0,
            msg: ok,
            results: book_data
        })

    # 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)
        # 当校验失败,马上终止当前视图方法,抛异常返回给前台
        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()),
]

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

drf 序列化

原文:https://www.cnblogs.com/Fzhiyuan/p/11699887.html

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