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序列化模块ModelSerializer

时间:2019-10-17 10:26:10      阅读:76      评论:0      收藏:0      [点我收藏+]

标签:erro   extra   mobile   max   obj   ice   api   tin   document   

课程准备

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

"""
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
"""

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,作为基表的Model不能在数据库中形成对应的表
    class Meta:
        abstract = True

提取每个表都有的字段,创建基类,其它表基础该基类

断关联多表关系

知识点(重点)
"""
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
    db_constraint=False - 断关联
    
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
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

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
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
class BookModelDeserializer(ModelSerializer):
    class Meta:
        model = models.Book
        fields = (name, price, publish, authors)
        # extra_kwargs 用来完成反序列化字段的 系统校验规则
        extra_kwargs = {
            name: {
                required: True,
                min_length: 1,
                error_messages: {
                    required: 必填项,
                    min_length: 太短,
                }
            }
        }
    
    # 局部钩子
    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
    # 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

    # ModelSerializer类已经帮我们实现了 create 与 update 方法
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()),
]

 

序列化模块ModelSerializer

标签:erro   extra   mobile   max   obj   ice   api   tin   document   

原文地址:https://www.cnblogs.com/AbrahamChen/p/11690318.html

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