Django REST framework 中的序列化器

2021-12-23 16:48:45

在此之前定义一个序列化工具：
 
 
views中的的代码
from rest_framework.viewsets import ModelViewSet

from .models import BookInfo

from .serializers import BookInfoSerializers

class BookInfoViewSet(ModelViewSet):

    queryset = BookInfo.objects.all() # 取序列化模型

    serializer_class = BookInfoSerializers # 指定序列化的类
 
定制url
from django.conf.urls import url, include

from . import views

from rest_framework.routers import DefaultRouter

router = DefaultRouter()

router.register(r"books", views.BookInfoViewSet)

urlpatterns = [

    url(r'^index/$', views.index),

]

urlpatterns += router.urls
 
访问路径配置
http://127.0.0.1:8000/app001/books/
 
 
定制普通的序列化类
已有的model数据类型如下所示：
class BookInfo(models.Model):

    btitle = models.CharField(max_length=20, verbose_name='名称')

    bpub_date = models.DateField(verbose_name='发布日期')

    bread = models.IntegerField(default=0, verbose_name='阅读量')

    bcomment = models.IntegerField(default=0, verbose_name='评论量')

    is_delete = models.BooleanField(default=False, verbose_name='逻辑删除')

    class Meta:

        db_table = 'tb_books'  # 指明数据库表名

        verbose_name = '图书'  # 在admin站点中显示的名称

        verbose_name_plural = verbose_name  # 显示的复数名称

    def __str__(self):

        return self.btitle
 
 
继承serializers.Serializer的序列化器：
# 为以上的model定制一个序列化器
from rest_framework import serializers

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20)

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)
 
 
演示效果（python manages.py shell的环境下运行）：
# 查询图书的的对象

from app001.models import BookInfo

book = BookInfo.objects.all()[0]

# 构造序列化器

from app001.serializers import BookInfoSerializers

serializer = BookInfoSerializers(book)

# 获取序列化之后的属性

print(serializer.data)

# 打印效果：

"""

{'id': 1, 'bpub_date': '1980-05-01', 'btitle': '射雕英雄传', 'is_delete': False, 'bcomment': 34, 'bread': 12}

"""
 
 
 
model类
class HeroInfo(models.Model):

    GENDER_CHOICES = (

        (0, 'male'),

        (1, 'female')

    )

    hname = models.CharField(max_length=20, verbose_name='名称')

    hgender = models.SmallIntegerField(choices=GENDER_CHOICES, default=0, verbose_name='性别')

    hcomment = models.CharField(max_length=200, null=True, verbose_name='描述信息')

    hbook = models.ForeignKey(BookInfo, on_delete=models.CASCADE, verbose_name='图书')  # 外键

    is_delete = models.BooleanField(default=False, verbose_name='逻辑删除')

    class Meta:

        db_table = 'tb_heros'

        verbose_name = '英雄'

        verbose_name_plural = verbose_name

    def __str__(self):

        return self.hname
 
 
序列化器
from rest_framework import serializers

class HeroInfoSerializers(serializers.Serializer):

    """英雄数据序列化器"""

    GENDER_CHOICES = (

        (0, 'male'),

        (1, 'female')

    )

    # hname = models.CharField(max_length=20, verbose_name='名称')

    id = serializers.IntegerField(label='ID', read_only=True)

    # hgender = models.SmallIntegerField(choices=GENDER_CHOICES, default=0, verbose_name='性别')

    hgender = serializers.ChoiceField(choices=GENDER_CHOICES, label='性别', required=False)

    # hcomment = models.CharField(max_length=200, null=True, verbose_name='描述信息')

    hcomment = serializers.CharField(label='描述信息', max_length=200, required=False, allow_null=True)

    # hbook = models.ForeignKey(BookInfo, on_delete=models.CASCADE, verbose_name='图书')  # 外键

    hbook = serializers.PrimaryKeyRelatedField(label='图书', read_only=True)

    # is_delete = models.BooleanField(default=False, verbose_name='逻辑删除')
 
 
 
 
交互界面输出
# 查询英雄的对象
from app001.models import HeroInfo

hero = HeroInfo.objects.all()[0]

from app001.serializers import HeroInfoSerializers

hs = HeroInfoSerializers(hero)

print(hs.data)
"""
{'hgender': 1, 'id': 1, 'hcomment': '降龙掌', 'hbook': '射雕英雄传'}
 
{'hgender': 1, 'id': 1, 'hcomment': '降龙掌', 'hbook': 1}
"""
此字段将被序列化为关联对象的主键。
 
（hbook = serializers.PrimaryKeyRelatedField(label='图书', read_only=True)
hbook = serializers.PrimaryKeyRelatedField(label='图书',queryset=BookInfo.objects.all())）
print(hs.data)
"""
{'hgender': 1, 'id': 1, 'hcomment': '降龙掌', 'hbook': 1}
"""
（hbook = serializers.StringRelatedField(label='图书')）
print(hs.data)
"""
{'hgender': 1, 'id': 1, 'hcomment': '降龙掌', 'hbook': '射雕英雄传'}
"""
 
（    hbook = serializers.SlugRelatedField(label='图书', read_only=True, slug_field='bpub_date')
 
）
{'hbook': datetime.date(1980, 5, 1), 'hcomment': '降龙掌', 'hgender': 1, 'id': 1}
 
（    hbook = BookInfoSerializers()
 
）
{'hgender': 1, 'hcomment': '降龙掌', 'id': 1, 'hbook': OrderedDict([('id', 1), ('btitle', '射雕英雄传'), ('bpub_date', '1980-05-01'), ('bread', 12), ('bcomment', 34), ('is_delete', False)])}
 
 
 
（    hbook = BookRelateField(read_only="True")）
{'hcomment': '降龙掌', 'hbook': 'Book: 1 射雕英雄传', 'id': 1, 'hgender': 1}
 
 
 
（    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增
 
）
 
测试命令
from app001.models import BookInfo

book = BookInfo.objects.all()[0]

# 构造序列化器

from app001.serializers import BookInfoSerializers

bs = BookInfoSerializers(book)

# 获取序列化之后的属性

print(bs.data)
 
 
{'bread': 12, 'is_delete': False, 'bpub_date': '1980-05-01', 'heroinfo_set': [1, 2, 3, 4, 5], 'btitle': '射雕英雄传', 'id': 1, 'bcomment': 34}
 
 
 
from app001.serializers import BookInfoSerializers

data = {'bpub_date': 123}

serializer = BookInfoSerializers(data=data)

serializer.is_valid()

serializer.errors

serializer.validated_data
 
 
from app001.serializers import BookInfoSerializers

data = {'bpub_date': "1993-12-27", 'btitle': 'python'}

serializer = BookInfoSerializers(data=data)

serializer.is_valid()

serializer.errors

serializer.validated_data
"""
OrderedDict([('btitle', 'python'), ('bpub_date', datetime.date(1993, 12, 27))])
 
"""
 
 
验证失败报404异常
serializer.is_valid(raise_exception=True)
 
from rest_framework import serializers

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20)

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)

    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增

    def validate_btitle(self, value):

        if 'django' not in value.lower():

            raise serializers.ValidationError("图书不是关于Django的")

        return value
 
from app001.serializers import BookInfoSerializers
data = {'bpub_date': "1993-12-27", 'btitle': 'python_django'}
serializer = BookInfoSerializers(data=data)
serializer.is_valid()
serializer.errors
serializer.validated_data
"""
OrderedDict([('btitle', 'python_django'), ('bpub_date', datetime.date(1993, 12, 27))])
 
"""
 
在序列化器中定义一个validate（）在这个方法中定义的字段会在最后被验证；
from rest_framework import serializers

def about_django(value):

    if 'django' not in value.lower():

        raise serializers.ValidationError("about_django中抛出图书不是关于Django的")

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20,validators=[about_django])

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)

    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增

    def validate(self, attrs):

        bread = attrs['bread']

        bcomment = attrs['bcomment']

        if bread < bcomment:

            raise serializers.ValidationError('阅读量小于评论量')

        return attrs
 
 
 
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 34, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'python_django'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

False

>>> serializer.errors

{'non_field_errors': [ErrorDetail(string='阅读量小于评论量', code='invalid')]}

>>> serializer.validated_data

{}
抛出异常：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 14, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'ptython'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

False

>>> serializer.errors

{'btitle': [ErrorDetail(string='about_django中抛出图书不是关于Django的', code='invalid')]}

>>> serializer.validated_data

{}

>>>
 
 
在序列化器类的内部定义一个方法，来验证字段的属性（注意定义的函数的结构）；
from rest_framework import serializers

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20,validators=[about_django])

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)

    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增

    def validate_btitle(self, value):

        if 'django' not in value.lower():

            raise serializers.ValidationError("图书不是关于Django的")

        return value
 
验证成功：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'python_django'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

True

>>> serializer.errors

{}

>>> serializer.validated_data

OrderedDict([('btitle', 'python_django'), ('bpub_date', datetime.date(1993, 12, 27)), ('bread', 12), ('bcomment', 10)])

>>>
 
 
验证失败：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'ptython'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

False

>>> serializer.errors

{'btitle': [ErrorDetail(string='图书不是关于Django的', code='invalid')]}

>>> serializer.validated_data

{}
 
 
在序列化器的外部定义一个方法，将该方法加入到字段中作为字段的验证方法
from rest_framework import serializers

def about_django(value):

    if 'django' not in value.lower():

        raise serializers.ValidationError("图书不是关于Django的")

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20,validators=[about_django])

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)

    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增

    def validate_btitle(self, value):

        if 'django' not in value.lower():

            raise serializers.ValidationError("图书不是关于Django的")

        return value

    def validate(self, attrs):

        bread = attrs['bread']

        bcomment = attrs['bcomment']

        if bread < bcomment:

            raise serializers.ValidationError('阅读量小于评论量')

        return attrs
 
返回成功：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'ptython_django'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

True

>>> serializer.errors

{}

>>> serializer.validated_data

OrderedDict([('btitle', 'ptython_django'), ('bpub_date', datetime.date(1993, 12, 27)), ('bread', 12), ('bcomment', 10)])
 
返回失败：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'ptython'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

False

>>> serializer.errors

{'btitle': [ErrorDetail(string='about_django中抛出图书不是关于Django的', code='invalid')]}

>>> serializer.validated_data

{}
 
 
验证顺序：
验证顺序：
1，model字段本身;
2，字段中定义的validators;
3,序列化器中定义的对字段的验证方法validate_字段名；
4, 序列话器中validate的方法。
 
单字段唯一；
from rest_framework.validators import UniqueValidator

slug = SlugField(

    max_length=100,

    validators=[UniqueValidator(queryset=BlogPost.objects.all())]

)
 
 
联合唯一；
from rest_framework.validators import UniqueTogetherValidator

class ExampleSerializer(serializers.Serializer):

# ...

class Meta:

validators = [

UniqueTogetherValidator(

queryset=ToDoItem.objects.all(),

fields=('list', 'position')

)

]
 
 
序列化后的数据保存
 
验证未通过程序包报错：
>>> from app001.serializers import BookInfoSerializers

>>> data = {'btitle': '封神演义'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

False

>>> serializer.save()

Traceback (most recent call last):

  File "<console>", line 1, in <module>

  File "/home/python/.virtualenvs/djf/lib/python3.5/site-packages/rest_framework/serializers.py", line 184, in save

    'You cannot call `.save()` on a serializer with invalid data.'

AssertionError: You cannot call `.save()` on a serializer with invalid data.
 
 
验证通过并保存
>>> from app001.serializers import BookInfoSerializers

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1993-12-27", 'btitle': 'ptython_django'}

>>> serializer = BookInfoSerializers(data=data)

>>> serializer.is_valid()

True

>>> serializer.save()

<BookInfo: ptython_django>
 
 
 
序列化器的定义
from rest_framework import serializers

def about_django(value):

    if 'django' not in value.lower():

        raise serializers.ValidationError("about_django中抛出图书不是关于Django的")

class BookInfoSerializers(serializers.Serializer):

    """ 图书列表序列化器"""

    id = serializers.IntegerField(label="ID", read_only=True)

    btitle = serializers.CharField(label="名称", max_length=20, validators=[about_django])

    bpub_date = serializers.DateField(label='发布日期', required=False)

    bread = serializers.IntegerField(label='阅读量', required=False)

    bcomment = serializers.IntegerField(label='评论量', required=False)

    is_delete = serializers.BooleanField(label='逻辑删除', required=False)

    heroinfo_set = serializers.PrimaryKeyRelatedField(read_only=True, many=True)  # 新增

    def validate_btitle(self, value):

        if 'django' not in value.lower():

            raise serializers.ValidationError("图书不是关于Django的")

        return value

    def create(self, validated_data):

        """新建"""

        return BookInfo.objects.create(**validated_data)

    def update(self, instance, validated_data):

        """更新，instance为要更新的对象实例"""

        instance.btitle = validated_data.get('btitle', instance.btitle)

        instance.bpub_date = validated_data.get('bpub_date', instance.bpub_date)

        instance.bread = validated_data.get('bread', instance.bread)

        instance.bcomment = validated_data.get('bcomment', instance.bcomment)

        instance.save()

        return instance
 
成功创建对象
>>> from app001.serializers import BookInfoSerializers

>>> # from app001.models import BookInfo

>>> # book = BookInfo.objects.filter(btitle="ptython_django")[0]

>>> book = BookInfo.objects.get(id=10)

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1994-12-27", 'btitle': 'ptython_django'}

>>> # data = {'bpub_date': "1994-12-27",'bcomment': 10, 'bread': 12,}

>>> serializer = BookInfoSerializers(book, data=data)

>>> serializer.is_valid()

True

>>> serializer.save()

<BookInfo: ptython_django>

>>> book.btitle

'ptython_django'

>>>
 
成功修改对象传入对象中的属性；
>>> from app001.serializers import BookInfoSerializers

>>> from app001.models import BookInfo

>>> book = BookInfo.objects.filter(btitle="ptython_django")[0]

>>> data = {'bcomment': 10, 'bread': 12,'bpub_date': "1995-12-27", 'btitle': 'ptython_django'}

>>> serializer = BookInfoSerializers(book, data=data)

>>> serializer.is_valid()

True

>>> serializer.save()

<BookInfo: ptython_django>

>>> book.btitle

'ptython_django'

>>> book.bpub_date

datetime.date(1995, 12, 27)
 
 
 
修改通过书名取到的的对象的值；
>>> from app001.serializers import BookInfoSerializers

>>> from app001.models import BookInfo

>>> book = BookInfo.objects.filter(btitle="ptython_django")[0]

>>> data = {'bpub_date': "1996-12-27", 'btitle': 'ptython_django'}

>>> serializer = BookInfoSerializers(book, data=data)

>>> serializer.is_valid()

True

>>> serializer.save()

<BookInfo: ptython_django>

>>> book.btitle

'ptython_django'

>>> book.bpub_date

datetime.date(1996, 12, 27)
 
 
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