drf 序列化 反序列化

Posted 2021-03-25 zrh-960906

准备：

　配置：settings.py

INSTALLED_APPS = [
    ‘rest_framework‘,
]

DATABASES = {
    ‘default‘: {
        ‘ENGINE‘: ‘django.db.backends.mysql‘,
        ‘NAME‘: ‘dg_proj‘,
        ‘USER‘: ‘root‘,
        ‘PASSWORD‘: ‘123‘,
    }
}

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‘)

REST_FRAMEWORK = {
# 全局配置异常模块
    ‘EXCEPTION_HANDLER‘: ‘api.exception.exception_handler‘,
}

任何__init__文件

import pymysql
pymysql.install_as_MySQLdb()

主路由

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}),
]

子路由

from django.conf.urls import url
from . import views

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

model 类　　多表设计

# 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不能在数据库形成对应的表，设置abstract=True
    class Meta:
        abstract = True

class Book(BaseModel):
    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‘
    )
    
    @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 = 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 = 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 = 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

admin.py 中注册

from . import models

admin.site.register(models.Author)
admin.site.register(models.AuthorDetail)
admin.site.register(models.Book)
admin.site.register(models.Publish)

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):
    # 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
    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‘}

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
        })

反序列化

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 系统校验规则
        extra_kwargs = {
            ‘name‘: {
                ‘required‘: True,
                ‘min_length‘: 1,
                ‘error_message‘: {
                    ‘required‘: ‘必填项‘,
                    ‘min_length‘: ‘太短‘
                }
            }
        }

    # 局部钩子
    def validate_name(self,value):
          # 书名不能含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

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，终止当前视图方法，抛出异常返回给前台
        book_ser.is_valid(raise_exception=True)
        book_obj = book_ser.save()
        return Response({
            ‘status‘:0,
            ‘msg‘:‘ok‘,
            ‘results‘:serializers.BookModelDeserializer(book_obj).data
        })

序列化与反序列化整合（重点）

　　fields中设置所有序列化与反序列化字段,  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)

　　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):
        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)
        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
        })

    def delete(self,request,*args,**kwargs):
　　　　# 单删 有pk   群删 无pks
        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‘
        })