14 ListModelSerializer组件

ListModelSerializer模块
自定义反序列化字段
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一些只参与反序列化的字段，但是不是与数据库关联的

在序列化类中规定，并在校验字段时从校验的参数字典中剔除

class PublishModelSerializer(serializers.ModelSerializer):
# 自定义不入库的 反序列化 字段
re_name = serializers.CharField(write_only=True)
class Meta:
model = models.Publish
fields = ('name', 're_name', 'address')
def validate(self, attrs):
name = attrs.get('name')
re_name = attrs.pop('re_name') # 剔除
if name != re_name:
raise serializers.ValidationError({'re_name': '确认名字有误'})
return attrs
2、模型类中自定义序列化深度
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model类中自定义插拔的外键序列化字段，可以采用外键关联表的序列化类来完成深度查询

class Book(BaseModel):
# ...
@property
def publish_detail(self):
from . import serializers
data = serializers.PublishModelSerializer(self.publish).data
return data
3、接口操作总结
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单查群查、单删群删、单增群增、单改群改

路由层：api/url.py
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from django.conf.urls import url
from . import views
urlpatterns = [
# ...
url(r'^v3/books/$', views.BookV3APIView.as_view()),
url(r'^v3/books/(?P.*)/$', views.BookV3APIView.as_view()),
]
模型层：api/models.py
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修改部分：取消book类 name 与 publish 联合唯一，

from django.db import models
from utils.model import BaseModel
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.png')
publish = models.ForeignKey(to='Publish', null=True,
related_name='books',
db_constraint=False,
on_delete=models.DO_NOTHING,
)
authors = models.ManyToManyField(to='Author', null=True,
related_name='books',
db_constraint=False,
)

@property
def publish_name(self):
    return self.publish.name

@property
def authors_info(self):
    author_list = []
    for author in self.authors.all():
        author_list.append({
            'name': author.name,
            'age': author.age,
            'mobile': author.detail.mobile
        })
    return author_list

@property
def publish_bac(self):
    from . import serializers
    data = serializers.PublishModelSerializer(self.publish).data
    return data

class Meta:
    db_table = 'old_boy_book'
    verbose_name = '书籍'
    verbose_name_plural = verbose_name
    # 联合唯一
    # unique_together = ('name', 'publish')

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 = 'old_boy_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()

@property
def mobile(self):
    return self.detail.mobile

class Meta:
    db_table = 'old_boy_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', null=True,
                              related_name='detail',
                              db_constraint=False,
                              on_delete=models.CASCADE
                              )

class Meta:
    db_table = 'old_boy_author_detail'
    verbose_name = '作者详情'
    verbose_name_plural = verbose_name

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

序列化层：api/serializers.py
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群增与群改反序列化实现

1）ModelSerializer默认不通过群改功能，需要在Meta中设置 list_serializer_class

2）自定义ListSerializer子类，重写update方法，将子类绑定给 list_serializer_class

3）重写update方法中通过 代表要更新的对象们instance 及 提供的更新数据们validated_data

得到 更新后的对象们instance 返回

class BookV3ListSerializer(serializers.ListSerializer):
def update(self, instance, validated_data):
'''
:param instance: [book_obj1, ..., book_obj2]
:param validated_data: [{更新数据的字段}, ..., {更新数据的字段}]
:return: [book_new_obj1, ..., book_new_obj2]
'''
for index, obj in enumerate(instance): # type: int, models.Book
# 单个对象数据更新 - 一个个属性更新值
for attr, value in validated_data[index].items():
# 对象有更新数据字典的key对应的属性，才完成该属性的值更新
if hasattr(obj, attr):
setattr(obj, attr, value)
# 信息同步到数据库
obj.save()
return instance

class BookV3ModelSerializer(serializers.ModelSerializer):
class Meta:
model = models.Book
fields = ('name', 'price', 'publish', 'authors', 'img', 'publish_name', 'authors_info')
list_serializer_class = BookV3ListSerializer
extra_kwargs = {
'publish': {
'required': True,
'write_only': True
},
'authors': {
'required': True,
'write_only': True
},
'img': {
'read_only': True
}
}
def validate_name(self, value):
if 'sb' in value:
raise serializers.ValidationError('书名有敏感词汇')
return value
def validate(self, attrs):
name = attrs.get('name')
publish = attrs.get('publish')
if models.Book.objects.filter(name=name, publish=publish):
raise serializers.ValidationError({'book': '书籍以存在'})
return attrs
视图层：api/views.py
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class BookV3APIView(APIView):
# 单查群查
def get(self, request, *args, **kwargs):
pk = kwargs.get('pk')
if pk:
book_obj = models.Book.objects.filter(is_delete=False, pk=pk).first()
if not book_obj:
return APIResponse(1, 'pk error')
book_ser = serializers.BookV3ModelSerializer(book_obj)
return APIResponse(0, 'ok', results=book_ser.data)
book_query = models.Book.objects.filter(is_delete=False).all().order_by('-id')
book_ser = serializers.BookV3ModelSerializer(book_query, many=True)
return APIResponse(0, 'ok', results=book_ser.data)

# 单增群增
def post(self, request, *args, **kwargs):
    # 单增 /books/  data  {}
    # 群增 /books/  data  [{}, ..., {}]
    request_data = request.data
    if isinstance(request_data, dict):
        data = [request_data, ]
    elif isinstance(request_data, list):
        data = request_data
    else:
        return APIResponse(1, '数据格式有误')
    book_ser = serializers.BookV3ModelSerializer(data=data, many=True)
    if book_ser.is_valid():
        book_obj_list = book_ser.save()
        return APIResponse(0, 'ok',
            results=serializers.BookV3ModelSerializer(book_obj_list, many=True).data
        )
    else:
        return APIResponse(1, '添加失败', results=book_ser.errors)

    
"""
1）先确定要更新的对象 主键们 与 数据们
2）通过校验数据库剔除 已删除的对象 与 不存在的对象
    主键们 => 剔除过程 => 可以修改的对象们
    数据们 => 剔除过程 => 可以修改的对象们对应的数据们
3）反序列化及校验过程
    通过 => save() 完成更新
    失败 => ser_obj.errors 返回
"""
# 单改群改
def patch(self, request, *args, **kwargs):
    # 单改 /books/(pk)/  data  {"name": "new_name", ...}
    # 群改 /books/  data  [{"pk": 1, "name": "new_name", ...}, ...,{"pk": n, "name": "new_name", ...}]
    # 结果：
    # pks = [1, ..., n] => book_query => instance
    # data = [{"name": "new_name", ...}, ..., {"name": "new_name", ...}] => data

    # 数据预处理
    pk = kwargs.get('pk')
    request_data = request.data
    if pk:
        if not isinstance(request_data, dict):
            return APIResponse(1, '单改数据有误')
        pks = [pk, ]
        data = [request_data, ]
    elif isinstance(request_data, list):
        try:
            pks = []
            for dic in request_data:
                pks.append(dic.pop('pk'))
            data = request_data
        except:
            return APIResponse(1, '群改数据有误')
    else:
        return APIResponse(1, '数据格式有误')

    # 将 已删除的书籍 与 不存在的书籍 剔除 (提供修改的数据相对应也剔除)
    book_query = []
    filter_data = []
    for index, pk in enumerate(pks):
        book_obj = models.Book.objects.filter(is_delete=False, pk=pk).first()
        if book_obj:
            book_query.append(book_obj)
            filter_data.append(data[index])
    # 反序列化完成数据的修改
    book_ser = serializers.BookV3ModelSerializer(instance=book_query, data=filter_data, many=True, partial=True)
    if book_ser.is_valid():
        book_obj_list = book_ser.save()
        return APIResponse(1, 'ok',
            results=serializers.BookV3ModelSerializer(book_obj_list, many=True).data
        )
    else:
        return APIResponse(1, '更新失败', results=book_ser.errors)

# 单删群删  
def delete(self, request, *args, **kwargs):
    # 单删 /books/(pk)/
    # 群删 /books/  数据包携带 pks => request.data
    pk = kwargs.get('pk')
    if pk:
        pks = [pk]
    else:
        pks = request.data.get('pks')
    if not pks:
        return APIResponse(1, '删除失败')
    book_query = models.Book.objects.filter(is_delete=False, pk__in=pks)
    if not book_query.update(is_delete=True):  # 操作的记录大于0就记录删除成功
        return APIResponse(1, '删除失败')
    return APIResponse(0, '删除成功')