Django框架序列化与反序列化操作详解

class BookInfoSerializer(serializers.Serializer):
 """图书数据序列化器"""
 id = serializers.IntegerField(label='ID', read_only=True)
 name = serializers.CharField(label='名称', max_length=20)
 pub_date = serializers.DateField(label='发布日期', required=False)
 readcount = serializers.IntegerField(label='阅读量', required=False)
 commentcount = serializers.IntegerField(label='评论量', required=False)
 image = serializers.ImageField(label='图片', required=False)

Serializer(instance, data, **kwarg)

serializer = AccountSerializer(account, context={'request': request})

from book.models import BookInfo
book = BookInfo.objects.get(id=4) # 单个对象
books = BookInfo.objects.all() # 多个对象

from book.serializers import BookInfoSerializer
serializer = BookInfoSerializer(book) # 单个对象
serializers = BookInfoSerializer(books,many=True) # 多个对象需要添加many参数

serializer.data

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

book=serializers.PrimaryKeyRelatedField(label='图书',queryset=BookInfo.objects.all())

book = serializers.StringRelatedField(label='图书')

book = BookInfoSerializer()

from book.serializers import BookInfoSerializer
data = {'pub_date':'2010-1-1','name':'python高级'}
serializer = BookInfoSerializer(data=data)
serializer.is_valid() # 验证成功返回True，失败返回False

def validate_字段名(self,value):
...
return value

def validate_readcount(self,value):
  if value < 0:
   raise serializers.ValidationError('阅读量不能为负数')
  # 验证完成之后,需要将 value返回
  return value

 def validate(self,attrs)
...
  return attrs

def validate(self, data):
  # attrs = data
  # params --> 序列化器data --> attrs
  """
  data = {
   'name':'python',
   'pub_date':'2000-1-1',
   'readcount':10,
   'commentcount':100
  }
  """
  readcount = data.get('readcount')
  # if readcount<0:
  #  raise serializers.ValidationError()
  commentcount = data.get('commentcount')
  if readcount<commentcount:
   raise serializers.ValidationError('评论量不能大于阅读量')
  #校验完成之后,必须要将数据返回回去
  return data

name=serializers.CharField(max_length=20,validators=[custom_validate)]
def custom_validate(self):
if self == 'admin':
raise serializers.ValidationError('admin不可用')
 raise serializers.ValidationError('我就是来捣乱的')

def create(self, validated_data):
  # validated_data 验证之后的数据
  # params(前端提交的数据) --> data(序列器接受的数据) --> attrs(多个字段 校验) --> validated_data(校验之后)
  # 如果前段提交的数据 经过序列化器的验证之后完全满足需求,则
  # validated_data = params
  """
   validated_data:
  data = {
   'name':'python',
   'pub_date':'2000-1-1',
   'readcount':10000,
   'commentcount':100
  }
  """
  # book = BookInfo()
  # book.save()
  book = BookInfo.objects.create(**validated_data)
  # 需要将创建的对象返回
  return book
( return BookInfo.objects.create(**validated_data)也可)

 def update(self, instance, validated_data):
"""更新，instance为要更新的对象实例"""
 instance.name = validated_data.get('name', instance.name)
 instance.pub_date = validated_data.get('pub_date', instance.pub_date)
 instance.readcount = validated_data.get('readcount', instance.readcount)
...
instance.save()
 return instance

book = serializer.save()

serializer.save(owner=request.user)

serializer = BookInfoSerializer(instance=book, data={'pub_date': '2999-1-1'}, partial=True)

class BookInfoSerializer(serializers.ModelSerializer):

 class Meta:
  model = BookInfo
  fields = '__all__'

fields = '__all__'

exclude = ['xxx', 'xxxx'...]

fields = ['xxx', 'xxxx'...]

read_only_fields = ['xxx', 'xxxx'...]

class BookInfoSerializer(serializers.ModelSerializer):
class Meta:
model = BookInfo
 fields = ('id','name', 'readcount', 'commentcount')
 read_only_fields = ('id', 'readcount', 'commentcount')
 extra_kwargs = {
  'readcount': {'min_value': 0, 'required': True},
  'commentcount': {'max_value': 0, 'required': True},
 }