# 舉例子
mobile = serializers.CharField(max_length=11, min_length=11)
age = serializers.IntegerField(min_value=1, max_value=100)
# format可以設(shè)置時間的格式，下面例子會輸出如:2018-1-24 12:10
pay_time = serializers.DateTimeField(read_only=True,format='%Y-%m-%d %H:%M')
is_hot = serializers.BooleanField()

order_sn = serializers.CharField(readonly=True)
write_only: 與read_only對應(yīng) 
required: 顧名思義，就是這個字段是否必填。 
allow_null/allow_blank：是否允許為NULL/空 。 
error_messages：出錯時，信息提示。
name = serializers.CharField(required=True, min_length=6,
  error_messages={
   'min_length': '名字不能小于6個字符',
   'required': '請?zhí)顚懨?})
label: 字段顯示設(shè)置，如 label='驗(yàn)證碼' 
help_text: 在指定字段增加一些提示文字，這兩個字段作用于api頁面比較有用 
style: 說明字段的類型，這樣看可能比較抽象，看下面例子：
# 在api頁面，輸入密碼就會以*顯示
password = serializers.CharField(
 style={'input_type': 'password'})
# 會顯示選項(xiàng)框
color_channel = serializers.ChoiceField(
 choices=['red', 'green', 'blue'],
 style={'base_template': 'radio.html'})

# 這樣就可以直接獲取到當(dāng)前用戶
user = serializers.HiddenField(
 default=serializers.CurrentUserDefault())

# 只截取一部分
class CreateModelMixin(object):
 def create(self, request, *args, **kwargs):
 serializer = self.get_serializer(data=request.data)
 serializer.is_valid(raise_exception=True)
 self.perform_create(serializer)
 headers = self.get_success_headers(serializer.data)
 return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)

 def perform_create(self, serializer):
 serializer.save()

class UpdateModelMixin(object):
 def update(self, request, *args, **kwargs):
 partial = kwargs.pop('partial', False)
 instance = self.get_object()
 serializer = self.get_serializer(instance, data=request.data, partial=partial)
 serializer.is_valid(raise_exception=True)
 self.perform_update(serializer)

 if getattr(instance, '_prefetched_objects_cache', None):
  # If 'prefetch_related' has been applied to a queryset, we need to
  # forcibly invalidate the prefetch cache on the instance.
  instance._prefetched_objects_cache = {}

 return Response(serializer.data)

 def perform_update(self, serializer):
 serializer.save()

# serializer.py
def save(self, **kwargs):
# 略去一些稍微無關(guān)的內(nèi)容
 ···
 if self.instance is not None:
 self.instance = self.update(self.instance, validated_data)
  ···
 else:
 self.instance = self.create(validated_data)
  ···
 return self.instance

# 假設(shè)現(xiàn)在是個博客，有一個創(chuàng)建文章，與修改文章的功能, model為Article。
class ArticleSerializer(serializers.Serializer):
 user = serializers.HiddenField(
 default=serializers.CurrentUserDefault())
 name = serializers.CharField(max_length=20)
 content = serializers.CharField()

 def create(self, validated_data):
 # 除了用戶，其他數(shù)據(jù)可以從validated_data這個字典中獲取
 # 注意，users在這里是放在上下文中的request，而不是直接的request
 user = self.context['request'].user
 name = validated_data['name ']
 content = validated_data['content ']
 return Article.objects.create(**validated_data)

 def update(self, instance, validated_data):
 # 更新的特別之處在于你已經(jīng)獲取到了這個對象instance
 instance.name = validated_data.get('name')
 instance.content = validated_data.get('content')
 instance.save()
 return instance

# CreateModelMixin
serializer = self.get_serializer(data=request.data)
# UpdateModelMixin
serializer = self.get_serializer(instance, data=request.data, partial=partial)

mobile_phone = serializers.CharField(max_length=11, min_length=11）

def validate_mobile_phone(self, mobile_phone):
 # 注意參數(shù)，self以及字段名
 # 注意函數(shù)名寫法，validate_ + 字段名字
 if not re.match(REGEX_MOBILE, mobile):
 # REGEX_MOBILE表示手機(jī)的正則表達(dá)式
 raise serializers.ValidationError("手機(jī)號碼非法")
 return mobile_phone

start = serializers.DateTimeField()
 finish = serializers.DateTimeField()

 def validate(self, attrs):
 # 傳進(jìn)來什么參數(shù)，就返回什么參數(shù)，一般情況下用attrs
 if data['start'] > data['finish']:
  raise serializers.ValidationError("finish must occur after start")
 return attrs

order_sn = serializers.CharField(readonly=True)
def validate(self, attrs):
 # 調(diào)用一個方法生成order_sn
 attrs['order_sn'] = generate_order_sn()
 return attrs

validators可以直接作用于某個字段，這個時候，它與單獨(dú)的validate作用差不多

def multiple_of_ten(value):
 if value % 10 != 0:
 raise serializers.ValidationError('Not a multiple of ten')

class GameRecord(serializers.Serializer):
 score = IntegerField(validators=[multiple_of_ten])

username = serializers.CharField(
 max_length=11, 
 min_length=11,
 validators=[UniqueValidator(queryset=UserProfile.objects.all())
 ）

class Meta:
 validators = [
  UniqueTogetherValidator(
  queryset=UserFav.objects.all(),
  fields=('user', 'course'),
  message='已經(jīng)收藏'
  )]

class UserDetailSerializer(serializers.ModelSerializer):
 """
 用戶詳情序列化
 """

 class Meta:
 model = User
 fields = ("name", "gender", "birthday", "email", "mobile")
 # fields = '__all__': 表示所有字段
 # exclude = ('add_time',): 除去指定的某些字段
 # 這三種方式，存在一個即可

def validate(self, attrs):
 del attrs["code"]
 return attrs

class UserSerializer(serializers.ModelSerializer): 
 days_since_joined = serializers.SerializerMethodField()
 # 方法寫法：get_ + 字段
 def get_days_since_joined(self, obj):
 # obj指這個model的對象
 return (now() - obj.date_joined).days

 class Meta:
 model = User

class Course(model.Model):
 category = models.ForeignKey(CourseCategory, related_name='courses')
# 反向取課程，通過related_name
# 一對多，一個類別下有多個課程，一定要設(shè)定many=True
courses = CourseSerializer(many=True)

parent_category = models.ForeignKey('self', null=True, blank=True, 
   verbose_name='父類目別',
   related_name='sub_cat')

courses = SerializerMethodField()
def get_courses(self, obj):
 all_courses = Course.objects.filter(category__parent_category_id=obj.id)
 courses_serializer = CourseSerializer(all_course, many=True, 
   context={'request': self.context['request']})
 return courses_serializer.data