python-django rest framework框架之序列化
序列化与反序列化： 对象 -> 字符串 序列化 字符串 -> 对象 反序列化
rest framework序列化+Form 目的： 解决QuerySet序列化问题 功能：解析 和 过滤 - QuerySet类型 -> 列表、字典 - 请求验证 序列化： a. 基本操作： class UsersSerializer(serializers.Serializer): #定义这个类相当于一个序列化模板 name = serializers.CharField() pwd = serializers.CharField() class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 # user_list = models.UserInfo.objects.all() # ser = UsersSerializer(instance=user_list,many=True) # return Response(ser.data) # 方式二之单对象 user = models.UserInfo.objects.all().first() ser = UsersSerializer(instance=user, many=False) return Response(ser.data) b. 跨表 class UsersSerializer(serializers.Serializer): name = serializers.CharField() pwd = serializers.CharField() group_id = serializers.CharField() xxxx = serializers.CharField(source="group.title") x1 = serializers.CharField(source="group.mu.name") class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() ser = UsersSerializer(instance=user_list,many=True) return Response(ser.data) c. 复杂序列化 解决方案一： manytomany 自定义一个类，继承CharField，重写to_representation方法 class MyCharField(serializers.CharField): def to_representation(self, value): data_list = [] for row in value: data_list.append(row.name) return data_list class UsersSerializer(serializers.Serializer): name = serializers.CharField() # obj.name pwd = serializers.CharField() # obj.pwd group_id = serializers.CharField() # obj.group_id xxxx = serializers.CharField(source="group.title") # obj.group.title x1 = serializers.CharField(source="group.mu.name") # obj.mu.name # x2 = serializers.CharField(source="roles.all") # obj.mu.name x2 = MyCharField(source="roles.all") # obj.mu.name 解决方案二： class MyCharField(serializers.CharField): def to_representation(self, value): return {'id':value.pk, 'name':value.name} class UsersSerializer(serializers.Serializer): name = serializers.CharField() # obj.name pwd = serializers.CharField() # obj.pwd group_id = serializers.CharField() # obj.group_id xxxx = serializers.CharField(source="group.title") # obj.group.title x1 = serializers.CharField(source="group.mu.name") # obj.mu.name # x2 = serializers.CharField(source="roles.all") # obj.mu.name x2 = serializers.ListField(child=MyCharField(),source="roles.all") # obj.mu.name 解决方案三（*）： class UsersSerializer(serializers.Serializer): name = serializers.CharField() # obj.name pwd = serializers.CharField() # obj.pwd group_id = serializers.CharField() # obj.group_id xxxx = serializers.CharField(source="group.title") # obj.group.title x1 = serializers.CharField(source="group.mu.name") # obj.mu.name # x2 = serializers.CharField(source="roles.all") # obj.mu.name # x2 = serializers.ListField(child=MyCharField(),source="roles.all") # obj.mu.name x2 = serializers.SerializerMethodField() def get_x2(self,obj): obj.roles.all() role_list = obj.roles.filter(id__gt=1) data_list = [] for row in role_list: data_list.append({'pk':row.pk,'name':row.name}) return data_list 以上三种都是使用相同的视图： class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() # [obj1,obj2,obj3] ser = UsersSerializer(instance=user_list,many=True) return Response(ser.data) d. 基于Model class UsersSerializer(serializers.ModelSerializer): class Meta: model = models.UserInfo fields = "__all__" # fields = ['name', 'pwd','group'] depth = 1 class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() # [obj1,obj2,obj3] ser = UsersSerializer(instance=user_list,many=True) return Response(ser.data) e. 生成URL class UsersSerializer(serializers.ModelSerializer): group = serializers.HyperlinkedIdentityField(view_name='detail') class Meta: model = models.UserInfo fields = "__all__" fields = ['name', 'pwd','group'] depth = 1 class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() # [obj1,obj2,obj3] ser = UsersSerializer(instance=user_list,many=True,context={'request':request}) return Response(ser.data) f. 全局生成URL class UsersSerializer(serializers.HyperlinkedModelSerializer): class Meta: model = models.UserInfo fields = "__all__" # fields = ['id','name','pwd'] class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() # [obj1,obj2,obj3] ser = UsersSerializer(instance=user_list,many=True,context={'request':request}) return Response(ser.data) 请求数据验证： a. class PasswordValidator(object): def __init__(self, base): self.base = base def __call__(self, value): if value != self.base: message = '用户输入的值必须是 %s.' % self.base raise serializers.ValidationError(message) def set_context(self, serializer_field): """ This hook is called by the serializer instance, prior to the validation call being made. """ # 执行验证之前调用,serializer_fields是当前字段对象 pass class UsersSerializer(serializers.Serializer): name = serializers.CharField(min_length=6) pwd = serializers.CharField(error_messages={'required': '密码不能为空'}, validators=[PasswordValidator('666')]) b. class PasswordValidator(object): def __init__(self, base): self.base = base def __call__(self, value): if value != self.base: message = '用户输入的值必须是 %s.' % self.base raise serializers.ValidationError(message) def set_context(self, serializer_field): """ This hook is called by the serializer instance, prior to the validation call being made. """ # 执行验证之前调用,serializer_fields是当前字段对象 pass class UsersSerializer(serializers.ModelSerializer): class Meta: model = models.UserInfo fields = "__all__" extra_kwargs = { 'name': {'min_length': 6}, 'pwd': {'validators': [PasswordValidator(666), ]} } - 钩子函数
def validate_字段(self,validated_value):
可以抛出异常 raise ValidationError(detail='xxxxxx')
可以返回正确的值 return validated_value 使用： class UsersView(APIView): def get(self,request,*args,**kwargs): self.dispatch # 方式一： # user_list = models.UserInfo.objects.all().values('name','pwd','group__id',"group__title") # return Response(user_list) # 方式二之多对象 user_list = models.UserInfo.objects.all() # [obj1,obj2,obj3] ser = UsersSerializer(instance=user_list,many=True,context={'request':request}) return Response(ser.data) def post(self,request,*args,**kwargs): ser = UsersSerializer(data=request.data) if ser.is_valid(): print(ser.validated_data) else: print(ser.errors) return Response('...')
钩子函数源码：
class BaseSerializer(Field): def is_valid(self, raise_exception=False): if not hasattr(self, '_validated_data'): try: #执行run_validation方法 self._validated_data = self.run_validation(self.initial_data) except ValidationError as exc: self._validated_data = {} self._errors = exc.detail else: self._errors = {} return not bool(self._errors)
class Serializer(BaseSerializer): def run_validation(self, data=empty): #执行to_internal_value 方法 value = self.to_internal_value(data) return value
class Serializer(BaseSerializer): def to_internal_value(self, data): for field in fields: #这步就是在找钩子函数 validate_method = getattr(self, 'validate_' + field.field_name, None) primitive_value = field.get_value(data) try: validated_value = field.run_validation(primitive_value) #在这步执行钩子函数 if validate_method is not None: validated_value = validate_method(validated_value) #捕捉异常 except ValidationError as exc: errors[field.field_name] = exc.detail except DjangoValidationError as exc: errors[field.field_name] = get_error_detail(exc) except SkipField: pass else: set_value(ret, field.source_attrs, validated_value) if errors: raise ValidationError(errors) return ret
