实例化Django REST框架序列化程序时出错

Question

我遇到了DRF和一些序列化程序的奇怪问题。

这里是我的模型：

class Accommodation(models.Model): 
    created = models.DateTimeField(auto_now_add=True) 
    modified = models.DateTimeField(auto_now=True) 
    product = models.OneToOneField(
     Product, 
     on_delete=models.CASCADE, 
     primary_key=True, 
    ) 
    description = models.TextField(null=True, blank=True, verbose_name=_(u'Description')) 
    shared_accommodation = models.BooleanField(default=False) 
    accommodation_unit_quantity = models.PositiveSmallIntegerField(default=1, 
                   verbose_name=_(u'Number of acommodation units ' 
                       u'for this acommodation')) 
    accommodation_unit_name = models.TextField(null=False, blank=False, verbose_name=_(u'Name for accommodation units ' 
                        u'for this accommodation')) 

    class Meta: 
     verbose_name_plural = _(u'Accommodations') 

    def __unicode__(self): 
     return u'{0} <{1}>'.format(self.product.name, self.product.school) 

class Product(AbstractProduct): 

    name = models.CharField(max_length=50, verbose_name=_(u'Name')) 
    school = models.ForeignKey('school.School') 
    levels = models.ManyToManyField('school.Level',verbose_name=_(u'Level')) 
    age = IntegerRangeField(null=True) 
    gender = models.CharField(choices=GENDER_CHOICES, max_length=1, null=True, blank=True, verbose_name=_(u'Gender')) 
    num_sessions = models.PositiveSmallIntegerField(
     verbose_name=_(u'Number of sessions'), 
     default=1, 
     help_text=_(u"Number of sessions that the product has."), 
    ) 
    school_category = models.ForeignKey(
     'school.Category', 
     blank=True, null=True, 
     verbose_name=_(u'Category') 
    ) 
    addons = models.ManyToManyField('self', 
     verbose_name=_(u'Administrators'), 
     through='AddonInService', 
     symmetrical=False, 
     related_name='addon_can_be_used_in' 
    ) 

    pay_option = models.CharField(choices=PAYMENT_OPTIONS, max_length=1, null=True, blank=True, verbose_name=_(u'Pay_option'), default='U') 
    payment_type = models.CharField(choices=PAYMENT_TYPE, max_length=1, null=True, blank=True, verbose_name=_(u'pay_type')) 
    payment_amount = models.FloatField(verbose_name=_(u'Amount'), default=0.0) 

    objects = ProductManager() 

    class Meta(AbstractProduct.Meta): 
     verbose_name_plural = _(u'Products') 

    def __unicode__(self): 
     return self.name 

正如你所看到的，基本上是一个产品可以是住宿。下面是串行器

class AccommodationSerializer(serializers.ModelSerializer): 
    class Meta: 
     model = Accommodation 
     fields = [ 
      'description', 
      'shared_accommodation', 
      'accommodation_unit_quantity', 
      'accommodation_unit_name', 
     ] 


class ProductAccommodationSerializer(ProductSerializer): 

    accommodation = AccommodationSerializer() 

    class Meta(ProductSerializer.Meta): 
     fields = [ 
      'id', 
      'structure', 
      'upc', 
      'title', 
      'slug', 
      'description', 
      'rating', 
      'date_created', 
      'date_updated', 
      'is_discountable', 
      'name', 
      'age', 
      'gender', 
      'num_sessions', 
      'parent', 
      'product_class', 
      'school', 
      'levels', 
      'school_category', 
      'addons', 
      'color', 
      'price', 
      'all_prices', 
      'variants', 
      'pay_option', 
      'payment_type', 
      'payment_amount', 
      'accommodation', 
     ] 

    def create(self, validated_data): 
     accommodation_data = validated_data.pop('accommodation') 

     levels = [] 
     if 'levels' in validated_data: 
      levels = validated_data.pop('levels') 

     product = Product.objects.create(**validated_data) 
     school_accommodation, created = ProductClass.objects.get_or_create(name='School Accommodation') 
     if created: 
      product.product_class = school_accommodation 
     for lev in levels: 
      product.levels.add(lev) 
     product.save() 

     acc = AccommodationSerializer(product=product, **accommodation_data) 
     acc.save() 
     return product 

class ProductSerializer(serializers.ModelSerializer): 
    age = IntegerRangeField() 
    addons = AddonSerializer(many=True, read_only=True) 
    # Get the price for the Product, using the property in the Model 
    price = serializers.DecimalField(required=False, max_digits=7, 
           decimal_places=2, source='get_price', 
           read_only=True) 
    color = serializers.SerializerMethodField() 

    all_prices = PriceSerializer(source='stockrecords', many=True, 
            required=False) 

    variants = VariantSerializer(many=True, source='children', required=False) 

    class Meta: 
     model = Product 
     fields = [ 
      'id', 
      'structure', 
      'upc', 
      'title', 
      'slug', 
      'description', 
      'rating', 
      'date_created', 
      'date_updated', 
      'is_discountable', 
      'name', 
      'age', 
      'gender', 
      'num_sessions', 
      'parent', 
      'product_class', 
      'school', 
      'levels', 
      'school_category', 
      'addons', 
      'color', 
      'price', 
      'all_prices', 
      'variants', 
      'pay_option', 
      'payment_type', 
      'payment_amount' 
     ] 

执行一个简单的测试，我尝试创建一个旅馆，我得到以下错误：

Traceback (most recent call last): 
File "/home/internetmosquito/git/mvp_opencoast/opencoast_django/opencoast/applications/accommodation/tests/test_accommodations.py", line 165, in test_create_accommodation 
response = self.client.post(url, data, format='json') 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/test.py", line 170, in post 
path, data=data, format=format, content_type=content_type, **extra) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/test.py", line 92, in post 
return self.generic('POST', path, data, content_type, **extra) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/django/test/client.py", line 380, in generic 
return self.request(**r) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/test.py", line 159, in request 
return super(APIClient, self).request(**kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/test.py", line 111, in request 
request = super(APIRequestFactory, self).request(**kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/django/test/client.py", line 467, in request 
six.reraise(*exc_info) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 149, in get_response 
response = self.process_exception_by_middleware(e, request) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 147, in get_response 
response = wrapped_callback(request, *callback_args, **callback_kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view 
return view_func(*args, **kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/viewsets.py", line 87, in view 
return self.dispatch(request, *args, **kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/views.py", line 466, in dispatch 
response = self.handle_exception(exc) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/views.py", line 463, in dispatch 
response = handler(request, *args, **kwargs) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/mixins.py", line 21, in create 
self.perform_create(serializer) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/mixins.py", line 26, in perform_create 
serializer.save() 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/serializers.py", line 191, in save 
self.instance = self.create(validated_data) 
File "/home/internetmosquito/git/mvp_opencoast/opencoast_django/opencoast/applications/accommodation/serializers.py", line 77, in create 
acc = AccommodationSerializer(product=product, **accommodation_data) 
File "/home/internetmosquito/python_envs/opencoast_django/local/lib/python2.7/site-packages/rest_framework/serializers.py", line 95, in __init__ 
super(BaseSerializer, self).__init__(**kwargs) 
TypeError: __init__() got an unexpected keyword argument 'product' 

试图删除

产品=产品

从

acc = AccommodationSerializer(product=product, **accommodation_data) 

但是然后我得到相同的错误，但与'shared_accommodation'字段而不是产品

我在这里做错了什么？有任何想法吗？

编辑：添加ProductSerializer，我错过了一个遗憾

第二个编辑：试图创建时

class AccommodationSerializer(serializers.ModelSerializer): 
    class Meta: 
     model = Accommodation 
     fields = [ 
      'product', 
      'description', 
      'shared_accommodation', 
      'accommodation_unit_quantity', 
      'accommodation_unit_name', 
     ] 

但后来：正如一些建议，我已经添加了产品领域的AccommodationSerializer一个例子，我得到以下错误：

{'accommodation': OrderedDict([('product', [u'This field is required.'])])} 

滑稽的是，如果我的产品添加到测试数据有效载荷（尽管我还没有创建produc T取代我所说的终点的时间作出住宿，上面dissappears错误）：

data = { 
     "name": "Hotel Hudson", 
     "slug": "hotel-hudson", 
     "age": {'upper': 99, 'lower': 18}, 
     "school": school1.id, 
     "levels": [school1.level_set.all()[0].id], 
     "accommodation": { 
      "product": 1, 
      "description": "A very nice hotel", 
      "shared_accommodation": False, 
      "accommodation_unit_quantity": 1, 
      "accommodation_unit_name": "Room", 
      "accommodation_units": [ 
       { 
        'name': "Room-1", 
        'max_pax': 1, 
       }, 
       { 
        'name': "Room-2", 
        'max_pax': 3, 
       }, 
      ] 
     }, 
    } 

虽然这是有趣的，这显然不是我想要的......我不想不必传递假设产品ID在调用端点时创建一个Accommodation ...任何指针？

Answer 1

使用data字段将是正确的方法，因为DRF串行器层次结构中的关键字不是通用的。如果您为data指定的字典有效，则可以使用.save()（在致电.is_valid()后）创建模型实例。在创建模型之前，字典当然可以增加更多的属性。但要小心，序列化程序只使用在序列化程序的Meta.fields字段中指定的属性。

这里是关键点，为什么你的方法毕竟不能工作：AccomodationSerializer.Meta.fields不包括product字段，如果你想创建一个模型，这是必须的。

使用AccommodationSerializer从Accommodation模型中读取或者您想发布模型的部分结构出于某种原因是很好的。但是如果你想用它来创建一个模型实例，你必须指定所有不为空或者具有默认值的字段。

除了在此处使用AccommodationSerializer的，你可以只要致电：

Accommodation.objects.create(product=product, **accommodation_data) 

我试图建立一个最小的例子。希望这可以帮助。

models.py：

class Owner(models.Model): 

    owner_name = models.CharField(max_length=255) 


class Product(models.Model): 

    name = models.CharField(max_length=255) 
    owner = models.OneToOneField(Owner) 

serializer.py

class OwnerSerializer(serializers.ModelSerializer): 

    class Meta: 
     model = Owner 
     fields = [ 
      'owner_name', 
     ] 

class ProductSerializer(serializers.ModelSerializer): 

    owner = OwnerSerializer(read_only=True) 

    class Meta: 
     model = Product 
     fields = [ 
      'owner', 
      'name', 
     ] 


class ProductOwnerSerializer(serializers.ModelSerializer): 

    product = ProductSerializer() 

    class Meta: 
     model = Owner 
     fields = [ 
      'product', 
      'owner_name', 
     ] 

    def create(self, validated_data): 
     product_data = validated_data.pop('product') 
     owner = Owner.objects.create(**validated_data) 
     Product.objects.create(owner=owner, **product_data) 
     return owner 

我也同意Jerzyk的评论，我真的不喜欢Meta(Superclass)，似乎是一个反模式我。