Django Rest框架和Django-Hvad [英] Django Rest Framework and Django-Hvad
问题描述
所以我需要为我的DRF API提供一些模型翻译支持，我开始使用django-hvad。
这似乎对我的django应用程序很好我在DRF APi中遇到一些问题。
我正在尝试创建一个简单的POST请求，我收到一个错误：
访问一个已翻译的字段要求该实例具有翻译加载，或以当前语言（en）从数据库加载的有效翻译
以下是我的型号，序列化器和视图：
型号：
class Mission（TranslatableModel）：
translations = TranslatedFields（
mission = models.CharField（max_length = 255，help_text =Mission name），
）
def __unicode __（self）：
return self.lazy_translation_getter（'mission'，str（self.pk））
Serializer：
class MissionSerializer（serializers ModelSerializer）pre>
task = serializers.CharField（source ='mission'）
class Meta：
model = Mission
Viewset：
class MissionViewSet（viewsets.ModelViewSet）：
queryset = Mission.objects.language（）。all（）
serializer_class = MissionSerializer
authentication_classes =（NoAuthentication，）
permission_classes =（AllowAny，）
def get_queryset（self）：
＃设置语言为翻译
user_language = self.request.GET.get（'language'）
如果user_language：
translation.activate（ user_language）
return Mission.objects.language（）。all（）
有没有人知道我怎么可以绕过这个？我也开放给其他建议的应用程序已知工作，但我真的很想有一个这样的工作
解决方案我得到了工作感谢这里的光谱 https://github.com/KristianOellegaard/django-hvad/issues / 211
这个问题，我想是DRF试图对模型做一些内省。我在我的一个项目中使用DRF，在TranslatableModel上。它需要一些胶水才能正常工作。我曾经建议向hvad补充说，但我们得出结论，这将会过度扩展功能集。也许是另一个模块有一天，但是我没有足够的时间来维护这个hvad。
自从我实现以来已经有一段时间了，所以这里是是：
＃hvad兼容性rest_framework - JHA
class TranslatableModelSerializerOptions（serializers.ModelSerializerOptions）：
def __init __（self，meta）：
super（TranslatableModelSerializerOptions，self）.__ init __（meta）
＃我们需要这个丑陋的hack作为ModelSerializer hardcodes一个read_only_fields检查
self.translated_read_only_fields = getattr（meta，'translated_read_only_fields'，（））
self.translated_write_only_fields = getattr（meta，'translated_write_only_fields'，（））
class HyperlinkedTranslatableModelSerializerOptions（serializers.HyperlinkedModelSerializerOptions）：
def __init __（self，meta）：
super（HyperlinkedTranslatableModelSerializerOptions，self）.__ init __（meta）
＃我们n eed这个丑陋的hack作为ModelSerializer硬编码一个read_only_fields检查
self.translated_read_only_fields = getattr（meta，'converted_read_only_fields'，（））
self.translated_write_only_fields = getattr（meta，'translations_write_only_fields'，（））
class TranslatableModelMixin（object）：
def get_default_fields（self）：
fields = super（TranslatableModelMixin，self）.get_default_fields（）
fields.update（self._get_translated_fields ）
返回字段
def _get_translated_fields（self）：
ret = OrderedDict（）
trans_model = self.opts.model._meta.translations_model
opts = trans_model._meta
forward_rels = [opts.fields中的字段字段
如果field.serialize而不是field.name（'id'，'master'）] $ b $对于forward_rels，trans_field的b
如果trans_field.rel：
raise Runti meError（）
field = self.get_field（trans_field）
if field：
ret [trans_field.name] = field
for field_name in self.opts.translated_read_only_fields ：
as ret中的field_name
ret [field_name] .read_only = True
在self.opts.translated_write_only_fields中的field_name：
assert中的field_name
ret [field_name] .write_only = True
return ret
def restore_object（self，attrs，instance = None）：
new_attrs = attrs.copy（）
lang = attrs ['language_code']
del new_attrs ['language_code']
如果实例为无：
＃创建一个空实例，预翻译
instance = self.opts.model（）
instance.translate（lang）
else：
＃检查我们正在更新正确的翻译
tcache = self.opts.model._meta.translations_cache
翻译= getattr（实例，tcache，无）
如果没有翻译或翻译.language_code！= lang：
＃nope，得到翻译我们正在更新，或创建它，如果需要
try：
translation = instance.translations.get_language（lang）
except instance.translations.model.DoesNotExist：
instance.translate（lang ）
else：
setattr（instance，tcache，translation）
return super（TranslatableModelMixin，self）.restore_object（new_attrs，instance）
class TranslatableModelSerializer（TranslatableModelMixin，serializers.ModelSerializer）：
_options_class = TranslatableModelSerializerOptions
class HyperlinkedTranslatableModelSerializer（TranslatableModelMixin，
serializers.HyperlinkedMo delSerializer）：
_options_class = HyperlinkedTranslatableModelSerializerOptions
从那里，你只是从
TranslatableModelSerializer或HyperlinkedTranslatableModelSerializer。在POST时，您应该简单地将language_code作为正常字段添加为JSON / XML /的一部分。
主要技巧在restore_object方法中。对象创建需要包括翻译加载。
so i needed to had some model-translation support for my DRF API and i started using django-hvad.
It seems to work well with my django application but i am getting some issues with the DRF APi.
I am trying to create a simple POST request and i am getting a error:
Accessing a translated field requires that the instance has a translation loaded, or a valid translation in current language (en) loadable from the databaseHere are my models, serializers and viewsets:
Model:
class Mission(TranslatableModel): translations = TranslatedFields( mission=models.CharField(max_length=255, help_text="Mission name"), ) def __unicode__(self): return self.lazy_translation_getter('mission', str(self.pk))Serializer:
class MissionSerializer(serializers.ModelSerializer): mission = serializers.CharField(source='mission') class Meta: model = MissionViewset:
class MissionViewSet(viewsets.ModelViewSet): queryset = Mission.objects.language().all() serializer_class = MissionSerializer authentication_classes = (NoAuthentication,) permission_classes = (AllowAny,) def get_queryset(self): # Set Language For Translations user_language = self.request.GET.get('language') if user_language: translation.activate(user_language) return Mission.objects.language().all()Does anyone know how i can get around this?? I am also opened to other suggested apps known to work but i would really like to have this one working
解决方案I got this to work thanks to the Spectras here https://github.com/KristianOellegaard/django-hvad/issues/211
The issue, I guess is DRF tries to do some introspection on the model. I do use DRF in a project of mine, on a TranslatableModel. It needs some glue to work properly. I once suggested adding that to hvad, but we concluded that that would be overextending the feature set. Maybe another module some day, but I don't have enough time to maintain both hvad and that.
It's been some time since I implemented it, so here it is as is:
# hvad compatibility for rest_framework - JHA class TranslatableModelSerializerOptions(serializers.ModelSerializerOptions): def __init__(self, meta): super(TranslatableModelSerializerOptions, self).__init__(meta) # We need this ugly hack as ModelSerializer hardcodes a read_only_fields check self.translated_read_only_fields = getattr(meta, 'translated_read_only_fields', ()) self.translated_write_only_fields = getattr(meta, 'translated_write_only_fields', ()) class HyperlinkedTranslatableModelSerializerOptions(serializers.HyperlinkedModelSerializerOptions): def __init__(self, meta): super(HyperlinkedTranslatableModelSerializerOptions, self).__init__(meta) # We need this ugly hack as ModelSerializer hardcodes a read_only_fields check self.translated_read_only_fields = getattr(meta, 'translated_read_only_fields', ()) self.translated_write_only_fields = getattr(meta, 'translated_write_only_fields', ()) class TranslatableModelMixin(object): def get_default_fields(self): fields = super(TranslatableModelMixin, self).get_default_fields() fields.update(self._get_translated_fields()) return fields def _get_translated_fields(self): ret = OrderedDict() trans_model = self.opts.model._meta.translations_model opts = trans_model._meta forward_rels = [field for field in opts.fields if field.serialize and not field.name in ('id', 'master')] for trans_field in forward_rels: if trans_field.rel: raise RuntimeError() field = self.get_field(trans_field) if field: ret[trans_field.name] = field for field_name in self.opts.translated_read_only_fields: assert field_name in ret ret[field_name].read_only = True for field_name in self.opts.translated_write_only_fields: assert field_name in ret ret[field_name].write_only = True return ret def restore_object(self, attrs, instance=None): new_attrs = attrs.copy() lang = attrs['language_code'] del new_attrs['language_code'] if instance is None: # create an empty instance, pre-translated instance = self.opts.model() instance.translate(lang) else: # check we are updating the correct translation tcache = self.opts.model._meta.translations_cache translation = getattr(instance, tcache, None) if not translation or translation.language_code != lang: # nope, get the translation we are updating, or create it if needed try: translation = instance.translations.get_language(lang) except instance.translations.model.DoesNotExist: instance.translate(lang) else: setattr(instance, tcache, translation) return super(TranslatableModelMixin, self).restore_object(new_attrs, instance) class TranslatableModelSerializer(TranslatableModelMixin, serializers.ModelSerializer): _options_class = TranslatableModelSerializerOptions class HyperlinkedTranslatableModelSerializer(TranslatableModelMixin, serializers.HyperlinkedModelSerializer): _options_class = HyperlinkedTranslatableModelSerializerOptionsFrom there, you just inherit your serializers from
TranslatableModelSerializerorHyperlinkedTranslatableModelSerializer. When POSTing, you should simple add language_code as a normal field as part of your JSON / XML / whatever.The main trick is in the restore_object method. Object creation needs to include translation loading.
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