Django高级编程之自定义Field实现多语言

from django.conf import settingsfrom django.db import modelsfrom django.utils.translation import get_languageclass MultilingualField(models.Field): SUPPORTED_FIELD_TYPES = [models.CharField, models.TextField] def __init__(self, verbose_name=None, **kwargs):  self.localized_field_model = None  for model in MultilingualField.SUPPORTED_FIELD_TYPES:   if issubclass(self.__class__, model):    self.localized_field_model = model  self._blank = kwargs.get("blank", False)  self._editable = kwargs.get("editable", True)  super().__init__(verbose_name, **kwargs) @staticmethod def localized_field_name(name, lang_code):  lang_code_safe = lang_code.replace("-", "_")  return f"{name}_{lang_code_safe}" def get_localized_field(self, lang_code, lang_name):  _blank = (self._blank     if lang_code == settings.LANGUAGE_CODE     else True)  localized_field = self.localized_field_model(   f"{self.verbose_name} ({lang_name})",   name=self.name,   primary_key=self.primary_key,   max_length=self.max_length,   unique=self.unique,   blank=_blank,   null=False, # we ignore the null argument!   db_index=self.db_index,   default=self.default or "",   editable=self._editable,   serialize=self.serialize,   choices=self.choices,   help_text=self.help_text,   db_column=None,   db_tablespace=self.db_tablespace)  return localized_field def contribute_to_class(self, cls, name,       private_only=False):  def translated_value(self):   language = get_language()   val = self.__dict__.get(    MultilingualField.localized_field_name(      name, language))   if not val:    val = self.__dict__.get(     MultilingualField.localized_field_name(       name, settings.LANGUAGE_CODE))   return val  # generate language-specific fields dynamically  if not cls._meta.abstract:   if self.localized_field_model:    for lang_code, lang_name in settings.LANGUAGES:     localized_field = self.get_localized_field(      lang_code, lang_name)     localized_field.contribute_to_class(       cls,       MultilingualField.localized_field_name(         name, lang_code))    setattr(cls, name, property(translated_value))   else:    super().contribute_to_class(     cls, name, private_only)class MultilingualCharField(models.CharField, MultilingualField): passclass MultilingualTextField(models.TextField, MultilingualField): pass

LANGUAGE_CODE = 'zh-hans'TIME_ZONE = 'Asia/Shanghai'LANGUAGES = ( ('en-us', 'US English'), ('zh-hans', 'Asia/Shanghai'))

from django.db import modelsfrom django.utils.translation import ugettext_lazy as _from utils.fields import ( MultilingualCharField, MultilingualTextField)class Item(models.Model): title = MultilingualCharField(_('Title'), max_length=200) description = MultilingualTextField(_('Description'), blank=True) content = MultilingualTextField(_('Content')) def __str__(self):  return self.title