class TranslatableModelForm(
with_metaclass(TranslatableModelFormMetaclass, ModelForm)):
def __init__(self,
data=None,
files=None,
auto_id='id_%s',
prefix=None,
initial=None,
error_class=ErrorList,
label_suffix=':',
empty_permitted=False,
instance=None):
opts = self._meta
model_opts = opts.model._meta
object_data = {}
language = getattr(self, 'language', get_language())
if instance is not None:
trans = get_cached_translation(instance)
if not trans:
try:
trans = get_translation(instance, language)
except model_opts.translations_model.DoesNotExist:
trans = None
if trans:
object_data = model_to_dict(trans, opts.fields, opts.exclude)
if initial is not None:
object_data.update(initial)
initial = object_data
super(TranslatableModelForm,
self).__init__(data, files, auto_id, prefix, object_data,
error_class, label_suffix, empty_permitted,
instance)
def save(self, commit=True):
if self.instance.pk is None:
fail_message = 'created'
new = True
else:
fail_message = 'changed'
new = False
if self.errors:
opts = self.instance._meta
raise ValueError("The %s could not be %s because the data didn't"
" validate." % (opts.object_name, fail_message))
trans_model = self.instance._meta.translations_model
language_code = self.cleaned_data.get('language_code', get_language())
if not new:
trans = get_cached_translation(self.instance)
if not trans or trans.language_code != language_code:
try:
trans = get_translation(self.instance, language_code)
except trans_model.DoesNotExist:
trans = trans_model()
else:
trans = trans_model()
trans = construct_instance(self, trans, self._meta.fields)
trans.language_code = language_code
trans.master = self.instance
self.instance = combine(trans, self.Meta.model)
super(TranslatableModelForm, self).save(commit=commit)
return self.instance
def _post_clean(self):
if self.instance.pk:
try:
# Don't use self.instance.language_code here! That will fail if
# the instance is not translated into the current language. If
# it succeeded, then the instance would already be translated,
# and there'd be no point combining it with the same
# translation again.
trans = get_translation(self.instance, self.language)
trans.master = self.instance
self.instance = combine(trans, self.Meta.model)
except self.instance._meta.translations_model.DoesNotExist:
self.instance = self.instance.translate(self.language)
return super(TranslatableModelForm, self)._post_clean()
class CustomMetaclassModel(
with_metaclass(CustomMetaclass, TranslatableModel)):
translations = TranslatedFields()
class TranslatableModel(with_metaclass(TranslatableModelBase, models.Model)):
"""
Base model for all models supporting translated fields (via TranslatedFields).
"""
# change the default manager to the translation manager
objects = TranslationManager()
class Meta:
abstract = True
def __init__(self, *args, **kwargs):
tkwargs = {} # translated fields
skwargs = {} # shared fields
if 'master' in kwargs.keys():
raise RuntimeError(
"Cannot init %s class with a 'master' argument" % \
self.__class__.__name__
)
# filter out all the translated fields (including 'master' and 'language_code')
primary_key_names = ('pk', self._meta.pk.name)
for key in list(kwargs.keys()):
if key in self._translated_field_names:
if not key in primary_key_names:
# we exclude the pk of the shared model
tkwargs[key] = kwargs.pop(key)
if not tkwargs.keys():
# if there where no translated options, then we assume this is a
# regular init and don't want to do any funky stuff
super(TranslatableModel, self).__init__(*args, **kwargs)
return
# there was at least one of the translated fields (or a language_code)
# in kwargs. We need to do magic.
# extract all the shared fields (including the pk)
for key in list(kwargs.keys()):
if key in self._shared_field_names:
skwargs[key] = kwargs.pop(key)
# do the regular init minus the translated fields
super(TranslatableModel, self).__init__(*args, **skwargs)
# prepopulate the translations model cache with an translation model
tkwargs['language_code'] = tkwargs.get('language_code', get_language())
tkwargs['master'] = self
translated = self._meta.translations_model(*args, **tkwargs)
setattr(self, self._meta.translations_cache, translated)
@classmethod
def contribute_translations(cls, rel):
"""
Contribute translations options to the inner Meta class and set the
descriptors.
This get's called from TranslatableModelBase.__new__
"""
opts = cls._meta
opts.translations_accessor = rel.get_accessor_name()
opts.translations_model = rel.model
opts.translations_cache = '%s_cache' % rel.get_accessor_name()
trans_opts = opts.translations_model._meta
# Set descriptors
ignore_fields = [
'pk',
'master',
opts.translations_model._meta.pk.name,
]
for field in trans_opts.fields:
if field.name in ignore_fields:
continue
if field.name == 'language_code':
attr = LanguageCodeAttribute(opts)
else:
attr = TranslatedAttribute(opts, field.name)
setattr(cls, field.name, attr)
@classmethod
def save_translations(cls, instance, **kwargs):
"""
When this instance is saved, also save the (cached) translation
"""
opts = cls._meta
if hasattr(instance, opts.translations_cache):
trans = getattr(instance, opts.translations_cache)
if not trans.master_id:
trans.master = instance
trans.save()
def translate(self, language_code):
"""
Returns an Model instance in the specified language.
Does NOT check if the translation already exists!
Does NOT interact with the database.
This will refresh the translations cache attribute on the instance.
"""
tkwargs = {
'language_code': language_code,
'master': self,
}
translated = self._meta.translations_model(**tkwargs)
setattr(self, self._meta.translations_cache, translated)
return self
def safe_translation_getter(self, name, default=None):
cache = getattr(self, self._meta.translations_cache, None)
if not cache:
return default
return getattr(cache, name, default)
def lazy_translation_getter(self, name, default=None):
"""
Lazy translation getter that fetches translations from DB in case the instance is currently untranslated and
saves the translation instance in the translation cache
"""
stuff = self.safe_translation_getter(name, NoTranslation)
if stuff is not NoTranslation:
return stuff
# get all translations
translations = getattr(self, self._meta.translations_accessor).all()
# if no translation exists, bail out now
if len(translations) == 0:
return default
# organize translations into a nice dict
translation_dict = dict((t.language_code, t) for t in translations)
# see if we have the right language, or any language in fallbacks
for code in (get_language(),
settings.LANGUAGE_CODE) + FALLBACK_LANGUAGES:
try:
translation = translation_dict[code]
except KeyError:
continue
break
else:
# none of the fallbacks was found, pick an arbitrary translation
translation = translation_dict.popitem()[1]
setattr(self, self._meta.translations_cache, translation)
return getattr(translation, name, default)
def get_available_languages(self):
qs = getattr(self, self._meta.translations_accessor).all()
if qs._result_cache is not None:
return [obj.language_code for obj in qs]
return qs.values_list('language_code', flat=True)
#===========================================================================
# Internals
#===========================================================================
@property
def _shared_field_names(self):
if getattr(self, '_shared_field_names_cache', None) is None:
self._shared_field_names_cache = self._meta.get_all_field_names()
return self._shared_field_names_cache
@property
def _translated_field_names(self):
if getattr(self, '_translated_field_names_cache', None) is None:
self._translated_field_names_cache = self._meta.translations_model._meta.get_all_field_names(
)
return self._translated_field_names_cache
class TranslatableModelForm(
with_metaclass(TranslatableModelFormMetaclass, ModelForm)):
def __init__(self,
data=None,
files=None,
auto_id='id_%s',
prefix=None,
initial=None,
error_class=ErrorList,
label_suffix=':',
empty_permitted=False,
instance=None):
opts = self._meta
model_opts = opts.model._meta
object_data = {}
language = getattr(self, 'language', get_language())
if instance is not None:
trans = get_cached_translation(instance)
if not trans:
try:
trans = get_translation(instance, language)
except model_opts.translations_model.DoesNotExist:
trans = None
if trans:
object_data = model_to_dict(trans, opts.fields, opts.exclude)
if initial is not None:
object_data.update(initial)
initial = object_data
super(TranslatableModelForm,
self).__init__(data, files, auto_id, prefix, object_data,
error_class, label_suffix, empty_permitted,
instance)
def save(self, commit=True):
if self.instance.pk is None:
fail_message = 'created'
new = True
else:
fail_message = 'changed'
new = False
super(TranslatableModelForm, self).save(True)
trans_model = self.instance._meta.translations_model
language_code = self.cleaned_data.get('language_code', get_language())
if not new:
trans = get_cached_translation(self.instance)
if not trans or trans.language_code != language_code:
try:
trans = get_translation(self.instance, language_code)
except trans_model.DoesNotExist:
trans = trans_model()
else:
trans = trans_model()
trans.language_code = language_code
trans.master = self.instance
trans = save_instance(self,
trans,
self._meta.fields,
fail_message,
commit,
construct=True)
return combine(trans, self.Meta.model)
def _post_clean(self):
if self.instance.pk:
try:
trans = trans = get_translation(self.instance,
self.instance.language_code)
trans.master = self.instance
self.instance = combine(trans, self.Meta.model)
except self.instance._meta.translations_model.DoesNotExist:
language_code = self.cleaned_data.get('language_code',
get_language())
self.instance = self.instance.translate(language_code)
return super(TranslatableModelForm, self)._post_clean()
class TranslatableModel(with_metaclass(TranslatableModelBase, models.Model)):
"""
Base model for all models supporting translated fields (via TranslatedFields).
"""
# change the default manager to the translation manager
objects = TranslationManager()
class Meta:
abstract = True
def __init__(self, *args, **kwargs):
tkwargs = {} # translated fields
skwargs = {} # shared fields
if 'master' in kwargs.keys():
raise RuntimeError(
"Cannot init %s class with a 'master' argument" % \
self.__class__.__name__
)
# filter out all the translated fields (including 'master' and 'language_code')
primary_key_names = ('pk', self._meta.pk.name)
for key in list(kwargs.keys()):
if key in self._translated_field_names:
if not key in primary_key_names:
# we exclude the pk of the shared model
tkwargs[key] = kwargs.pop(key)
if not tkwargs.keys():
# if there where no translated options, then we assume this is a
# regular init and don't want to do any funky stuff
super(TranslatableModel, self).__init__(*args, **kwargs)
return
# there was at least one of the translated fields (or a language_code)
# in kwargs. We need to do magic.
# extract all the shared fields (including the pk)
for key in list(kwargs.keys()):
if key in self._shared_field_names:
skwargs[key] = kwargs.pop(key)
# do the regular init minus the translated fields
super(TranslatableModel, self).__init__(*args, **skwargs)
# prepopulate the translations model cache with an translation model
tkwargs['language_code'] = tkwargs.get('language_code', get_language())
tkwargs['master'] = self
translated = self._meta.translations_model(*args, **tkwargs)
setattr(self, self._meta.translations_cache, translated)
@classmethod
def contribute_translations(cls, rel):
"""
Contribute translations options to the inner Meta class and set the
descriptors.
This get's called from TranslatableModelBase.__new__
"""
opts = cls._meta
opts.translations_accessor = rel.get_accessor_name()
opts.translations_model = rel.model
opts.translations_cache = '%s_cache' % rel.get_accessor_name()
trans_opts = opts.translations_model._meta
# Set descriptors
ignore_fields = [
'pk',
'master',
opts.translations_model._meta.pk.name,
]
for field in trans_opts.fields:
if field.name in ignore_fields:
continue
if field.name == 'language_code':
attr = LanguageCodeAttribute(opts)
else:
attr = TranslatedAttribute(opts, field.name)
setattr(cls, field.name, attr)
@classmethod
def save_translations(cls, instance, **kwargs):
"""
When this instance is saved, also save the (cached) translation
"""
opts = cls._meta
if hasattr(instance, opts.translations_cache):
trans = getattr(instance, opts.translations_cache)
if not trans.master_id:
trans.master = instance
trans.save()
def translate(self, language_code):
"""
Returns an Model instance in the specified language.
Does NOT check if the translation already exists!
Does NOT interact with the database.
This will refresh the translations cache attribute on the instance.
"""
tkwargs = {
'language_code': language_code,
'master': self,
}
translated = self._meta.translations_model(**tkwargs)
setattr(self, self._meta.translations_cache, translated)
return self
def safe_translation_getter(self, name, default=None):
cache = getattr(self, self._meta.translations_cache, None)
if not cache:
return default
return getattr(cache, name, default)
def lazy_translation_getter(self, name, default=None):
"""
Lazy translation getter that fetches translations from DB in case the instance is currently untranslated and
saves the translation instance in the translation cache
"""
stuff = self.safe_translation_getter(name, NoTranslation)
if stuff is not NoTranslation:
return stuff
# get all translations
translations = self._meta.translations_model.objects.filter(
master__pk=self.pk)
# make them a nice dict
translation_dict = {}
for translation in translations:
translation_dict[translation.language_code] = translation
# see if we have the right language
correct_language = translation_dict.get(get_language())
if correct_language:
# CACHE IT!
setattr(self, self._meta.translations_cache, correct_language)
return getattr(correct_language, name, default)
# Nope? Ok, let's try the default language for the installation
default_language = translation_dict.get(settings.LANGUAGE_CODE)
if default_language:
# CACHE IT!
setattr(self, self._meta.translations_cache, default_language)
return getattr(default_language, name, default)
# *Sigh*, OK, any available langauge?
try:
any_language = list(translation_dict.values())[0]
except IndexError:
# OK, can't say we didn't try!
return default
setattr(self, self._meta.translations_cache, any_language)
return getattr(any_language, name, default)
def get_available_languages(self):
manager = self._meta.translations_model.objects
return manager.filter(master=self).values_list('language_code',
flat=True)
#===========================================================================
# Internals
#===========================================================================
@property
def _shared_field_names(self):
if getattr(self, '_shared_field_names_cache', None) is None:
self._shared_field_names_cache = self._meta.get_all_field_names()
return self._shared_field_names_cache
@property
def _translated_field_names(self):
if getattr(self, '_translated_field_names_cache', None) is None:
self._translated_field_names_cache = self._meta.translations_model._meta.get_all_field_names(
)
return self._translated_field_names_cache