def create_translation(self, language_code, **fields):
"""
Add a translation to the model.
The :func:`save_translations` function is called afterwards.
The object will be saved immediately, similar to
calling :func:`~django.db.models.manager.Manager.create`
or :func:`~django.db.models.fields.related.RelatedManager.create` on related fields.
"""
if language_code is None:
raise ValueError(get_null_language_error())
meta = self._parler_meta
if self._translations_cache[meta.root_model].get(language_code, None): # MISSING evaluates to False too
raise ValueError("Translation already exists: {0}".format(language_code))
# Save all fields in the proper translated model.
for translation in self._set_translated_fields(language_code, **fields):
self.save_translation(translation)
def create_translation(self, language_code, **fields):
"""
Add a translation to the model.
The :func:`save_translations` function is called afterwards.
The object will be saved immediately, similar to
calling :func:`~django.db.models.manager.Manager.create`
or :func:`~django.db.models.fields.related.RelatedManager.create` on related fields.
"""
if language_code is None:
raise ValueError(get_null_language_error())
meta = self._parler_meta
if self._translations_cache[meta.root_model].get(language_code, None): # MISSING evaluates to False too
raise ValueError("Translation already exists: {0}".format(language_code))
# Save all fields in the proper translated model.
for translation in self._set_translated_fields(language_code, **fields):
self.save_translation(translation)
def delete_translation(self, language_code, related_name=None):
"""
Delete a translation from a model.
:param language_code: The language to remove.
:param related_name: If given, only the model matching that related_name is removed.
"""
if language_code is None:
raise ValueError(get_null_language_error())
if related_name is None:
metas = self._parler_meta
else:
metas = [self._parler_meta[related_name]]
num_deleted = 0
for meta in metas:
try:
translation = self._get_translated_model(language_code, meta=meta)
except meta.model.DoesNotExist:
continue
# By using the regular model delete, the cache is properly cleared
# (via _delete_cached_translation) and signals are emitted.
translation.delete()
num_deleted += 1
# Clear other local caches
try:
del self._translations_cache[meta.model][language_code]
except KeyError:
pass
try:
del self._prefetched_objects_cache[meta.rel_name]
except (AttributeError, KeyError):
pass
if not num_deleted:
raise ValueError("Translation does not exist: {0}".format(language_code))
return num_deleted
def delete_translation(self, language_code, related_name=None):
"""
Delete a translation from a model.
:param language_code: The language to remove.
:param related_name: If given, only the model matching that related_name is removed.
"""
if language_code is None:
raise ValueError(get_null_language_error())
if related_name is None:
metas = self._parler_meta
else:
metas = [self._parler_meta[related_name]]
num_deleted = 0
for meta in metas:
try:
translation = self._get_translated_model(language_code, meta=meta)
except meta.model.DoesNotExist:
continue
# By using the regular model delete, the cache is properly cleared
# (via _delete_cached_translation) and signals are emitted.
translation.delete()
num_deleted += 1
# Clear other local caches
try:
del self._translations_cache[meta.model][language_code]
except KeyError:
pass
try:
del self._prefetched_objects_cache[meta.rel_name]
except (AttributeError, KeyError):
pass
if not num_deleted:
raise ValueError("Translation does not exist: {0}".format(language_code))
return num_deleted
def has_translation(self, language_code=None, related_name=None):
"""
Return whether a translation for the given language exists.
Defaults to the current language code.
.. versionadded 1.2 Added the ``related_name`` parameter.
"""
if language_code is None:
language_code = self._current_language
if language_code is None:
raise ValueError(get_null_language_error())
meta = self._parler_meta._get_extension_by_related_name(related_name)
try:
# Check the local cache directly, and the answer is known.
# NOTE this may also return newly auto created translations which are not saved yet.
return self._translations_cache[meta.model][language_code] is not MISSING
except KeyError:
# If there is a prefetch, will be using that.
# However, don't assume the prefetch contains all possible languages.
# With Django 1.8, there are custom Prefetch objects.
# TODO: improve this, detect whether this is the case.
if language_code in self._read_prefetched_translations(meta=meta):
return True
# Try to fetch from the cache first.
# If the cache returns the fallback, it means the original does not exist.
object = get_cached_translation(self, language_code, related_name=related_name, use_fallback=True)
if object is not None:
return object.language_code == language_code
try:
# Fetch from DB, fill the cache.
self._get_translated_model(language_code, use_fallback=False, auto_create=False, meta=meta)
except meta.model.DoesNotExist:
return False
else:
return True
def has_translation(self, language_code=None, related_name=None):
"""
Return whether a translation for the given language exists.
Defaults to the current language code.
.. versionadded 1.2 Added the ``related_name`` parameter.
"""
if language_code is None:
language_code = self._current_language
if language_code is None:
raise ValueError(get_null_language_error())
meta = self._parler_meta._get_extension_by_related_name(related_name)
try:
# Check the local cache directly, and the answer is known.
# NOTE this may also return newly auto created translations which are not saved yet.
return self._translations_cache[meta.model][language_code] is not MISSING
except KeyError:
# If there is a prefetch, will be using that.
# However, don't assume the prefetch contains all possible languages.
# With Django 1.8, there are custom Prefetch objects.
# TODO: improve this, detect whether this is the case.
if language_code in self._read_prefetched_translations(meta=meta):
return True
# Try to fetch from the cache first.
# If the cache returns the fallback, it means the original does not exist.
object = get_cached_translation(self, language_code, related_name=related_name, use_fallback=True)
if object is not None:
return object.language_code == language_code
try:
# Fetch from DB, fill the cache.
self._get_translated_model(language_code, use_fallback=False, auto_create=False, meta=meta)
except meta.model.DoesNotExist:
return False
else:
return True
def get_language(self, language_code, site_id=None):
"""
Return the language settings for the current site
This function can be used with other settings variables
to support modules which create their own variation of the ``PARLER_LANGUAGES`` setting.
For an example, see :func:`~parler.appsettings.add_default_language_settings`.
"""
if language_code is None:
raise ValueError(get_null_language_error())
if site_id is None:
site_id = getattr(settings, "SITE_ID", None)
for lang_dict in self.get(site_id, ()):
if lang_dict["code"] == language_code:
return lang_dict
# no language match, search for variant: fr-ca falls back to fr
for lang_dict in self.get(site_id, ()):
if lang_dict["code"].split("-")[0] == language_code.split("-")[0]:
return lang_dict
return self["default"]
def get_language(self, language_code, site_id=None):
"""
Return the language settings for the current site
This function can be used with other settings variables
to support modules which create their own variation of the ``PARLER_LANGUAGES`` setting.
For an example, see :func:`~parler.appsettings.add_default_language_settings`.
"""
if language_code is None:
raise ValueError(get_null_language_error())
if site_id is None:
site_id = getattr(settings, 'SITE_ID', None)
for lang_dict in self.get(site_id, ()):
if lang_dict['code'] == language_code:
return lang_dict
# no language match, search for variant: fr-ca falls back to fr
for lang_dict in self.get(site_id, ()):
if lang_dict['code'].split('-')[0] == language_code.split('-')[0]:
return lang_dict
return self['default']
def _get_translated_model(self, language_code=None, use_fallback=False, auto_create=False, meta=None):
"""
Fetch the translated fields model.
"""
if self._parler_meta is None:
raise ImproperlyConfigured("No translation is assigned to the current model!")
if self._translations_cache is None:
raise RuntimeError("Accessing translated fields before super.__init__() is not possible.")
if not language_code:
language_code = self._current_language
if language_code is None:
raise ValueError(get_null_language_error())
if meta is None:
meta = self._parler_meta.root # work on base model by default
local_cache = self._translations_cache[meta.model]
# 1. fetch the object from the local cache
try:
object = local_cache[language_code]
# If cached object indicates the language doesn't exist, need to query the fallback.
if object is not MISSING:
return object
except KeyError:
# 2. No cache, need to query
# Check that this object already exists, would be pointless otherwise to check for a translation.
if not self._state.adding and self.pk is not None:
prefetch = self._get_prefetched_translations(meta=meta)
if prefetch is not None:
# 2.1, use prefetched data
# If the object is not found in the prefetched data (which contains all translations),
# it's pointless to check for memcached (2.2) or perform a single query (2.3)
for object in prefetch:
if object.language_code == language_code:
local_cache[language_code] = object
_cache_translation(object) # Store in memcached
return object
else:
# 2.2, fetch from memcached
object = get_cached_translation(self, language_code, related_name=meta.rel_name, use_fallback=use_fallback)
if object is not None:
# Track in local cache
if object.language_code != language_code:
local_cache[language_code] = MISSING # Set fallback marker
local_cache[object.language_code] = object
return object
elif local_cache.get(language_code, None) is MISSING:
# If get_cached_translation() explicitly set the "does not exist" marker,
# there is no need to try a database query.
pass
else:
# 2.3, fetch from database
try:
object = self._get_translated_queryset(meta).get(language_code=language_code)
except meta.model.DoesNotExist:
pass
else:
local_cache[language_code] = object
_cache_translation(object) # Store in memcached
return object
# Not in cache, or default.
# Not fetched from DB
# 3. Auto create?
if auto_create:
# Auto create policy first (e.g. a __set__ call)
kwargs = {
'language_code': language_code,
}
if self.pk:
# ID might be None at this point, and Django 1.8 does not allow that.
kwargs['master'] = self
object = meta.model(**kwargs)
local_cache[language_code] = object
# Not stored in memcached here yet, first fill + save it.
return object
# 4. Fallback?
fallback_msg = None
lang_dict = get_language_settings(language_code)
if language_code not in local_cache:
# Explicitly set a marker for the fact that this translation uses the fallback instead.
# Avoid making that query again.
local_cache[language_code] = MISSING # None value is the marker.
if not self._state.adding or self.pk is not None:
_cache_translation_needs_fallback(self, language_code, related_name=meta.rel_name)
fallback_choices = [lang_dict['code']] + list(lang_dict['fallbacks'])
if use_fallback and fallback_choices:
# Jump to fallback language, return directly.
# Don't cache under this language_code
for fallback_lang in fallback_choices:
if fallback_lang == language_code: # Skip the current language, could also be fallback 1 of 2 choices
continue
try:
return self._get_translated_model(fallback_lang, use_fallback=False, auto_create=auto_create, meta=meta)
except meta.model.DoesNotExist:
pass
fallback_msg = " (tried fallbacks {0})".format(', '.join(lang_dict['fallbacks']))
# None of the above, bail out!
raise meta.model.DoesNotExist(
"{0} does not have a translation for the current language!\n"
"{0} ID #{1}, language={2}{3}".format(self._meta.verbose_name, self.pk, language_code, fallback_msg or ''
))
def _get_translated_model(self, language_code=None, use_fallback=False, auto_create=False, meta=None):
"""
Fetch the translated fields model.
"""
if self._parler_meta is None:
raise ImproperlyConfigured("No translation is assigned to the current model!")
if self._translations_cache is None:
raise RuntimeError("Accessing translated fields before super.__init__() is not possible.")
if not language_code:
language_code = self._current_language
if language_code is None:
raise ValueError(get_null_language_error())
if meta is None:
meta = self._parler_meta.root # work on base model by default
local_cache = self._translations_cache[meta.model]
# 1. fetch the object from the local cache
try:
object = local_cache[language_code]
# If cached object indicates the language doesn't exist, need to query the fallback.
if object is not MISSING:
return object
except KeyError:
# 2. No cache, need to query
# Check that this object already exists, would be pointless otherwise to check for a translation.
if not self._state.adding and self.pk is not None:
prefetch = self._get_prefetched_translations(meta=meta)
if prefetch is not None:
# 2.1, use prefetched data
# If the object is not found in the prefetched data (which contains all translations),
# it's pointless to check for memcached (2.2) or perform a single query (2.3)
for object in prefetch:
if object.language_code == language_code:
local_cache[language_code] = object
_cache_translation(object) # Store in memcached
return object
else:
# 2.2, fetch from memcached
object = get_cached_translation(self, language_code, related_name=meta.rel_name, use_fallback=use_fallback)
if object is not None:
# Track in local cache
if object.language_code != language_code:
local_cache[language_code] = MISSING # Set fallback marker
local_cache[object.language_code] = object
return object
elif local_cache.get(language_code, None) is MISSING:
# If get_cached_translation() explicitly set the "does not exist" marker,
# there is no need to try a database query.
pass
else:
# 2.3, fetch from database
try:
object = self._get_translated_queryset(meta).get(language_code=language_code)
except meta.model.DoesNotExist:
pass
else:
local_cache[language_code] = object
_cache_translation(object) # Store in memcached
return object
# Not in cache, or default.
# Not fetched from DB
# 3. Auto create?
if auto_create:
# Auto create policy first (e.g. a __set__ call)
kwargs = {
'language_code': language_code,
}
if self.pk:
# ID might be None at this point, and Django 1.8 does not allow that.
kwargs['master'] = self
object = meta.model(**kwargs)
local_cache[language_code] = object
# Not stored in memcached here yet, first fill + save it.
return object
# 4. Fallback?
fallback_msg = None
lang_dict = get_language_settings(language_code)
if language_code not in local_cache:
# Explicitly set a marker for the fact that this translation uses the fallback instead.
# Avoid making that query again.
local_cache[language_code] = MISSING # None value is the marker.
if not self._state.adding or self.pk is not None:
_cache_translation_needs_fallback(self, language_code, related_name=meta.rel_name)
fallback_choices = [lang_dict['code']] + list(lang_dict['fallbacks'])
if use_fallback and fallback_choices:
# Jump to fallback language, return directly.
# Don't cache under this language_code
for fallback_lang in fallback_choices:
if fallback_lang == language_code: # Skip the current language, could also be fallback 1 of 2 choices
continue
try:
return self._get_translated_model(fallback_lang, use_fallback=False, auto_create=auto_create, meta=meta)
except meta.model.DoesNotExist:
pass
fallback_msg = " (tried fallbacks {0})".format(', '.join(lang_dict['fallbacks']))
# None of the above, bail out!
raise meta.model.DoesNotExist(
"{0} does not have a translation for the current language!\n"
"{0} ID #{1}, language={2}{3}".format(self._meta.verbose_name, self.pk, language_code, fallback_msg or ''
))