517 lines
18 KiB
Python
517 lines
18 KiB
Python
"""Translation helper functions."""
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import functools
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import gettext as gettext_module
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import os
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import re
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import sys
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import warnings
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from collections import OrderedDict
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from threading import local
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from django.apps import apps
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from django.conf import settings
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from django.conf.locale import LANG_INFO
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from django.core.exceptions import AppRegistryNotReady
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from django.core.signals import setting_changed
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from django.dispatch import receiver
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from django.utils.safestring import SafeData, mark_safe
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from . import LANGUAGE_SESSION_KEY, to_language, to_locale
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# Translations are cached in a dictionary for every language.
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# The active translations are stored by threadid to make them thread local.
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_translations = {}
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_active = local()
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# The default translation is based on the settings file.
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_default = None
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# magic gettext number to separate context from message
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CONTEXT_SEPARATOR = "\x04"
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# Format of Accept-Language header values. From RFC 2616, section 14.4 and 3.9
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# and RFC 3066, section 2.1
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accept_language_re = re.compile(r'''
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([A-Za-z]{1,8}(?:-[A-Za-z0-9]{1,8})*|\*) # "en", "en-au", "x-y-z", "es-419", "*"
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(?:\s*;\s*q=(0(?:\.\d{,3})?|1(?:\.0{,3})?))? # Optional "q=1.00", "q=0.8"
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(?:\s*,\s*|$) # Multiple accepts per header.
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''', re.VERBOSE)
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language_code_re = re.compile(
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r'^[a-z]{1,8}(?:-[a-z0-9]{1,8})*(?:@[a-z0-9]{1,20})?$',
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re.IGNORECASE
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)
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language_code_prefix_re = re.compile(r'^/(\w+([@-]\w+)?)(/|$)')
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@receiver(setting_changed)
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def reset_cache(**kwargs):
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"""
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Reset global state when LANGUAGES setting has been changed, as some
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languages should no longer be accepted.
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"""
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if kwargs['setting'] in ('LANGUAGES', 'LANGUAGE_CODE'):
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check_for_language.cache_clear()
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get_languages.cache_clear()
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get_supported_language_variant.cache_clear()
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class DjangoTranslation(gettext_module.GNUTranslations):
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"""
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Set up the GNUTranslations context with regard to output charset.
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This translation object will be constructed out of multiple GNUTranslations
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objects by merging their catalogs. It will construct an object for the
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requested language and add a fallback to the default language, if it's
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different from the requested language.
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"""
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domain = 'django'
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def __init__(self, language, domain=None, localedirs=None):
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"""Create a GNUTranslations() using many locale directories"""
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gettext_module.GNUTranslations.__init__(self)
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if domain is not None:
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self.domain = domain
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self.__language = language
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self.__to_language = to_language(language)
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self.__locale = to_locale(language)
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self._catalog = None
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# If a language doesn't have a catalog, use the Germanic default for
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# pluralization: anything except one is pluralized.
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self.plural = lambda n: int(n != 1)
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if self.domain == 'django':
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if localedirs is not None:
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# A module-level cache is used for caching 'django' translations
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warnings.warn("localedirs is ignored when domain is 'django'.", RuntimeWarning)
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localedirs = None
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self._init_translation_catalog()
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if localedirs:
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for localedir in localedirs:
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translation = self._new_gnu_trans(localedir)
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self.merge(translation)
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else:
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self._add_installed_apps_translations()
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self._add_local_translations()
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if self.__language == settings.LANGUAGE_CODE and self.domain == 'django' and self._catalog is None:
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# default lang should have at least one translation file available.
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raise IOError("No translation files found for default language %s." % settings.LANGUAGE_CODE)
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self._add_fallback(localedirs)
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if self._catalog is None:
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# No catalogs found for this language, set an empty catalog.
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self._catalog = {}
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def __repr__(self):
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return "<DjangoTranslation lang:%s>" % self.__language
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def _new_gnu_trans(self, localedir, use_null_fallback=True):
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"""
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Return a mergeable gettext.GNUTranslations instance.
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A convenience wrapper. By default gettext uses 'fallback=False'.
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Using param `use_null_fallback` to avoid confusion with any other
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references to 'fallback'.
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"""
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return gettext_module.translation(
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domain=self.domain,
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localedir=localedir,
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languages=[self.__locale],
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codeset='utf-8',
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fallback=use_null_fallback,
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)
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def _init_translation_catalog(self):
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"""Create a base catalog using global django translations."""
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settingsfile = sys.modules[settings.__module__].__file__
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localedir = os.path.join(os.path.dirname(settingsfile), 'locale')
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translation = self._new_gnu_trans(localedir)
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self.merge(translation)
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def _add_installed_apps_translations(self):
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"""Merge translations from each installed app."""
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try:
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app_configs = reversed(list(apps.get_app_configs()))
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except AppRegistryNotReady:
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raise AppRegistryNotReady(
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"The translation infrastructure cannot be initialized before the "
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"apps registry is ready. Check that you don't make non-lazy "
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"gettext calls at import time.")
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for app_config in app_configs:
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localedir = os.path.join(app_config.path, 'locale')
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if os.path.exists(localedir):
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translation = self._new_gnu_trans(localedir)
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self.merge(translation)
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def _add_local_translations(self):
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"""Merge translations defined in LOCALE_PATHS."""
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for localedir in reversed(settings.LOCALE_PATHS):
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translation = self._new_gnu_trans(localedir)
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self.merge(translation)
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def _add_fallback(self, localedirs=None):
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"""Set the GNUTranslations() fallback with the default language."""
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# Don't set a fallback for the default language or any English variant
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# (as it's empty, so it'll ALWAYS fall back to the default language)
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if self.__language == settings.LANGUAGE_CODE or self.__language.startswith('en'):
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return
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if self.domain == 'django':
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# Get from cache
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default_translation = translation(settings.LANGUAGE_CODE)
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else:
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default_translation = DjangoTranslation(
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settings.LANGUAGE_CODE, domain=self.domain, localedirs=localedirs
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)
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self.add_fallback(default_translation)
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def merge(self, other):
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"""Merge another translation into this catalog."""
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if not getattr(other, '_catalog', None):
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return # NullTranslations() has no _catalog
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if self._catalog is None:
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# Take plural and _info from first catalog found (generally Django's).
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self.plural = other.plural
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self._info = other._info.copy()
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self._catalog = other._catalog.copy()
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else:
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self._catalog.update(other._catalog)
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if other._fallback:
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self.add_fallback(other._fallback)
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def language(self):
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"""Return the translation language."""
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return self.__language
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def to_language(self):
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"""Return the translation language name."""
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return self.__to_language
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def translation(language):
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"""
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Return a translation object in the default 'django' domain.
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"""
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global _translations
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if language not in _translations:
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_translations[language] = DjangoTranslation(language)
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return _translations[language]
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def activate(language):
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"""
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Fetch the translation object for a given language and install it as the
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current translation object for the current thread.
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"""
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if not language:
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return
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_active.value = translation(language)
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def deactivate():
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"""
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Uninstall the active translation object so that further _() calls resolve
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to the default translation object.
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"""
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if hasattr(_active, "value"):
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del _active.value
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def deactivate_all():
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"""
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Make the active translation object a NullTranslations() instance. This is
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useful when we want delayed translations to appear as the original string
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for some reason.
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"""
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_active.value = gettext_module.NullTranslations()
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_active.value.to_language = lambda *args: None
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def get_language():
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"""Return the currently selected language."""
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t = getattr(_active, "value", None)
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if t is not None:
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try:
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return t.to_language()
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except AttributeError:
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pass
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# If we don't have a real translation object, assume it's the default language.
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return settings.LANGUAGE_CODE
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def get_language_bidi():
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"""
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Return selected language's BiDi layout.
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* False = left-to-right layout
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* True = right-to-left layout
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"""
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lang = get_language()
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if lang is None:
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return False
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else:
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base_lang = get_language().split('-')[0]
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return base_lang in settings.LANGUAGES_BIDI
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def catalog():
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"""
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Return the current active catalog for further processing.
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This can be used if you need to modify the catalog or want to access the
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whole message catalog instead of just translating one string.
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"""
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global _default
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t = getattr(_active, "value", None)
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if t is not None:
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return t
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if _default is None:
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_default = translation(settings.LANGUAGE_CODE)
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return _default
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def gettext(message):
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"""
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Translate the 'message' string. It uses the current thread to find the
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translation object to use. If no current translation is activated, the
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message will be run through the default translation object.
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"""
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global _default
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eol_message = message.replace('\r\n', '\n').replace('\r', '\n')
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if eol_message:
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_default = _default or translation(settings.LANGUAGE_CODE)
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translation_object = getattr(_active, "value", _default)
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result = translation_object.gettext(eol_message)
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else:
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# Return an empty value of the corresponding type if an empty message
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# is given, instead of metadata, which is the default gettext behavior.
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result = type(message)('')
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if isinstance(message, SafeData):
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return mark_safe(result)
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return result
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def pgettext(context, message):
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msg_with_ctxt = "%s%s%s" % (context, CONTEXT_SEPARATOR, message)
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result = gettext(msg_with_ctxt)
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if CONTEXT_SEPARATOR in result:
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# Translation not found
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result = message
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elif isinstance(message, SafeData):
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result = mark_safe(result)
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return result
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def gettext_noop(message):
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"""
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Mark strings for translation but don't translate them now. This can be
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used to store strings in global variables that should stay in the base
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language (because they might be used externally) and will be translated
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later.
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"""
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return message
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def do_ntranslate(singular, plural, number, translation_function):
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global _default
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t = getattr(_active, "value", None)
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if t is not None:
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return getattr(t, translation_function)(singular, plural, number)
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if _default is None:
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_default = translation(settings.LANGUAGE_CODE)
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return getattr(_default, translation_function)(singular, plural, number)
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def ngettext(singular, plural, number):
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"""
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Return a string of the translation of either the singular or plural,
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based on the number.
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"""
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return do_ntranslate(singular, plural, number, 'ngettext')
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def npgettext(context, singular, plural, number):
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msgs_with_ctxt = ("%s%s%s" % (context, CONTEXT_SEPARATOR, singular),
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"%s%s%s" % (context, CONTEXT_SEPARATOR, plural),
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number)
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result = ngettext(*msgs_with_ctxt)
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if CONTEXT_SEPARATOR in result:
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# Translation not found
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result = ngettext(singular, plural, number)
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return result
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def all_locale_paths():
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"""
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Return a list of paths to user-provides languages files.
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"""
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globalpath = os.path.join(
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os.path.dirname(sys.modules[settings.__module__].__file__), 'locale')
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app_paths = []
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for app_config in apps.get_app_configs():
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locale_path = os.path.join(app_config.path, 'locale')
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if os.path.exists(locale_path):
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app_paths.append(locale_path)
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return [globalpath] + list(settings.LOCALE_PATHS) + app_paths
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@functools.lru_cache(maxsize=1000)
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def check_for_language(lang_code):
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"""
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Check whether there is a global language file for the given language
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code. This is used to decide whether a user-provided language is
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available.
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lru_cache should have a maxsize to prevent from memory exhaustion attacks,
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as the provided language codes are taken from the HTTP request. See also
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<https://www.djangoproject.com/weblog/2007/oct/26/security-fix/>.
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"""
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# First, a quick check to make sure lang_code is well-formed (#21458)
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if lang_code is None or not language_code_re.search(lang_code):
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return False
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return any(
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gettext_module.find('django', path, [to_locale(lang_code)]) is not None
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for path in all_locale_paths()
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)
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@functools.lru_cache()
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def get_languages():
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"""
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Cache of settings.LANGUAGES in an OrderedDict for easy lookups by key.
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"""
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return OrderedDict(settings.LANGUAGES)
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@functools.lru_cache(maxsize=1000)
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def get_supported_language_variant(lang_code, strict=False):
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"""
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Return the language code that's listed in supported languages, possibly
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selecting a more generic variant. Raise LookupError if nothing is found.
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If `strict` is False (the default), look for a country-specific variant
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when neither the language code nor its generic variant is found.
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lru_cache should have a maxsize to prevent from memory exhaustion attacks,
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as the provided language codes are taken from the HTTP request. See also
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<https://www.djangoproject.com/weblog/2007/oct/26/security-fix/>.
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"""
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if lang_code:
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# If 'fr-ca' is not supported, try special fallback or language-only 'fr'.
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possible_lang_codes = [lang_code]
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try:
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possible_lang_codes.extend(LANG_INFO[lang_code]['fallback'])
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except KeyError:
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pass
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generic_lang_code = lang_code.split('-')[0]
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possible_lang_codes.append(generic_lang_code)
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supported_lang_codes = get_languages()
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for code in possible_lang_codes:
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if code in supported_lang_codes and check_for_language(code):
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return code
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if not strict:
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# if fr-fr is not supported, try fr-ca.
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for supported_code in supported_lang_codes:
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if supported_code.startswith(generic_lang_code + '-'):
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return supported_code
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raise LookupError(lang_code)
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def get_language_from_path(path, strict=False):
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"""
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Return the language code if there's a valid language code found in `path`.
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If `strict` is False (the default), look for a country-specific variant
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when neither the language code nor its generic variant is found.
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"""
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regex_match = language_code_prefix_re.match(path)
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if not regex_match:
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return None
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lang_code = regex_match.group(1)
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try:
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return get_supported_language_variant(lang_code, strict=strict)
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except LookupError:
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return None
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def get_language_from_request(request, check_path=False):
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"""
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Analyze the request to find what language the user wants the system to
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show. Only languages listed in settings.LANGUAGES are taken into account.
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If the user requests a sublanguage where we have a main language, we send
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out the main language.
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If check_path is True, the URL path prefix will be checked for a language
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code, otherwise this is skipped for backwards compatibility.
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"""
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if check_path:
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lang_code = get_language_from_path(request.path_info)
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if lang_code is not None:
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return lang_code
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supported_lang_codes = get_languages()
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if hasattr(request, 'session'):
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lang_code = request.session.get(LANGUAGE_SESSION_KEY)
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if lang_code in supported_lang_codes and lang_code is not None and check_for_language(lang_code):
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return lang_code
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lang_code = request.COOKIES.get(settings.LANGUAGE_COOKIE_NAME)
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try:
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return get_supported_language_variant(lang_code)
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except LookupError:
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pass
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accept = request.META.get('HTTP_ACCEPT_LANGUAGE', '')
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for accept_lang, unused in parse_accept_lang_header(accept):
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if accept_lang == '*':
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break
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if not language_code_re.search(accept_lang):
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continue
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try:
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return get_supported_language_variant(accept_lang)
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except LookupError:
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continue
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try:
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return get_supported_language_variant(settings.LANGUAGE_CODE)
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except LookupError:
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return settings.LANGUAGE_CODE
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@functools.lru_cache(maxsize=1000)
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def parse_accept_lang_header(lang_string):
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"""
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Parse the lang_string, which is the body of an HTTP Accept-Language
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header, and return a tuple of (lang, q-value), ordered by 'q' values.
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Return an empty tuple if there are any format errors in lang_string.
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"""
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result = []
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pieces = accept_language_re.split(lang_string.lower())
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if pieces[-1]:
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return ()
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for i in range(0, len(pieces) - 1, 3):
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first, lang, priority = pieces[i:i + 3]
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if first:
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return ()
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if priority:
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priority = float(priority)
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else:
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priority = 1.0
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result.append((lang, priority))
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result.sort(key=lambda k: k[1], reverse=True)
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return tuple(result)
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