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import copy
import logging, os
import gettext as _gettext
from gettext import NullTranslations, GNUTranslations
import warnings
import tg
from tg.util import lazify
from tg._compat import PY3, string_type
log = logging.getLogger(__name__)
class LanguageError(Exception):
"""Exception raised when a problem occurs with changing languages"""
def _parse_locale(identifier, sep='_'):
Took from Babel,
Parse a locale identifier into a tuple of the form::
``(language, territory, script, variant)``
>>> parse_locale('zh_CN')
('zh', 'CN', None, None)
>>> parse_locale('zh_Hans_CN')
('zh', 'CN', 'Hans', None)
The default component separator is "_", but a different separator can be
specified using the `sep` parameter:
:see: `IETF RFC 4646 <>`_
if '.' in identifier:
# this is probably the charset/encoding, which we don't care about
identifier = identifier.split('.', 1)[0]
if '@' in identifier:
# this is a locale modifier such as @euro, which we don't care about
# either
identifier = identifier.split('@', 1)[0]
parts = identifier.split(sep)
lang = parts.pop(0).lower()
if not lang.isalpha():
raise ValueError('expected only letters, got %r' % lang)
script = territory = variant = None
if parts:
if len(parts[0]) == 4 and parts[0].isalpha():
script = parts.pop(0).title()
if parts:
if len(parts[0]) == 2 and parts[0].isalpha():
territory = parts.pop(0).upper()
elif len(parts[0]) == 3 and parts[0].isdigit():
territory = parts.pop(0)
if parts:
if len(parts[0]) == 4 and parts[0][0].isdigit() or\
len(parts[0]) >= 5 and parts[0][0].isalpha():
variant = parts.pop()
if parts:
raise ValueError('%r is not a valid locale identifier' % identifier)
return lang, territory, script, variant
def gettext_noop(value):
"""Mark a string for translation without translating it. Returns
return value
def ugettext(value):
"""Mark a string for translation. Returns the localized unicode
string of value.
Mark a string to be localized as follows::
_('This should be in lots of languages')
if PY3: #pragma: no cover
return tg.translator.gettext(value)
return tg.translator.ugettext(value)
lazy_ugettext = lazify(ugettext)
def ungettext(singular, plural, n):
"""Mark a string for translation. Returns the localized unicode
string of the pluralized value.
This does a plural-forms lookup of a message id. ``singular`` is
used as the message id for purposes of lookup in the catalog, while
``n`` is used to determine which plural form to use. The returned
message is a Unicode string.
Mark a string to be localized as follows::
ungettext('There is %(num)d file here', 'There are %(num)d files here',
n) % {'num': n}
if PY3: #pragma: no cover
return tg.translator.ngettext(singular, plural, n)
return tg.translator.ungettext(singular, plural, n)
lazy_ungettext = lazify(ungettext)
def _translator_from_mofiles(domain, mofiles, class_=None, fallback=False):
Adapted from python translation function in gettext module
to work with a provided list of mo files
if class_ is None:
class_ = GNUTranslations
if not mofiles:
if fallback:
return NullTranslations()
raise LanguageError('No translation file found for domain %s' % domain)
result = None
for mofile in mofiles:
key = (class_, os.path.abspath(mofile))
if t is None:
with open(mofile, 'rb') as fp:
# Cache Translator to avoid reading it again
t = _TRANSLATORS_CACHE.setdefault(key, class_(fp))
t = copy.copy(t)
if result is None:
# Copy the translation object to be able to append fallbacks
# without affecting the cached object.
result = t
return result
def _get_translator(lang, tgl=None, tg_config=None, **kwargs):
"""Utility method to get a valid translator object from a language name"""
if tg_config:
conf = tg_config
if tgl:
conf = tgl.config
else: # pragma: no cover
#backward compatibility with explicit calls without
#specifying local context or config.
conf = tg.config.current_conf()
if not lang:
return NullTranslations()
localedir = conf['localedir']
except KeyError: # pragma: no cover
localedir = os.path.join(conf['paths']['root'], 'i18n')
app_domain = conf['package'].__name__
if not isinstance(lang, list):
lang = [lang]
mofiles = []
supported_languages = []
for l in lang:
mo = _gettext.find(app_domain, localedir=localedir, languages=[l], all=False)
if mo is not None:
translator = _translator_from_mofiles(app_domain, mofiles, **kwargs)
except IOError as ioe:
raise LanguageError('IOError: %s' % ioe)
translator.tg_lang = lang
translator.tg_supported_lang = supported_languages
return translator
def get_lang(all=True):
Return the current i18n languages used
returns ``None`` if no supported language is available (no translations
are in place) or a list of languages.
In case ``all`` parameter is ``False`` only the languages for which
the application is providing a translation are returned. Otherwise
all the languages preferred by the user are returned.
if all is False:
return getattr(tg.translator, 'tg_supported_lang', [])
return getattr(tg.translator, 'tg_lang', [])
def add_fallback(lang, **kwargs):
"""Add a fallback language from which words not matched in other
languages will be translated to.
This fallback will be associated with the currently selected
language -- that is, resetting the language via set_lang() resets
the current fallbacks.
This function can be called multiple times to add multiple
tgl = tg.request_local.context._current_obj()
return tg.translator.add_fallback(_get_translator(lang, tgl=tgl, **kwargs))
sanitized_language_cache = {}
def sanitize_language_code(lang):
"""Sanitize the language code if the spelling is slightly wrong.
For instance, 'pt-br' and 'pt_br' should be interpreted as 'pt_BR'.
lang = sanitized_language_cache[lang]
orig_lang = lang
lang = '_'.join(filter(None, _parse_locale(lang)[:2]))
except ValueError:
if '-' in lang:
lang = '_'.join(filter(None, _parse_locale(lang, sep='-')[:2]))
except ValueError:
sanitized_language_cache[orig_lang] = lang
return lang
def set_request_lang(languages, tgl=None):
"""Set the current request language(s) used for translations
without touching the session language.
languages should be a string or a list of strings.
First lang will be used as main lang, others as fallbacks.
# the logging to the screen was removed because
# the printing to the screen for every problem causes serious slow down.
if not tgl:
tgl = tg.request_local.context._current_obj()
# Should only raise exceptions in case of IO errors,
# so we let them propagate to the developer.
tgl.translator = _get_translator(languages, tgl=tgl, fallback=True)
# If the application has a set of supported translation
# limit the formencode translations to those so that
# we don't get the application in a language and
# the errors in another one
supported_languages = get_lang(all=False)
if supported_languages:
languages = supported_languages
set_formencode_translation(languages, tgl=tgl)
except LanguageError:
def set_temporary_lang(*args, **kwargs):
warnings.warn("i18n.set_temporary_lang has been deprecated in favor of"
"i18n.set_request_lang and will be removed.", DeprecationWarning)
return set_request_lang(*args, **kwargs)
def set_lang(languages, **kwargs):
"""Set the current language(s) used for translations
in current call and session.
languages should be a string or a list of strings.
First lang will be used as main lang, others as fallbacks.
tgl = tg.request_local.context._current_obj()
set_request_lang(languages, tgl)
if tgl.session:
tgl.session[tgl.config.get('lang_session_key', 'tg_lang')] = languages
FormEncodeMissing = '_MISSING_FORMENCODE'
formencode = None
_localdir = None
def set_formencode_translation(languages, tgl=None):
"""Set request specific translation of FormEncode."""
global formencode, _localdir
if formencode is FormEncodeMissing: # pragma: no cover
if formencode is None:
import formencode
_localdir = formencode.api.get_localedir()
except ImportError: # pragma: no cover
formencode = FormEncodeMissing
if not tgl: # pragma: no cover
tgl = tg.request_local.context._current_obj()
formencode_translation = _gettext.translation('FormEncode',
except IOError as error:
raise LanguageError('IOError: %s' % error)
tgl.translator._formencode_translation = formencode_translation
# Idea stolen from Pylons
def _formencode_gettext(value):
trans = ugettext(value)
# Translation failed, try formencode
if trans == value:
fetrans = tg.translator._formencode_translation
except (AttributeError, TypeError):
# the translator was not set in the TG context
# we are certainly in the test framework
# let's make sure won't return something that is ok with the caller
fetrans = None
if not fetrans:
fetrans = NullTranslations()
translator_gettext = getattr(fetrans, 'ugettext', fetrans.gettext)
trans = translator_gettext(value)
return trans
__all__ = [
"set_lang", "get_lang", "add_fallback",
"set_request_lang", "set_temporary_lang",
"ugettext", "lazy_ugettext", "ungettext", "lazy_ungettext"
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