# -*- coding: utf-8 -*- """ flask_babelex ~~~~~~~~~~~~~ Implements i18n/l10n support for Flask applications based on Babel. :copyright: (c) 2013 by Serge S. Koval, Armin Ronacher and contributors. :license: BSD, see LICENSE for more details. """ from __future__ import absolute_import import os # this is a workaround for a snow leopard bug that babel does not # work around :) if os.environ.get('LC_CTYPE', '').lower() == 'utf-8': os.environ['LC_CTYPE'] = 'en_US.utf-8' from datetime import datetime from flask import _request_ctx_stack from babel import dates, numbers, support, Locale from babel.support import NullTranslations from werkzeug.datastructures import ImmutableDict try: from pytz.gae import pytz except ImportError: from pytz import timezone, UTC else: timezone = pytz.timezone UTC = pytz.UTC from flask_babelex._compat import string_types _DEFAULT_LOCALE = Locale.parse('en') class Babel(object): """Central controller class that can be used to configure how Flask-Babel behaves. Each application that wants to use Flask-Babel has to create, or run :meth:`init_app` on, an instance of this class after the configuration was initialized. """ default_date_formats = ImmutableDict({ 'time': 'medium', 'date': 'medium', 'datetime': 'medium', 'time.short': None, 'time.medium': None, 'time.full': None, 'time.long': None, 'date.short': None, 'date.medium': None, 'date.full': None, 'date.long': None, 'datetime.short': None, 'datetime.medium': None, 'datetime.full': None, 'datetime.long': None, }) def __init__(self, app=None, default_locale='en', default_timezone='UTC', date_formats=None, configure_jinja=True, default_domain=None): self._default_locale = default_locale self._default_timezone = default_timezone self._date_formats = date_formats self._configure_jinja = configure_jinja self.app = app self._locale_cache = dict() if default_domain is None: self._default_domain = Domain() else: self._default_domain = default_domain self.locale_selector_func = None self.timezone_selector_func = None if app is not None: self.init_app(app) def init_app(self, app): """Set up this instance for use with *app*, if no app was passed to the constructor. """ self.app = app app.babel_instance = self if not hasattr(app, 'extensions'): app.extensions = {} app.extensions['babel'] = self app.config.setdefault('BABEL_DEFAULT_LOCALE', self._default_locale) app.config.setdefault('BABEL_DEFAULT_TIMEZONE', self._default_timezone) if self._date_formats is None: self._date_formats = self.default_date_formats.copy() #: a mapping of Babel datetime format strings that can be modified #: to change the defaults. If you invoke :func:`format_datetime` #: and do not provide any format string Flask-Babel will do the #: following things: #: #: 1. look up ``date_formats['datetime']``. By default ``'medium'`` #: is returned to enforce medium length datetime formats. #: 2. ``date_formats['datetime.medium'] (if ``'medium'`` was #: returned in step one) is looked up. If the return value #: is anything but `None` this is used as new format string. #: otherwise the default for that language is used. self.date_formats = self._date_formats if self._configure_jinja: app.jinja_env.filters.update( datetimeformat=format_datetime, dateformat=format_date, timeformat=format_time, timedeltaformat=format_timedelta, numberformat=format_number, decimalformat=format_decimal, currencyformat=format_currency, percentformat=format_percent, scientificformat=format_scientific, ) app.jinja_env.add_extension('jinja2.ext.i18n') app.jinja_env.install_gettext_callables( lambda x: get_domain().get_translations().ugettext(x), lambda s, p, n: get_domain().get_translations().ungettext(s, p, n), newstyle=True ) def localeselector(self, f): """Registers a callback function for locale selection. The default behaves as if a function was registered that returns `None` all the time. If `None` is returned, the locale falls back to the one from the configuration. This has to return the locale as string (eg: ``'de_AT'``, ''`en_US`'') """ assert self.locale_selector_func is None, \ 'a localeselector function is already registered' self.locale_selector_func = f return f def timezoneselector(self, f): """Registers a callback function for timezone selection. The default behaves as if a function was registered that returns `None` all the time. If `None` is returned, the timezone falls back to the one from the configuration. This has to return the timezone as string (eg: ``'Europe/Vienna'``) """ assert self.timezone_selector_func is None, \ 'a timezoneselector function is already registered' self.timezone_selector_func = f return f def list_translations(self): """Returns a list of all the locales translations exist for. The list returned will be filled with actual locale objects and not just strings. .. versionadded:: 0.6 """ dirname = os.path.join(self.app.root_path, 'translations') if not os.path.isdir(dirname): return [] result = [] for folder in os.listdir(dirname): locale_dir = os.path.join(dirname, folder, 'LC_MESSAGES') if not os.path.isdir(locale_dir): continue if filter(lambda x: x.endswith('.mo'), os.listdir(locale_dir)): result.append(Locale.parse(folder)) if not result: result.append(Locale.parse(self._default_locale)) return result @property def default_locale(self): """The default locale from the configuration as instance of a `babel.Locale` object. """ return self.load_locale(self.app.config['BABEL_DEFAULT_LOCALE']) @property def default_timezone(self): """The default timezone from the configuration as instance of a `pytz.timezone` object. """ return timezone(self.app.config['BABEL_DEFAULT_TIMEZONE']) def load_locale(self, locale): """Load locale by name and cache it. Returns instance of a `babel.Locale` object. """ rv = self._locale_cache.get(locale) if rv is None: self._locale_cache[locale] = rv = Locale.parse(locale) return rv def get_locale(): """Returns the locale that should be used for this request as `babel.Locale` object. This returns `None` if used outside of a request. If flask-babel was not attached to the Flask application, will return 'en' locale. """ ctx = _request_ctx_stack.top if ctx is None: return None locale = getattr(ctx, 'babel_locale', None) if locale is None: babel = ctx.app.extensions.get('babel') if babel is None: locale = _DEFAULT_LOCALE else: if babel.locale_selector_func is not None: rv = babel.locale_selector_func() if rv is None: locale = babel.default_locale else: locale = babel.load_locale(rv) else: locale = babel.default_locale ctx.babel_locale = locale return locale def get_timezone(): """Returns the timezone that should be used for this request as `pytz.timezone` object. This returns `None` if used outside of a request. If flask-babel was not attached to application, will return UTC timezone object. """ ctx = _request_ctx_stack.top tzinfo = getattr(ctx, 'babel_tzinfo', None) if tzinfo is None: babel = ctx.app.extensions.get('babel') if babel is None: tzinfo = UTC else: if babel.timezone_selector_func is None: tzinfo = babel.default_timezone else: rv = babel.timezone_selector_func() if rv is None: tzinfo = babel.default_timezone else: if isinstance(rv, string_types): tzinfo = timezone(rv) else: tzinfo = rv ctx.babel_tzinfo = tzinfo return tzinfo def refresh(): """Refreshes the cached timezones and locale information. This can be used to switch a translation between a request and if you want the changes to take place immediately, not just with the next request:: user.timezone = request.form['timezone'] user.locale = request.form['locale'] refresh() flash(gettext('Language was changed')) Without that refresh, the :func:`~flask.flash` function would probably return English text and a now German page. """ ctx = _request_ctx_stack.top for key in 'babel_locale', 'babel_tzinfo': if hasattr(ctx, key): delattr(ctx, key) def _get_format(key, format): """A small helper for the datetime formatting functions. Looks up format defaults for different kinds. """ babel = _request_ctx_stack.top.app.extensions.get('babel') if babel is not None: formats = babel.date_formats else: formats = Babel.default_date_formats if format is None: format = formats[key] if format in ('short', 'medium', 'full', 'long'): rv = formats['%s.%s' % (key, format)] if rv is not None: format = rv return format def to_user_timezone(datetime): """Convert a datetime object to the user's timezone. This automatically happens on all date formatting unless rebasing is disabled. If you need to convert a :class:`datetime.datetime` object at any time to the user's timezone (as returned by :func:`get_timezone` this function can be used). """ if datetime.tzinfo is None: datetime = datetime.replace(tzinfo=UTC) tzinfo = get_timezone() return tzinfo.normalize(datetime.astimezone(tzinfo)) def to_utc(datetime): """Convert a datetime object to UTC and drop tzinfo. This is the opposite operation to :func:`to_user_timezone`. """ if datetime.tzinfo is None: datetime = get_timezone().localize(datetime) return datetime.astimezone(UTC).replace(tzinfo=None) def format_datetime(datetime=None, format=None, rebase=True): """Return a date formatted according to the given pattern. If no :class:`~datetime.datetime` object is passed, the current time is assumed. By default rebasing happens which causes the object to be converted to the users's timezone (as returned by :func:`to_user_timezone`). This function formats both date and time. The format parameter can either be ``'short'``, ``'medium'``, ``'long'`` or ``'full'`` (in which cause the language's default for that setting is used, or the default from the :attr:`Babel.date_formats` mapping is used) or a format string as documented by Babel. This function is also available in the template context as filter named `datetimeformat`. """ format = _get_format('datetime', format) return _date_format(dates.format_datetime, datetime, format, rebase) def format_date(date=None, format=None, rebase=True): """Return a date formatted according to the given pattern. If no :class:`~datetime.datetime` or :class:`~datetime.date` object is passed, the current time is assumed. By default rebasing happens which causes the object to be converted to the users's timezone (as returned by :func:`to_user_timezone`). This function only formats the date part of a :class:`~datetime.datetime` object. The format parameter can either be ``'short'``, ``'medium'``, ``'long'`` or ``'full'`` (in which cause the language's default for that setting is used, or the default from the :attr:`Babel.date_formats` mapping is used) or a format string as documented by Babel. This function is also available in the template context as filter named `dateformat`. """ if rebase and isinstance(date, datetime): date = to_user_timezone(date) format = _get_format('date', format) return _date_format(dates.format_date, date, format, rebase) def format_time(time=None, format=None, rebase=True): """Return a time formatted according to the given pattern. If no :class:`~datetime.datetime` object is passed, the current time is assumed. By default rebasing happens which causes the object to be converted to the users's timezone (as returned by :func:`to_user_timezone`). This function formats both date and time. The format parameter can either be ``'short'``, ``'medium'``, ``'long'`` or ``'full'`` (in which cause the language's default for that setting is used, or the default from the :attr:`Babel.date_formats` mapping is used) or a format string as documented by Babel. This function is also available in the template context as filter named `timeformat`. """ format = _get_format('time', format) return _date_format(dates.format_time, time, format, rebase) def format_timedelta(datetime_or_timedelta, granularity='second'): """Format the elapsed time from the given date to now or the given timedelta. This currently requires an unreleased development version of Babel. This function is also available in the template context as filter named `timedeltaformat`. """ if isinstance(datetime_or_timedelta, datetime): datetime_or_timedelta = datetime.utcnow() - datetime_or_timedelta return dates.format_timedelta(datetime_or_timedelta, granularity, locale=get_locale()) def _date_format(formatter, obj, format, rebase, **extra): """Internal helper that formats the date.""" locale = get_locale() extra = {} if formatter is not dates.format_date and rebase: extra['tzinfo'] = get_timezone() return formatter(obj, format, locale=locale, **extra) def format_number(number): """Return the given number formatted for the locale in request :param number: the number to format :return: the formatted number :rtype: unicode """ locale = get_locale() return numbers.format_number(number, locale=locale) def format_decimal(number, format=None): """Return the given decimal number formatted for the locale in request :param number: the number to format :param format: the format to use :return: the formatted number :rtype: unicode """ locale = get_locale() return numbers.format_decimal(number, format=format, locale=locale) def format_currency(number, currency, format=None): """Return the given number formatted for the locale in request :param number: the number to format :param currency: the currency code :param format: the format to use :return: the formatted number :rtype: unicode """ locale = get_locale() return numbers.format_currency( number, currency, format=format, locale=locale ) def format_percent(number, format=None): """Return formatted percent value for the locale in request :param number: the number to format :param format: the format to use :return: the formatted percent number :rtype: unicode """ locale = get_locale() return numbers.format_percent(number, format=format, locale=locale) def format_scientific(number, format=None): """Return value formatted in scientific notation for the locale in request :param number: the number to format :param format: the format to use :return: the formatted percent number :rtype: unicode """ locale = get_locale() return numbers.format_scientific(number, format=format, locale=locale) class Domain(object): """Localization domain. By default will use look for tranlations in Flask application directory and "messages" domain - all message catalogs should be called ``messages.mo``. """ def __init__(self, dirname=None, domain='messages'): self.dirname = dirname self.domain = domain self.cache = dict() def as_default(self): """Set this domain as default for the current request""" ctx = _request_ctx_stack.top if ctx is None: raise RuntimeError("No request context") ctx.babel_domain = self def get_translations_cache(self, ctx): """Returns dictionary-like object for translation caching""" return self.cache def get_translations_path(self, ctx): """Returns translations directory path. Override if you want to implement custom behavior. """ return self.dirname or os.path.join(ctx.app.root_path, 'translations') def get_translations(self): """Returns the correct gettext translations that should be used for this request. This will never fail and return a dummy translation object if used outside of the request or if a translation cannot be found. """ ctx = _request_ctx_stack.top if ctx is None: return NullTranslations() locale = get_locale() cache = self.get_translations_cache(ctx) translations = cache.get(str(locale)) if translations is None: dirname = self.get_translations_path(ctx) translations = support.Translations.load(dirname, locale, domain=self.domain) cache[str(locale)] = translations return translations def gettext(self, string, **variables): """Translates a string with the current locale and passes in the given keyword arguments as mapping to a string formatting string. :: gettext(u'Hello World!') gettext(u'Hello %(name)s!', name='World') """ t = self.get_translations() if variables: return t.ugettext(string) % variables else: return t.ugettext(string) def ngettext(self, singular, plural, num, **variables): """Translates a string with the current locale and passes in the given keyword arguments as mapping to a string formatting string. The `num` parameter is used to dispatch between singular and various plural forms of the message. It is available in the format string as ``%(num)d`` or ``%(num)s``. The source language should be English or a similar language which only has one plural form. :: ngettext(u'%(num)d Apple', u'%(num)d Apples', num=len(apples)) """ variables.setdefault('num', num) t = self.get_translations() return t.ungettext(singular, plural, num) % variables def pgettext(self, context, string, **variables): """Like :func:`gettext` but with a context. .. versionadded:: 0.7 """ t = self.get_translations() return t.upgettext(context, string) % variables def npgettext(self, context, singular, plural, num, **variables): """Like :func:`ngettext` but with a context. .. versionadded:: 0.7 """ variables.setdefault('num', num) t = self.get_translations() return t.unpgettext(context, singular, plural, num) % variables def lazy_gettext(self, string, **variables): """Like :func:`gettext` but the string returned is lazy which means it will be translated when it is used as an actual string. Example:: hello = lazy_gettext(u'Hello World') @app.route('/') def index(): return unicode(hello) """ from speaklater import make_lazy_string return make_lazy_string(self.gettext, string, **variables) def lazy_pgettext(self, context, string, **variables): """Like :func:`pgettext` but the string returned is lazy which means it will be translated when it is used as an actual string. .. versionadded:: 0.7 """ from speaklater import make_lazy_string return make_lazy_string(self.pgettext, context, string, **variables) # This is the domain that will be used if there is no request context (and thus no app) # or if the app isn't initialized for babel. Note that if there is no request context, # then the standard Domain will use NullTranslations domain = Domain() def get_domain(): """Return the correct translation domain that is used for this request. This will return the default domain (e.g. "messages" in /translations") if none is set for this request. """ ctx = _request_ctx_stack.top if ctx is None: return domain try: return ctx.babel_domain except AttributeError: pass babel = ctx.app.extensions.get('babel') if babel is not None: d = babel._default_domain else: d = domain ctx.babel_domain = d return d # Create shortcuts for the default Flask domain def gettext(*args, **kwargs): return get_domain().gettext(*args, **kwargs) _ = gettext def ngettext(*args, **kwargs): return get_domain().ngettext(*args, **kwargs) def pgettext(*args, **kwargs): return get_domain().pgettext(*args, **kwargs) def npgettext(*args, **kwargs): return get_domain().npgettext(*args, **kwargs) def lazy_gettext(*args, **kwargs): from speaklater import make_lazy_string return make_lazy_string(gettext, *args, **kwargs) def lazy_pgettext(*args, **kwargs): from speaklater import make_lazy_string return make_lazy_string(pgettext, *args, **kwargs)