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