Source code for babel.support

"""
    babel.support
    ~~~~~~~~~~~~~

    Several classes and functions that help with integrating and using Babel
    in applications.

    .. note: the code in this module is not used by Babel itself

    :copyright: (c) 2013-2024 by the Babel Team.
    :license: BSD, see LICENSE for more details.
"""
from __future__ import annotations

import decimal
import gettext
import locale
import os
from collections.abc import Iterator
from typing import TYPE_CHECKING, Any, Callable, Iterable

from babel.core import Locale
from babel.dates import format_date, format_datetime, format_time, format_timedelta
from babel.numbers import (
    format_compact_currency,
    format_compact_decimal,
    format_currency,
    format_decimal,
    format_percent,
    format_scientific,
)

if TYPE_CHECKING:
    from typing_extensions import Literal

    from babel.dates import _PredefinedTimeFormat


[docs] class Format: """Wrapper class providing the various date and number formatting functions bound to a specific locale and time-zone. >>> from babel.util import UTC >>> from datetime import date >>> fmt = Format('en_US', UTC) >>> fmt.date(date(2007, 4, 1)) u'Apr 1, 2007' >>> fmt.decimal(1.2345) u'1.234' """ def __init__( self, locale: Locale | str, tzinfo: datetime.tzinfo | None = None, *, numbering_system: Literal["default"] | str = "latn", ) -> None: """Initialize the formatter. :param locale: the locale identifier or `Locale` instance :param tzinfo: the time-zone info (a `tzinfo` instance or `None`) :param numbering_system: The numbering system used for formatting number symbols. Defaults to "latn". The special value "default" will use the default numbering system of the locale. """ self.locale = Locale.parse(locale) self.tzinfo = tzinfo self.numbering_system = numbering_system
[docs] def date( self, date: datetime.date | None = None, format: _PredefinedTimeFormat | str = 'medium', ) -> str: """Return a date formatted according to the given pattern. >>> from datetime import date >>> fmt = Format('en_US') >>> fmt.date(date(2007, 4, 1)) u'Apr 1, 2007' """ return format_date(date, format, locale=self.locale)
[docs] def datetime( self, datetime: datetime.date | None = None, format: _PredefinedTimeFormat | str = 'medium', ) -> str: """Return a date and time formatted according to the given pattern. >>> from datetime import datetime >>> from babel.dates import get_timezone >>> fmt = Format('en_US', tzinfo=get_timezone('US/Eastern')) >>> fmt.datetime(datetime(2007, 4, 1, 15, 30)) u'Apr 1, 2007, 11:30:00\u202fAM' """ return format_datetime(datetime, format, tzinfo=self.tzinfo, locale=self.locale)
[docs] def time( self, time: datetime.time | datetime.datetime | None = None, format: _PredefinedTimeFormat | str = 'medium', ) -> str: """Return a time formatted according to the given pattern. >>> from datetime import datetime >>> from babel.dates import get_timezone >>> fmt = Format('en_US', tzinfo=get_timezone('US/Eastern')) >>> fmt.time(datetime(2007, 4, 1, 15, 30)) u'11:30:00\u202fAM' """ return format_time(time, format, tzinfo=self.tzinfo, locale=self.locale)
[docs] def timedelta( self, delta: datetime.timedelta | int, granularity: Literal["year", "month", "week", "day", "hour", "minute", "second"] = "second", threshold: float = 0.85, format: Literal["narrow", "short", "medium", "long"] = "long", add_direction: bool = False, ) -> str: """Return a time delta according to the rules of the given locale. >>> from datetime import timedelta >>> fmt = Format('en_US') >>> fmt.timedelta(timedelta(weeks=11)) u'3 months' """ return format_timedelta(delta, granularity=granularity, threshold=threshold, format=format, add_direction=add_direction, locale=self.locale)
[docs] def number(self, number: float | decimal.Decimal | str) -> str: """Return an integer number formatted for the locale. >>> fmt = Format('en_US') >>> fmt.number(1099) u'1,099' """ return format_decimal(number, locale=self.locale, numbering_system=self.numbering_system)
[docs] def decimal(self, number: float | decimal.Decimal | str, format: str | None = None) -> str: """Return a decimal number formatted for the locale. >>> fmt = Format('en_US') >>> fmt.decimal(1.2345) u'1.234' """ return format_decimal(number, format, locale=self.locale, numbering_system=self.numbering_system)
[docs] def compact_decimal( self, number: float | decimal.Decimal | str, format_type: Literal['short', 'long'] = 'short', fraction_digits: int = 0, ) -> str: """Return a number formatted in compact form for the locale. >>> fmt = Format('en_US') >>> fmt.compact_decimal(123456789) u'123M' >>> fmt.compact_decimal(1234567, format_type='long', fraction_digits=2) '1.23 million' """ return format_compact_decimal( number, format_type=format_type, fraction_digits=fraction_digits, locale=self.locale, numbering_system=self.numbering_system, )
[docs] def currency(self, number: float | decimal.Decimal | str, currency: str) -> str: """Return a number in the given currency formatted for the locale. """ return format_currency(number, currency, locale=self.locale, numbering_system=self.numbering_system)
[docs] def compact_currency( self, number: float | decimal.Decimal | str, currency: str, format_type: Literal['short'] = 'short', fraction_digits: int = 0, ) -> str: """Return a number in the given currency formatted for the locale using the compact number format. >>> Format('en_US').compact_currency(1234567, "USD", format_type='short', fraction_digits=2) '$1.23M' """ return format_compact_currency(number, currency, format_type=format_type, fraction_digits=fraction_digits, locale=self.locale, numbering_system=self.numbering_system)
[docs] def percent(self, number: float | decimal.Decimal | str, format: str | None = None) -> str: """Return a number formatted as percentage for the locale. >>> fmt = Format('en_US') >>> fmt.percent(0.34) u'34%' """ return format_percent(number, format, locale=self.locale, numbering_system=self.numbering_system)
[docs] def scientific(self, number: float | decimal.Decimal | str) -> str: """Return a number formatted using scientific notation for the locale. """ return format_scientific(number, locale=self.locale, numbering_system=self.numbering_system)
class LazyProxy: """Class for proxy objects that delegate to a specified function to evaluate the actual object. >>> def greeting(name='world'): ... return 'Hello, %s!' % name >>> lazy_greeting = LazyProxy(greeting, name='Joe') >>> print(lazy_greeting) Hello, Joe! >>> u' ' + lazy_greeting u' Hello, Joe!' >>> u'(%s)' % lazy_greeting u'(Hello, Joe!)' This can be used, for example, to implement lazy translation functions that delay the actual translation until the string is actually used. The rationale for such behavior is that the locale of the user may not always be available. In web applications, you only know the locale when processing a request. The proxy implementation attempts to be as complete as possible, so that the lazy objects should mostly work as expected, for example for sorting: >>> greetings = [ ... LazyProxy(greeting, 'world'), ... LazyProxy(greeting, 'Joe'), ... LazyProxy(greeting, 'universe'), ... ] >>> greetings.sort() >>> for greeting in greetings: ... print(greeting) Hello, Joe! Hello, universe! Hello, world! """ __slots__ = ['_func', '_args', '_kwargs', '_value', '_is_cache_enabled', '_attribute_error'] if TYPE_CHECKING: _func: Callable[..., Any] _args: tuple[Any, ...] _kwargs: dict[str, Any] _is_cache_enabled: bool _value: Any _attribute_error: AttributeError | None def __init__(self, func: Callable[..., Any], *args: Any, enable_cache: bool = True, **kwargs: Any) -> None: # Avoid triggering our own __setattr__ implementation object.__setattr__(self, '_func', func) object.__setattr__(self, '_args', args) object.__setattr__(self, '_kwargs', kwargs) object.__setattr__(self, '_is_cache_enabled', enable_cache) object.__setattr__(self, '_value', None) object.__setattr__(self, '_attribute_error', None) @property def value(self) -> Any: if self._value is None: try: value = self._func(*self._args, **self._kwargs) except AttributeError as error: object.__setattr__(self, '_attribute_error', error) raise if not self._is_cache_enabled: return value object.__setattr__(self, '_value', value) return self._value def __contains__(self, key: object) -> bool: return key in self.value def __bool__(self) -> bool: return bool(self.value) def __dir__(self) -> list[str]: return dir(self.value) def __iter__(self) -> Iterator[Any]: return iter(self.value) def __len__(self) -> int: return len(self.value) def __str__(self) -> str: return str(self.value) def __add__(self, other: object) -> Any: return self.value + other def __radd__(self, other: object) -> Any: return other + self.value def __mod__(self, other: object) -> Any: return self.value % other def __rmod__(self, other: object) -> Any: return other % self.value def __mul__(self, other: object) -> Any: return self.value * other def __rmul__(self, other: object) -> Any: return other * self.value def __call__(self, *args: Any, **kwargs: Any) -> Any: return self.value(*args, **kwargs) def __lt__(self, other: object) -> bool: return self.value < other def __le__(self, other: object) -> bool: return self.value <= other def __eq__(self, other: object) -> bool: return self.value == other def __ne__(self, other: object) -> bool: return self.value != other def __gt__(self, other: object) -> bool: return self.value > other def __ge__(self, other: object) -> bool: return self.value >= other def __delattr__(self, name: str) -> None: delattr(self.value, name) def __getattr__(self, name: str) -> Any: if self._attribute_error is not None: raise self._attribute_error return getattr(self.value, name) def __setattr__(self, name: str, value: Any) -> None: setattr(self.value, name, value) def __delitem__(self, key: Any) -> None: del self.value[key] def __getitem__(self, key: Any) -> Any: return self.value[key] def __setitem__(self, key: Any, value: Any) -> None: self.value[key] = value def __copy__(self) -> LazyProxy: return LazyProxy( self._func, enable_cache=self._is_cache_enabled, *self._args, # noqa: B026 **self._kwargs, ) def __deepcopy__(self, memo: Any) -> LazyProxy: from copy import deepcopy return LazyProxy( deepcopy(self._func, memo), enable_cache=deepcopy(self._is_cache_enabled, memo), *deepcopy(self._args, memo), # noqa: B026 **deepcopy(self._kwargs, memo), ) class NullTranslations(gettext.NullTranslations): if TYPE_CHECKING: _info: dict[str, str] _fallback: NullTranslations | None DEFAULT_DOMAIN = None def __init__(self, fp: gettext._TranslationsReader | None = None) -> None: """Initialize a simple translations class which is not backed by a real catalog. Behaves similar to gettext.NullTranslations but also offers Babel's on *gettext methods (e.g. 'dgettext()'). :param fp: a file-like object (ignored in this class) """ # These attributes are set by gettext.NullTranslations when a catalog # is parsed (fp != None). Ensure that they are always present because # some *gettext methods (including '.gettext()') rely on the attributes. self._catalog: dict[tuple[str, Any] | str, str] = {} self.plural: Callable[[float | decimal.Decimal], int] = lambda n: int(n != 1) super().__init__(fp=fp) self.files = list(filter(None, [getattr(fp, 'name', None)])) self.domain = self.DEFAULT_DOMAIN self._domains: dict[str, NullTranslations] = {} def dgettext(self, domain: str, message: str) -> str: """Like ``gettext()``, but look the message up in the specified domain. """ return self._domains.get(domain, self).gettext(message) def ldgettext(self, domain: str, message: str) -> str: """Like ``lgettext()``, but look the message up in the specified domain. """ import warnings warnings.warn( 'ldgettext() is deprecated, use dgettext() instead', DeprecationWarning, stacklevel=2, ) return self._domains.get(domain, self).lgettext(message) def udgettext(self, domain: str, message: str) -> str: """Like ``ugettext()``, but look the message up in the specified domain. """ return self._domains.get(domain, self).ugettext(message) # backward compatibility with 0.9 dugettext = udgettext def dngettext(self, domain: str, singular: str, plural: str, num: int) -> str: """Like ``ngettext()``, but look the message up in the specified domain. """ return self._domains.get(domain, self).ngettext(singular, plural, num) def ldngettext(self, domain: str, singular: str, plural: str, num: int) -> str: """Like ``lngettext()``, but look the message up in the specified domain. """ import warnings warnings.warn( 'ldngettext() is deprecated, use dngettext() instead', DeprecationWarning, stacklevel=2, ) return self._domains.get(domain, self).lngettext(singular, plural, num) def udngettext(self, domain: str, singular: str, plural: str, num: int) -> str: """Like ``ungettext()`` but look the message up in the specified domain. """ return self._domains.get(domain, self).ungettext(singular, plural, num) # backward compatibility with 0.9 dungettext = udngettext # Most of the downwards code, until it gets included in stdlib, from: # https://bugs.python.org/file10036/gettext-pgettext.patch # # The encoding of a msgctxt and a msgid in a .mo file is # msgctxt + "\x04" + msgid (gettext version >= 0.15) CONTEXT_ENCODING = '%s\x04%s' def pgettext(self, context: str, message: str) -> str | object: """Look up the `context` and `message` id in the catalog and return the corresponding message string, as an 8-bit string encoded with the catalog's charset encoding, if known. If there is no entry in the catalog for the `message` id and `context` , and a fallback has been set, the look up is forwarded to the fallback's ``pgettext()`` method. Otherwise, the `message` id is returned. """ ctxt_msg_id = self.CONTEXT_ENCODING % (context, message) missing = object() tmsg = self._catalog.get(ctxt_msg_id, missing) if tmsg is missing: tmsg = self._catalog.get((ctxt_msg_id, self.plural(1)), missing) if tmsg is not missing: return tmsg if self._fallback: return self._fallback.pgettext(context, message) return message def lpgettext(self, context: str, message: str) -> str | bytes | object: """Equivalent to ``pgettext()``, but the translation is returned in the preferred system encoding, if no other encoding was explicitly set with ``bind_textdomain_codeset()``. """ import warnings warnings.warn( 'lpgettext() is deprecated, use pgettext() instead', DeprecationWarning, stacklevel=2, ) tmsg = self.pgettext(context, message) encoding = getattr(self, "_output_charset", None) or locale.getpreferredencoding() return tmsg.encode(encoding) if isinstance(tmsg, str) else tmsg def npgettext(self, context: str, singular: str, plural: str, num: int) -> str: """Do a plural-forms lookup of a message id. `singular` is used as the message id for purposes of lookup in the catalog, while `num` is used to determine which plural form to use. The returned message string is an 8-bit string encoded with the catalog's charset encoding, if known. If the message id for `context` is not found in the catalog, and a fallback is specified, the request is forwarded to the fallback's ``npgettext()`` method. Otherwise, when ``num`` is 1 ``singular`` is returned, and ``plural`` is returned in all other cases. """ ctxt_msg_id = self.CONTEXT_ENCODING % (context, singular) try: tmsg = self._catalog[(ctxt_msg_id, self.plural(num))] return tmsg except KeyError: if self._fallback: return self._fallback.npgettext(context, singular, plural, num) if num == 1: return singular else: return plural def lnpgettext(self, context: str, singular: str, plural: str, num: int) -> str | bytes: """Equivalent to ``npgettext()``, but the translation is returned in the preferred system encoding, if no other encoding was explicitly set with ``bind_textdomain_codeset()``. """ import warnings warnings.warn( 'lnpgettext() is deprecated, use npgettext() instead', DeprecationWarning, stacklevel=2, ) ctxt_msg_id = self.CONTEXT_ENCODING % (context, singular) try: tmsg = self._catalog[(ctxt_msg_id, self.plural(num))] encoding = getattr(self, "_output_charset", None) or locale.getpreferredencoding() return tmsg.encode(encoding) except KeyError: if self._fallback: return self._fallback.lnpgettext(context, singular, plural, num) if num == 1: return singular else: return plural def upgettext(self, context: str, message: str) -> str: """Look up the `context` and `message` id in the catalog and return the corresponding message string, as a Unicode string. If there is no entry in the catalog for the `message` id and `context`, and a fallback has been set, the look up is forwarded to the fallback's ``upgettext()`` method. Otherwise, the `message` id is returned. """ ctxt_message_id = self.CONTEXT_ENCODING % (context, message) missing = object() tmsg = self._catalog.get(ctxt_message_id, missing) if tmsg is missing: if self._fallback: return self._fallback.upgettext(context, message) return str(message) assert isinstance(tmsg, str) return tmsg def unpgettext(self, context: str, singular: str, plural: str, num: int) -> str: """Do a plural-forms lookup of a message id. `singular` is used as the message id for purposes of lookup in the catalog, while `num` is used to determine which plural form to use. The returned message string is a Unicode string. If the message id for `context` is not found in the catalog, and a fallback is specified, the request is forwarded to the fallback's ``unpgettext()`` method. Otherwise, when `num` is 1 `singular` is returned, and `plural` is returned in all other cases. """ ctxt_message_id = self.CONTEXT_ENCODING % (context, singular) try: tmsg = self._catalog[(ctxt_message_id, self.plural(num))] except KeyError: if self._fallback: return self._fallback.unpgettext(context, singular, plural, num) tmsg = str(singular) if num == 1 else str(plural) return tmsg def dpgettext(self, domain: str, context: str, message: str) -> str | object: """Like `pgettext()`, but look the message up in the specified `domain`. """ return self._domains.get(domain, self).pgettext(context, message) def udpgettext(self, domain: str, context: str, message: str) -> str: """Like `upgettext()`, but look the message up in the specified `domain`. """ return self._domains.get(domain, self).upgettext(context, message) # backward compatibility with 0.9 dupgettext = udpgettext def ldpgettext(self, domain: str, context: str, message: str) -> str | bytes | object: """Equivalent to ``dpgettext()``, but the translation is returned in the preferred system encoding, if no other encoding was explicitly set with ``bind_textdomain_codeset()``. """ return self._domains.get(domain, self).lpgettext(context, message) def dnpgettext(self, domain: str, context: str, singular: str, plural: str, num: int) -> str: """Like ``npgettext``, but look the message up in the specified `domain`. """ return self._domains.get(domain, self).npgettext(context, singular, plural, num) def udnpgettext(self, domain: str, context: str, singular: str, plural: str, num: int) -> str: """Like ``unpgettext``, but look the message up in the specified `domain`. """ return self._domains.get(domain, self).unpgettext(context, singular, plural, num) # backward compatibility with 0.9 dunpgettext = udnpgettext def ldnpgettext(self, domain: str, context: str, singular: str, plural: str, num: int) -> str | bytes: """Equivalent to ``dnpgettext()``, but the translation is returned in the preferred system encoding, if no other encoding was explicitly set with ``bind_textdomain_codeset()``. """ return self._domains.get(domain, self).lnpgettext(context, singular, plural, num) ugettext = gettext.NullTranslations.gettext ungettext = gettext.NullTranslations.ngettext class Translations(NullTranslations, gettext.GNUTranslations): """An extended translation catalog class.""" DEFAULT_DOMAIN = 'messages' def __init__(self, fp: gettext._TranslationsReader | None = None, domain: str | None = None): """Initialize the translations catalog. :param fp: the file-like object the translation should be read from :param domain: the message domain (default: 'messages') """ super().__init__(fp=fp) self.domain = domain or self.DEFAULT_DOMAIN ugettext = gettext.GNUTranslations.gettext ungettext = gettext.GNUTranslations.ngettext @classmethod def load( cls, dirname: str | os.PathLike[str] | None = None, locales: Iterable[str | Locale] | str | Locale | None = None, domain: str | None = None, ) -> NullTranslations: """Load translations from the given directory. :param dirname: the directory containing the ``MO`` files :param locales: the list of locales in order of preference (items in this list can be either `Locale` objects or locale strings) :param domain: the message domain (default: 'messages') """ if not domain: domain = cls.DEFAULT_DOMAIN filename = gettext.find(domain, dirname, _locales_to_names(locales)) if not filename: return NullTranslations() with open(filename, 'rb') as fp: return cls(fp=fp, domain=domain) def __repr__(self) -> str: version = self._info.get('project-id-version') return f'<{type(self).__name__}: "{version}">' def add(self, translations: Translations, merge: bool = True): """Add the given translations to the catalog. If the domain of the translations is different than that of the current catalog, they are added as a catalog that is only accessible by the various ``d*gettext`` functions. :param translations: the `Translations` instance with the messages to add :param merge: whether translations for message domains that have already been added should be merged with the existing translations """ domain = getattr(translations, 'domain', self.DEFAULT_DOMAIN) if merge and domain == self.domain: return self.merge(translations) existing = self._domains.get(domain) if merge and isinstance(existing, Translations): existing.merge(translations) else: translations.add_fallback(self) self._domains[domain] = translations return self def merge(self, translations: Translations): """Merge the given translations into the catalog. Message translations in the specified catalog override any messages with the same identifier in the existing catalog. :param translations: the `Translations` instance with the messages to merge """ if isinstance(translations, gettext.GNUTranslations): self._catalog.update(translations._catalog) if isinstance(translations, Translations): self.files.extend(translations.files) return self def _locales_to_names( locales: Iterable[str | Locale] | str | Locale | None, ) -> list[str] | None: """Normalize a `locales` argument to a list of locale names. :param locales: the list of locales in order of preference (items in this list can be either `Locale` objects or locale strings) """ if locales is None: return None if isinstance(locales, Locale): return [str(locales)] if isinstance(locales, str): return [locales] return [str(locale) for locale in locales]