django/templatetags/i18n.py
from decimal import Decimal
from django.conf import settings
from django.template import Library, Node, TemplateSyntaxError, Variable
from django.template.base import TokenType, render_value_in_context
from django.template.defaulttags import token_kwargs
from django.utils import translation
from django.utils.safestring import SafeData, SafeString, mark_safe
register = Library()
class GetAvailableLanguagesNode(Node):
def __init__(self, variable):
self.variable = variable
def render(self, context):
context[self.variable] = [
(k, translation.gettext(v)) for k, v in settings.LANGUAGES
]
return ""
class GetLanguageInfoNode(Node):
def __init__(self, lang_code, variable):
self.lang_code = lang_code
self.variable = variable
def render(self, context):
lang_code = self.lang_code.resolve(context)
context[self.variable] = translation.get_language_info(lang_code)
return ""
class GetLanguageInfoListNode(Node):
def __init__(self, languages, variable):
self.languages = languages
self.variable = variable
def get_language_info(self, language):
# ``language`` is either a language code string or a sequence
# with the language code as its first item
if len(language[0]) > 1:
return translation.get_language_info(language[0])
else:
return translation.get_language_info(str(language))
def render(self, context):
langs = self.languages.resolve(context)
context[self.variable] = [self.get_language_info(lang) for lang in langs]
return ""
class GetCurrentLanguageNode(Node):
def __init__(self, variable):
self.variable = variable
def render(self, context):
context[self.variable] = translation.get_language()
return ""
class GetCurrentLanguageBidiNode(Node):
def __init__(self, variable):
self.variable = variable
def render(self, context):
context[self.variable] = translation.get_language_bidi()
return ""
class TranslateNode(Node):
child_nodelists = ()
def __init__(self, filter_expression, noop, asvar=None, message_context=None):
self.noop = noop
self.asvar = asvar
self.message_context = message_context
self.filter_expression = filter_expression
if isinstance(self.filter_expression.var, str):
self.filter_expression.is_var = True
self.filter_expression.var = Variable("'%s'" % self.filter_expression.var)
def render(self, context):
self.filter_expression.var.translate = not self.noop
if self.message_context:
self.filter_expression.var.message_context = self.message_context.resolve(
context
)
output = self.filter_expression.resolve(context)
value = render_value_in_context(output, context)
# Restore percent signs. Percent signs in template text are doubled
# so they are not interpreted as string format flags.
is_safe = isinstance(value, SafeData)
value = value.replace("%%", "%")
value = mark_safe(value) if is_safe else value
if self.asvar:
context[self.asvar] = value
return ""
else:
return value
class BlockTranslateNode(Node):
def __init__(
self,
extra_context,
singular,
plural=None,
countervar=None,
counter=None,
message_context=None,
trimmed=False,
asvar=None,
tag_name="blocktranslate",
):
self.extra_context = extra_context
self.singular = singular
self.plural = plural
self.countervar = countervar
self.counter = counter
self.message_context = message_context
self.trimmed = trimmed
self.asvar = asvar
self.tag_name = tag_name
def __repr__(self):
return (
f"<{self.__class__.__qualname__}: "
f"extra_context={self.extra_context!r} "
f"singular={self.singular!r} plural={self.plural!r}>"
)
def render_token_list(self, tokens):
result = []
vars = []
for token in tokens:
if token.token_type == TokenType.TEXT:
result.append(token.contents.replace("%", "%%"))
elif token.token_type == TokenType.VAR:
result.append("%%(%s)s" % token.contents)
vars.append(token.contents)
msg = "".join(result)
if self.trimmed:
msg = translation.trim_whitespace(msg)
return msg, vars
def render(self, context, nested=False):
if self.message_context:
message_context = self.message_context.resolve(context)
else:
message_context = None
# Update() works like a push(), so corresponding context.pop() is at
# the end of function
context.update(
{var: val.resolve(context) for var, val in self.extra_context.items()}
)
singular, vars = self.render_token_list(self.singular)
if self.plural and self.countervar and self.counter:
count = self.counter.resolve(context)
if not isinstance(count, (Decimal, float, int)):
raise TemplateSyntaxError(
"%r argument to %r tag must be a number."
% (self.countervar, self.tag_name)
)
context[self.countervar] = count
plural, plural_vars = self.render_token_list(self.plural)
if message_context:
result = translation.npgettext(message_context, singular, plural, count)
else:
result = translation.ngettext(singular, plural, count)
vars.extend(plural_vars)
else:
if message_context:
result = translation.pgettext(message_context, singular)
else:
result = translation.gettext(singular)
default_value = context.template.engine.string_if_invalid
def render_value(key):
if key in context:
val = context[key]
else:
val = default_value % key if "%s" in default_value else default_value
return render_value_in_context(val, context)
data = {v: render_value(v) for v in vars}
context.pop()
try:
result %= data
except (KeyError, ValueError):
if nested:
# Either string is malformed, or it's a bug
raise TemplateSyntaxError(
"%r is unable to format string returned by gettext: %r "
"using %r" % (self.tag_name, result, data)
)
with translation.override(None):
result = self.render(context, nested=True)
if self.asvar:
context[self.asvar] = SafeString(result)
return ""
else:
return result
class LanguageNode(Node):
def __init__(self, nodelist, language):
self.nodelist = nodelist
self.language = language
def render(self, context):
with translation.override(self.language.resolve(context)):
output = self.nodelist.render(context)
return output
@register.tag("get_available_languages")
def do_get_available_languages(parser, token):
"""
Store a list of available languages in the context.
Usage::
{% get_available_languages as languages %}
{% for language in languages %}
...
{% endfor %}
This puts settings.LANGUAGES into the named variable.
"""
# token.split_contents() isn't useful here because this tag doesn't accept
# variable as arguments.
args = token.contents.split()
if len(args) != 3 or args[1] != "as":
raise TemplateSyntaxError(
"'get_available_languages' requires 'as variable' (got %r)" % args
)
return GetAvailableLanguagesNode(args[2])
@register.tag("get_language_info")
def do_get_language_info(parser, token):
"""
Store the language information dictionary for the given language code in a
context variable.
Usage::
{% get_language_info for LANGUAGE_CODE as l %}
{{ l.code }}
{{ l.name }}
{{ l.name_translated }}
{{ l.name_local }}
{{ l.bidi|yesno:"bi-directional,uni-directional" }}
"""
args = token.split_contents()
if len(args) != 5 or args[1] != "for" or args[3] != "as":
raise TemplateSyntaxError(
"'%s' requires 'for string as variable' (got %r)" % (args[0], args[1:])
)
return GetLanguageInfoNode(parser.compile_filter(args[2]), args[4])
@register.tag("get_language_info_list")
def do_get_language_info_list(parser, token):
"""
Store a list of language information dictionaries for the given language
codes in a context variable. The language codes can be specified either as
a list of strings or a settings.LANGUAGES style list (or any sequence of
sequences whose first items are language codes).
Usage::
{% get_language_info_list for LANGUAGES as langs %}
{% for l in langs %}
{{ l.code }}
{{ l.name }}
{{ l.name_translated }}
{{ l.name_local }}
{{ l.bidi|yesno:"bi-directional,uni-directional" }}
{% endfor %}
"""
args = token.split_contents()
if len(args) != 5 or args[1] != "for" or args[3] != "as":
raise TemplateSyntaxError(
"'%s' requires 'for sequence as variable' (got %r)" % (args[0], args[1:])
)
return GetLanguageInfoListNode(parser.compile_filter(args[2]), args[4])
@register.filter
def language_name(lang_code):
return translation.get_language_info(lang_code)["name"]
@register.filter
def language_name_translated(lang_code):
english_name = translation.get_language_info(lang_code)["name"]
return translation.gettext(english_name)
@register.filter
def language_name_local(lang_code):
return translation.get_language_info(lang_code)["name_local"]
@register.filter
def language_bidi(lang_code):
return translation.get_language_info(lang_code)["bidi"]
@register.tag("get_current_language")
def do_get_current_language(parser, token):
"""
Store the current language in the context.
Usage::
{% get_current_language as language %}
This fetches the currently active language and puts its value into the
``language`` context variable.
"""
# token.split_contents() isn't useful here because this tag doesn't accept
# variable as arguments.
args = token.contents.split()
if len(args) != 3 or args[1] != "as":
raise TemplateSyntaxError(
"'get_current_language' requires 'as variable' (got %r)" % args
)
return GetCurrentLanguageNode(args[2])
@register.tag("get_current_language_bidi")
def do_get_current_language_bidi(parser, token):
"""
Store the current language layout in the context.
Usage::
{% get_current_language_bidi as bidi %}
This fetches the currently active language's layout and puts its value into
the ``bidi`` context variable. True indicates right-to-left layout,
otherwise left-to-right.
"""
# token.split_contents() isn't useful here because this tag doesn't accept
# variable as arguments.
args = token.contents.split()
if len(args) != 3 or args[1] != "as":
raise TemplateSyntaxError(
"'get_current_language_bidi' requires 'as variable' (got %r)" % args
)
return GetCurrentLanguageBidiNode(args[2])
@register.tag("translate")
@register.tag("trans")
def do_translate(parser, token):
"""
Mark a string for translation and translate the string for the current
language.
Usage::
{% translate "this is a test" %}
This marks the string for translation so it will be pulled out by
makemessages into the .po files and runs the string through the translation
engine.
There is a second form::
{% translate "this is a test" noop %}
This marks the string for translation, but returns the string unchanged.
Use it when you need to store values into forms that should be translated
later on.
You can use variables instead of constant strings
to translate stuff you marked somewhere else::
{% translate variable %}
This tries to translate the contents of the variable ``variable``. Make
sure that the string in there is something that is in the .po file.
It is possible to store the translated string into a variable::
{% translate "this is a test" as var %}
{{ var }}
Contextual translations are also supported::
{% translate "this is a test" context "greeting" %}
This is equivalent to calling pgettext instead of (u)gettext.
"""
bits = token.split_contents()
if len(bits) < 2:
raise TemplateSyntaxError("'%s' takes at least one argument" % bits[0])
message_string = parser.compile_filter(bits[1])
remaining = bits[2:]
noop = False
asvar = None
message_context = None
seen = set()
invalid_context = {"as", "noop"}
while remaining:
option = remaining.pop(0)
if option in seen:
raise TemplateSyntaxError(
"The '%s' option was specified more than once." % option,
)
elif option == "noop":
noop = True
elif option == "context":
try:
value = remaining.pop(0)
except IndexError:
raise TemplateSyntaxError(
"No argument provided to the '%s' tag for the context option."
% bits[0]
)
if value in invalid_context:
raise TemplateSyntaxError(
"Invalid argument '%s' provided to the '%s' tag for the context "
"option" % (value, bits[0]),
)
message_context = parser.compile_filter(value)
elif option == "as":
try:
value = remaining.pop(0)
except IndexError:
raise TemplateSyntaxError(
"No argument provided to the '%s' tag for the as option." % bits[0]
)
asvar = value
else:
raise TemplateSyntaxError(
"Unknown argument for '%s' tag: '%s'. The only options "
"available are 'noop', 'context' \"xxx\", and 'as VAR'."
% (
bits[0],
option,
)
)
seen.add(option)
return TranslateNode(message_string, noop, asvar, message_context)
@register.tag("blocktranslate")
@register.tag("blocktrans")
def do_block_translate(parser, token):
"""
Translate a block of text with parameters.
Usage::
{% blocktranslate with bar=foo|filter boo=baz|filter %}
This is {{ bar }} and {{ boo }}.
{% endblocktranslate %}
Additionally, this supports pluralization::
{% blocktranslate count count=var|length %}
There is {{ count }} object.
{% plural %}
There are {{ count }} objects.
{% endblocktranslate %}
This is much like ngettext, only in template syntax.
The "var as value" legacy format is still supported::
{% blocktranslate with foo|filter as bar and baz|filter as boo %}
{% blocktranslate count var|length as count %}
The translated string can be stored in a variable using `asvar`::
{% blocktranslate with bar=foo|filter boo=baz|filter asvar var %}
This is {{ bar }} and {{ boo }}.
{% endblocktranslate %}
{{ var }}
Contextual translations are supported::
{% blocktranslate with bar=foo|filter context "greeting" %}
This is {{ bar }}.
{% endblocktranslate %}
This is equivalent to calling pgettext/npgettext instead of
(u)gettext/(u)ngettext.
"""
bits = token.split_contents()
options = {}
remaining_bits = bits[1:]
asvar = None
while remaining_bits:
option = remaining_bits.pop(0)
if option in options:
raise TemplateSyntaxError(
"The %r option was specified more than once." % option
)
if option == "with":
value = token_kwargs(remaining_bits, parser, support_legacy=True)
if not value:
raise TemplateSyntaxError(
'"with" in %r tag needs at least one keyword argument.' % bits[0]
)
elif option == "count":
value = token_kwargs(remaining_bits, parser, support_legacy=True)
if len(value) != 1:
raise TemplateSyntaxError(
'"count" in %r tag expected exactly '
"one keyword argument." % bits[0]
)
elif option == "context":
try:
value = remaining_bits.pop(0)
value = parser.compile_filter(value)
except Exception:
raise TemplateSyntaxError(
'"context" in %r tag expected exactly one argument.' % bits[0]
)
elif option == "trimmed":
value = True
elif option == "asvar":
try:
value = remaining_bits.pop(0)
except IndexError:
raise TemplateSyntaxError(
"No argument provided to the '%s' tag for the asvar option."
% bits[0]
)
asvar = value
else:
raise TemplateSyntaxError(
"Unknown argument for %r tag: %r." % (bits[0], option)
)
options[option] = value
if "count" in options:
countervar, counter = next(iter(options["count"].items()))
else:
countervar, counter = None, None
if "context" in options:
message_context = options["context"]
else:
message_context = None
extra_context = options.get("with", {})
trimmed = options.get("trimmed", False)
singular = []
plural = []
while parser.tokens:
token = parser.next_token()
if token.token_type in (TokenType.VAR, TokenType.TEXT):
singular.append(token)
else:
break
if countervar and counter:
if token.contents.strip() != "plural":
raise TemplateSyntaxError(
"%r doesn't allow other block tags inside it" % bits[0]
)
while parser.tokens:
token = parser.next_token()
if token.token_type in (TokenType.VAR, TokenType.TEXT):
plural.append(token)
else:
break
end_tag_name = "end%s" % bits[0]
if token.contents.strip() != end_tag_name:
raise TemplateSyntaxError(
"%r doesn't allow other block tags (seen %r) inside it"
% (bits[0], token.contents)
)
return BlockTranslateNode(
extra_context,
singular,
plural,
countervar,
counter,
message_context,
trimmed=trimmed,
asvar=asvar,
tag_name=bits[0],
)
@register.tag
def language(parser, token):
"""
Enable the given language just for this block.
Usage::
{% language "de" %}
This is {{ bar }} and {{ boo }}.
{% endlanguage %}
"""
bits = token.split_contents()
if len(bits) != 2:
raise TemplateSyntaxError("'%s' takes one argument (language)" % bits[0])
language = parser.compile_filter(bits[1])
nodelist = parser.parse(("endlanguage",))
parser.delete_first_token()
return LanguageNode(nodelist, language)