Django Utils¶
This document covers all stable modules in django.utils
. Most of the
modules in django.utils
are designed for internal use and only the
following parts can be considered stable and thus backwards compatible as per
the internal release deprecation policy.
django.utils.cache
¶
This module contains helper functions for controlling HTTP caching. It does so
by managing the Vary
header of responses. It includes functions to patch
the header of response objects directly and decorators that change functions to
do that header-patching themselves.
For information on the Vary
header, see RFC 7231#section-7.1.4.
Essentially, the Vary
HTTP header defines which headers a cache should take
into account when building its cache key. Requests with the same path but
different header content for headers named in Vary
need to get different
cache keys to prevent delivery of wrong content.
For example, internationalization middleware would
need to distinguish caches by the Accept-language
header.
-
patch_cache_control
(response, **kwargs)[source]¶ This function patches the
Cache-Control
header by adding all keyword arguments to it. The transformation is as follows:- All keyword parameter names are turned to lowercase, and underscores are converted to hyphens.
- If the value of a parameter is
True
(exactlyTrue
, not just a true value), only the parameter name is added to the header. - All other parameters are added with their value, after applying
str()
to it.
-
get_max_age
(response)[source]¶ Returns the max-age from the response Cache-Control header as an integer (or
None
if it wasn’t found or wasn’t an integer).
-
patch_response_headers
(response, cache_timeout=None)[source]¶ Adds some useful headers to the given
HttpResponse
object:Expires
Cache-Control
Each header is only added if it isn’t already set.
cache_timeout
is in seconds. TheCACHE_MIDDLEWARE_SECONDS
setting is used by default.
-
add_never_cache_headers
(response)[source]¶ Adds a
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
header to a response to indicate that a page should never be cached.
-
patch_vary_headers
(response, newheaders)[source]¶ Adds (or updates) the
Vary
header in the givenHttpResponse
object.newheaders
is a list of header names that should be inVary
. Existing headers inVary
aren’t removed.
-
get_cache_key
(request, key_prefix=None)[source]¶ Returns a cache key based on the request path. It can be used in the request phase because it pulls the list of headers to take into account from the global path registry and uses those to build a cache key to check against.
If there is no headerlist stored, the page needs to be rebuilt, so this function returns
None
.
-
learn_cache_key
(request, response, cache_timeout=None, key_prefix=None)[source]¶ Learns what headers to take into account for some request path from the response object. It stores those headers in a global path registry so that later access to that path will know what headers to take into account without building the response object itself. The headers are named in the
Vary
header of the response, but we want to prevent response generation.The list of headers to use for cache key generation is stored in the same cache as the pages themselves. If the cache ages some data out of the cache, this just means that we have to build the response once to get at the Vary header and so at the list of headers to use for the cache key.
django.utils.dateparse
¶
The functions defined in this module share the following properties:
- They accept strings in ISO 8601 date/time formats (or some close
alternatives) and return objects from the corresponding classes in Python’s
datetime
module. - They raise
ValueError
if their input is well formatted but isn’t a valid date or time. - They return
None
if it isn’t well formatted at all. - They accept up to picosecond resolution in input, but they truncate it to microseconds, since that’s what Python supports.
-
parse_date
(value)[source]¶ Parses a string and returns a
datetime.date
.
-
parse_time
(value)[source]¶ Parses a string and returns a
datetime.time
.UTC offsets aren’t supported; if
value
describes one, the result isNone
.
-
parse_datetime
(value)[source]¶ Parses a string and returns a
datetime.datetime
.UTC offsets are supported; if
value
describes one, the result’stzinfo
attribute is aFixedOffset
instance.
-
parse_duration
(value)[source]¶ Parses a string and returns a
datetime.timedelta
.Expects data in the format
"DD HH:MM:SS.uuuuuu"
or as specified by ISO 8601 (e.g.P4DT1H15M20S
which is equivalent to4 1:15:20
) or PostgreSQL’s day-time interval format (e.g.3 days 04:05:06
).Changed in Django 2.0:Support for PostgreSQL’s interval format was added.
django.utils.decorators
¶
-
method_decorator
(decorator, name='')[source]¶ Converts a function decorator into a method decorator. It can be used to decorate methods or classes; in the latter case,
name
is the name of the method to be decorated and is required.decorator
may also be a list or tuple of functions. They are wrapped in reverse order so that the call order is the order in which the functions appear in the list/tuple.See decorating class based views for example usage.
-
decorator_from_middleware
(middleware_class)[source]¶ Given a middleware class, returns a view decorator. This lets you use middleware functionality on a per-view basis. The middleware is created with no params passed.
It assumes middleware that’s compatible with the old style of Django 1.9 and earlier (having methods like
process_request()
,process_exception()
, andprocess_response()
).
-
decorator_from_middleware_with_args
(middleware_class)[source]¶ Like
decorator_from_middleware
, but returns a function that accepts the arguments to be passed to the middleware_class. For example, thecache_page()
decorator is created from theCacheMiddleware
like this:cache_page = decorator_from_middleware_with_args(CacheMiddleware) @cache_page(3600) def my_view(request): pass
django.utils.encoding
¶
-
python_2_unicode_compatible
()[source]¶ A decorator that defines
__unicode__
and__str__
methods under Python 2. Under Python 3 it does nothing.To support Python 2 and 3 with a single code base, define a
__str__
method returning text (usesix.text_type()
if you’re doing some casting) and apply this decorator to the class.
-
smart_text
(s, encoding='utf-8', strings_only=False, errors='strict')[source]¶ Returns a
str
object representing arbitrary objects
. Treats bytestrings using theencoding
codec.If
strings_only
isTrue
, don’t convert (some) non-string-like objects.
-
is_protected_type
(obj)[source]¶ Determine if the object instance is of a protected type.
Objects of protected types are preserved as-is when passed to
force_text(strings_only=True)
.
-
force_text
(s, encoding='utf-8', strings_only=False, errors='strict')[source]¶ Similar to
smart_text
, except that lazy instances are resolved to strings, rather than kept as lazy objects.If
strings_only
isTrue
, don’t convert (some) non-string-like objects.
-
smart_bytes
(s, encoding='utf-8', strings_only=False, errors='strict')[source]¶ Returns a bytestring version of arbitrary object
s
, encoded as specified inencoding
.If
strings_only
isTrue
, don’t convert (some) non-string-like objects.
-
force_bytes
(s, encoding='utf-8', strings_only=False, errors='strict')[source]¶ Similar to
smart_bytes
, except that lazy instances are resolved to bytestrings, rather than kept as lazy objects.If
strings_only
isTrue
, don’t convert (some) non-string-like objects.
-
smart_str
(s, encoding='utf-8', strings_only=False, errors='strict')¶ Alias of
smart_text()
. This function returns astr
or a lazy string.For instance, this is suitable for writing to
sys.stdout
.Alias of
smart_bytes()
on Python 2 (in older versions of Django that support it).
-
force_str
(s, encoding='utf-8', strings_only=False, errors='strict')¶ Alias of
force_text()
. This function always returns astr
.Alias of
force_bytes()
on Python 2 (in older versions of Django that support it).
-
iri_to_uri
(iri)[source]¶ Convert an Internationalized Resource Identifier (IRI) portion to a URI portion that is suitable for inclusion in a URL.
This is the algorithm from section 3.1 of RFC 3987#section-3.1, slightly simplified since the input is assumed to be a string rather than an arbitrary byte stream.
Takes an IRI (string or UTF-8 bytes) and returns a string containing the encoded result.
-
uri_to_iri
(uri)[source]¶ Converts a Uniform Resource Identifier into an Internationalized Resource Identifier.
This is an algorithm from section 3.2 of RFC 3987#section-3.2.
Takes a URI in ASCII bytes and returns a string containing the encoded result.
-
filepath_to_uri
(path)[source]¶ Convert a file system path to a URI portion that is suitable for inclusion in a URL. The path is assumed to be either UTF-8 bytes or string.
This method will encode certain characters that would normally be recognized as special characters for URIs. Note that this method does not encode the ‘ character, as it is a valid character within URIs. See
encodeURIComponent()
JavaScript function for more details.Returns an ASCII string containing the encoded result.
django.utils.feedgenerator
¶
Sample usage:
>>> from django.utils import feedgenerator
>>> feed = feedgenerator.Rss201rev2Feed(
... title="Poynter E-Media Tidbits",
... link="http://www.poynter.org/column.asp?id=31",
... description="A group Weblog by the sharpest minds in online media/journalism/publishing.",
... language="en",
... )
>>> feed.add_item(
... title="Hello",
... link="http://www.holovaty.com/test/",
... description="Testing.",
... )
>>> with open('test.rss', 'w') as fp:
... feed.write(fp, 'utf-8')
For simplifying the selection of a generator use feedgenerator.DefaultFeed
which is currently Rss201rev2Feed
For definitions of the different versions of RSS, see: https://web.archive.org/web/20110718035220/http://diveintomark.org/archives/2004/02/04/incompatible-rss
-
get_tag_uri
(url, date)[source]¶ Creates a TagURI.
See https://web.archive.org/web/20110514113830/http://diveintomark.org/archives/2004/05/28/howto-atom-id
SyndicationFeed
¶
-
class
SyndicationFeed
[source]¶ Base class for all syndication feeds. Subclasses should provide write().
-
__init__
(title, link, description, language=None, author_email=None, author_name=None, author_link=None, subtitle=None, categories=None, feed_url=None, feed_copyright=None, feed_guid=None, ttl=None, **kwargs)[source]¶ Initialize the feed with the given dictionary of metadata, which applies to the entire feed.
Any extra keyword arguments you pass to
__init__
will be stored inself.feed
.All parameters should be strings, except
categories
, which should be a sequence of strings.
-
add_item
(title, link, description, author_email=None, author_name=None, author_link=None, pubdate=None, comments=None, unique_id=None, categories=(), item_copyright=None, ttl=None, updateddate=None, enclosures=None, **kwargs)[source]¶ Adds an item to the feed. All args are expected to be strings except
pubdate
andupdateddate
, which aredatetime.datetime
objects, andenclosures
, which is a list ofEnclosure
instances.
-
root_attributes
()[source]¶ Return extra attributes to place on the root (i.e. feed/channel) element. Called from
write()
.
-
add_root_elements
(handler)[source]¶ Add elements in the root (i.e. feed/channel) element. Called from
write()
.
-
item_attributes
(item)[source]¶ Return extra attributes to place on each item (i.e. item/entry) element.
-
django.utils.functional
¶
-
class
cached_property
(func, name=None)[source]¶ The
@cached_property
decorator caches the result of a method with a singleself
argument as a property. The cached result will persist as long as the instance does, so if the instance is passed around and the function subsequently invoked, the cached result will be returned.Consider a typical case, where a view might need to call a model’s method to perform some computation, before placing the model instance into the context, where the template might invoke the method once more:
# the model class Person(models.Model): def friends(self): # expensive computation ... return friends # in the view: if person.friends(): ...
And in the template you would have:
{% for friend in person.friends %}
Here,
friends()
will be called twice. Since the instanceperson
in the view and the template are the same, decorating thefriends()
method with@cached_property
can avoid that:from django.utils.functional import cached_property class Person(models.Model): @cached_property def friends(self): ...
Note that as the method is now a property, in Python code it will need to be accessed appropriately:
# in the view: if person.friends: ...
The cached value can be treated like an ordinary attribute of the instance:
# clear it, requiring re-computation next time it's called del person.friends # or delattr(person, "friends") # set a value manually, that will persist on the instance until cleared person.friends = ["Huckleberry Finn", "Tom Sawyer"]
As well as offering potential performance advantages,
@cached_property
can ensure that an attribute’s value does not change unexpectedly over the life of an instance. This could occur with a method whose computation is based ondatetime.now()
, or simply if a change were saved to the database by some other process in the brief interval between subsequent invocations of a method on the same instance.You can use the
name
argument to make cached properties of other methods. For example, if you had an expensiveget_friends()
method and wanted to allow calling it without retrieving the cached value, you could write:friends = cached_property(get_friends, name='friends')
While
person.get_friends()
will recompute the friends on each call, the value of the cached property will persist until you delete it as described above:x = person.friends # calls first time y = person.get_friends() # calls again z = person.friends # does not call x is z # is True
Warning
cached_property
doesn’t work properly with a mangled name unless it’s passed aname
of the form_Class__attribute
:__friends = cached_property(get_friends, name='_Person__friends')
-
keep_lazy
(func, *resultclasses)[source]¶ Django offers many utility functions (particularly in
django.utils
) that take a string as their first argument and do something to that string. These functions are used by template filters as well as directly in other code.If you write your own similar functions and deal with translations, you’ll face the problem of what to do when the first argument is a lazy translation object. You don’t want to convert it to a string immediately, because you might be using this function outside of a view (and hence the current thread’s locale setting will not be correct).
For cases like this, use the
django.utils.functional.keep_lazy()
decorator. It modifies the function so that if it’s called with a lazy translation as one of its arguments, the function evaluation is delayed until it needs to be converted to a string.For example:
from django.utils.functional import keep_lazy, keep_lazy_text def fancy_utility_function(s, ...): # Do some conversion on string 's' ... fancy_utility_function = keep_lazy(str)(fancy_utility_function) # Or more succinctly: @keep_lazy(str) def fancy_utility_function(s, ...): ...
The
keep_lazy()
decorator takes a number of extra arguments (*args
) specifying the type(s) that the original function can return. A common use case is to have functions that return text. For these, you can just pass thestr
type tokeep_lazy
(or even simpler, use thekeep_lazy_text()
decorator described in the next section).Using this decorator means you can write your function and assume that the input is a proper string, then add support for lazy translation objects at the end.
-
keep_lazy_text
(func)[source]¶ A shortcut for
keep_lazy(str)(func)
.If you have a function that returns text and you want to be able to take lazy arguments while delaying their evaluation, simply use this decorator:
from django.utils.functional import keep_lazy, keep_lazy_text # Our previous example was: @keep_lazy(str) def fancy_utility_function(s, ...): ... # Which can be rewritten as: @keep_lazy_text def fancy_utility_function(s, ...): ...
django.utils.html
¶
Usually you should build up HTML using Django’s templates to make use of its
autoescape mechanism, using the utilities in django.utils.safestring
where appropriate. This module provides some additional low level utilities for
escaping HTML.
-
escape
(text)[source]¶ Returns the given text with ampersands, quotes and angle brackets encoded for use in HTML. The input is first coerced to a string and the output has
mark_safe()
applied.
-
conditional_escape
(text)[source]¶ Similar to
escape()
, except that it doesn’t operate on pre-escaped strings, so it will not double escape.
-
format_html
(format_string, *args, **kwargs)[source]¶ This is similar to
str.format()
, except that it is appropriate for building up HTML fragments. All args and kwargs are passed throughconditional_escape()
before being passed tostr.format()
.For the case of building up small HTML fragments, this function is to be preferred over string interpolation using
%
orstr.format()
directly, because it applies escaping to all arguments - just like the template system applies escaping by default.So, instead of writing:
mark_safe("%s <b>%s</b> %s" % ( some_html, escape(some_text), escape(some_other_text), ))
You should instead use:
format_html("{} <b>{}</b> {}", mark_safe(some_html), some_text, some_other_text, )
This has the advantage that you don’t need to apply
escape()
to each argument and risk a bug and an XSS vulnerability if you forget one.Note that although this function uses
str.format()
to do the interpolation, some of the formatting options provided bystr.format()
(e.g. number formatting) will not work, since all arguments are passed throughconditional_escape()
which (ultimately) callsforce_text()
on the values.
-
format_html_join
(sep, format_string, args_generator)[source]¶ A wrapper of
format_html()
, for the common case of a group of arguments that need to be formatted using the same format string, and then joined usingsep
.sep
is also passed throughconditional_escape()
.args_generator
should be an iterator that returns the sequence ofargs
that will be passed toformat_html()
. For example:format_html_join( '\n', "<li>{} {}</li>", ((u.first_name, u.last_name) for u in users) )
Tries to remove anything that looks like an HTML tag from the string, that is anything contained within
<>
.Absolutely NO guarantee is provided about the resulting string being HTML safe. So NEVER mark safe the result of a
strip_tag
call without escaping it first, for example withescape()
.For example:
strip_tags(value)
If
value
is"<b>Joel</b> <button>is</button> a <span>slug</span>"
the return value will be"Joel is a slug"
.If you are looking for a more robust solution, take a look at the bleach Python library.
-
html_safe
()[source]¶ The
__html__()
method on a class helps non-Django templates detect classes whose output doesn’t require HTML escaping.This decorator defines the
__html__()
method on the decorated class by wrapping__str__()
inmark_safe()
. Ensure the__str__()
method does indeed return text that doesn’t require HTML escaping.
django.utils.http
¶
-
urlencode
(query, doseq=False)[source]¶ A version of Python’s
urllib.parse.urlencode()
function that can operate onMultiValueDict
and non-string values.
Deprecated since version 2.1: Use
http_date()
instead, which follows the latest RFC.Formats the time to ensure compatibility with Netscape’s cookie standard.
Accepts a floating point number expressed in seconds since the epoch in UTC–such as that outputted by
time.time()
. If set toNone
, defaults to the current time.Outputs a string in the format
Wdy, DD-Mon-YYYY HH:MM:SS GMT
.
-
http_date
(epoch_seconds=None)[source]¶ Formats the time to match the RFC 1123 date format as specified by HTTP RFC 7231#section-7.1.1.1.
Accepts a floating point number expressed in seconds since the epoch in UTC–such as that outputted by
time.time()
. If set toNone
, defaults to the current time.Outputs a string in the format
Wdy, DD Mon YYYY HH:MM:SS GMT
.
django.utils.module_loading
¶
Functions for working with Python modules.
-
import_string
(dotted_path)[source]¶ Imports a dotted module path and returns the attribute/class designated by the last name in the path. Raises
ImportError
if the import failed. For example:from django.utils.module_loading import import_string ValidationError = import_string('django.core.exceptions.ValidationError')
is equivalent to:
from django.core.exceptions import ValidationError
django.utils.safestring
¶
Functions and classes for working with “safe strings”: strings that can be displayed safely without further escaping in HTML. Marking something as a “safe string” means that the producer of the string has already turned characters that should not be interpreted by the HTML engine (e.g. ‘<’) into the appropriate entities.
-
class
SafeString
¶ A
str
subclass that has been specifically marked as “safe” (requires no further escaping) for HTML output purposes. Alias ofSafeText
.
-
class
SafeText
[source]¶ A
str
subclass that has been specifically marked as “safe” for HTML output purposes.
-
mark_safe
(s)[source]¶ Explicitly mark a string as safe for (HTML) output purposes. The returned object can be used everywhere a string is appropriate.
Can be called multiple times on a single string.
Can also be used as a decorator.
For building up fragments of HTML, you should normally be using
django.utils.html.format_html()
instead.String marked safe will become unsafe again if modified. For example:
>>> mystr = '<b>Hello World</b> ' >>> mystr = mark_safe(mystr) >>> type(mystr) <class 'django.utils.safestring.SafeText'> >>> mystr = mystr.strip() # removing whitespace >>> type(mystr) <type 'str'>
django.utils.text
¶
-
format_lazy
(format_string, *args, **kwargs)¶ A version of
str.format()
for whenformat_string
,args
, and/orkwargs
contain lazy objects. The first argument is the string to be formatted. For example:from django.utils.text import format_lazy from django.utils.translation import pgettext_lazy urlpatterns = [ path(format_lazy('{person}/<int:pk>/', person=pgettext_lazy('URL', 'person')), PersonDetailView.as_view()), ]
This example allows translators to translate part of the URL. If “person” is translated to “persona”, the regular expression will match
persona/(?P<pk>\d+)/$
, e.g.persona/5/
.
-
slugify
(value, allow_unicode=False)[source]¶ Converts a string to a URL slug by:
- Converting to ASCII if
allow_unicode
isFalse
(the default). - Removing characters that aren’t alphanumerics, underscores, hyphens, or whitespace.
- Removing leading and trailing whitespace.
- Converting to lowercase.
- Replacing any whitespace or repeated dashes with single dashes.
For example:
>>> slugify(' Joel is a slug ') 'joel-is-a-slug'
If you want to allow Unicode characters, pass
allow_unicode=True
. For example:>>> slugify('你好 World', allow_unicode=True) '你好-world'
- Converting to ASCII if
django.utils.timezone
¶
-
class
FixedOffset
(offset=None, name=None)[source]¶ A
tzinfo
subclass modeling a fixed offset from UTC.offset
is an integer number of minutes east of UTC.
-
get_fixed_timezone
(offset)[source]¶ Returns a
tzinfo
instance that represents a time zone with a fixed offset from UTC.offset
is adatetime.timedelta
or an integer number of minutes. Use positive values for time zones east of UTC and negative values for west of UTC.
-
get_default_timezone
()[source]¶ Returns a
tzinfo
instance that represents the default time zone.
-
get_default_timezone_name
()[source]¶ Returns the name of the default time zone.
-
get_current_timezone
()[source]¶ Returns a
tzinfo
instance that represents the current time zone.
-
get_current_timezone_name
()[source]¶ Returns the name of the current time zone.
-
activate
(timezone)[source]¶ Sets the current time zone. The
timezone
argument must be an instance of atzinfo
subclass or a time zone name.
-
deactivate
()[source]¶ Unsets the current time zone.
-
override
(timezone)[source]¶ This is a Python context manager that sets the current time zone on entry with
activate()
, and restores the previously active time zone on exit. If thetimezone
argument isNone
, the current time zone is unset on entry withdeactivate()
instead.override
is also usable as a function decorator.
-
localtime
(value=None, timezone=None)[source]¶ Converts an aware
datetime
to a different time zone, by default the current time zone.When
value
is omitted, it defaults tonow()
.This function doesn’t work on naive datetimes; use
make_aware()
instead.
-
localdate
(value=None, timezone=None)[source]¶ Uses
localtime()
to convert an awaredatetime
to adate()
in a different time zone, by default the current time zone.When
value
is omitted, it defaults tonow()
.This function doesn’t work on naive datetimes.
-
now
()[source]¶ Returns a
datetime
that represents the current point in time. Exactly what’s returned depends on the value ofUSE_TZ
:- If
USE_TZ
isFalse
, this will be a naive datetime (i.e. a datetime without an associated timezone) that represents the current time in the system’s local timezone. - If
USE_TZ
isTrue
, this will be an aware datetime representing the current time in UTC. Note thatnow()
will always return times in UTC regardless of the value ofTIME_ZONE
; you can uselocaltime()
to get the time in the current time zone.
- If
-
is_aware
(value)[source]¶ Returns
True
ifvalue
is aware,False
if it is naive. This function assumes thatvalue
is adatetime
.
-
is_naive
(value)[source]¶ Returns
True
ifvalue
is naive,False
if it is aware. This function assumes thatvalue
is adatetime
.
-
make_aware
(value, timezone=None, is_dst=None)[source]¶ Returns an aware
datetime
that represents the same point in time asvalue
intimezone
,value
being a naivedatetime
. Iftimezone
is set toNone
, it defaults to the current time zone.The
pytz.AmbiguousTimeError
exception is raised if you try to makevalue
aware during a DST transition where the same time occurs twice (when reverting from DST). Settingis_dst
toTrue
orFalse
will avoid the exception by choosing if the time is pre-transition or post-transition respectively.The
pytz.NonExistentTimeError
exception is raised if you try to makevalue
aware during a DST transition such that the time never occurred (when entering into DST). Settingis_dst
toTrue
orFalse
will avoid the exception by moving the hour backwards or forwards by 1 respectively. For example,is_dst=True
would change a nonexistent time of 2:30 to 1:30 andis_dst=False
would change the time to 3:30.
-
make_naive
(value, timezone=None)[source]¶ Returns a naive
datetime
that represents intimezone
the same point in time asvalue
,value
being an awaredatetime
. Iftimezone
is set toNone
, it defaults to the current time zone.
django.utils.translation
¶
For a complete discussion on the usage of the following see the translation documentation.
The u
prefix on the functions below comes from a difference in Python 2
between unicode and bytestrings. If your code doesn’t support Python 2, use the
functions without the u
.
-
ugettext
(message)¶ Translates
message
and returns it as a string.
-
pgettext
(context, message)[source]¶ Translates
message
given thecontext
and returns it as a string.For more information, see Contextual markers.
-
gettext_lazy
(message)¶
-
ugettext_lazy
(message)¶
-
pgettext_lazy
(context, message)¶ Same as the non-lazy versions above, but using lazy execution.
-
ugettext_noop
(message)¶ Marks strings for translation but doesn’t translate them now. This can be used to store strings in global variables that should stay in the base language (because they might be used externally) and will be translated later.
-
ungettext
(singular, plural, number)¶ Translates
singular
andplural
and returns the appropriate string based onnumber
.
-
npgettext
(context, singular, plural, number)[source]¶ Translates
singular
andplural
and returns the appropriate string based onnumber
and thecontext
.
-
ungettext_lazy
(singular, plural, number)¶
-
npgettext_lazy
(context, singular, plural, number)[source]¶ Same as the non-lazy versions above, but using lazy execution.
-
activate
(language)[source]¶ Fetches the translation object for a given language and activates it as the current translation object for the current thread.
-
deactivate
()[source]¶ Deactivates the currently active translation object so that further _ calls will resolve against the default translation object, again.
-
deactivate_all
()[source]¶ Makes the active translation object a
NullTranslations()
instance. This is useful when we want delayed translations to appear as the original string for some reason.
-
override
(language, deactivate=False)[source]¶ A Python context manager that uses
django.utils.translation.activate()
to fetch the translation object for a given language, activates it as the translation object for the current thread and reactivates the previous active language on exit. Optionally, it can simply deactivate the temporary translation on exit withdjango.utils.translation.deactivate()
if thedeactivate
argument isTrue
. If you passNone
as the language argument, aNullTranslations()
instance is activated within the context.override
is also usable as a function decorator.
-
check_for_language
(lang_code)[source]¶ Checks whether there is a global language file for the given language code (e.g. ‘fr’, ‘pt_BR’). This is used to decide whether a user-provided language is available.
-
get_language
()[source]¶ Returns the currently selected language code. Returns
None
if translations are temporarily deactivated (bydeactivate_all()
or whenNone
is passed tooverride()
).
-
get_language_bidi
()[source]¶ Returns selected language’s BiDi layout:
False
= left-to-right layoutTrue
= right-to-left layout
-
get_language_from_request
(request, check_path=False)[source]¶ Analyzes the request to find what language the user wants the system to show. Only languages listed in settings.LANGUAGES are taken into account. If the user requests a sublanguage where we have a main language, we send out the main language.
If
check_path
isTrue
, the function first checks the requested URL for whether its path begins with a language code listed in theLANGUAGES
setting.
-
get_supported_language_variant
(lang_code, strict=False)[source]¶ - New in Django 2.1.
Returns
lang_code
if it’s in theLANGUAGES
setting, possibly selecting a more generic variant. For example,'es'
is returned iflang_code
is'es-ar'
and'es'
is inLANGUAGES
but'es-ar'
isn’t.If
strict
isFalse
(the default), a country-specific variant may be returned when neither the language code nor its generic variant is found. For example, if only'es-co'
is inLANGUAGES
, that’s returned forlang_code
s like'es'
and'es-ar'
. Those matches aren’t returned ifstrict=True
.Raises
LookupError
if nothing is found.
-
templatize
(src)[source]¶ Turns a Django template into something that is understood by
xgettext
. It does so by translating the Django translation tags into standardgettext
function invocations.
-
LANGUAGE_SESSION_KEY
¶ Session key under which the active language for the current session is stored.