from threading import local
from urllib.parse import urlsplit, urlunsplit
from django.utils.encoding import iri_to_uri
from django.utils.functional import lazy
from django.utils.translation import override
from .exceptions import NoReverseMatch, Resolver404
from .resolvers import get_ns_resolver, get_resolver
from .utils import get_callable
# SCRIPT_NAME prefixes for each thread are stored here. If there's no entry for
# the current thread (which is the only one we ever access), it is assumed to
# be empty.
_prefixes = local()
# Overridden URLconfs for each thread are stored here.
_urlconfs = local()
[docs]def resolve(path, urlconf=None):
if urlconf is None:
urlconf = get_urlconf()
return get_resolver(urlconf).resolve(path)
[docs]def reverse(viewname, urlconf=None, args=None, kwargs=None, current_app=None):
if urlconf is None:
urlconf = get_urlconf()
resolver = get_resolver(urlconf)
args = args or []
kwargs = kwargs or {}
prefix = get_script_prefix()
if not isinstance(viewname, str):
view = viewname
else:
parts = viewname.split(':')
parts.reverse()
view = parts[0]
path = parts[1:]
if current_app:
current_path = current_app.split(':')
current_path.reverse()
else:
current_path = None
resolved_path = []
ns_pattern = ''
ns_converters = {}
while path:
ns = path.pop()
current_ns = current_path.pop() if current_path else None
# Lookup the name to see if it could be an app identifier.
try:
app_list = resolver.app_dict[ns]
# Yes! Path part matches an app in the current Resolver.
if current_ns and current_ns in app_list:
# If we are reversing for a particular app, use that
# namespace.
ns = current_ns
elif ns not in app_list:
# The name isn't shared by one of the instances (i.e.,
# the default) so pick the first instance as the default.
ns = app_list[0]
except KeyError:
pass
if ns != current_ns:
current_path = None
try:
extra, resolver = resolver.namespace_dict[ns]
resolved_path.append(ns)
ns_pattern = ns_pattern + extra
ns_converters.update(resolver.pattern.converters)
except KeyError as key:
if resolved_path:
raise NoReverseMatch(
"%s is not a registered namespace inside '%s'" %
(key, ':'.join(resolved_path))
)
else:
raise NoReverseMatch("%s is not a registered namespace" % key)
if ns_pattern:
resolver = get_ns_resolver(ns_pattern, resolver, tuple(ns_converters.items()))
return iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))
reverse_lazy = lazy(reverse, str)
def clear_url_caches():
get_callable.cache_clear()
get_resolver.cache_clear()
get_ns_resolver.cache_clear()
def set_script_prefix(prefix):
"""
Set the script prefix for the current thread.
"""
if not prefix.endswith('/'):
prefix += '/'
_prefixes.value = prefix
[docs]def get_script_prefix():
"""
Return the currently active script prefix. Useful for client code that
wishes to construct their own URLs manually (although accessing the request
instance is normally going to be a lot cleaner).
"""
return getattr(_prefixes, "value", '/')
def clear_script_prefix():
"""
Unset the script prefix for the current thread.
"""
try:
del _prefixes.value
except AttributeError:
pass
def set_urlconf(urlconf_name):
"""
Set the URLconf for the current thread (overriding the default one in
settings). If urlconf_name is None, revert back to the default.
"""
if urlconf_name:
_urlconfs.value = urlconf_name
else:
if hasattr(_urlconfs, "value"):
del _urlconfs.value
def get_urlconf(default=None):
"""
Return the root URLconf to use for the current thread if it has been
changed from the default one.
"""
return getattr(_urlconfs, "value", default)
def is_valid_path(path, urlconf=None):
"""
Return True if the given path resolves against the default URL resolver,
False otherwise. This is a convenience method to make working with "is
this a match?" cases easier, avoiding try...except blocks.
"""
try:
resolve(path, urlconf)
return True
except Resolver404:
return False
def translate_url(url, lang_code):
"""
Given a URL (absolute or relative), try to get its translated version in
the `lang_code` language (either by i18n_patterns or by translated regex).
Return the original URL if no translated version is found.
"""
parsed = urlsplit(url)
try:
match = resolve(parsed.path)
except Resolver404:
pass
else:
to_be_reversed = "%s:%s" % (match.namespace, match.url_name) if match.namespace else match.url_name
with override(lang_code):
try:
url = reverse(to_be_reversed, args=match.args, kwargs=match.kwargs)
except NoReverseMatch:
pass
else:
url = urlunsplit((parsed.scheme, parsed.netloc, url, parsed.query, parsed.fragment))
return url
Oct 31, 2018