"""
This module converts requested URLs to callback view functions.
RegexURLResolver is the main class here. Its resolve() method takes a URL (as
a string) and returns a tuple in this format:
(view_function, function_args, function_kwargs)
"""
import re
from django.http import Http404
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured,ViewDoesNotExist
from django.utils.datastructures import MultiValueDict
from django.utils.encoding import iri_to_uri,force_unicode,smart_str
from django.utils.functional import memoize
from django.utils.importlib import import_module
from django.utils.regex_helper import normalize
from django.utils.thread_support import currentThread
_resolver_cache = {} # Maps URLconf modules to RegexURLResolver instances.
_callable_cache = {} # Maps view and url pattern names to their view functions.
# 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 = {}
# Overridden URLconfs for each thread are stored here.
_urlconfs = {}
class Resolver404(Http404):
pass
class NoReverseMatch(Exception):
# Don't make this raise an error when used in a template.
silent_variable_failure = True
def get_callable(lookup_view, can_fail=False):
"""
Convert a string version of a function name to the callable object.
If the lookup_view is not an import path, it is assumed to be a URL pattern
label and the original string is returned.
If can_fail is True, lookup_view might be a URL pattern label, so errors
during the import fail and the string is returned.
"""
if not callable(lookup_view):
try:
# Bail early for non-ASCII strings (they can't be functions).
lookup_view = lookup_view.encode('ascii')
mod_name, func_name = get_mod_func(lookup_view)
if func_name != '':
lookup_view = getattr(import_module(mod_name), func_name)
if not callable(lookup_view):
raise AttributeError("'%s.%s' is not a callable." % (mod_name, func_name))
except (ImportError, AttributeError):
if not can_fail:
raise
except UnicodeEncodeError:
pass
return lookup_view
get_callable = memoize(get_callable, _callable_cache, 1)
def get_resolver(urlconf):
if urlconf is None:
from django.conf import settings
urlconf = settings.ROOT_URLCONF
return RegexURLResolver(r'^/', urlconf)
get_resolver = memoize(get_resolver, _resolver_cache, 1)
def get_mod_func(callback):
# Converts 'django.views.news.stories.story_detail' to
# ['django.views.news.stories', 'story_detail']
try:
dot = callback.rindex('.')
except ValueError:
return callback, ''
return callback[:dot], callback[dot+1:]
class RegexURLPattern(object):
def __init__(self, regex, callback, default_args=None, name=None):
# regex is a string representing a regular expression.
# callback is either a string like 'foo.views.news.stories.story_detail'
# which represents the path to a module and a view function name, or a
# callable object (view).
self.regex = re.compile(regex, re.UNICODE)
if callable(callback):
self._callback = callback
else:
self._callback = None
self._callback_str = callback
self.default_args = default_args or {}
self.name = name
def __repr__(self):
return '<%s %s %s>' % (self.__class__.__name__, self.name, self.regex.pattern)
def add_prefix(self, prefix):
"""
Adds the prefix string to a string-based callback.
"""
if not prefix or not hasattr(self, '_callback_str'):
return
self._callback_str = prefix + '.' + self._callback_str
def resolve(self, path):
match = self.regex.search(path)
if match:
# If there are any named groups, use those as kwargs, ignoring
# non-named groups. Otherwise, pass all non-named arguments as
# positional arguments.
kwargs = match.groupdict()
if kwargs:
args = ()
else:
args = match.groups()
# In both cases, pass any extra_kwargs as **kwargs.
kwargs.update(self.default_args)
return self.callback, args, kwargs
def _get_callback(self):
if self._callback is not None:
return self._callback
try:
self._callback = get_callable(self._callback_str)
except ImportError, e:
mod_name, _ = get_mod_func(self._callback_str)
raise ViewDoesNotExist("Could not import %s. Error was: %s" % (mod_name, str(e)))
except AttributeError, e:
mod_name, func_name = get_mod_func(self._callback_str)
raise ViewDoesNotExist("Tried %s in module %s. Error was: %s" % (func_name, mod_name, str(e)))
return self._callback
callback = property(_get_callback)
class RegexURLResolver(object):
def __init__(self, regex, urlconf_name, default_kwargs=None, app_name=None, namespace=None):
# regex is a string representing a regular expression.
# urlconf_name is a string representing the module containing URLconfs.
self.regex = re.compile(regex, re.UNICODE)
self.urlconf_name = urlconf_name
if not isinstance(urlconf_name, basestring):
self._urlconf_module = self.urlconf_name
self.callback = None
self.default_kwargs = default_kwargs or {}
self.namespace = namespace
self.app_name = app_name
self._reverse_dict = None
self._namespace_dict = None
self._app_dict = None
def __repr__(self):
return '<%s %s (%s:%s) %s>' % (self.__class__.__name__, self.urlconf_name, self.app_name, self.namespace, self.regex.pattern)
def _populate(self):
lookups = MultiValueDict()
namespaces = {}
apps = {}
for pattern in reversed(self.url_patterns):
p_pattern = pattern.regex.pattern
if p_pattern.startswith('^'):
p_pattern = p_pattern[1:]
if isinstance(pattern, RegexURLResolver):
if pattern.namespace:
namespaces[pattern.namespace] = (p_pattern, pattern)
if pattern.app_name:
apps.setdefault(pattern.app_name, []).append(pattern.namespace)
else:
parent = normalize(pattern.regex.pattern)
for name in pattern.reverse_dict:
for matches, pat in pattern.reverse_dict.getlist(name):
new_matches = []
for piece, p_args in parent:
new_matches.extend([(piece + suffix, p_args + args) for (suffix, args) in matches])
lookups.appendlist(name, (new_matches, p_pattern + pat))
for namespace, (prefix, sub_pattern) in pattern.namespace_dict.items():
namespaces[namespace] = (p_pattern + prefix, sub_pattern)
for app_name, namespace_list in pattern.app_dict.items():
apps.setdefault(app_name, []).extend(namespace_list)
else:
bits = normalize(p_pattern)
lookups.appendlist(pattern.callback, (bits, p_pattern))
lookups.appendlist(pattern.name, (bits, p_pattern))
self._reverse_dict = lookups
self._namespace_dict = namespaces
self._app_dict = apps
def _get_reverse_dict(self):
if self._reverse_dict is None:
self._populate()
return self._reverse_dict
reverse_dict = property(_get_reverse_dict)
def _get_namespace_dict(self):
if self._namespace_dict is None:
self._populate()
return self._namespace_dict
namespace_dict = property(_get_namespace_dict)
def _get_app_dict(self):
if self._app_dict is None:
self._populate()
return self._app_dict
app_dict = property(_get_app_dict)
def resolve(self, path):
tried = []
match = self.regex.search(path)
if match:
new_path = path[match.end():]
for pattern in self.url_patterns:
try:
sub_match = pattern.resolve(new_path)
except Resolver404, e:
sub_tried = e.args[0].get('tried')
if sub_tried is not None:
tried.extend([(pattern.regex.pattern + ' ' + t) for t in sub_tried])
else:
tried.append(pattern.regex.pattern)
else:
if sub_match:
sub_match_dict = dict([(smart_str(k), v) for k, v in match.groupdict().items()])
sub_match_dict.update(self.default_kwargs)
for k, v in sub_match[2].iteritems():
sub_match_dict[smart_str(k)] = v
return sub_match[0], sub_match[1], sub_match_dict
tried.append(pattern.regex.pattern)
raise Resolver404({'tried': tried, 'path': new_path})
raise Resolver404({'path' : path})
def _get_urlconf_module(self):
try:
return self._urlconf_module
except AttributeError:
self._urlconf_module = import_module(self.urlconf_name)
return self._urlconf_module
urlconf_module = property(_get_urlconf_module)
def _get_url_patterns(self):
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
try:
iter(patterns)
except TypeError:
raise ImproperlyConfigured("The included urlconf %s doesn't have any patterns in it" % self.urlconf_name)
return patterns
url_patterns = property(_get_url_patterns)
def _resolve_special(self, view_type):
callback = getattr(self.urlconf_module, 'handler%s' % view_type)
try:
return get_callable(callback), {}
except (ImportError, AttributeError), e:
raise ViewDoesNotExist("Tried %s. Error was: %s" % (callback, str(e)))
def resolve404(self):
return self._resolve_special('404')
def resolve500(self):
return self._resolve_special('500')
def reverse(self, lookup_view, *args, **kwargs):
if args and kwargs:
raise ValueError("Don't mix *args and **kwargs in call to reverse()!")
try:
lookup_view = get_callable(lookup_view, True)
except (ImportError, AttributeError), e:
raise NoReverseMatch("Error importing '%s': %s." % (lookup_view, e))
possibilities = self.reverse_dict.getlist(lookup_view)
for possibility, pattern in possibilities:
for result, params in possibility:
if args:
if len(args) != len(params):
continue
unicode_args = [force_unicode(val) for val in args]
candidate = result % dict(zip(params, unicode_args))
else:
if set(kwargs.keys()) != set(params):
continue
unicode_kwargs = dict([(k, force_unicode(v)) for (k, v) in kwargs.items()])
candidate = result % unicode_kwargs
if re.search(u'^%s' % pattern, candidate, re.UNICODE):
return candidate
# lookup_view can be URL label, or dotted path, or callable, Any of
# these can be passed in at the top, but callables are not friendly in
# error messages.
m = getattr(lookup_view, '__module__', None)
n = getattr(lookup_view, '__name__', None)
if m is not None and n is not None:
lookup_view_s = "%s.%s" % (m, n)
else:
lookup_view_s = lookup_view
raise NoReverseMatch("Reverse for '%s' with arguments '%s' and keyword "
"arguments '%s' not found." % (lookup_view_s, args, kwargs))
def resolve(path, urlconf=None):
if urlconf is None:
urlconf = get_urlconf()
return get_resolver(urlconf).resolve(path)
def reverse(viewname, urlconf=None, args=None, kwargs=None, prefix=None, current_app=None):
if urlconf is None:
urlconf = get_urlconf()
resolver = get_resolver(urlconf)
args = args or []
kwargs = kwargs or {}
if prefix is None:
prefix = get_script_prefix()
if not isinstance(viewname, basestring):
view = viewname
else:
parts = viewname.split(':')
parts.reverse()
view = parts[0]
path = parts[1:]
resolved_path = []
while path:
ns = path.pop()
# 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_app and current_app in app_list:
# If we are reversing for a particular app, use that namespace
ns = current_app
elif ns not in app_list:
# The name isn't shared by one of the instances (i.e., the default)
# so just pick the first instance as the default.
ns = app_list[0]
except KeyError:
pass
try:
extra, resolver = resolver.namespace_dict[ns]
resolved_path.append(ns)
prefix = prefix + extra
except KeyError, 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)
return iri_to_uri(u'%s%s' % (prefix, resolver.reverse(view,
*args, **kwargs)))
def clear_url_caches():
global _resolver_cache
global _callable_cache
_resolver_cache.clear()
_callable_cache.clear()
def set_script_prefix(prefix):
"""
Sets the script prefix for the current thread.
"""
if not prefix.endswith('/'):
prefix += '/'
_prefixes[currentThread()] = prefix
def get_script_prefix():
"""
Returns 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 _prefixes.get(currentThread(), u'/')
def set_urlconf(urlconf_name):
"""
Sets the URLconf for the current thread (overriding the default one in
settings). Set to None to revert back to the default.
"""
thread = currentThread()
if urlconf_name:
_urlconfs[thread] = urlconf_name
else:
# faster than wrapping in a try/except
if thread in _urlconfs:
del _urlconfs[thread]
def get_urlconf(default=None):
"""
Returns the root URLconf to use for the current thread if it has been
changed from the default one.
"""
thread = currentThread()
if thread in _urlconfs:
return _urlconfs[thread]
return default
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