""" 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) """ from __future__ import unicode_literals import functools from importlib import import_module import re from threading import local from django.http import Http404 from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist from django.utils.datastructures import MultiValueDict from django.utils.encoding import force_str, force_text, iri_to_uri from django.utils.functional import lazy from django.utils.http import urlquote from django.utils.module_loading import module_has_submodule from django.utils.regex_helper import normalize from django.utils import six, lru_cache from django.utils.translation import get_language # 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() class ResolverMatch(object): def __init__(self, func, args, kwargs, url_name=None, app_name=None, namespaces=None): self.func = func self.args = args self.kwargs = kwargs self.app_name = app_name if namespaces: self.namespaces = [x for x in namespaces if x] else: self.namespaces = [] if not url_name: if not hasattr(func, '__name__'): # An instance of a callable class url_name = '.'.join([func.__class__.__module__, func.__class__.__name__]) else: # A function url_name = '.'.join([func.__module__, func.__name__]) self.url_name = url_name @property def namespace(self): return ':'.join(self.namespaces) @property def view_name(self): return ':'.join(filter(bool, (self.namespace, self.url_name))) def __getitem__(self, index): return (self.func, self.args, self.kwargs)[index] def __repr__(self): return "ResolverMatch(func=%s, args=%s, kwargs=%s, url_name='%s', app_name='%s', namespace='%s')" % ( self.func, self.args, self.kwargs, self.url_name, self.app_name, self.namespace) class Resolver404(Http404): pass class NoReverseMatch(Exception): pass @lru_cache.lru_cache(maxsize=None) 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): mod_name, func_name = get_mod_func(lookup_view) if func_name == '': return lookup_view try: mod = import_module(mod_name) except ImportError: parentmod, submod = get_mod_func(mod_name) if (not can_fail and submod != '' and not module_has_submodule(import_module(parentmod), submod)): raise ViewDoesNotExist( "Could not import %s. Parent module %s does not exist." % (lookup_view, mod_name)) if not can_fail: raise else: try: lookup_view = getattr(mod, func_name) if not callable(lookup_view): raise ViewDoesNotExist( "Could not import %s.%s. View is not callable." % (mod_name, func_name)) except AttributeError: if not can_fail: raise ViewDoesNotExist( "Could not import %s. View does not exist in module %s." % (lookup_view, mod_name)) return lookup_view @lru_cache.lru_cache(maxsize=None) def get_resolver(urlconf): if urlconf is None: from django.conf import settings urlconf = settings.ROOT_URLCONF return RegexURLResolver(r'^/', urlconf) @lru_cache.lru_cache(maxsize=None) def get_ns_resolver(ns_pattern, resolver): # Build a namespaced resolver for the given parent urlconf pattern. # This makes it possible to have captured parameters in the parent # urlconf pattern. ns_resolver = RegexURLResolver(ns_pattern, resolver.url_patterns) return RegexURLResolver(r'^/', [ns_resolver]) 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 LocaleRegexProvider(object): """ A mixin to provide a default regex property which can vary by active language. """ def __init__(self, regex): # regex is either a string representing a regular expression, or a # translatable string (using ugettext_lazy) representing a regular # expression. self._regex = regex self._regex_dict = {} @property def regex(self): """ Returns a compiled regular expression, depending upon the activated language-code. """ language_code = get_language() if language_code not in self._regex_dict: if isinstance(self._regex, six.string_types): regex = self._regex else: regex = force_text(self._regex) try: compiled_regex = re.compile(regex, re.UNICODE) except re.error as e: raise ImproperlyConfigured( '"%s" is not a valid regular expression: %s' % (regex, six.text_type(e))) self._regex_dict[language_code] = compiled_regex return self._regex_dict[language_code] class RegexURLPattern(LocaleRegexProvider): def __init__(self, regex, callback, default_args=None, name=None): LocaleRegexProvider.__init__(self, regex) # 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). 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 force_str('<%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 ResolverMatch(self.callback, args, kwargs, self.name) @property def callback(self): if self._callback is not None: return self._callback self._callback = get_callable(self._callback_str) return self._callback class RegexURLResolver(LocaleRegexProvider): def __init__(self, regex, urlconf_name, default_kwargs=None, app_name=None, namespace=None): LocaleRegexProvider.__init__(self, regex) # urlconf_name is a string representing the module containing URLconfs. self.urlconf_name = urlconf_name if not isinstance(urlconf_name, six.string_types): 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 = {} self._namespace_dict = {} self._app_dict = {} # set of dotted paths to all functions and classes that are used in # urlpatterns self._callback_strs = set() self._populated = False def __repr__(self): if isinstance(self.urlconf_name, list) and len(self.urlconf_name): # Don't bother to output the whole list, it can be huge urlconf_repr = '<%s list>' % self.urlconf_name[0].__class__.__name__ else: urlconf_repr = repr(self.urlconf_name) return str('<%s %s (%s:%s) %s>') % ( self.__class__.__name__, urlconf_repr, self.app_name, self.namespace, self.regex.pattern) def _populate(self): lookups = MultiValueDict() namespaces = {} apps = {} language_code = get_language() for pattern in reversed(self.url_patterns): if hasattr(pattern, '_callback_str'): self._callback_strs.add(pattern._callback_str) elif hasattr(pattern, '_callback'): callback = pattern._callback if isinstance(callback, functools.partial): callback = callback.func if not hasattr(callback, '__name__'): lookup_str = callback.__module__ + "." + callback.__class__.__name__ else: lookup_str = callback.__module__ + "." + callback.__name__ self._callback_strs.add(lookup_str) 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_pat = pattern.regex.pattern for name in pattern.reverse_dict: for matches, pat, defaults in pattern.reverse_dict.getlist(name): new_matches = normalize(parent_pat + pat) lookups.appendlist(name, (new_matches, p_pattern + pat, dict(defaults, **pattern.default_kwargs))) 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) self._callback_strs.update(pattern._callback_strs) else: bits = normalize(p_pattern) lookups.appendlist(pattern.callback, (bits, p_pattern, pattern.default_args)) if pattern.name is not None: lookups.appendlist(pattern.name, (bits, p_pattern, pattern.default_args)) self._reverse_dict[language_code] = lookups self._namespace_dict[language_code] = namespaces self._app_dict[language_code] = apps self._populated = True @property def reverse_dict(self): language_code = get_language() if language_code not in self._reverse_dict: self._populate() return self._reverse_dict[language_code] @property def namespace_dict(self): language_code = get_language() if language_code not in self._namespace_dict: self._populate() return self._namespace_dict[language_code] @property def app_dict(self): language_code = get_language() if language_code not in self._app_dict: self._populate() return self._app_dict[language_code] def _is_callback(self, name): if not self._populated: self._populate() return name in self._callback_strs def resolve(self, path): path = force_text(path) # path may be a reverse_lazy object 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 as e: sub_tried = e.args[0].get('tried') if sub_tried is not None: tried.extend([pattern] + t for t in sub_tried) else: tried.append([pattern]) else: if sub_match: sub_match_dict = dict(match.groupdict(), **self.default_kwargs) sub_match_dict.update(sub_match.kwargs) return ResolverMatch(sub_match.func, sub_match.args, sub_match_dict, sub_match.url_name, self.app_name or sub_match.app_name, [self.namespace] + sub_match.namespaces) tried.append([pattern]) raise Resolver404({'tried': tried, 'path': new_path}) raise Resolver404({'path': path}) @property def urlconf_module(self): try: return self._urlconf_module except AttributeError: self._urlconf_module = import_module(self.urlconf_name) return self._urlconf_module @property def url_patterns(self): # urlconf_module might be a valid set of patterns, so we default to it patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module) try: iter(patterns) except TypeError: msg = ( "The included urlconf '{name}' does not appear to have any " "patterns in it. If you see valid patterns in the file then " "the issue is probably caused by a circular import." ) raise ImproperlyConfigured(msg.format(name=self.urlconf_name)) return patterns def _resolve_special(self, view_type): callback = getattr(self.urlconf_module, 'handler%s' % view_type, None) if not callback: # No handler specified in file; use default # Lazy import, since django.urls imports this file from django.conf import urls callback = getattr(urls, 'handler%s' % view_type) return get_callable(callback), {} def resolve400(self): return self._resolve_special('400') def resolve403(self): return self._resolve_special('403') def resolve404(self): return self._resolve_special('404') def resolve500(self): return self._resolve_special('500') def reverse(self, lookup_view, *args, **kwargs): return self._reverse_with_prefix(lookup_view, '', *args, **kwargs) def _reverse_with_prefix(self, lookup_view, _prefix, *args, **kwargs): if args and kwargs: raise ValueError("Don't mix *args and **kwargs in call to reverse()!") text_args = [force_text(v) for v in args] text_kwargs = dict((k, force_text(v)) for (k, v) in kwargs.items()) if not self._populated: self._populate() try: if self._is_callback(lookup_view): lookup_view = get_callable(lookup_view, True) except (ImportError, AttributeError) as e: raise NoReverseMatch("Error importing '%s': %s." % (lookup_view, e)) possibilities = self.reverse_dict.getlist(lookup_view) prefix_norm, prefix_args = normalize(urlquote(_prefix))[0] for possibility, pattern, defaults in possibilities: for result, params in possibility: if args: if len(args) != len(params) + len(prefix_args): continue candidate_subs = dict(zip(prefix_args + params, text_args)) else: if set(kwargs.keys()) | set(defaults.keys()) != set(params) | set(defaults.keys()) | set(prefix_args): continue matches = True for k, v in defaults.items(): if kwargs.get(k, v) != v: matches = False break if not matches: continue candidate_subs = text_kwargs # WSGI provides decoded URLs, without %xx escapes, and the URL # resolver operates on such URLs. First substitute arguments # without quoting to build a decoded URL and look for a match. # Then, if we have a match, redo the substitution with quoted # arguments in order to return a properly encoded URL. candidate_pat = prefix_norm.replace('%', '%%') + result if re.search('^%s%s' % (prefix_norm, pattern), candidate_pat % candidate_subs, re.UNICODE): candidate_subs = dict((k, urlquote(v)) for (k, v) in candidate_subs.items()) url = candidate_pat % candidate_subs # Don't allow construction of scheme relative urls. if url.startswith('//'): url = '/%%2F%s' % url[2:] return url # 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 patterns = [pattern for (possibility, pattern, defaults) in possibilities] raise NoReverseMatch("Reverse for '%s' with arguments '%s' and keyword " "arguments '%s' not found. %d pattern(s) tried: %s" % (lookup_view_s, args, kwargs, len(patterns), patterns)) class LocaleRegexURLResolver(RegexURLResolver): """ A URL resolver that always matches the active language code as URL prefix. Rather than taking a regex argument, we just override the ``regex`` function to always return the active language-code as regex. """ def __init__(self, urlconf_name, default_kwargs=None, app_name=None, namespace=None): super(LocaleRegexURLResolver, self).__init__( None, urlconf_name, default_kwargs, app_name, namespace) @property def regex(self): language_code = get_language() if language_code not in self._regex_dict: regex_compiled = re.compile('^%s/' % language_code, re.UNICODE) self._regex_dict[language_code] = regex_compiled return self._regex_dict[language_code] 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, six.string_types): view = viewname else: parts = viewname.split(':') parts.reverse() view = parts[0] path = parts[1:] resolved_path = [] ns_pattern = '' 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) ns_pattern = ns_pattern + extra 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) 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): """ Sets the script prefix for the current thread. """ if not prefix.endswith('/'): prefix += '/' _prefixes.value = 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 getattr(_prefixes, "value", '/') def clear_script_prefix(): """ Unsets the script prefix for the current thread. """ try: del _prefixes.value except AttributeError: pass 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. """ if urlconf_name: _urlconfs.value = urlconf_name else: if hasattr(_urlconfs, "value"): del _urlconfs.value def get_urlconf(default=None): """ Returns 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): """ Returns 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 unnecessarily indented try...except blocks. """ try: resolve(path, urlconf) return True except Resolver404: return False