242 lines
9.5 KiB
Python
242 lines
9.5 KiB
Python
"""
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This module converts requested URLs to callback view functions.
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RegexURLResolver is the main class here. Its resolve() method takes a URL (as
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a string) and returns a tuple in this format:
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(view_function, function_args, function_kwargs)
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"""
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from django.http import Http404
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from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist
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import re
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class Resolver404(Http404):
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pass
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class NoReverseMatch(Exception):
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# Don't make this raise an error when used in a template.
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silent_variable_failure = True
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def get_mod_func(callback):
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# Converts 'django.views.news.stories.story_detail' to
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# ['django.views.news.stories', 'story_detail']
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try:
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dot = callback.rindex('.')
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except ValueError:
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return callback, ''
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return callback[:dot], callback[dot+1:]
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def reverse_helper(regex, *args, **kwargs):
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"""
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Does a "reverse" lookup -- returns the URL for the given args/kwargs.
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The args/kwargs are applied to the given compiled regular expression.
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For example:
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>>> reverse_helper(re.compile('^places/(\d+)/$'), 3)
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'places/3/'
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>>> reverse_helper(re.compile('^places/(?P<id>\d+)/$'), id=3)
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'places/3/'
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>>> reverse_helper(re.compile('^people/(?P<state>\w\w)/(\w+)/$'), 'adrian', state='il')
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'people/il/adrian/'
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Raises NoReverseMatch if the args/kwargs aren't valid for the regex.
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"""
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# TODO: Handle nested parenthesis in the following regex.
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result = re.sub(r'\(([^)]+)\)', MatchChecker(args, kwargs), regex.pattern)
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return result.replace('^', '').replace('$', '')
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class MatchChecker(object):
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"Class used in reverse RegexURLPattern lookup."
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def __init__(self, args, kwargs):
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self.args, self.kwargs = args, kwargs
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self.current_arg = 0
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def __call__(self, match_obj):
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# match_obj.group(1) is the contents of the parenthesis.
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# First we need to figure out whether it's a named or unnamed group.
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#
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grouped = match_obj.group(1)
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m = re.search(r'^\?P<(\w+)>(.*?)$', grouped)
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if m: # If this was a named group...
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# m.group(1) is the name of the group
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# m.group(2) is the regex.
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try:
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value = self.kwargs[m.group(1)]
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except KeyError:
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# It was a named group, but the arg was passed in as a
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# positional arg or not at all.
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try:
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value = self.args[self.current_arg]
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self.current_arg += 1
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except IndexError:
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# The arg wasn't passed in.
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raise NoReverseMatch('Not enough positional arguments passed in')
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test_regex = m.group(2)
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else: # Otherwise, this was a positional (unnamed) group.
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try:
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value = self.args[self.current_arg]
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self.current_arg += 1
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except IndexError:
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# The arg wasn't passed in.
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raise NoReverseMatch('Not enough positional arguments passed in')
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test_regex = grouped
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# Note we're using re.match here on purpose because the start of
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# to string needs to match.
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if not re.match(test_regex + '$', str(value)): # TODO: Unicode?
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raise NoReverseMatch("Value %r didn't match regular expression %r" % (value, test_regex))
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return str(value) # TODO: Unicode?
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class RegexURLPattern(object):
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def __init__(self, regex, callback, default_args=None):
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# regex is a string representing a regular expression.
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# callback is either a string like 'foo.views.news.stories.story_detail'
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# which represents the path to a module and a view function name, or a
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# callable object (view).
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self.regex = re.compile(regex)
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if callable(callback):
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self._callback = callback
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else:
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self._callback = None
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self._callback_str = callback
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self.default_args = default_args or {}
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def resolve(self, path):
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match = self.regex.search(path)
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if match:
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# If there are any named groups, use those as kwargs, ignoring
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# non-named groups. Otherwise, pass all non-named arguments as
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# positional arguments.
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kwargs = match.groupdict()
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if kwargs:
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args = ()
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if not kwargs:
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args = match.groups()
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# In both cases, pass any extra_kwargs as **kwargs.
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kwargs.update(self.default_args)
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return self.callback, args, kwargs
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def _get_callback(self):
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if self._callback is not None:
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return self._callback
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mod_name, func_name = get_mod_func(self._callback_str)
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try:
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self._callback = getattr(__import__(mod_name, {}, {}, ['']), func_name)
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except ImportError, e:
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raise ViewDoesNotExist, "Could not import %s. Error was: %s" % (mod_name, str(e))
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except AttributeError, e:
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raise ViewDoesNotExist, "Tried %s in module %s. Error was: %s" % (func_name, mod_name, str(e))
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return self._callback
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callback = property(_get_callback)
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def reverse(self, viewname, *args, **kwargs):
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mod_name, func_name = get_mod_func(viewname)
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try:
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lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name)
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except (ImportError, AttributeError):
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raise NoReverseMatch
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if lookup_view != self.callback:
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raise NoReverseMatch
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return self.reverse_helper(*args, **kwargs)
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def reverse_helper(self, *args, **kwargs):
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return reverse_helper(self.regex, *args, **kwargs)
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class RegexURLResolver(object):
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def __init__(self, regex, urlconf_name, default_kwargs=None):
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# regex is a string representing a regular expression.
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# urlconf_name is a string representing the module containing urlconfs.
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self.regex = re.compile(regex)
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self.urlconf_name = urlconf_name
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self.callback = None
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self.default_kwargs = default_kwargs or {}
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def resolve(self, path):
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tried = []
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match = self.regex.search(path)
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if match:
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new_path = path[match.end():]
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for pattern in self.urlconf_module.urlpatterns:
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try:
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sub_match = pattern.resolve(new_path)
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except Resolver404, e:
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tried.extend([(pattern.regex.pattern + ' ' + t) for t in e.args[0]['tried']])
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else:
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if sub_match:
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sub_match_dict = dict(self.default_kwargs, **sub_match[2])
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return sub_match[0], sub_match[1], dict(match.groupdict(), **sub_match_dict)
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tried.append(pattern.regex.pattern)
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raise Resolver404, {'tried': tried, 'path': new_path}
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def _get_urlconf_module(self):
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try:
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return self._urlconf_module
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except AttributeError:
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try:
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self._urlconf_module = __import__(self.urlconf_name, {}, {}, [''])
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except ValueError, e:
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# Invalid urlconf_name, such as "foo.bar." (note trailing period)
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raise ImproperlyConfigured, "Error while importing URLconf %r: %s" % (self.urlconf_name, e)
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return self._urlconf_module
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urlconf_module = property(_get_urlconf_module)
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def _get_url_patterns(self):
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return self.urlconf_module.urlpatterns
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url_patterns = property(_get_url_patterns)
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def _resolve_special(self, view_type):
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callback = getattr(self.urlconf_module, 'handler%s' % view_type)
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mod_name, func_name = get_mod_func(callback)
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try:
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return getattr(__import__(mod_name, {}, {}, ['']), func_name), {}
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except (ImportError, AttributeError), e:
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raise ViewDoesNotExist, "Tried %s. Error was: %s" % (callback, str(e))
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def resolve404(self):
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return self._resolve_special('404')
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def resolve500(self):
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return self._resolve_special('500')
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def reverse(self, lookup_view, *args, **kwargs):
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if not callable(lookup_view):
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mod_name, func_name = get_mod_func(lookup_view)
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try:
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lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name)
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except (ImportError, AttributeError):
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raise NoReverseMatch
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for pattern in self.urlconf_module.urlpatterns:
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if isinstance(pattern, RegexURLResolver):
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try:
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return pattern.reverse_helper(lookup_view, *args, **kwargs)
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except NoReverseMatch:
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continue
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elif pattern.callback == lookup_view:
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try:
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return pattern.reverse_helper(*args, **kwargs)
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except NoReverseMatch:
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continue
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raise NoReverseMatch
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def reverse_helper(self, lookup_view, *args, **kwargs):
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sub_match = self.reverse(lookup_view, *args, **kwargs)
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result = reverse_helper(self.regex, *args, **kwargs)
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return result + sub_match
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def resolve(path, urlconf=None):
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if urlconf is None:
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from django.conf import settings
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urlconf = settings.ROOT_URLCONF
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resolver = RegexURLResolver(r'^/', urlconf)
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return resolver.resolve(path)
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def reverse(viewname, urlconf=None, args=None, kwargs=None):
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args = args or []
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kwargs = kwargs or {}
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if urlconf is None:
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from django.conf import settings
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urlconf = settings.ROOT_URLCONF
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resolver = RegexURLResolver(r'^/', urlconf)
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return '/' + resolver.reverse(viewname, *args, **kwargs)
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