from __future__ import absolute_import
import re
try:
from django.urls import get_resolver
except ImportError:
from django.core.urlresolvers import get_resolver
class RouteResolver(object):
_optional_group_matcher = re.compile(r'\(\?\:([^\)]+)\)')
_named_group_matcher = re.compile(r'\(\?P<(\w+)>[^\)]+\)')
_non_named_group_matcher = re.compile(r'\([^\)]+\)')
# [foo|bar|baz]
_either_option_matcher = re.compile(r'\[([^\]]+)\|([^\]]+)\]')
_camel_re = re.compile(r'([A-Z]+)([a-z])')
_cache = {}
def _simplify(self, pattern):
r"""
Clean up urlpattern regexes into something readable by humans:
From:
> "^(?P<sport_slug>\w+)/athletes/(?P<athlete_slug>\w+)/$"
To:
> "{sport_slug}/athletes/{athlete_slug}/"
"""
# remove optional params
# TODO(dcramer): it'd be nice to change these into [%s] but it currently
# conflicts with the other rules because we're doing regexp matches
# rather than parsing tokens
result = self._optional_group_matcher.sub(lambda m: '%s' % m.group(1), pattern)
# handle named groups first
result = self._named_group_matcher.sub(lambda m: '{%s}' % m.group(1), result)
# handle non-named groups
result = self._non_named_group_matcher.sub('{var}', result)
# handle optional params
result = self._either_option_matcher.sub(lambda m: m.group(1), result)
# clean up any outstanding regex-y characters.
result = result.replace('^', '').replace('$', '') \
.replace('?', '').replace('//', '/').replace('\\', '')
return result
def _resolve(self, resolver, path, parents=None):
match = resolver.regex.search(path)
if not match:
return
if parents is None:
parents = [resolver]
elif resolver not in parents:
parents = parents + [resolver]
new_path = path[match.end():]
for pattern in resolver.url_patterns:
# this is an include()
if not pattern.callback:
match = self._resolve(pattern, new_path, parents)
if match:
return match
continue
elif not pattern.regex.search(new_path):
continue
try:
return self._cache[pattern]
except KeyError:
pass
prefix = ''.join(self._simplify(p.regex.pattern) for p in parents)
result = prefix + self._simplify(pattern.regex.pattern)
if not result.startswith('/'):
result = '/' + result
self._cache[pattern] = result
return result
def resolve(self, path, urlconf=None):
resolver = get_resolver(urlconf)
match = self._resolve(resolver, path)
return match or path
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