Imported Django from private SVN repository (created from r. 8825)

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/urlresolvers.py

@@ -0,0 +1,96 @@
+"""
+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, dict_of_view_function_args)
+"""
+
+from django.core.exceptions import Http404, ViewDoesNotExist
+import re
+
+def get_mod_func(callback):
+    # Converts 'django.views.news.stories.story_detail' to
+    # ['django.views.news.stories', 'story_detail']
+    dot = callback.rindex('.')
+    return callback[:dot], callback[dot+1:]
+
+class RegexURLPattern:
+    def __init__(self, regex, callback, default_args=None):
+        self.regex = re.compile(regex)
+        # callback is something like 'foo.views.news.stories.story_detail',
+        # which represents the path to a module and a view function name.
+        self.callback = callback
+        self.default_args = default_args or {}
+
+    def search(self, path):
+        match = self.regex.search(path)
+        if match:
+            args = dict(match.groupdict(), **self.default_args)
+            try: # Lazily load self.func.
+                return self.func, args
+            except AttributeError:
+                self.func = self.get_callback()
+            return self.func, args
+
+    def get_callback(self):
+        mod_name, func_name = get_mod_func(self.callback)
+        try:
+            return getattr(__import__(mod_name, '', '', ['']), func_name)
+        except (ImportError, AttributeError):
+            raise ViewDoesNotExist, self.callback
+
+class RegexURLMultiplePattern:
+    def __init__(self, regex, urlconf_module):
+        self.regex = re.compile(regex)
+        # urlconf_module is a string representing the module containing urlconfs.
+        self.urlconf_module = urlconf_module
+
+    def search(self, path):
+        match = self.regex.search(path)
+        if match:
+            new_path = path[match.end():]
+            try: # Lazily load self.url_patterns.
+                self.url_patterns
+            except AttributeError:
+                self.url_patterns = self.get_url_patterns()
+            for pattern in self.url_patterns:
+                sub_match = pattern.search(new_path)
+                if sub_match:
+                    return sub_match
+
+    def get_url_patterns(self):
+        return __import__(self.urlconf_module, '', '', ['']).urlpatterns
+
+class RegexURLResolver:
+    def __init__(self, url_patterns):
+        # url_patterns is a list of RegexURLPattern or RegexURLMultiplePattern objects.
+        self.url_patterns = url_patterns
+
+    def resolve(self, app_path):
+        # app_path is the full requested Web path. This is assumed to have a
+        # leading slash but doesn't necessarily have a trailing slash.
+        # Examples:
+        #     "/news/2005/may/"
+        #     "/news/"
+        #     "/polls/latest"
+        # A home (root) page is represented by "/".
+        app_path = app_path[1:] # Trim leading slash.
+        for pattern in self.url_patterns:
+            match = pattern.search(app_path)
+            if match:
+                return match
+        # None of the regexes matched, so raise a 404.
+        raise Http404, app_path
+
+class Error404Resolver:
+    def __init__(self, callback):
+        self.callback = callback
+
+    def resolve(self):
+        mod_name, func_name = get_mod_func(self.callback)
+        try:
+            return getattr(__import__(mod_name, '', '', ['']), func_name), {}
+        except (ImportError, AttributeError):
+            raise ViewDoesNotExist, self.callback