diff -r e94ab812c0c8 -r 185504387370 lib/urltree.py --- a/lib/urltree.py Sun Feb 08 03:13:11 2009 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,670 +0,0 @@ -""" - Tree-based URL mapping -""" - -import re -import os.path - -# for Mapper -from lib import map - -class URLError (Exception) : - """ - Error with an URL definition - """ - - pass - -class LabelValue (object) : - """ - Represents the value of a ValueLabel... love these names - """ - - def __init__ (self, label, value) : - """ - Just store - """ - - self.label = label - self.value = value - - def __str__ (self) : - return "%s=%r" % (self.label.key, self.value) - - def __repr__ (self) : - return "<%s>" % self - -class Label (object) : - """ - Base class for URL labels (i.e. the segments of the URL between /s) - """ - - @staticmethod - def parse (mask, defaults, types) : - """ - Parse the given label-segment, and return a *Label instance - """ - - # empty? - if not mask : - return EmptyLabel() - - # simple value? - match = SimpleValueLabel.EXPR.match(mask) - - if match : - # key - key = match.group('key') - - # type - type = match.group("type") - - # lookup type, None for default - type = types[type] - - # defaults? - default = defaults.get(key) - - if not default : - default = match.group('default') - - if default : - # apply type to default - default = type(default) - - # build - return SimpleValueLabel(key, type, default) - - # static? - match = StaticLabel.EXPR.match(mask) - - if match : - return StaticLabel(match.group('name')) - - # invalid - raise URLError("Invalid label: %r" % (mask, )) - - def match (self, value=None) : - """ - Match this label against the given value, returning either True to match without a value, a LabelValue - object, or boolean false to not match. - - If value is None, this means that only a default value should be returned. - """ - - abstract - - def build (self, value_dict) : - """ - Return a string representing this label, using the values in the given value_dict if needed - """ - - abstract - -class EmptyLabel (Label) : - """ - An empty label, i.e. just a slash in the URL - """ - - def __eq__ (self, other) : - """ - Just compares type - """ - - return isinstance(other, EmptyLabel) - - def match (self, value=None) : - """ - Match empty string -> True - """ - - # no default - if value is None : - return False - - # only empty segments - if value == '' : - return True - - def build (self, values) : - return str(self) - - def __str__ (self) : - return '' - -class StaticLabel (Label) : - """ - A simple literal Label, used for fixed terms in the URL - """ - - EXPR = re.compile(r'^(?P[a-zA-Z_.-]+)$') - - def __init__ (self, name) : - """ - The given name is the literal name of this label - """ - - self.name = name - - def __eq__ (self, other) : - """ - Compares names - """ - - return isinstance(other, StaticLabel) and self.name == other.name - - def match (self, value=None) : - """ - Match exactly -> True - """ - - # no defaults - if value is None : - return False - - # match name - if value == self.name : - return True - - def build (self, values) : - return str(self) - - def __str__ (self) : - return self.name - -class ValueLabel (Label) : - """ - A label with a key and a value - - XXX: do we even need this? - """ - - def __init__ (self, key, default) : - """ - Set the key and default value. Default value may be None if there is no default value defined - """ - - self.key = key - self.default = default - - def __eq__ (self, other) : - """ - Compares keys - """ - - return isinstance(other, ValueLabel) and self.key == other.key - - def build (self, values) : - """ - Return either the assigned value from values, our default value, or raise an error - """ - - value = values.get(self.key) - - if not value and self.default : - value = self.default - - elif not value : - raise URLError("No value given for label %r" % (self.key, )) - - return value - -class SimpleValueLabel (ValueLabel) : - """ - A label that has a name and a simple string value - """ - - EXPR = re.compile(r'^\{(?P[a-zA-Z_][a-zA-Z0-9_]*)(:(?P[a-zA-Z_][a-zA-Z0-9_]*))?(=(?P[^}]+))?\}$') - - def __init__ (self, key, type=str, default=None) : - """ - The given key is the name of this label's value - """ - - # type - self.type = type - - # store - self.key = key - self.default = default - - def match (self, value=None) : - """ - Match -> LabelValue - """ - - # default? - if value is None and self.default : - return LabelValue(self, self.default) - - # only non-empty values! - elif value : - # convert with type - try : - value = self.type(value) - - except Exception, e : - raise URLError("Bad value %r for type %s: %s: %s" % (value, self.type.__name__, type(e).__name__, e)) - - return LabelValue(self, value) - - def __str__ (self) : - return '{%s%s%s}' % ( - self.key, - ':%s' % (self.type.__name__ ) if self.type != str else '', - '=%s' % (self.default, ) if self.default else '', - ) - -class URLConfig (object) : - """ - Global configuration relevant to all URLs - """ - - # built-in type codes - BUILTIN_TYPES = { - # default - None : str, - - # string - 'str' : str, - - # integer - 'int' : int, - } - - def __init__ (self, type_dict=None) : - """ - Create an URLConfig for use with URL - - If type_dict is given, it should be a mapping of type names -> callables, and they will be available for - type specifications in addition to the defaults. - """ - - # build our type_dict - self.type_dict = self.BUILTIN_TYPES.copy() - - # apply the given type_dict - if type_dict : - self.type_dict.update(type_dict) - -class URL (object) : - """ - Represents a specific URL - """ - - - def __init__ (self, config, url_mask, handler, type_dict=None, **defaults) : - """ - Create an URL using the given URLConfig, with the given url mask, handler, and default values. - """ - - # store - self.config = config - self.url_mask = url_mask - self.handler = handler - self.defaults = defaults - - # query string - self.query_args = dict() - - # parse any query string - # XXX: conflicts with regexp syntax - if '/?' in url_mask : - url_mask, query_mask = url_mask.split('/?') - - else : - query_mask = None - - # build our label path - self.label_path = [Label.parse(mask, defaults, config.type_dict) for mask in url_mask.split('/')] - - # build our query args list - if query_mask : - # split into items - for query_item in query_mask.split('&') : - # parse default - if '=' in query_item : - query_item, default = query_item.split('=') - - else : - default = None - - # parse type - if ':' in query_item : - query_item, type = query_item.split(':') - else : - type = None - - # parse key - key = query_item - - # type - type = self.config.type_dict[type] - - # add to query_args as (type, default) tuple - self.query_args[key] = (type, type(default) if default else default) - - def get_label_path (self) : - """ - Returns a list containing the labels in this url - """ - - # copy self.label_path - return list(self.label_path) - - def execute (self, request, label_values) : - """ - Invoke the handler, using the given label values - """ - - # start with the defaults - kwargs = self.defaults.copy() - - # then add all the values - for label_value in label_values : - kwargs[label_value.label.key] = label_value.value - - # then parse all query args - for key, value in request.get_args() : - # lookup spec - type, default = self.query_args[key] - - # normalize empty value to None - if not value : - value = None - - else : - # process value - value = type(value) - - # set default? - if not value : - if default : - value = default - - if default == '' : - # do not pass key at all - continue - - # otherwise, fail - raise URLError("No value given for required argument: %r" % (key, )) - - # set key - kwargs[key] = value - - # then check all query args - for key, (type, default) in self.query_args.iteritems() : - # skip those already present - if key in kwargs : - continue - - # apply default? - if default is None : - raise URLError("Missing required argument: %r" % (key, )) - - elif default == '' : - # skip empty default - continue - - else : - # set default - kwargs[key] = default - - # execute the handler - return self.handler(request, **kwargs) - - def build (self, request, **values) : - """ - Build an absolute URL pointing to this target, with the given values - """ - - # build URL from request page prefix and our labels - return request.page_prefix + '/'.join(label.build(values) for label in self.label_path) - - def __str__ (self) : - return '/'.join(str(label) for label in self.label_path) - - def __repr__ (self) : - return "URL(%r, %r)" % (str(self), self.handler) - -class URLNode (object) : - """ - Represents a node in the URLTree - """ - - def __init__ (self, parent, label) : - """ - Initialize with the given parent and label, empty children dict - """ - - # the parent URLNode - self.parent = parent - - # this node's Label - self.label = label - - # list of child URLNodes - self.children = [] - - # this node's URL, set by add_url for an empty label_path - self.url = None - - def _build_child (self, label) : - """ - Build, insert and return a new child Node - """ - - # build new child - child = URLNode(self, label) - - # add to children - self.children.append(child) - - # return - return child - - def add_url (self, url, label_path) : - """ - Add a URL object to this node under the given path. Uses recursion to process the path. - - The label_path argument is a (partial) label path as returned by URL.get_label_path. - - If label_path is empty (len zero, or begins with EmptyLabel), then the given url is assigned to this node, if no - url was assigned before. - """ - - # matches this node? - if not label_path or isinstance(label_path[0], EmptyLabel) : - if self.url : - raise URLError(url, "node already defined") - - else : - # set - self.url = url - - else : - # pop child label from label_path - child_label = label_path.pop(0) - - # look for the child to recurse into - child = None - - # look for an existing child with that label - for child in self.children : - if child.label == child_label : - # found, use this - break - - else : - # build a new child - child = self._build_child(child_label) - - # recurse to handle the rest of the label_path - child.add_url(url, label_path) - - def match (self, label_path) : - """ - Locate the URL object corresponding to the given label_path value under this node. - - Returns a (url, label_values) tuple - """ - - # determine value to use - value = None - - # empty label_path? - if not label_path or label_path[0] == '' : - # the search ends at this node - if self.url : - # this URL is the best match - return (self.url, []) - - elif not self.children : - # incomplete URL - raise URLError("no URL handler defined for this Node") - - else : - # use default value, i.e. Label.match(None) - label = None - - else : - # pop the next label from the label path - label = label_path.pop(0) - - # return one match... - match = value = None - - # recurse through our children, DFS - for child in self.children : - # match value - value = child.label.match(label) - - # skip those that don't match at all - if not value : - continue; - - # already found a match? :/ - if match : - raise URLError("Ambiguous URL") - - # ok, but continue looking to make sure there's no ambiguous URLs - match = child - - # found something? - if not match : - raise URLError("No child found for label: %s + %s + %s" % (self.get_url(), label, '/'.join(str(l) for l in label_path))) - - # ok, recurse into the match - url, label_value = match.match(label_path) - - # add our value? - if isinstance(value, LabelValue) : - label_value.append(value) - - # return the match - return url, label_value - - def get_url (self) : - """ - Returns the URL for this node, by iterating over our parents - """ - - # URL segments in reverse order - segments = [''] - - # start with ourself - node = self - - # iterate up to root - while node : - segments.append(str(node.label)) - - node = node.parent - - # reverse - segments.reverse() - - # return - return '/'.join(segments) - - def dump (self, indent=0) : - """ - Returns a multi-line string representation of this Node - """ - - return '\n'.join([ - "%-45s%s" % ( - ' '*indent + str(self.label) + ('/' if self.children else ''), - (' -> %r' % self.url) if self.url else '' - ) - ] + [ - child.dump(indent + 4) for child in self.children - ]) - - def __str__ (self) : - return "%s/[%s]" % (self.label, ','.join(str(child) for child in self.children)) - -class URLTree (map.Mapper) : - """ - Map requests to handlers, using a defined tree of URLs - """ - - def __init__ (self, url_list) : - """ - Initialize the tree using the given list of URLs - """ - - # root node - self.root = URLNode(None, EmptyLabel()) - - # just add each URL - for url in url_list : - self.add_url(url) - - def add_url (self, url) : - """ - Adds the given URL to the tree. The URL must begin with a root slash. - """ - # get url's label path - path = url.get_label_path() - - # should begin with root - root_label = path.pop(0) - assert root_label == self.root.label, "URL must begin with root" - - # add to root - self.root.add_url(url, path) - - def match (self, url) : - """ - Find the URL object best corresponding to the given url, matching any ValueLabels. - - Returns an (URL, [LabelValue]) tuple. - """ - - # split it into labels - path = url.split('/') - - # empty URL is empty - if url : - # ensure that it doesn't start with a / - assert not self.root.label.match(path[0]), "URL must not begin with root" - - # just match starting at root - return self.root.match(path) - - def handle_request (self, request) : - """ - Looks up the request's URL, and invokes its handler - """ - - # get the requested URL - request_url = request.get_page_name() - - # find the URL+values to use - url, label_values = self.match(request_url) - - # let the URL handle it - return url.execute(request, label_values) - -