--- 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<name>[a-zA-Z_.-]+)$')
-
- def __init__ (self, name) :
- """
- The given name is the literal name of this label
- """
-
- self.name = name
-
- def __eq__ (self, other) :
- """
- Compares names
- """
-
- return isinstance(other, StaticLabel) and self.name == other.name
-
- def match (self, value=None) :
- """
- Match exactly -> True
- """
-
- # no defaults
- if value is None :
- return False
-
- # match name
- if value == self.name :
- return True
-
- def build (self, values) :
- return str(self)
-
- def __str__ (self) :
- return self.name
-
-class ValueLabel (Label) :
- """
- A label with a key and a value
-
- XXX: do we even need this?
- """
-
- def __init__ (self, key, default) :
- """
- Set the key and default value. Default value may be None if there is no default value defined
- """
-
- self.key = key
- self.default = default
-
- def __eq__ (self, other) :
- """
- Compares keys
- """
-
- return isinstance(other, ValueLabel) and self.key == other.key
-
- def build (self, values) :
- """
- Return either the assigned value from values, our default value, or raise an error
- """
-
- value = values.get(self.key)
-
- if not value and self.default :
- value = self.default
-
- elif not value :
- raise URLError("No value given for label %r" % (self.key, ))
-
- return value
-
-class SimpleValueLabel (ValueLabel) :
- """
- A label that has a name and a simple string value
- """
-
- EXPR = re.compile(r'^\{(?P<key>[a-zA-Z_][a-zA-Z0-9_]*)(:(?P<type>[a-zA-Z_][a-zA-Z0-9_]*))?(=(?P<default>[^}]+))?\}$')
-
- 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)
-
-