terom@29: 
terom@29: """
terom@29:     URL mapping for the irclogs.qmsk.net site
terom@29: """
terom@29: 
terom@36: import re
terom@37: import os.path
terom@36: 
terom@29: # our own handlers
terom@29: import handlers
terom@29: 
terom@36: # mapper
terom@36: from lib import map
terom@29: 
terom@36: class URLError (Exception) :
terom@29:     """
terom@36:         Error with an URL definition
terom@29:     """
terom@29: 
terom@36:     pass
terom@29: 
terom@37: class LabelValue (object) :
terom@37:     """
terom@37:         Represents the value of a ValueLabel...
terom@37:     """
terom@37: 
terom@37:     def __init__ (self, label, value) :
terom@37:         """
terom@37:             Just store
terom@37:         """
terom@37: 
terom@37:         self.label = label
terom@37:         self.value = value
terom@37:     
terom@37:     def __str__ (self) :
terom@37:         return "%s=%s" % (self.label.key, self.value)
terom@37: 
terom@37:     def __repr__ (self) :
terom@37:         return "<%s>" % self
terom@37: 
terom@36: class Label (object) :
terom@36:     """
terom@36:         Base class for URL labels (i.e. the segments of the URL between /s)
terom@36:     """
terom@36: 
terom@36:     @staticmethod
terom@36:     def parse (mask, defaults) :
terom@36:         """
terom@36:             Parse the given label-segment, and return a *Label instance
terom@36:         """
terom@36: 
terom@36:         # empty?
terom@36:         if not mask :
terom@36:             return EmptyLabel()
terom@36: 
terom@36:         # simple value?
terom@36:         match = SimpleValueLabel.EXPR.match(mask)
terom@36: 
terom@36:         if match :
terom@36:             # key
terom@36:             key = match.group('key')
terom@36: 
terom@36:             # default?
terom@36:             default = defaults.get(key)
terom@36: 
terom@36:             # build
terom@36:             return SimpleValueLabel(key, default)
terom@36:         
terom@36:         # static?
terom@36:         match = StaticLabel.EXPR.match(mask)
terom@36: 
terom@36:         if match :
terom@36:             return StaticLabel(match.group('name'))
terom@36: 
terom@36:         # invalid
terom@36:         raise URLError("Invalid label: %r" % (mask, ))
terom@37:     
terom@38:     def match (self, value=None) :
terom@37:         """
terom@37:             Match this label against the given value, returning either True to match without a value, a LabelValue
terom@38:             object, or boolean false to not match.
terom@38: 
terom@38:             If value is None, this means that only a default value should be accepted. XXX: currently returned default
terom@38:             is not used.
terom@37:         """
terom@36: 
terom@37:         abstract
terom@36: 
terom@36: class EmptyLabel (Label) :
terom@36:     """
terom@36:         An empty label, i.e. just a slash in the URL
terom@36:     """
terom@36:     
terom@36:     def __eq__ (self, other) :
terom@36:         """
terom@36:             Just compares type
terom@36:         """
terom@36: 
terom@36:         return isinstance(other, EmptyLabel)
terom@36:     
terom@38:     def match (self, value=None) :
terom@37:         """
terom@37:             Match empty string -> True
terom@37:         """
terom@38:         
terom@38:         # no default
terom@38:         if value is None :
terom@38:             return False
terom@38:         
terom@38:         # only empty segments
terom@37:         if value == '' :
terom@37:             return True
terom@37: 
terom@36:     def __str__ (self) :
terom@36:         return ''
terom@36: 
terom@36: class StaticLabel (Label) :
terom@36:     """
terom@36:         A simple literal Label, used for fixed terms in the URL
terom@36:     """
terom@36: 
terom@36:     EXPR = re.compile(r'^(?P<name>[a-zA-Z_.-]+)$')
terom@36: 
terom@36:     def __init__ (self, name) :
terom@36:         """
terom@36:             The given name is the literal name of this label
terom@36:         """
terom@36: 
terom@36:         self.name = name
terom@36: 
terom@36:     def __eq__ (self, other) :
terom@36:         """
terom@36:             Compares names
terom@36:         """
terom@36: 
terom@36:         return isinstance(other, StaticLabel) and self.name == other.name
terom@36:     
terom@38:     def match (self, value=None) :
terom@37:         """
terom@37:             Match exactly -> True
terom@37:         """
terom@37: 
terom@38:         # no defaults
terom@38:         if value is None :
terom@38:             return False
terom@38:         
terom@38:         # match name
terom@37:         if value == self.name :
terom@37:             return True
terom@37: 
terom@36:     def __str__ (self) :
terom@36:         return self.name
terom@36: 
terom@36: class ValueLabel (Label) :
terom@36:     """
terom@36:         A label with a key and a value
terom@37: 
terom@37:         XXX: do we even need this?
terom@36:     """
terom@36: 
terom@36:     def __init__ (self, key, default) :
terom@36:         """
terom@36:             Set the key and default value. Default value may be None if there is no default value defined
terom@36:         """
terom@36: 
terom@36:         self.key = key
terom@36:         self.default = default
terom@36: 
terom@36:     def __eq__ (self, other) :
terom@36:         """
terom@36:             Compares keys
terom@36:         """
terom@36: 
terom@36:         return isinstance(other, ValueLabel) and self.key == other.key
terom@36: 
terom@36: class SimpleValueLabel (ValueLabel) :
terom@36:     """
terom@36:         A label that has a name and a simple string value
terom@36:     """
terom@36: 
terom@36:     EXPR = re.compile(r'^\{(?P<key>[a-zA-Z_][a-zA-Z0-9_]*)\}$')
terom@36: 
terom@36:     def __init__ (self, key, default) :
terom@36:         """
terom@36:             The given key is the name of this label's value
terom@36:         """
terom@36: 
terom@36:         super(SimpleValueLabel, self).__init__(key, default)
terom@36:     
terom@38:     def match (self, value=None) :
terom@37:         """
terom@37:             Match -> LabelValue
terom@37:         """
terom@38:         
terom@38:         # default?
terom@38:         if value is None and self.default :
terom@38:             return LabelValue(self, self.default)
terom@38:         
terom@38:         # only non-empty values!
terom@38:         elif value :
terom@38:             return LabelValue(self, value)
terom@37: 
terom@36:     def __str__ (self) :
terom@36:         if self.default :
terom@36:             return '{%s=%s}' % (self.key, self.default)
terom@36:             
terom@36:         else :
terom@36:             return '{%s}' % (self.key, )
terom@36: 
terom@36: class URL (object) :
terom@36:     """
terom@36:         Represents a specific URL
terom@36:     """
terom@36: 
terom@36:     def __init__ (self, url_mask, handler, **defaults) :
terom@36:         """
terom@36:             Create an URL with the given url mask, handler, and default values
terom@36:         """
terom@36: 
terom@36:         # store
terom@36:         self.url_mask = url_mask
terom@36:         self.handler = handler
terom@36:         self.defaults = defaults
terom@36: 
terom@36:         # build our labels
terom@36:         self.label_path = [Label.parse(mask, defaults) for mask in url_mask.split('/')]
terom@36:         
terom@36:     def get_label_path (self) :
terom@36:         """
terom@36:             Returns a list containing the labels in this url
terom@36:         """
terom@36:         
terom@36:         # copy self.label_path
terom@36:         return list(self.label_path)
terom@36: 
terom@37:     def execute (self, request, label_values) :
terom@36:         """
terom@37:             Invoke the handler, using the given label values
terom@36:         """
terom@37:         
terom@37:         # start with the defaults
terom@37:         kwargs = self.defaults()
terom@36: 
terom@37:         # then add all the values
terom@37:         for label_value in label_values :
terom@37:             kwargs[label_value.label.key] = label_value.value
terom@37:             
terom@37:         # execute the handler
terom@37:         return self.handler(request, **kwargs)
terom@37: 
terom@36:     def __str__ (self) :
terom@36:         return '/'.join(str(label) for label in self.label_path)
terom@36:     
terom@36:     def __repr__ (self) :
terom@36:         return "URL(%r, %r)" % (str(self), self.handler)
terom@36: 
terom@36: class URLNode (object) :
terom@36:     """
terom@36:         Represents a node in the URLTree
terom@36:     """
terom@36: 
terom@36:     def __init__ (self, parent, label) :
terom@36:         """
terom@36:             Initialize with the given parent and label, empty children dict
terom@36:         """
terom@36:         
terom@36:         # the parent URLNode
terom@36:         self.parent = parent
terom@36: 
terom@36:         # this node's Label
terom@36:         self.label = label
terom@36: 
terom@36:         # list of child URLNodes
terom@36:         self.children = []
terom@36: 
terom@36:         # this node's URL, set by add_url for an empty label_path
terom@36:         self.url = None
terom@36: 
terom@36:     def _build_child (self, label) :
terom@36:         """
terom@36:             Build, insert and return a new child Node
terom@36:         """
terom@36:         
terom@36:         # build new child
terom@36:         child = URLNode(self, label)
terom@36:         
terom@36:         # add to children
terom@36:         self.children.append(child)
terom@36: 
terom@36:         # return
terom@36:         return child
terom@36: 
terom@36:     def add_url (self, url, label_path) :
terom@36:         """
terom@36:             Add a URL object to this node under the given path. Uses recursion to process the path.
terom@36: 
terom@36:             The label_path argument is a (partial) label path as returned by URL.get_label_path.
terom@36: 
terom@36:             If label_path is empty (len zero, or begins with EmptyLabel), then the given url is assigned to this node, if no
terom@36:             url was assigned before.
terom@36:         """
terom@36:         
terom@36:         # matches this node?
terom@36:         if not label_path or isinstance(label_path[0], EmptyLabel) :
terom@36:             if self.url :
terom@36:                 raise URLError(url, "node already defined")
terom@36: 
terom@36:             else :
terom@36:                 # set
terom@36:                 self.url = url
terom@36: 
terom@36:         else :
terom@36:             # pop child label from label_path
terom@36:             child_label = label_path.pop(0)
terom@36: 
terom@36:             # look for the child to recurse into
terom@36:             child = None
terom@36: 
terom@36:             # look for an existing child with that label
terom@36:             for child in self.children :
terom@36:                 if child.label == child_label :
terom@36:                     # found, use this
terom@36:                     break
terom@36: 
terom@36:             else :
terom@36:                 # build a new child
terom@36:                 child = self._build_child(child_label)
terom@36: 
terom@36:             # recurse to handle the rest of the label_path
terom@36:             child.add_url(url, label_path)
terom@36:     
terom@37:     def match (self, label_path) :
terom@36:         """
terom@37:             Locate the URL object corresponding to the given label_path value under this node.
terom@36: 
terom@37:             Returns a (url, label_values) tuple
terom@36:         """
terom@36: 
terom@36:         # empty label_path?
terom@37:         if not label_path or label_path[0] == '' :
terom@37:             # the search ends at this node
terom@36:             if self.url :
terom@36:                 # this URL is the best match
terom@37:                 return (self.url, [])
terom@36:             
terom@38:             # look for default-only values, DFS
terom@38:             for child in self.children :
terom@38:                 # does the child's label accept a default match?
terom@38:                 if child.label.match() :
terom@38:                     return child.match(label_path)
terom@38: 
terom@36:             else :
terom@36:                 # incomplete URL
terom@37:                 raise URLError("no URL handler defined for this Node")
terom@36:         
terom@36:         else :
terom@37:             # pop the next label from the label path
terom@36:             label = label_path.pop(0)
terom@36: 
terom@37:             # return one match...
terom@37:             match = value = None
terom@36: 
terom@36:             # recurse through our children
terom@36:             for child in self.children :
terom@37:                 # match value
terom@37:                 value = child.label.match(label)
terom@36: 
terom@37:                 # skip those that don't match at all
terom@37:                 if not value :
terom@37:                     continue;
terom@37:                 
terom@37:                 # already found a match? :/
terom@37:                 if match :
terom@37:                     raise URLError("Ambiguous URL")
terom@37: 
terom@37:                 # ok, but continue looking to make sure there's no ambiguous URLs
terom@37:                 match = child
terom@37:             
terom@37:             # found something?
terom@37:             if not match :
terom@37:                 raise URLError("No child found for label")
terom@37: 
terom@37:             # ok, recurse into the match
terom@37:             url, label_value = match.match(label_path)
terom@37: 
terom@37:             # add our value?
terom@37:             if isinstance(value, LabelValue) :
terom@37:                 label_value.append(value)
terom@37: 
terom@37:             # return the match
terom@37:             return url, label_value
terom@36:     
terom@36:     def dump (self, indent=0) :
terom@36:         """
terom@36:             Returns a multi-line string representation of this Node
terom@36:         """
terom@36: 
terom@36:         return '\n'.join([
terom@36:             "%-45s%s" % (
terom@36:                 ' '*indent + str(self.label) + ('/' if self.children else ''), 
terom@36:                 (' -> %r' % self.url) if self.url else ''
terom@36:             )
terom@36:         ] + [
terom@36:             child.dump(indent + 4) for child in self.children
terom@36:         ])
terom@36: 
terom@36:     def __str__ (self) :
terom@36:         return "%s/[%s]" % (self.label, ','.join(str(child) for child in self.children))
terom@36: 
terom@36: class URLTree (map.Mapper) :
terom@36:     """
terom@36:         Map requests to handlers, using a defined tree of URLs
terom@36:     """
terom@36: 
terom@36:     def __init__ (self, url_list) :
terom@36:         """
terom@36:             Initialize the tree using the given list of URLs
terom@36:         """
terom@36: 
terom@36:         # root node
terom@36:         self.root = URLNode(None, EmptyLabel())
terom@36:         
terom@36:         # just add each URL
terom@36:         for url in url_list :
terom@36:             self.add_url(url)
terom@36: 
terom@36:     def add_url (self, url) :
terom@36:         """
terom@36:             Adds the given URL to the tree. The URL must begin with a root slash.
terom@36:         """
terom@36:         # get url's label path
terom@36:         path = url.get_label_path()
terom@36: 
terom@36:         # should begin with root
terom@36:         root_label = path.pop(0)
terom@36:         assert root_label == self.root.label, "URL must begin with root"
terom@36: 
terom@36:         # add to root
terom@36:         self.root.add_url(url, path)
terom@36:         
terom@36:     def match (self, url) :
terom@36:         """
terom@37:             Find the URL object best corresponding to the given url, matching any ValueLabels.
terom@37: 
terom@37:             Returns an (URL, [LabelValue]) tuple.
terom@36:         """
terom@36: 
terom@36:         # normalize the URL
terom@36:         url = os.path.normpath(url)
terom@36: 
terom@36:         # split it into labels
terom@37:         path = url.split('/')
terom@37: 
terom@37:         # ensure that it starts with a /
terom@37:         root_label = path.pop(0)
terom@37:         assert self.root.label.match(root_label), "URL must begin with root"
terom@36: 
terom@36:         # just match starting at root
terom@37:         return self.root.match(path)
terom@36: 
terom@36:     def handle_request (self, request) :
terom@36:         """
terom@36:             Looks up the request's URL, and invokes its handler
terom@36:         """
terom@36:         
terom@36:         # get the request's URL path
terom@37:         url, label_values = self.match(request.get_page_name())
terom@36: 
terom@36:         # let the URL handle it
terom@37:         url.execute(request, label_values)
terom@36: 
terom@36: # urls
terom@36: index           = URL(  '/',                                            handlers.index                                          )
terom@36: channel_view    = URL(  '/channel/{channel}',                           handlers.channel_view                                   )
terom@36: channel_last    = URL(  '/channel/{channel}/last/{count}/{format}',     handlers.channel_last,      count=100, format="html"    )
terom@36: channel_search  = URL(  '/channel/{channel}/search',                    handlers.channel_search                                 )
terom@36: 
terom@36: # mapper
terom@36: mapper = URLTree([index, channel_view, channel_last, channel_search])
terom@36: