terom@30: """
terom@30:     Handles mapping URLs to request handlers
terom@30: """
terom@30: 
terom@30: import http
terom@30: import handler
terom@30: 
terom@30: class MappingError (http.ResponseError) :
terom@30:     """
terom@30:         URL could not be mapped
terom@30:     """
terom@30: 
terom@30:     def __init__ (self, url) :
terom@30:         super(MappingError, self).__init__("URL not found: %s" % (url, ), status='404 Not Found')
terom@30: 
terom@31: class Mapper (handler.RequestHandler) :
terom@30:     """
terom@31:         Looks up the handler to use based on the URL
terom@30:     """
terom@30: 
terom@31:     def handle_request (self, request) :
terom@30:         """
terom@31:             Map the given request
terom@30:         """
terom@30: 
terom@30:         abstract
terom@30: 
terom@30: class Mapping (object) :
terom@30:     """
terom@30:         A mapping object for StaticMapping
terom@30:     """
terom@30: 
terom@30:     def test (self, request) :
terom@30:         """
terom@30:             Either return a handler, or None
terom@30:         """
terom@30: 
terom@30:         abstract
terom@30: 
terom@30: class RegexpMapping (object) :
terom@30:     """
terom@30:         A mapping object that uses regular expressions
terom@30:     """
terom@30: 
terom@30:     def __init__ (self, regexp, handler) :
terom@30:         pass
terom@30: 
terom@30:     def test (self, request) :
terom@30:         xxx
terom@30: 
terom@30: class SimpleMapping (object) :
terom@30:     """
terom@30:         A mapping object that uses simple expressions
terom@30:     """
terom@30: 
terom@30:     def __init__ (self, expression, handler) :
terom@30:         pass
terom@30: 
terom@30:     def test (self, request) :
terom@30:         xxx
terom@30: 
terom@30: class StaticMapping (Mapper) :
terom@30:     """
terom@30:         Translates requests to handlers using a list of pre-determined Mapping's
terom@30:     """
terom@30: 
terom@30:     def __init__ (self, mappings) :
terom@30:         # store
terom@30:         self.mappings = mappings
terom@30: 
terom@30:     def map_request (self, request) :
terom@30:         """
terom@30:             Returns the appropriate handler
terom@30:         """
terom@30: 
terom@31:         # find handler to use
terom@31:         handler = None
terom@31: 
terom@30:         # just test each mapping in turn
terom@30:         for mapping in self.mappings :
terom@30:             handler = mapping.test(request)
terom@30: 
terom@30:             if handler :
terom@31:                 break
terom@30:         
terom@31:         if not handler :
terom@31:             # fail, not found
terom@31:             raise MappingError(request.get_page_name())
terom@30:         
terom@31:         # passthrough
terom@31:         return handler.handle_request(request)
terom@30: 
terom@30: # "friendly" names
terom@30: map     = SimpleMapping
terom@30: mapre   = RegexpMapping
terom@30: