terom@171: """
terom@171:     Handles mapping URLs to request handlers
terom@171: """
terom@171: 
terom@171: import http
terom@171: import handler
terom@171: 
terom@176: class MapperError (http.ResponseError) :
terom@171:     """
terom@171:         URL could not be mapped
terom@171:     """
terom@171: 
terom@171:     def __init__ (self, url) :
terom@176:         super(MapperError, self).__init__("URL not found: %s" % (url, ), status='404 Not Found')
terom@171: 
terom@172: class Mapper (handler.RequestHandler) :
terom@171:     """
terom@172:         Looks up the handler to use based on the URL
terom@171:     """
terom@171: 
terom@172:     def handle_request (self, request) :
terom@171:         """
terom@172:             Map the given request
terom@171:         """
terom@171: 
terom@171:         abstract
terom@171: 
terom@171: class Mapping (object) :
terom@171:     """
terom@171:         A mapping object for StaticMapping
terom@171:     """
terom@171: 
terom@171:     def test (self, request) :
terom@171:         """
terom@171:             Either return a handler, or None
terom@171:         """
terom@171: 
terom@171:         abstract
terom@171: 
terom@171: class RegexpMapping (object) :
terom@171:     """
terom@171:         A mapping object that uses regular expressions
terom@171:     """
terom@171: 
terom@171:     def __init__ (self, regexp, handler) :
terom@171:         pass
terom@171: 
terom@171:     def test (self, request) :
terom@171:         xxx
terom@171: 
terom@171: class SimpleMapping (object) :
terom@171:     """
terom@171:         A mapping object that uses simple expressions
terom@171:     """
terom@171: 
terom@171:     def __init__ (self, expression, handler) :
terom@171:         pass
terom@171: 
terom@171:     def test (self, request) :
terom@171:         xxx
terom@171: 
terom@176: class StaticMapper (Mapper) :
terom@171:     """
terom@171:         Translates requests to handlers using a list of pre-determined Mapping's
terom@171:     """
terom@171: 
terom@171:     def __init__ (self, mappings) :
terom@171:         # store
terom@171:         self.mappings = mappings
terom@171: 
terom@173:     def handle_request (self, request) :
terom@171:         """
terom@171:             Returns the appropriate handler
terom@171:         """
terom@171: 
terom@172:         # find handler to use
terom@172:         handler = None
terom@172: 
terom@171:         # just test each mapping in turn
terom@171:         for mapping in self.mappings :
terom@171:             handler = mapping.test(request)
terom@171: 
terom@171:             if handler :
terom@172:                 break
terom@171:         
terom@172:         if not handler :
terom@172:             # fail, not found
terom@176:             raise MapperError(request.get_page_name())
terom@171:         
terom@172:         # passthrough
terom@172:         return handler.handle_request(request)
terom@171: 
terom@171: # "friendly" names
terom@171: map     = SimpleMapping
terom@171: mapre   = RegexpMapping
terom@171: