1

"""

     2

    Handles mapping URLs to request handlers

     3

"""

     4

     5

import http

     6

import handler

     7

     8

class MappingError (http.ResponseError) :

     9

    """

    10

        URL could not be mapped

    11

    """

    12

    13

    def __init__ (self, url) :

    14

        super(MappingError, self).__init__("URL not found: %s" % (url, ), status='404 Not Found')

    15

    16

class Mapper (handler.RequestHandler) :

    17

    """

    18

        Looks up the handler to use based on the URL

    19

    """

    20

    21

    def handle_request (self, request) :

    22

        """

    23

            Map the given request

    24

        """

    25

    26

        abstract

    27

    28

class Mapping (object) :

    29

    """

    30

        A mapping object for StaticMapping

    31

    """

    32

    33

    def test (self, request) :

    34

        """

    35

            Either return a handler, or None

    36

        """

    37

    38

        abstract

    39

    40

class RegexpMapping (object) :

    41

    """

    42

        A mapping object that uses regular expressions

    43

    """

    44

    45

    def __init__ (self, regexp, handler) :

    46

        pass

    47

    48

    def test (self, request) :

    49

        xxx

    50

    51

class SimpleMapping (object) :

    52

    """

    53

        A mapping object that uses simple expressions

    54

    """

    55

    56

    def __init__ (self, expression, handler) :

    57

        pass

    58

    59

    def test (self, request) :

    60

        xxx

    61

    62

class StaticMapping (Mapper) :

    63

    """

    64

        Translates requests to handlers using a list of pre-determined Mapping's

    65

    """

    66

    67

    def __init__ (self, mappings) :

    68

        # store

    69

        self.mappings = mappings

    70

    72

        """

    73

            Returns the appropriate handler

    74

        """

    75

    76

        # find handler to use

    77

        handler = None

    78

    79

        # just test each mapping in turn

    80

        for mapping in self.mappings :

    81

            handler = mapping.test(request)

    82

    83

            if handler :

    84

                break

    85

    86

        if not handler :

    87

            # fail, not found

    88

            raise MappingError(request.get_page_name())

    89

    90

        # passthrough

    91

        return handler.handle_request(request)

    92

    93

# "friendly" names

    94

map     = SimpleMapping

    95

mapre   = RegexpMapping

    96