1
# Copyright (C) 2008 Canonical Ltd
3
# This program is free software; you can redistribute it and/or modify
4
# it under the terms of the GNU General Public License as published by
5
# the Free Software Foundation; either version 2 of the License, or
6
# (at your option) any later version.
8
# This program is distributed in the hope that it will be useful,
9
# but WITHOUT ANY WARRANTY; without even the implied warranty of
10
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11
# GNU General Public License for more details.
13
# You should have received a copy of the GNU General Public License
14
# along with this program; if not, write to the Free Software
15
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17
"""Directory service registration and usage.
19
Directory services are utilities that provide a mapping from URL-like strings
20
to true URLs. Examples include lp:urls and per-user location aliases.
23
from bzrlib import registry
25
class DirectoryServiceRegistry(registry.Registry):
26
"""This object maintains and uses a list of directory services.
28
Directory services may be registered via the standard Registry methods.
29
They will be invoked if their key is a prefix of the supplied URL.
31
Each item registered should be a factory of objects that provide a look_up
32
method, as invoked by dereference. Specifically, look_up should accept a
33
name and URL, and return a URL.
36
def dereference(self, url):
37
"""Dereference a supplied URL if possible.
39
URLs that match a registered directory service prefix are looked up in
40
it. Non-matching urls are returned verbatim.
42
This is applied only once; the resulting URL must not be one that
43
requires further dereferencing.
45
:param url: The URL to dereference
46
:return: The dereferenced URL if applicable, the input URL otherwise.
48
match = self.get_prefix(url)
52
return service().look_up(name, url)
54
directories = DirectoryServiceRegistry()