path_canonicalizer.py revision ca12bfac764ba476d6cd062bf1dde12cc64c3f40 
1# Copyright 2013 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging
6import os
7import posixpath
8import traceback
9
10from branch_utility import BranchUtility
11from file_system import FileNotFoundError
12from third_party.json_schema_compiler.model import UnixName
13import svn_constants
14
15def _SimplifyFileName(file_name):
16  return (posixpath.splitext(file_name)[0]
17      .lower()
18      .replace('.', '')
19      .replace('-', '')
20      .replace('_', ''))
21
22class PathCanonicalizer(object):
23  '''Transforms paths into their canonical forms. Since the dev server has had
24  many incarnations - e.g. there didn't use to be apps/ - there may be old
25  paths lying around the webs. We try to redirect those to where they are now.
26  '''
27  def __init__(self, compiled_fs_factory):
28    # Map of simplified API names (for typo detection) to their real paths.
29    def make_public_apis(_, file_names):
30      return dict((_SimplifyFileName(name), name) for name in file_names)
31    self._public_apis = compiled_fs_factory.Create(make_public_apis,
32                                                   PathCanonicalizer)
33
34  def Canonicalize(self, path):
35    '''Returns the canonical path for |path|, and whether that path is a
36    permanent canonicalisation (e.g. when we redirect from a channel to a
37    channel-less URL) or temporary (e.g. when we redirect from an apps-only API
38    to an extensions one - we may at some point enable it for extensions).
39    '''
40    class ReturnType(object):
41      def __init__(self, path, permanent):
42        self.path = path
43        self.permanent = permanent
44
45      # Catch incorrect comparisons by disabling ==/!=.
46      def __eq__(self, _): raise NotImplementedError()
47      def __ne__(self, _): raise NotImplementedError()
48
49    # Strip any channel info off it. There are no channels anymore.
50    for channel_name in BranchUtility.GetAllChannelNames():
51      channel_prefix = channel_name + '/'
52      if path.startswith(channel_prefix):
53        # Redirect now so that we can set the permanent-redirect bit.  Channel
54        # redirects are the only things that should be permanent redirects;
55        # anything else *could* change, so is temporary.
56        return ReturnType(path[len(channel_prefix):], True)
57
58    # No further work needed for static.
59    if path.startswith('static/'):
60      return ReturnType(path, False)
61
62    # People go to just "extensions" or "apps". Redirect to the directory.
63    if path in ('extensions', 'apps'):
64      return ReturnType(path + '/', False)
65
66    # The rest of this function deals with trying to figure out what API page
67    # for extensions/apps to redirect to, if any. We see a few different cases
68    # here:
69    #  - Unqualified names ("browserAction.html"). These are easy to resolve;
70    #    figure out whether it's an extension or app API and redirect.
71    #     - but what if it's both? Well, assume extensions. Maybe later we can
72    #       check analytics and see which is more popular.
73    #  - Wrong names ("apps/browserAction.html"). This really does happen,
74    #    damn it, so do the above logic but record which is the default.
75    if path.startswith(('extensions/', 'apps/')):
76      default_platform, reference_path = path.split('/', 1)
77    else:
78      default_platform, reference_path = ('extensions', path)
79
80    try:
81      apps_public = self._public_apis.GetFromFileListing(
82          '/'.join((svn_constants.PUBLIC_TEMPLATE_PATH, 'apps')))
83      extensions_public = self._public_apis.GetFromFileListing(
84          '/'.join((svn_constants.PUBLIC_TEMPLATE_PATH, 'extensions')))
85    except FileNotFoundError:
86      # Probably offline.
87      logging.warning(traceback.format_exc())
88      return ReturnType(path, False)
89
90    simple_reference_path = _SimplifyFileName(reference_path)
91    apps_path = apps_public.get(simple_reference_path)
92    extensions_path = extensions_public.get(simple_reference_path)
93
94    if apps_path is None:
95      if extensions_path is None:
96        # No idea. Just return the original path. It'll probably 404.
97        pass
98      else:
99        path = 'extensions/%s' % extensions_path
100    else:
101      if extensions_path is None:
102        path = 'apps/%s' % apps_path
103      else:
104        assert apps_path == extensions_path
105        path = '%s/%s' % (default_platform, apps_path)
106
107    return ReturnType(path, False)
108