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1 | # GNU Mediagoblin -- federated, autonomous media hosting |
2 | # Copyright (C) 2011 Free Software Foundation, Inc | |
3 | # | |
4 | # This program is free software: you can redistribute it and/or modify | |
5 | # it under the terms of the GNU Affero General Public License as published by | |
6 | # the Free Software Foundation, either version 3 of the License, or | |
7 | # (at your option) any later version. | |
8 | # | |
9 | # This program is distributed in the hope that it will be useful, | |
10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | # GNU Affero General Public License for more details. | |
13 | # | |
14 | # You should have received a copy of the GNU Affero General Public License | |
15 | # along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | ||
779f2b94 | 17 | import os |
a6b378ef CAW |
18 | |
19 | from werkzeug.utils import secure_filename | |
20 | ||
21 | ||
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22 | class Error(Exception): pass |
23 | class InvalidFilepath(Error): pass | |
24 | ||
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25 | class NotImplementedError(Error): pass |
26 | ||
770c12be | 27 | |
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28 | def clean_listy_filepath(listy_filepath): |
29 | """ | |
30 | Take a listy filepath (like ['dir1', 'dir2', 'filename.jpg']) and | |
31 | clean out any nastiness from it. | |
32 | ||
33 | For example: | |
34 | >>> clean_listy_filepath([u'/dir1/', u'foo/../nasty', u'linooks.jpg']) | |
35 | [u'dir1', u'foo_.._nasty', u'linooks.jpg'] | |
36 | ||
37 | Args: | |
38 | - listy_filepath: a list of filepath components, mediagoblin | |
39 | storage API style. | |
40 | ||
41 | Returns: | |
42 | A cleaned list of unicode objects. | |
43 | """ | |
770c12be | 44 | cleaned_filepath = [ |
a6b378ef CAW |
45 | unicode(secure_filename(filepath)) |
46 | for filepath in listy_filepath] | |
47 | ||
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48 | if u'' in cleaned_filepath: |
49 | raise InvalidFilepath( | |
50 | "A filename component could not be resolved into a usable name.") | |
51 | ||
52 | return cleaned_filepath | |
53 | ||
a6b378ef | 54 | |
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55 | class StorageInterface(object): |
56 | """ | |
57 | Interface for the storage API. | |
58 | ||
59 | This interface doesn't actually provide behavior, but it defines | |
60 | what kind of storage patterns subclasses should provide. | |
61 | ||
62 | It is important to note that the storage API idea of a "filepath" | |
63 | is actually like ['dir1', 'dir2', 'file.jpg'], so keep that in | |
64 | mind while reading method documentation. | |
65 | """ | |
66 | # def __init__(self, *args, **kwargs): | |
67 | # pass | |
68 | ||
69 | def __raise_not_implemented(self): | |
70 | """ | |
71 | Raise a warning about some component not implemented by a | |
72 | subclass of this interface. | |
73 | """ | |
74 | raise NotImplementedError( | |
75 | "This feature not implemented in this storage API implementation.") | |
76 | ||
77 | def file_exists(self, filepath): | |
78 | """ | |
79 | Return a boolean asserting whether or not file at filepath | |
80 | exists in our storage system. | |
81 | ||
82 | Returns: | |
83 | True / False depending on whether file exists or not. | |
84 | """ | |
85 | # Subclasses should override this method. | |
86 | self.__raise_not_implemented() | |
87 | ||
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88 | def get_file(self, filepath, mode): |
89 | """ | |
90 | Return a file-like object for reading/writing from this filepath. | |
91 | ||
92 | Should create directories, buckets, whatever, as necessary. | |
93 | """ | |
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94 | # Subclasses should override this method. |
95 | self.__raise_not_implemented() | |
96 | ||
97 | def delete_file(self, filepath): | |
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98 | """ |
99 | Delete or dereference the file at filepath. | |
100 | ||
101 | This might need to delete directories, buckets, whatever, for | |
102 | cleanliness. (Be sure to avoid race conditions on that though) | |
103 | """ | |
0b9cf289 CAW |
104 | # Subclasses should override this method. |
105 | self.__raise_not_implemented() | |
106 | ||
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107 | def get_unique_filename(self, filepath): |
108 | """ | |
109 | If a filename at filepath already exists, generate a new name. | |
110 | ||
111 | Eg, if the filename doesn't exist: | |
112 | >>> storage_handler.get_unique_filename(['dir1', 'dir2', 'fname.jpg']) | |
113 | [u'dir1', u'dir2', u'fname.jpg'] | |
114 | ||
115 | But if a file does exist, let's get one back with at uuid tacked on: | |
116 | >>> storage_handler.get_unique_filename(['dir1', 'dir2', 'fname.jpg']) | |
ef10e3a2 | 117 | [u'dir1', u'dir2', u'd02c3571-dd62-4479-9d62-9e3012dada29-fname.jpg'] |
797be93c | 118 | """ |
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119 | if self.file_exists(filepath): |
120 | return filepath[:-1] + ["%s-%s" % (uuid.uuid4(), filepath[-1])] | |
121 | else: | |
122 | return filepath | |
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123 | |
124 | ||
125 | class BasicFileStorage(StorageInterface): | |
126 | """ | |
127 | Basic local filesystem implementation of storage API | |
128 | """ | |
129 | ||
130 | def __init__(self, base_dir, serve_url=None): | |
131 | """ | |
132 | Keyword arguments: | |
133 | - base_dir: Base directory things will be served out of. MUST | |
134 | be an absolute path. | |
135 | - serve_url: URL files will be served from | |
136 | """ | |
137 | self.base_dir = base_dir | |
138 | self.serve_url = serve_url | |
139 | ||
140 | def _resolve_filepath(self, filepath): | |
141 | """ | |
142 | Transform the given filepath into a local filesystem filepath. | |
143 | """ | |
144 | return os.path.join( | |
145 | self.base_dir, *clean_listy_filepath(filepath)) | |
146 | ||
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147 | def file_exists(self, filepath): |
148 | return os.path.exists(self._resolve_filepath(filepath)) | |
149 | ||
150 | def get_file(self, filepath, mode): | |
151 | pass | |
152 | ||
153 | def delete_file(self, filepath): | |
154 | pass |