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8e1e744d | 1 | # GNU MediaGoblin -- federated, autonomous media hosting |
a6b378ef CAW |
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 |
ffa22935 | 18 | import re |
f61a41b8 | 19 | import urlparse |
2fdec827 | 20 | import uuid |
a6b378ef CAW |
21 | |
22 | from werkzeug.utils import secure_filename | |
23 | ||
ffa22935 CAW |
24 | from mediagoblin import util |
25 | ||
d807b725 CAW |
26 | ######## |
27 | # Errors | |
28 | ######## | |
a6b378ef | 29 | |
770c12be CAW |
30 | class Error(Exception): pass |
31 | class InvalidFilepath(Error): pass | |
b1bb050b | 32 | class NoWebServing(Error): pass |
770c12be | 33 | |
797be93c CAW |
34 | class NotImplementedError(Error): pass |
35 | ||
770c12be | 36 | |
d807b725 CAW |
37 | ############################################### |
38 | # Storage interface & basic file implementation | |
39 | ############################################### | |
a6b378ef | 40 | |
797be93c CAW |
41 | class StorageInterface(object): |
42 | """ | |
43 | Interface for the storage API. | |
44 | ||
45 | This interface doesn't actually provide behavior, but it defines | |
46 | what kind of storage patterns subclasses should provide. | |
47 | ||
48 | It is important to note that the storage API idea of a "filepath" | |
49 | is actually like ['dir1', 'dir2', 'file.jpg'], so keep that in | |
50 | mind while reading method documentation. | |
5afb9227 CAW |
51 | |
52 | You should set up your __init__ method with whatever keyword | |
53 | arguments are appropriate to your storage system, but you should | |
54 | also passively accept all extraneous keyword arguments like: | |
55 | ||
56 | def __init__(self, **kwargs): | |
57 | pass | |
58 | ||
59 | See BasicFileStorage as a simple implementation of the | |
60 | StorageInterface. | |
797be93c | 61 | """ |
797be93c CAW |
62 | |
63 | def __raise_not_implemented(self): | |
64 | """ | |
65 | Raise a warning about some component not implemented by a | |
66 | subclass of this interface. | |
67 | """ | |
68 | raise NotImplementedError( | |
69 | "This feature not implemented in this storage API implementation.") | |
70 | ||
71 | def file_exists(self, filepath): | |
72 | """ | |
73 | Return a boolean asserting whether or not file at filepath | |
74 | exists in our storage system. | |
75 | ||
76 | Returns: | |
77 | True / False depending on whether file exists or not. | |
78 | """ | |
79 | # Subclasses should override this method. | |
80 | self.__raise_not_implemented() | |
81 | ||
cee7a1c1 | 82 | def get_file(self, filepath, mode='r'): |
b0de01cf CAW |
83 | """ |
84 | Return a file-like object for reading/writing from this filepath. | |
85 | ||
86 | Should create directories, buckets, whatever, as necessary. | |
87 | """ | |
0b9cf289 CAW |
88 | # Subclasses should override this method. |
89 | self.__raise_not_implemented() | |
90 | ||
91 | def delete_file(self, filepath): | |
b0de01cf CAW |
92 | """ |
93 | Delete or dereference the file at filepath. | |
94 | ||
95 | This might need to delete directories, buckets, whatever, for | |
96 | cleanliness. (Be sure to avoid race conditions on that though) | |
97 | """ | |
0b9cf289 CAW |
98 | # Subclasses should override this method. |
99 | self.__raise_not_implemented() | |
100 | ||
f61a41b8 | 101 | def file_url(self, filepath): |
644614d4 CAW |
102 | """ |
103 | Get the URL for this file. This assumes our storage has been | |
104 | mounted with some kind of URL which makes this possible. | |
105 | """ | |
106 | # Subclasses should override this method. | |
107 | self.__raise_not_implemented() | |
108 | ||
2d1a6073 | 109 | def get_unique_filepath(self, filepath): |
797be93c CAW |
110 | """ |
111 | If a filename at filepath already exists, generate a new name. | |
112 | ||
113 | Eg, if the filename doesn't exist: | |
114 | >>> storage_handler.get_unique_filename(['dir1', 'dir2', 'fname.jpg']) | |
115 | [u'dir1', u'dir2', u'fname.jpg'] | |
116 | ||
117 | But if a file does exist, let's get one back with at uuid tacked on: | |
118 | >>> storage_handler.get_unique_filename(['dir1', 'dir2', 'fname.jpg']) | |
ef10e3a2 | 119 | [u'dir1', u'dir2', u'd02c3571-dd62-4479-9d62-9e3012dada29-fname.jpg'] |
797be93c | 120 | """ |
b0bfb766 CAW |
121 | # Make sure we have a clean filepath to start with, since |
122 | # we'll be possibly tacking on stuff to the filename. | |
123 | filepath = clean_listy_filepath(filepath) | |
124 | ||
0b9cf289 CAW |
125 | if self.file_exists(filepath): |
126 | return filepath[:-1] + ["%s-%s" % (uuid.uuid4(), filepath[-1])] | |
127 | else: | |
128 | return filepath | |
779f2b94 CAW |
129 | |
130 | ||
131 | class BasicFileStorage(StorageInterface): | |
132 | """ | |
133 | Basic local filesystem implementation of storage API | |
134 | """ | |
135 | ||
5afb9227 | 136 | def __init__(self, base_dir, base_url=None, **kwargs): |
779f2b94 CAW |
137 | """ |
138 | Keyword arguments: | |
139 | - base_dir: Base directory things will be served out of. MUST | |
140 | be an absolute path. | |
b1bb050b | 141 | - base_url: URL files will be served from |
779f2b94 CAW |
142 | """ |
143 | self.base_dir = base_dir | |
b1bb050b | 144 | self.base_url = base_url |
779f2b94 CAW |
145 | |
146 | def _resolve_filepath(self, filepath): | |
147 | """ | |
148 | Transform the given filepath into a local filesystem filepath. | |
149 | """ | |
150 | return os.path.join( | |
151 | self.base_dir, *clean_listy_filepath(filepath)) | |
152 | ||
779f2b94 CAW |
153 | def file_exists(self, filepath): |
154 | return os.path.exists(self._resolve_filepath(filepath)) | |
155 | ||
cee7a1c1 CAW |
156 | def get_file(self, filepath, mode='r'): |
157 | # Make directories if necessary | |
158 | if len(filepath) > 1: | |
159 | directory = self._resolve_filepath(filepath[:-1]) | |
d0e3a534 | 160 | if not os.path.exists(directory): |
cee7a1c1 CAW |
161 | os.makedirs(directory) |
162 | ||
163 | # Grab and return the file in the mode specified | |
164 | return open(self._resolve_filepath(filepath), mode) | |
165 | ||
779f2b94 | 166 | def delete_file(self, filepath): |
b1bb050b CAW |
167 | # TODO: Also delete unused directories if empty (safely, with |
168 | # checks to avoid race conditions). | |
169 | os.remove(self._resolve_filepath(filepath)) | |
644614d4 | 170 | |
f61a41b8 | 171 | def file_url(self, filepath): |
b1bb050b CAW |
172 | if not self.base_url: |
173 | raise NoWebServing( | |
174 | "base_url not set, cannot provide file urls") | |
175 | ||
176 | return urlparse.urljoin( | |
177 | self.base_url, | |
178 | '/'.join(clean_listy_filepath(filepath))) | |
ffa22935 CAW |
179 | |
180 | ||
d807b725 CAW |
181 | ########### |
182 | # Utilities | |
183 | ########### | |
184 | ||
185 | def clean_listy_filepath(listy_filepath): | |
186 | """ | |
187 | Take a listy filepath (like ['dir1', 'dir2', 'filename.jpg']) and | |
188 | clean out any nastiness from it. | |
189 | ||
190 | For example: | |
191 | >>> clean_listy_filepath([u'/dir1/', u'foo/../nasty', u'linooks.jpg']) | |
192 | [u'dir1', u'foo_.._nasty', u'linooks.jpg'] | |
193 | ||
194 | Args: | |
195 | - listy_filepath: a list of filepath components, mediagoblin | |
196 | storage API style. | |
197 | ||
198 | Returns: | |
199 | A cleaned list of unicode objects. | |
200 | """ | |
201 | cleaned_filepath = [ | |
202 | unicode(secure_filename(filepath)) | |
203 | for filepath in listy_filepath] | |
204 | ||
205 | if u'' in cleaned_filepath: | |
206 | raise InvalidFilepath( | |
207 | "A filename component could not be resolved into a usable name.") | |
208 | ||
209 | return cleaned_filepath | |
210 | ||
211 | ||
ffa22935 CAW |
212 | def storage_system_from_paste_config(paste_config, storage_prefix): |
213 | """ | |
214 | Utility for setting up a storage system from the paste app config. | |
215 | ||
216 | Note that a special argument may be passed in to the paste_config | |
217 | which is "${storage_prefix}_storage_class" which will provide an | |
218 | import path to a storage system. This defaults to | |
219 | "mediagoblin.storage:BasicFileStorage" if otherwise undefined. | |
220 | ||
221 | Arguments: | |
222 | - paste_config: dictionary of config parameters | |
223 | - storage_prefix: the storage system we're setting up / will be | |
224 | getting keys/arguments from. For example 'publicstore' will | |
225 | grab all arguments that are like 'publicstore_FOO'. | |
226 | ||
227 | Returns: | |
228 | An instantiated storage system. | |
229 | ||
230 | Example: | |
231 | storage_system_from_paste_config( | |
232 | {'publicstore_base_url': '/media/', | |
233 | 'publicstore_base_dir': '/var/whatever/media/'}, | |
234 | 'publicstore') | |
235 | ||
236 | Will return: | |
237 | BasicFileStorage( | |
238 | base_url='/media/', | |
239 | base_dir='/var/whatever/media') | |
240 | """ | |
241 | prefix_re = re.compile('^%s_(.+)$' % re.escape(storage_prefix)) | |
242 | ||
243 | config_params = dict( | |
244 | [(prefix_re.match(key).groups()[0], value) | |
245 | for key, value in paste_config.iteritems() | |
246 | if prefix_re.match(key)]) | |
247 | ||
248 | if config_params.has_key('storage_class'): | |
249 | storage_class = config_params['storage_class'] | |
250 | config_params.pop('storage_class') | |
251 | else: | |
252 | storage_class = "mediagoblin.storage:BasicFileStorage" | |
253 | ||
254 | storage_class = util.import_component(storage_class) | |
255 | return storage_class(**config_params) |