1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
# IVLE - Informatics Virtual Learning Environment
# Copyright (C) 2009 The University of Melbourne
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# Author: William Grant
'''Media file support for the framework.'''
import os
import time
import inspect
import mimetypes
import email.utils
import ivle.conf
from ivle.config import Config
from ivle.webapp.base.views import BaseView
from ivle.webapp.base.plugins import PublicViewPlugin, ViewPlugin, MediaPlugin
from ivle.webapp.errors import NotFound, Forbidden
def media_url(req, plugin, path):
'''Generates a URL to a media file.
Plugin can be a string, in which case it is put into the path literally,
or a plugin object, in which case its name is looked up.
If a version is specified in the IVLE configuration, a versioned URL will
be generated.
'''
if not isinstance(plugin, basestring):
plugin = req.config.reverse_plugins[plugin]
config = Config()
media_path = os.path.join('+media', '+' + config['media']['version']) if \
config['media']['version'] else '+media'
return os.path.join(ivle.conf.root_dir, media_path, plugin, path)
class BaseMediaFileView(BaseView):
'''A view for media files.
This serves static files from directories registered by plugins.
Plugins wishing to export media should declare a 'media' attribute,
pointing to the directory to serve (relative to the module's directory).
The contents of that directory will then be available under
/+media/python.path.to.module.
'''
def __init__(self, req, ns, path):
self.ns = ns
self.path = path
def _make_filename(self, req):
raise NotImplementedError()
def render(self, req):
# If it begins with ".." or separator, it's illegal. Die.
if self.path.startswith("..") or self.path.startswith('/'):
raise Forbidden()
filename = self._make_filename(req)
# Find an appropriate MIME type.
(type, _) = mimetypes.guess_type(filename)
if type is None:
type = 'application/octet-stream'
# Get out if it is unreadable or a directory.
if not os.access(filename, os.F_OK):
raise NotFound()
if not os.access(filename, os.R_OK) or os.path.isdir(filename):
raise Forbidden()
req.content_type = type
req.sendfile(filename)
class MediaFileView(BaseMediaFileView):
'''A view for media files.
This serves static files from directories registered by plugins.
Plugins wishing to export media should declare a 'media' attribute,
pointing to the directory to serve (relative to the module's directory).
The contents of that directory will then be available under
/+media/python.path.to.module.
'''
permission = None
def _make_filename(self, req):
try:
plugin = req.config.plugins[self.ns]
except KeyError:
raise NotFound()
if not issubclass(plugin, MediaPlugin):
raise NotFound()
mediadir = plugin.media
plugindir = os.path.dirname(inspect.getmodule(plugin).__file__)
return os.path.join(plugindir, mediadir, self.path)
def get_permissions(self, user):
return set()
class VersionedMediaFileView(MediaFileView):
'''A view for versioned media files, with aggressive caching.
This serves static media files with a version string, and requests that
browsers cache them for a long time.
'''
def __init__(self, req, ns, path, version):
super(VersionedMediaFileView, self).__init__(req, ns, path)
self.version = version
def _make_filename(self, req):
if self.version != Config()['media']['version']:
raise NotFound()
# Don't expire for a year.
req.headers_out['Expires'] = email.utils.formatdate(
timeval=time.time() + (60*60*24*365),
localtime=False,
usegmt=True)
return super(VersionedMediaFileView, self)._make_filename(req)
# This maps a media namespace to an external dependency directory (in this
# case specified by the configuration option media/externals/jquery) and a
# list of permitted subpaths.
EXTERNAL_MEDIA_MAP = {'jquery': ('jquery', ['jquery.js'])}
class ExternalMediaFileView(BaseMediaFileView):
'''A view for media files from external dependencies.
This serves specific static files from external dependencies as defined in
the IVLE configuration.
'''
permission = None
def _make_filename(self, req):
try:
extern = EXTERNAL_MEDIA_MAP[self.ns]
except KeyError:
raise NotFound()
# Unless it's a whitelisted path, we don't want to hear about it.
if self.path not in extern[1]:
raise NotFound()
# Grab the admin-configured path for this particular external dep.
config = Config()
externdir = config['media']['externals'][extern[0]]
assert isinstance(externdir, basestring)
return os.path.join(externdir, self.path)
def get_permissions(self, user):
return set()
class ExternalVersionedMediaFileView(ExternalMediaFileView):
'''A view for versioned media files from external dependencies, with
aggressive caching.
This serves specific static media files from external dependencies with a
version string, and requests that browsers cache them for a long time.
'''
def __init__(self, req, ns, path, version):
super(ExternalVersionedMediaFileView, self).__init__(req, ns, path)
self.version = version
def _make_filename(self, req):
if self.version != Config()['media']['version']:
raise NotFound()
# Don't expire for a year.
req.headers_out['Expires'] = email.utils.formatdate(
timeval=time.time() + (60*60*24*365),
localtime=False,
usegmt=True)
return super(ExternalVersionedMediaFileView, self)._make_filename(req)
class Plugin(ViewPlugin, PublicViewPlugin):
urls = [
('+media/+:version/+external/:ns/*path', ExternalVersionedMediaFileView),
('+media/+external/:ns/*path', ExternalMediaFileView),
('+media/+:version/:ns/*path', VersionedMediaFileView),
('+media/:ns/*path', MediaFileView),
]
public_urls = urls
|