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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
|
# IVLE - Informatics Virtual Learning Environment
# Copyright (C) 2007-2008 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
# Module: util
# Author: Matt Giuca
# Date: 12/12/2007
# Contains common utility functions.
# Also initialises mime types library. You must import util before using
# Python's builtin mimetypes module to make sure local settings are applied.
import os
import mimetypes
import datetime
import ivle.conf
import ivle.conf.mimetypes
class IVLEError(Exception):
"""
This is the "standard" exception class for IVLE errors.
It is the ONLY exception which should propagate to the top - it will then
be displayed to the user as an HTTP error with the given code.
All other exceptions are considered IVLE bugs and should not occur
(they will display a traceback).
This error should not be raised directly. Call req.throw_error.
"""
def __init__(self, httpcode, message=None):
self.httpcode = httpcode
self.message = message
self.args = (httpcode, message)
class IVLEJailError(Exception):
"""
This exception indicates an error that occurred inside an IVLE CGI script
inside the jail. It should never be raised directly - only by the
interpreter.
Information will be retrieved from it, and then treated as a normal
error.
"""
def __init__(self, type_str, message, info):
self.type_str = type_str
self.message = message
self.info = info
class FakeObject(object):
""" A representation of an object that can't be Pickled """
def __init__(self, type, name, attrib={}):
self.type = type
self.name = name
self.attrib = attrib
def __repr__(self):
return "<Fake %s %s>"%(self.type, self.name)
def make_path(path):
"""Given a path relative to the IVLE root, makes the path relative to the
site root using ivle.conf.root_dir. This path can be used in URLs sent to
the client."""
return os.path.join(ivle.conf.root_dir, path)
def make_local_path(path):
"""Given a path relative to the IVLE root, on the local file system, makes
the path relative to the root using ivle.conf.share_path. This path can
be used in reading files from the local file system."""
return os.path.join(ivle.conf.share_path, 'www', path)
def unmake_path(path):
"""Given a path relative to the site root, makes the path relative to the
IVLE root by removing ivle.conf.root_dir if it appears at the beginning. If
it does not appear at the beginning, returns path unchanged. Also
normalises the path."""
path = os.path.normpath(path)
root = os.path.normpath(ivle.conf.root_dir)
if path.startswith(root):
path = path[len(root):]
# Take out the slash as well
if len(path) > 0 and path[0] == os.sep:
path = path[1:]
return path
def split_path(path):
"""Given a path, returns a tuple consisting of the top-level directory in
the path, and the rest of the path. Note that both items in the tuple will
NOT begin with a slash, regardless of whether the original path did. Also
normalises the path.
Always returns a pair of strings, except for one special case, in which
the path is completely empty (or just a single slash). In this case the
return value will be (None, ''). But still always returns a pair.
Examples:
>>> split_path("")
(None, '')
>>> split_path("/")
(None, '')
>>> split_path("home")
('home', '')
>>> split_path("home/docs/files")
('home', 'docs/files')
>>> split_path("//home/docs/files")
('', 'home/docs/files')
"""
path = os.path.normpath(path)
# Ignore the opening slash
if path.startswith(os.sep):
path = path[len(os.sep):]
if path == '' or path == '.':
return (None, '')
splitpath = path.split(os.sep, 1)
if len(splitpath) == 1:
return (splitpath[0], '')
else:
return tuple(splitpath)
def open_exercise_file(exercisename):
"""Given an exercise name, opens the corresponding XML file for reading.
Returns None if the exercise file was not found.
(For tutorials / worksheets).
"""
# First normalise the path
exercisename = os.path.normpath(exercisename)
# Now if it begins with ".." or separator, then it's illegal
if exercisename.startswith("..") or exercisename.startswith(os.sep):
exercisefile = None
else:
exercisefile = os.path.join(ivle.conf.exercises_base, exercisename)
try:
return open(exercisefile)
except (TypeError, IOError): # TypeError if exercisefile == None
return None
# Initialise mime types library
mimetypes.init()
for (ext, mimetype) in ivle.conf.mimetypes.additional_mime_types.items():
mimetypes.add_type(mimetype, ext)
def nice_filetype(filename):
"""Given a filename or basename, returns a "friendly" name for that
file's type.
eg. nice_mimetype("file.py") == "Python source code".
nice_filetype("file.bzg") == "BZG file".
nice_filetype("directory/") == "Directory".
"""
if filename[-1] == os.sep:
return "Directory"
else:
try:
return ivle.conf.mimetypes.nice_mimetypes[
mimetypes.guess_type(filename)[0]]
except KeyError:
filename = os.path.basename(filename)
try:
return filename[filename.rindex('.')+1:].upper() + " file"
except ValueError:
return "File"
def get_terms_of_service():
"""
Sends the Terms of Service document to the req object.
This consults conf to find out where the TOS is located on disk, and sends
that. If it isn't found, it sends a generic message explaining to admins
how to create a real one.
"""
try:
return open(ivle.conf.tos_path).read()
except IOError:
return """\
<p><b>*** SAMPLE ONLY ***</b></p>
<p>This is the text of the IVLE Terms of Service.</p>
<p>The administrator should create a license file with an appropriate
"Terms of Service" license for your organisation.</p>
<h2>Instructions for Administrators</h2>
<p>You are seeing this message because you have not configured a Terms of
Service document.</p>
<p>When you configured IVLE, you specified a path to the Terms of Service
document (this is found in <b><tt>ivle/conf/conf.py</tt></b> under
"<tt>tos_path</tt>").</p>
<p>Create a file at this location; an HTML file with the appropriately-worded
license.</p>
<p>This should be a normal XHTML file, except it should not contain
<tt>html</tt>, <tt>head</tt> or <tt>body</tt> elements - it should
just be the contents of a body element (IVLE will wrap it accordingly).</p>
<p>This will automatically be used as the license text instead of this
placeholder text.</p>
"""
def parse_iso8601(str):
"""Parses ISO8601 string into a datetime object."""
# FIXME: Terrific hack that means we only accept the format that is
# produced by json.js module when it encodes date objects.
return datetime.datetime.strptime(str, "%Y-%m-%dT%H:%M:%SZ")
def incomplete_utf8_sequence(byteseq):
"""
str -> int
Given a UTF-8-encoded byte sequence (str), returns the number of bytes at
the end of the string which comprise an incomplete UTF-8 character
sequence.
If the string is empty or ends with a complete character OR INVALID
sequence, returns 0.
Otherwise, returns 1-3 indicating the number of bytes in the final
incomplete (but valid) character sequence.
Does not check any bytes before the final sequence for correctness.
>>> incomplete_utf8_sequence("")
0
>>> incomplete_utf8_sequence("xy")
0
>>> incomplete_utf8_sequence("xy\xc3\xbc")
0
>>> incomplete_utf8_sequence("\xc3")
1
>>> incomplete_utf8_sequence("\xbc\xc3")
1
>>> incomplete_utf8_sequence("xy\xbc\xc3")
1
>>> incomplete_utf8_sequence("xy\xe0\xa0")
2
>>> incomplete_utf8_sequence("xy\xf4")
1
>>> incomplete_utf8_sequence("xy\xf4\x8f")
2
>>> incomplete_utf8_sequence("xy\xf4\x8f\xa0")
3
"""
count = 0
expect = None
for b in byteseq[::-1]:
b = ord(b)
count += 1
if b & 0x80 == 0x0:
# 0xxxxxxx (single-byte character)
expect = 1
break
elif b & 0xc0 == 0x80:
# 10xxxxxx (subsequent byte)
pass
elif b & 0xe0 == 0xc0:
# 110xxxxx (start of 2-byte sequence)
expect = 2
break
elif b & 0xf0 == 0xe0:
# 1110xxxx (start of 3-byte sequence)
expect = 3
break
elif b & 0xf8 == 0xf0:
# 11110xxx (start of 4-byte sequence)
expect = 4
break
else:
# Invalid byte
return 0
if count >= 4:
# Seen too many "subsequent bytes", invalid
return 0
if expect is None:
# We never saw a "first byte", invalid
return 0
# We now know expect and count
if count >= expect:
# Complete, or we saw an invalid sequence
return 0
elif count < expect:
# Incomplete
return count
def object_to_dict(attrnames, obj):
"""
Convert an object into a dictionary. This takes a shallow copy of the
object.
attrnames: Set (or iterable) of names of attributes to be copied into the
dictionary. (We don't auto-lookup, because this function needs to be
used on magical objects).
"""
return dict((k, getattr(obj, k))
for k in attrnames if not k.startswith('_'))
|