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
|
"""Mailcap file handling. See RFC 1524."""
import os
import warnings
import re
__all__ = ["getcaps","findmatch"]
_DEPRECATION_MSG = ('The {name} module is deprecated and will be removed in '
'Python {remove}. See the mimetypes module for an '
'alternative.')
warnings._deprecated(__name__, _DEPRECATION_MSG, remove=(3, 13))
def lineno_sort_key(entry):
# Sort in ascending order, with unspecified entries at the end
if 'lineno' in entry:
return 0, entry['lineno']
else:
return 1, 0
_find_unsafe = re.compile(r'[^\xa1-\U0010FFFF\w@+=:,./-]').search
class UnsafeMailcapInput(Warning):
"""Warning raised when refusing unsafe input"""
# Part 1: top-level interface.
def getcaps():
"""Return a dictionary containing the mailcap database.
The dictionary maps a MIME type (in all lowercase, e.g. 'text/plain')
to a list of dictionaries corresponding to mailcap entries. The list
collects all the entries for that MIME type from all available mailcap
files. Each dictionary contains key-value pairs for that MIME type,
where the viewing command is stored with the key "view".
"""
caps = {}
lineno = 0
for mailcap in listmailcapfiles():
try:
fp = open(mailcap, 'r')
except OSError:
continue
with fp:
morecaps, lineno = _readmailcapfile(fp, lineno)
for key, value in morecaps.items():
if not key in caps:
caps[key] = value
else:
caps[key] = caps[key] + value
return caps
def listmailcapfiles():
"""Return a list of all mailcap files found on the system."""
# This is mostly a Unix thing, but we use the OS path separator anyway
if 'MAILCAPS' in os.environ:
pathstr = os.environ['MAILCAPS']
mailcaps = pathstr.split(os.pathsep)
else:
if 'HOME' in os.environ:
home = os.environ['HOME']
else:
# Don't bother with getpwuid()
home = '.' # Last resort
mailcaps = [home + '/.mailcap', '/etc/mailcap',
'/usr/etc/mailcap', '/usr/local/etc/mailcap']
return mailcaps
# Part 2: the parser.
def readmailcapfile(fp):
"""Read a mailcap file and return a dictionary keyed by MIME type."""
warnings.warn('readmailcapfile is deprecated, use getcaps instead',
DeprecationWarning, 2)
caps, _ = _readmailcapfile(fp, None)
return caps
def _readmailcapfile(fp, lineno):
"""Read a mailcap file and return a dictionary keyed by MIME type.
Each MIME type is mapped to an entry consisting of a list of
dictionaries; the list will contain more than one such dictionary
if a given MIME type appears more than once in the mailcap file.
Each dictionary contains key-value pairs for that MIME type, where
the viewing command is stored with the key "view".
"""
caps = {}
while 1:
line = fp.readline()
if not line: break
# Ignore comments and blank lines
if line[0] == '#' or line.strip() == '':
continue
nextline = line
# Join continuation lines
while nextline[-2:] == '\\\n':
nextline = fp.readline()
if not nextline: nextline = '\n'
line = line[:-2] + nextline
# Parse the line
key, fields = parseline(line)
if not (key and fields):
continue
if lineno is not None:
fields['lineno'] = lineno
lineno += 1
# Normalize the key
types = key.split('/')
for j in range(len(types)):
types[j] = types[j].strip()
key = '/'.join(types).lower()
# Update the database
if key in caps:
caps[key].append(fields)
else:
caps[key] = [fields]
return caps, lineno
def parseline(line):
"""Parse one entry in a mailcap file and return a dictionary.
The viewing command is stored as the value with the key "view",
and the rest of the fields produce key-value pairs in the dict.
"""
fields = []
i, n = 0, len(line)
while i < n:
field, i = parsefield(line, i, n)
fields.append(field)
i = i+1 # Skip semicolon
if len(fields) < 2:
return None, None
key, view, rest = fields[0], fields[1], fields[2:]
fields = {'view': view}
for field in rest:
i = field.find('=')
if i < 0:
fkey = field
fvalue = ""
else:
fkey = field[:i].strip()
fvalue = field[i+1:].strip()
if fkey in fields:
# Ignore it
pass
else:
fields[fkey] = fvalue
return key, fields
def parsefield(line, i, n):
"""Separate one key-value pair in a mailcap entry."""
start = i
while i < n:
c = line[i]
if c == ';':
break
elif c == '\\':
i = i+2
else:
i = i+1
return line[start:i].strip(), i
# Part 3: using the database.
def findmatch(caps, MIMEtype, key='view', filename="/dev/null", plist=[]):
"""Find a match for a mailcap entry.
Return a tuple containing the command line, and the mailcap entry
used; (None, None) if no match is found. This may invoke the
'test' command of several matching entries before deciding which
entry to use.
"""
if _find_unsafe(filename):
msg = "Refusing to use mailcap with filename %r. Use a safe temporary filename." % (filename,)
warnings.warn(msg, UnsafeMailcapInput)
return None, None
entries = lookup(caps, MIMEtype, key)
# XXX This code should somehow check for the needsterminal flag.
for e in entries:
if 'test' in e:
test = subst(e['test'], filename, plist)
if test is None:
continue
if test and os.system(test) != 0:
continue
command = subst(e[key], MIMEtype, filename, plist)
if command is not None:
return command, e
return None, None
def lookup(caps, MIMEtype, key=None):
entries = []
if MIMEtype in caps:
entries = entries + caps[MIMEtype]
MIMEtypes = MIMEtype.split('/')
MIMEtype = MIMEtypes[0] + '/*'
if MIMEtype in caps:
entries = entries + caps[MIMEtype]
if key is not None:
entries = [e for e in entries if key in e]
entries = sorted(entries, key=lineno_sort_key)
return entries
def subst(field, MIMEtype, filename, plist=[]):
# XXX Actually, this is Unix-specific
res = ''
i, n = 0, len(field)
while i < n:
c = field[i]; i = i+1
if c != '%':
if c == '\\':
c = field[i:i+1]; i = i+1
res = res + c
else:
c = field[i]; i = i+1
if c == '%':
res = res + c
elif c == 's':
res = res + filename
elif c == 't':
if _find_unsafe(MIMEtype):
msg = "Refusing to substitute MIME type %r into a shell command." % (MIMEtype,)
warnings.warn(msg, UnsafeMailcapInput)
return None
res = res + MIMEtype
elif c == '{':
start = i
while i < n and field[i] != '}':
i = i+1
name = field[start:i]
i = i+1
param = findparam(name, plist)
if _find_unsafe(param):
msg = "Refusing to substitute parameter %r (%s) into a shell command" % (param, name)
warnings.warn(msg, UnsafeMailcapInput)
return None
res = res + param
# XXX To do:
# %n == number of parts if type is multipart/*
# %F == list of alternating type and filename for parts
else:
res = res + '%' + c
return res
def findparam(name, plist):
name = name.lower() + '='
n = len(name)
for p in plist:
if p[:n].lower() == name:
return p[n:]
return ''
# Part 4: test program.
def test():
import sys
caps = getcaps()
if not sys.argv[1:]:
show(caps)
return
for i in range(1, len(sys.argv), 2):
args = sys.argv[i:i+2]
if len(args) < 2:
print("usage: mailcap [MIMEtype file] ...")
return
MIMEtype = args[0]
file = args[1]
command, e = findmatch(caps, MIMEtype, 'view', file)
if not command:
print("No viewer found for", type)
else:
print("Executing:", command)
sts = os.system(command)
sts = os.waitstatus_to_exitcode(sts)
if sts:
print("Exit status:", sts)
def show(caps):
print("Mailcap files:")
for fn in listmailcapfiles(): print("\t" + fn)
print()
if not caps: caps = getcaps()
print("Mailcap entries:")
print()
ckeys = sorted(caps)
for type in ckeys:
print(type)
entries = caps[type]
for e in entries:
keys = sorted(e)
for k in keys:
print(" %-15s" % k, e[k])
print()
if __name__ == '__main__':
test()
|
