mimify.py 14.5 KB
Newer Older
1
#! /usr/bin/env python
2

3
"""Mimification and unmimification of mail messages.
4

5
Decode quoted-printable parts of a mail message or encode using
6 7 8
quoted-printable.

Usage:
Tim Peters's avatar
Tim Peters committed
9 10
        mimify(input, output)
        unmimify(input, output, decode_base64 = 0)
11 12 13 14 15 16 17
to encode and decode respectively.  Input and output may be the name
of a file or an open file object.  Only a readline() method is used
on the input file, only a write() method is used on the output file.
When using file names, the input and output file names may be the
same.

Interactive usage:
Tim Peters's avatar
Tim Peters committed
18 19
        mimify.py -e [infile [outfile]]
        mimify.py -d [infile [outfile]]
20 21
to encode and decode respectively.  Infile defaults to standard
input and outfile to standard output.
22
"""
23 24

# Configure
Tim Peters's avatar
Tim Peters committed
25 26 27
MAXLEN = 200    # if lines longer than this, encode as quoted-printable
CHARSET = 'ISO-8859-1'  # default charset for non-US-ASCII mail
QUOTE = '> '            # string replies are quoted with
28 29
# End configure

30
import re
31

32 33
__all__ = ["mimify","unmimify","mime_encode_header","mime_decode_header"]

34 35 36 37 38 39 40 41
qp = re.compile('^content-transfer-encoding:\\s*quoted-printable', re.I)
base64_re = re.compile('^content-transfer-encoding:\\s*base64', re.I)
mp = re.compile('^content-type:.*multipart/.*boundary="?([^;"\n]*)', re.I|re.S)
chrset = re.compile('^(content-type:.*charset=")(us-ascii|iso-8859-[0-9]+)(".*)', re.I|re.S)
he = re.compile('^-*\n')
mime_code = re.compile('=([0-9a-f][0-9a-f])', re.I)
mime_head = re.compile('=\\?iso-8859-1\\?q\\?([^? \t\n]+)\\?=', re.I)
repl = re.compile('^subject:\\s+re: ', re.I)
42 43

class File:
Tim Peters's avatar
Tim Peters committed
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
    """A simple fake file object that knows about limited read-ahead and
    boundaries.  The only supported method is readline()."""

    def __init__(self, file, boundary):
        self.file = file
        self.boundary = boundary
        self.peek = None

    def readline(self):
        if self.peek is not None:
            return ''
        line = self.file.readline()
        if not line:
            return line
        if self.boundary:
            if line == self.boundary + '\n':
                self.peek = line
                return ''
            if line == self.boundary + '--\n':
                self.peek = line
                return ''
        return line
66 67

class HeaderFile:
Tim Peters's avatar
Tim Peters committed
68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
    def __init__(self, file):
        self.file = file
        self.peek = None

    def readline(self):
        if self.peek is not None:
            line = self.peek
            self.peek = None
        else:
            line = self.file.readline()
        if not line:
            return line
        if he.match(line):
            return line
        while 1:
            self.peek = self.file.readline()
            if len(self.peek) == 0 or \
               (self.peek[0] != ' ' and self.peek[0] != '\t'):
                return line
            line = line + self.peek
            self.peek = None
89 90

def mime_decode(line):
Tim Peters's avatar
Tim Peters committed
91 92 93 94 95 96 97 98
    """Decode a single line of quoted-printable text to 8bit."""
    newline = ''
    pos = 0
    while 1:
        res = mime_code.search(line, pos)
        if res is None:
            break
        newline = newline + line[pos:res.start(0)] + \
99
                  chr(int(res.group(1), 16))
Tim Peters's avatar
Tim Peters committed
100 101
        pos = res.end(0)
    return newline + line[pos:]
102 103

def mime_decode_header(line):
Tim Peters's avatar
Tim Peters committed
104 105 106 107 108 109 110 111 112
    """Decode a header line to 8bit."""
    newline = ''
    pos = 0
    while 1:
        res = mime_head.search(line, pos)
        if res is None:
            break
        match = res.group(1)
        # convert underscores to spaces (before =XX conversion!)
Eric S. Raymond's avatar
Eric S. Raymond committed
113
        match = ' '.join(match.split('_'))
Tim Peters's avatar
Tim Peters committed
114 115 116
        newline = newline + line[pos:res.start(0)] + mime_decode(match)
        pos = res.end(0)
    return newline + line[pos:]
117

118
def unmimify_part(ifile, ofile, decode_base64 = 0):
Tim Peters's avatar
Tim Peters committed
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
    """Convert a quoted-printable part of a MIME mail message to 8bit."""
    multipart = None
    quoted_printable = 0
    is_base64 = 0
    is_repl = 0
    if ifile.boundary and ifile.boundary[:2] == QUOTE:
        prefix = QUOTE
    else:
        prefix = ''

    # read header
    hfile = HeaderFile(ifile)
    while 1:
        line = hfile.readline()
        if not line:
            return
        if prefix and line[:len(prefix)] == prefix:
            line = line[len(prefix):]
            pref = prefix
        else:
            pref = ''
        line = mime_decode_header(line)
        if qp.match(line):
            quoted_printable = 1
            continue        # skip this header
        if decode_base64 and base64_re.match(line):
            is_base64 = 1
            continue
        ofile.write(pref + line)
        if not prefix and repl.match(line):
            # we're dealing with a reply message
            is_repl = 1
        mp_res = mp.match(line)
        if mp_res:
            multipart = '--' + mp_res.group(1)
        if he.match(line):
            break
    if is_repl and (quoted_printable or multipart):
        is_repl = 0

    # read body
    while 1:
        line = ifile.readline()
        if not line:
            return
        line = re.sub(mime_head, '\\1', line)
        if prefix and line[:len(prefix)] == prefix:
            line = line[len(prefix):]
            pref = prefix
        else:
            pref = ''
##              if is_repl and len(line) >= 4 and line[:4] == QUOTE+'--' and line[-3:] != '--\n':
##                      multipart = line[:-1]
        while multipart:
            if line == multipart + '--\n':
                ofile.write(pref + line)
                multipart = None
                line = None
                break
            if line == multipart + '\n':
                ofile.write(pref + line)
                nifile = File(ifile, multipart)
                unmimify_part(nifile, ofile, decode_base64)
                line = nifile.peek
                if not line:
                    # premature end of file
                    break
                continue
            # not a boundary between parts
            break
        if line and quoted_printable:
            while line[-2:] == '=\n':
                line = line[:-2]
                newline = ifile.readline()
                if newline[:len(QUOTE)] == QUOTE:
                    newline = newline[len(QUOTE):]
                line = line + newline
            line = mime_decode(line)
        if line and is_base64 and not pref:
            import base64
            line = base64.decodestring(line)
        if line:
            ofile.write(pref + line)
202

203
def unmimify(infile, outfile, decode_base64 = 0):
Tim Peters's avatar
Tim Peters committed
204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
    """Convert quoted-printable parts of a MIME mail message to 8bit."""
    if type(infile) == type(''):
        ifile = open(infile)
        if type(outfile) == type('') and infile == outfile:
            import os
            d, f = os.path.split(infile)
            os.rename(infile, os.path.join(d, ',' + f))
    else:
        ifile = infile
    if type(outfile) == type(''):
        ofile = open(outfile, 'w')
    else:
        ofile = outfile
    nifile = File(ifile, None)
    unmimify_part(nifile, ofile, decode_base64)
    ofile.flush()
220

221 222
mime_char = re.compile('[=\177-\377]') # quote these chars in body
mime_header_char = re.compile('[=?\177-\377]') # quote these in header
223 224

def mime_encode(line, header):
Tim Peters's avatar
Tim Peters committed
225 226 227 228 229 230 231 232 233 234
    """Code a single line as quoted-printable.
    If header is set, quote some extra characters."""
    if header:
        reg = mime_header_char
    else:
        reg = mime_char
    newline = ''
    pos = 0
    if len(line) >= 5 and line[:5] == 'From ':
        # quote 'From ' at the start of a line for stupid mailers
235
        newline = ('=%02x' % ord('F')).upper()
Tim Peters's avatar
Tim Peters committed
236 237 238 239 240 241
        pos = 1
    while 1:
        res = reg.search(line, pos)
        if res is None:
            break
        newline = newline + line[pos:res.start(0)] + \
242
                  ('=%02x' % ord(res.group(0))).upper()
Tim Peters's avatar
Tim Peters committed
243 244 245 246 247 248 249 250 251 252 253 254
        pos = res.end(0)
    line = newline + line[pos:]

    newline = ''
    while len(line) >= 75:
        i = 73
        while line[i] == '=' or line[i-1] == '=':
            i = i - 1
        i = i + 1
        newline = newline + line[:i] + '=\n'
        line = line[i:]
    return newline + line
255

unknown's avatar
unknown committed
256
mime_header = re.compile('([ \t(]|^)([-a-zA-Z0-9_+]*[\177-\377][-a-zA-Z0-9_+\177-\377]*)(?=[ \t)]|\n)')
257 258

def mime_encode_header(line):
Tim Peters's avatar
Tim Peters committed
259 260 261 262 263 264 265
    """Code a single header line as quoted-printable."""
    newline = ''
    pos = 0
    while 1:
        res = mime_header.search(line, pos)
        if res is None:
            break
unknown's avatar
unknown committed
266
        newline = '%s%s%s=?%s?Q?%s?=' % \
Tim Peters's avatar
Tim Peters committed
267
                  (newline, line[pos:res.start(0)], res.group(1),
unknown's avatar
unknown committed
268
                   CHARSET, mime_encode(res.group(2), 1))
Tim Peters's avatar
Tim Peters committed
269 270
        pos = res.end(0)
    return newline + line[pos:]
271

272 273
mv = re.compile('^mime-version:', re.I)
cte = re.compile('^content-transfer-encoding:', re.I)
274
iso_char = re.compile('[\177-\377]')
275 276

def mimify_part(ifile, ofile, is_mime):
Tim Peters's avatar
Tim Peters committed
277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348
    """Convert an 8bit part of a MIME mail message to quoted-printable."""
    has_cte = is_qp = is_base64 = 0
    multipart = None
    must_quote_body = must_quote_header = has_iso_chars = 0

    header = []
    header_end = ''
    message = []
    message_end = ''
    # read header
    hfile = HeaderFile(ifile)
    while 1:
        line = hfile.readline()
        if not line:
            break
        if not must_quote_header and iso_char.search(line):
            must_quote_header = 1
        if mv.match(line):
            is_mime = 1
        if cte.match(line):
            has_cte = 1
            if qp.match(line):
                is_qp = 1
            elif base64_re.match(line):
                is_base64 = 1
        mp_res = mp.match(line)
        if mp_res:
            multipart = '--' + mp_res.group(1)
        if he.match(line):
            header_end = line
            break
        header.append(line)

    # read body
    while 1:
        line = ifile.readline()
        if not line:
            break
        if multipart:
            if line == multipart + '--\n':
                message_end = line
                break
            if line == multipart + '\n':
                message_end = line
                break
        if is_base64:
            message.append(line)
            continue
        if is_qp:
            while line[-2:] == '=\n':
                line = line[:-2]
                newline = ifile.readline()
                if newline[:len(QUOTE)] == QUOTE:
                    newline = newline[len(QUOTE):]
                line = line + newline
            line = mime_decode(line)
        message.append(line)
        if not has_iso_chars:
            if iso_char.search(line):
                has_iso_chars = must_quote_body = 1
        if not must_quote_body:
            if len(line) > MAXLEN:
                must_quote_body = 1

    # convert and output header and body
    for line in header:
        if must_quote_header:
            line = mime_encode_header(line)
        chrset_res = chrset.match(line)
        if chrset_res:
            if has_iso_chars:
                # change us-ascii into iso-8859-1
349
                if chrset_res.group(2).lower() == 'us-ascii':
Tim Peters's avatar
Tim Peters committed
350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
                    line = '%s%s%s' % (chrset_res.group(1),
                                       CHARSET,
                                       chrset_res.group(3))
            else:
                # change iso-8859-* into us-ascii
                line = '%sus-ascii%s' % chrset_res.group(1, 3)
        if has_cte and cte.match(line):
            line = 'Content-Transfer-Encoding: '
            if is_base64:
                line = line + 'base64\n'
            elif must_quote_body:
                line = line + 'quoted-printable\n'
            else:
                line = line + '7bit\n'
        ofile.write(line)
    if (must_quote_header or must_quote_body) and not is_mime:
        ofile.write('Mime-Version: 1.0\n')
        ofile.write('Content-Type: text/plain; ')
        if has_iso_chars:
            ofile.write('charset="%s"\n' % CHARSET)
        else:
            ofile.write('charset="us-ascii"\n')
    if must_quote_body and not has_cte:
        ofile.write('Content-Transfer-Encoding: quoted-printable\n')
    ofile.write(header_end)

    for line in message:
        if must_quote_body:
            line = mime_encode(line, 0)
        ofile.write(line)
    ofile.write(message_end)

    line = message_end
    while multipart:
        if line == multipart + '--\n':
            # read bit after the end of the last part
            while 1:
                line = ifile.readline()
                if not line:
                    return
                if must_quote_body:
                    line = mime_encode(line, 0)
                ofile.write(line)
        if line == multipart + '\n':
            nifile = File(ifile, multipart)
            mimify_part(nifile, ofile, 1)
            line = nifile.peek
            if not line:
                # premature end of file
                break
            ofile.write(line)
            continue
        # unexpectedly no multipart separator--copy rest of file
        while 1:
            line = ifile.readline()
            if not line:
                return
            if must_quote_body:
                line = mime_encode(line, 0)
            ofile.write(line)
410 411

def mimify(infile, outfile):
Tim Peters's avatar
Tim Peters committed
412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
    """Convert 8bit parts of a MIME mail message to quoted-printable."""
    if type(infile) == type(''):
        ifile = open(infile)
        if type(outfile) == type('') and infile == outfile:
            import os
            d, f = os.path.split(infile)
            os.rename(infile, os.path.join(d, ',' + f))
    else:
        ifile = infile
    if type(outfile) == type(''):
        ofile = open(outfile, 'w')
    else:
        ofile = outfile
    nifile = File(ifile, None)
    mimify_part(nifile, ofile, 0)
    ofile.flush()
428 429 430

import sys
if __name__ == '__main__' or (len(sys.argv) > 0 and sys.argv[0] == 'mimify'):
Tim Peters's avatar
Tim Peters committed
431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449
    import getopt
    usage = 'Usage: mimify [-l len] -[ed] [infile [outfile]]'

    decode_base64 = 0
    opts, args = getopt.getopt(sys.argv[1:], 'l:edb')
    if len(args) not in (0, 1, 2):
        print usage
        sys.exit(1)
    if (('-e', '') in opts) == (('-d', '') in opts) or \
       ((('-b', '') in opts) and (('-d', '') not in opts)):
        print usage
        sys.exit(1)
    for o, a in opts:
        if o == '-e':
            encode = mimify
        elif o == '-d':
            encode = unmimify
        elif o == '-l':
            try:
450
                MAXLEN = int(a)
451
            except (ValueError, OverflowError):
Tim Peters's avatar
Tim Peters committed
452 453 454 455 456 457 458 459 460 461 462 463 464
                print usage
                sys.exit(1)
        elif o == '-b':
            decode_base64 = 1
    if len(args) == 0:
        encode_args = (sys.stdin, sys.stdout)
    elif len(args) == 1:
        encode_args = (args[0], sys.stdout)
    else:
        encode_args = (args[0], args[1])
    if decode_base64:
        encode_args = encode_args + (decode_base64,)
    apply(encode, encode_args)