1 <?xml version="1.0" standalone="no"?>
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "file:///usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
5 <refentry id="mimedecode.py">
8 <title>mimedecode.py</title>
9 <productname>mimedecode.docbook</productname>
11 <firstname>Oleg</firstname>
12 <surname>Broytman</surname>
13 <email>phd@phdru.name</email>
17 <year>2001-2014</year>
18 <holder>PhiloSoft Design.</holder>
23 <refentrytitle>mimedecode.py</refentrytitle>
24 <manvolnum>1</manvolnum>
28 <refname>mimedecode.py</refname>
29 <refpurpose>decode MIME message</refpurpose>
34 <command>mimedecode.py</command>
36 <option>-h|--help</option>
39 <option>-V|--version</option>
42 <option>-cCDP</option>
45 <option>-f charset</option>
48 <option>-H|--host=hostname</option>
51 <option>-d header1[,header2,header3...]</option>
54 <option>-d *[,-header1,-header2,-header3...]</option>
57 <option>-p header1[,header2,header3,...]:param1[,param2,param3,...]</option>
60 <option>-p *[,-header1,-header2,-header3,...]:param1[,param2,param3,...]</option>
61 <option>-p header1[,header2,header3,...]:*[,-param1,-param2,-param3,...]</option>
62 <option>-p *[,-header1,-header2,-header3,...]:*[,-param1,-param2,-param3,...]</option>
65 <option>-r header1[,header2,header3...]</option>
68 <option>-r *[,-header1,-header2,-header3...]</option>
71 <option>-R header:param</option>
74 <option>-beit mask</option>
77 <option>-o output_file</option>
79 <arg choice="opt">input_file
80 <arg choice="opt">output_file</arg>
87 <title>DESCRIPTION</title>
89 Mail users, especially in non-English countries, often find that mail
90 messages arrived in different formats, with different content types, in
91 different encodings and charsets. Usually it is good because it allows to
92 use an appropriate format/encoding/whatever. Sometimes, though, some
93 unification is desirable. For example, one may want to put mail messages
94 into an archive, make HTML indices, run search indexer, etc. In such
95 situations converting messages to text in one character set and skipping
96 some binary attachments is much desirable.
100 Here is the solution - mimedecode.py!
104 This is a program to decode MIME messages. The program expects one input
105 file (either on command line or on stdin) which is treated as an RFC822
106 message, and decodes to stdout or an output file. If the file is not an
107 RFC822 message it is just copied to the output one-to-one. If the file is a
108 simple RFC822 message it is decoded as one part. If it is a MIME message
109 with multiple parts ("attachments") all parts are decoded. Decoding can be
110 controlled by command-line options.
114 First, for every part the program removes headers and parameters listed with
115 -r and -R options. Then, Subject and Content-Disposition headers (and all
116 headers listed with -d and -p options) are examined. If any of those exists,
117 they are decoded according to RFC2047. Content-Disposition header is not
118 decoded - only its "filename" parameter. Encoded header parameters violate
119 the RFC, but widely deployed anyway by ignorant coders who never even heard
120 about RFCs. Correct parameter encoding specified by RFC2231. This program
121 decodes RFC2231-encoded parameters, too.
125 Then the body of the message (or the current part) is decoded. Decoding
126 starts with looking at header Content-Transfer-Encoding. If the header
127 specifies non-8bit encoding (usually base64 or quoted-printable), the body
128 converted to 8bit. Then, if its content type is multipart (multipart/related
129 or multipart/mixed, e.g) every part is recursively decoded. If it is not
130 multipart, mailcap database is consulted to find a way to convert the body
131 to plain text. (I have no idea how mailcap can be configured on OSes other
132 than POSIX, please don't ask me; real OS users can consult my example at
133 <ulink url="http://phdru.name/Software/dotfiles/mailcap.html">http://phdru.name/Software/dotfiles/mailcap.html</ulink>).
134 The decoding process uses the first copiousoutput filter it can find. If
135 there are no filters the body just passed as is.
139 Then Content-Type header is consulted for charset. If it is not equal to the
140 current locale charset and recoding is allowed the body text is recoded.
141 Finally message headers and the body are flushed to stdout.
147 Please be warned that in the following options asterisk is a shell
148 metacharacter and should be escaped or quoted. Either write -d \*,-h1,-h2
149 or -d '*,-h1,-h2' or such.
154 <title>OPTIONS</title>
161 Print brief usage help and exit.
168 <term>--version</term>
171 Print version and exit.
180 Recode different character sets in message bodies to the current
181 default charset; this is the default.
190 Do not recode character sets in message bodies.
196 <term>-f charset</term>
199 Force this charset to be the current default charset instead of
206 <term>-H hostname</term>
207 <term>--host=hostname</term>
210 Use this hostname in X-MIME-Autoconverted headers instead of the
217 <term>-d header1[,header2,header3...]</term>
220 Add the header(s) to a list of headers to decode; initially the
221 list contains headers "From", "To", "Cc", "Reply-To",
222 "Mail-Followup-To" and "Subject".
228 <term>-d *[,-header1,-header2,-header3...]</term>
231 This variant completely changes headers decoding. First, the list of
232 headers to decode is cleared. Then all the headers are decoded
233 except the given list of exceptions (headers listed with '-'). In
234 this mode it would be meaningless to give more than one -d options
235 but the program doesn't enforce it.
244 Clear the list of headers to decode (make it empty).
250 <term>-p header1[,header2,header3,...]:param1[,param2,param3,...]</term>
253 Add the parameters(s) to a list of headers parameters to decode;
254 the parameters will be decoded only for the given header(s).
255 Initially the list contains header "Content-Type", parameter "name";
256 and header "Content-Disposition", parameter "filename".
262 <term>-p *[,-header1,-header2,-header3,...]:param1[,param2,param3,...]</term>
265 Add the parameters(s) to a list of headers parameters to decode;
266 the parameters will be decoded for all headers except the given
273 <term>-p header1[,header2,header3,...]:*[,-param1,-param2,-param3,...]</term>
276 Decode all parameters except listed for the given list of headers.
282 <term>-p *[,-header1,-header2,-header3,...]:*[,-param1,-param2,-param3,...]</term>
285 Decode all parameters except listed for all headers (except listed).
294 Clear the list of headers parameters to decode (make it empty).
300 <term>-r header1[,header2,header3...]</term>
303 Add the header(s) to a list of headers to remove completely;
304 initially the list is empty.
310 <term>-r *[,-header1,-header2,-header3...]</term>
313 Remove all headers except listed.
319 <term>-R header:param</term>
322 Add the pair (header, param) to a list of headers parameters to
323 remove; initially the list is empty.
332 Append mask to the list of binary content types; if the message to
333 decode has a part of this type the program will pass the part as is,
334 without any additional processing.
343 Append mask to the list of error content types; if the message to
344 decode has a part of this type the program fails with ValueError.
353 Append mask to the list of content types to ignore; if the message to
354 decode has a part of this type the program will not pass it, instead
355 a line "Message body of type `%s' skipped." will be issued.
364 Append mask to the list of content types to convert to text; if the
365 message to decode has a part of this type the program will consult
366 mailcap database, find first copiousoutput filter and convert the
373 <term>-o output_file</term>
376 Useful to set the output file in case of redirected stdin:
377 <programlisting language="sh">mimedecode.py -o output_file < input_file
378 cat input_file | mimedecode.py -o output_file</programlisting>
385 The 4 list options (-beit) require more explanation. They allow a user to
386 control body decoding with great flexibility. Think about said mail archive;
387 for example, its maintainer wants to put there only texts, convert
388 Postscript/PDF to text, pass HTML and images as is, and ignore everything
394 mimedecode.py -t application/postscript -t application/pdf -b text/html
395 -b 'image/*' -i '*/*'
400 When the program decodes a message (non-MIME or a non-multipart subpart of a
401 MIME message), it consults Content-Type header. The content type is searched
402 in all 4 lists, in order "text-binary-ignore-error". If found, appropriate
403 action performed. If not found, the program search the same lists for
404 "type/*" mask (the type of "text/html" is just "text"). If found,
405 appropriate action performed. If not found, the program search the same
406 lists for "*/*" mask. If found, appropriate action performed. If not found,
407 the program uses default action, which is to decode everything to text (if
408 mailcap specifies a filter).
412 Initially all 4 lists are empty, so without any additional parameters
413 the program always uses the default decoding.
419 <title>ENVIRONMENT</title>
421 <varlistentry><term>LANG</term></varlistentry>
422 <varlistentry><term>LC_ALL</term></varlistentry>
423 <varlistentry><term>LC_CTYPE</term></varlistentry>
426 Define current locale settings. Used to determine current default charset (if
427 your Python is properly installed and configured).
435 The program may produce incorrect MIME message. The purpose of the program
436 is to decode whatever it is possible to decode, not to produce absolutely
437 correct MIME output. The incorrect parts are obvious - decoded
438 From/To/Cc/Reply-To/Mail-Followup-To/Subject headers and filenames. Other
439 than that output is correct MIME message. The program does not try to guess
440 whether the headers are correct. For example, if a message header states
441 that charset is iso8859-5, but the body is actually in utf-8 the program
442 will recode the message with the wrong charset.
448 <title>AUTHOR</title>
450 <firstname>Oleg</firstname>
451 <surname>Broytman</surname>
452 <email>phd@phdru.name</email>
458 <title>COPYRIGHT</title>
460 Copyright (C) 2001-2014 PhiloSoft Design.
466 <title>LICENSE</title>
474 <title>NO WARRANTIES</title>
476 This program is distributed in the hope that it will be useful, but WITHOUT
477 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
478 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
485 <title>SEE ALSO</title>
487 mimedecode.py home page:
488 <ulink url="http://phdru.name/Software/Python/#mimedecode">http://phdru.name/Software/Python/#mimedecode</ulink>