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>-r header</option>
63 <option>-R header:param</option>
66 <option>--remove-params=header</option>
69 <option>-beit mask</option>
72 <option>-o output_file</option>
74 <arg choice="opt">input_file
75 <arg choice="opt">output_file</arg>
82 <title>DESCRIPTION</title>
84 Mail users, especially in non-English countries, often find that mail
85 messages arrived in different formats, with different content types, in
86 different encodings and charsets. Usually it is good because it allows to
87 use an appropriate format/encoding/whatever. Sometimes, though, some
88 unification is desirable. For example, one may want to put mail messages
89 into an archive, make HTML indices, run search indexer, etc. In such
90 situations converting messages to text in one character set and skipping
91 some binary attachments is much desirable.
95 Here is the solution - mimedecode.py!
99 This is a program to decode MIME messages. The program expects one input
100 file (either on command line or on stdin) which is treated as an RFC822
101 message, and decodes to stdout or an output file. If the file is not an
102 RFC822 message it is just copied to the output one-to-one. If the file is a
103 simple RFC822 message it is decoded as one part. If it is a MIME message
104 with multiple parts ("attachments") all parts are decoded. Decoding can be
105 controlled by command-line options.
109 First, for every part the program removes headers and parameters listed with
110 -r and -R options. Then, Subject and Content-Disposition headers (and all
111 headers listed with -d and -p options) are examined. If any of those exists,
112 they are decoded according to RFC2047. Content-Disposition header is not
113 decoded - only its "filename" parameter. Encoded header parameters violate
114 the RFC, but widely deployed anyway by ignorant coders who never even heard
115 about RFCs. Correct parameter encoding specified by RFC2231. This program
116 decodes RFC2231-encoded parameters, too.
120 Then the body of the message (or the current part) is decoded. Decoding
121 starts with looking at header Content-Transfer-Encoding. If the header
122 specifies non-8bit encoding (usually base64 or quoted-printable), the body
123 converted to 8bit. Then, if its content type is multipart (multipart/related
124 or multipart/mixed, e.g) every part is recursively decoded. If it is not
125 multipart, mailcap database is consulted to find a way to convert the body
126 to plain text. (I have no idea how mailcap can be configured on OSes other
127 than POSIX, please don't ask me; real OS users can consult my example at
128 <ulink url="http://phdru.name/Software/dotfiles/mailcap.html">http://phdru.name/Software/dotfiles/mailcap.html</ulink>).
129 The decoding process uses the first copiousoutput filter it can find. If
130 there are no filters the body just passed as is.
134 Then Content-Type header is consulted for charset. If it is not equal to the
135 current locale charset and recoding is allowed the body text is recoded.
136 Finally message headers and the body are flushed to stdout.
142 Please be warned that in the following options asterisk is a shell
143 metacharacter and should be escaped or quoted. Either write -d \*,-h1,-h2
144 or -d '*,-h1,-h2' or such.
149 <title>OPTIONS</title>
156 Print brief usage help and exit.
163 <term>--version</term>
166 Print version and exit.
175 Recode different character sets in message bodies to the current
176 default charset; this is the default.
185 Do not recode character sets in message bodies.
191 <term>-f charset</term>
194 Force this charset to be the current default charset instead of
201 <term>-H hostname</term>
202 <term>--host=hostname</term>
205 Use this hostname in X-MIME-Autoconverted headers instead of the
212 <term>-d header1[,header2,header3...]</term>
215 Add the header(s) to a list of headers to decode; initially the
216 list contains headers "From", "To", "Cc", "Reply-To",
217 "Mail-Followup-To" and "Subject".
223 <term>-d *[,-header1,-header2,-header3...]</term>
226 This variant completely changes headers decoding. First, the list of
227 headers to decode is cleared. Then all the headers are decoded
228 except the given list of exceptions (headers listed with '-'). In
229 this mode it would be meaningless to give more than one -d options
230 but the program doesn't enforce it.
239 Clear the list of headers to decode (make it empty).
245 <term>-p header1[,header2,header3,...]:param1[,param2,param3,...]</term>
248 Add the parameters(s) to a list of headers parameters to decode;
249 the parameters will be decoded only for the given header(s).
250 Initially the list contains header "Content-Type", parameter "name";
251 and header "Content-Disposition", parameter "filename".
257 <term>-p *[,-header1,-header2,-header3,...]:param1[,param2,param3,...]</term>
260 Add the parameters(s) to a list of headers parameters to decode;
261 the parameters will be decoded for all headers except the given
271 Clear the list of headers parameters to decode (make it empty).
277 <term>-r header</term>
280 Add the header to a list of headers to remove completely; initially
287 <term>-R header:param</term>
290 Add the pair (header, param) to a list of headers parameters to
291 remove; initially the list is empty.
297 <term>--remove-params=header</term>
300 Add the header to a list of headers from which all parameters will
301 be removed; initially the list is empty.
310 Append mask to the list of binary content types; if the message to
311 decode has a part of this type the program will pass the part as is,
312 without any additional processing.
321 Append mask to the list of error content types; if the message to
322 decode has a part of this type the program fails with ValueError.
331 Append mask to the list of content types to ignore; if the message to
332 decode has a part of this type the program will not pass it, instead
333 a line "Message body of type `%s' skipped." will be issued.
342 Append mask to the list of content types to convert to text; if the
343 message to decode has a part of this type the program will consult
344 mailcap database, find first copiousoutput filter and convert the
351 <term>-o output_file</term>
354 Useful to set the output file in case of redirected stdin:
355 <programlisting language="sh">mimedecode.py -o output_file < input_file
356 cat input_file | mimedecode.py -o output_file</programlisting>
363 The 4 list options (-beit) require more explanation. They allow a user to
364 control body decoding with great flexibility. Think about said mail archive;
365 for example, its maintainer wants to put there only texts, convert
366 Postscript/PDF to text, pass HTML and images as is, and ignore everything
372 mimedecode.py -t application/postscript -t application/pdf -b text/html
373 -b 'image/*' -i '*/*'
378 When the program decodes a message (non-MIME or a non-multipart subpart of a
379 MIME message), it consults Content-Type header. The content type is searched
380 in all 4 lists, in order "text-binary-ignore-error". If found, appropriate
381 action performed. If not found, the program search the same lists for
382 "type/*" mask (the type of "text/html" is just "text"). If found,
383 appropriate action performed. If not found, the program search the same
384 lists for "*/*" mask. If found, appropriate action performed. If not found,
385 the program uses default action, which is to decode everything to text (if
386 mailcap specifies a filter).
390 Initially all 4 lists are empty, so without any additional parameters
391 the program always uses the default decoding.
397 <title>ENVIRONMENT</title>
399 <varlistentry><term>LANG</term></varlistentry>
400 <varlistentry><term>LC_ALL</term></varlistentry>
401 <varlistentry><term>LC_CTYPE</term></varlistentry>
404 Define current locale settings. Used to determine current default charset (if
405 your Python is properly installed and configured).
413 The program may produce incorrect MIME message. The purpose of the program
414 is to decode whatever it is possible to decode, not to produce absolutely
415 correct MIME output. The incorrect parts are obvious - decoded
416 From/To/Cc/Reply-To/Mail-Followup-To/Subject headers and filenames. Other
417 than that output is correct MIME message. The program does not try to guess
418 whether the headers are correct. For example, if a message header states
419 that charset is iso8859-5, but the body is actually in utf-8 the program
420 will recode the message with the wrong charset.
426 <title>AUTHOR</title>
428 <firstname>Oleg</firstname>
429 <surname>Broytman</surname>
430 <email>phd@phdru.name</email>
436 <title>COPYRIGHT</title>
438 Copyright (C) 2001-2014 PhiloSoft Design.
444 <title>LICENSE</title>
452 <title>NO WARRANTIES</title>
454 This program is distributed in the hope that it will be useful, but WITHOUT
455 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
456 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
463 <title>SEE ALSO</title>
465 mimedecode.py home page:
466 <ulink url="http://phdru.name/Software/Python/#mimedecode">http://phdru.name/Software/Python/#mimedecode</ulink>