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 header</option>
54 <option>-p header:param</option>
57 <option>-r header</option>
60 <option>-R header:param</option>
63 <option>-beit mask</option>
66 <option>-o output_file</option>
68 <arg choice="opt">input_file
69 <arg choice="opt">output_file</arg>
76 <title>DESCRIPTION</title>
78 Mail users, especially in non-English countries, often find that mail
79 messages arrived in different formats, with different content types, in
80 different encodings and charsets. Usually it is good because it allows to
81 use an appropriate format/encoding/whatever. Sometimes, though, some
82 unification is desirable. For example, one may want to put mail messages
83 into an archive, make HTML indices, run search indexer, etc. In such
84 situations converting messages to text in one character set and skipping
85 some binary attachments is much desirable.
89 Here is the solution - mimedecode.py!
93 This is a program to decode MIME messages. The program expects one input
94 file (either on command line or on stdin) which is treated as an RFC822
95 message, and decodes to stdout or an output file. If the file is not an
96 RFC822 message it is just copied to the output one-to-one. If the file is a
97 simple RFC822 message it is decoded as one part. If it is a MIME message
98 with multiple parts ("attachments") all parts are decoded. Decoding can be
99 controlled by command-line options.
103 First, for every part the program removes headers and parameters listed with
104 -r and -R options. Then, Subject and Content-Disposition headers (and all
105 headers listed with -d and -p options) are examined. If any of those exists,
106 they are decoded according to RFC2047. Content-Disposition header is not
107 decoded - only its "filename" parameter. Encoded header parameters violate
108 the RFC, but widely deployed anyway by ignorant coders who never even heard
109 about RFCs. Correct parameter encoding specified by RFC2231. This program
110 decodes RFC2231-encoded parameters, too.
114 Then the body of the message (or the current part) is decoded. Decoding
115 starts with looking at header Content-Transfer-Encoding. If the header
116 specifies non-8bit encoding (usually base64 or quoted-printable), the body
117 converted to 8bit. Then, if its content type is multipart (multipart/related
118 or multipart/mixed, e.g) every part is recursively decoded. If it is not
119 multipart, mailcap database is consulted to find a way to convert the body
120 to plain text. (I have no idea how mailcap can be configured on OSes other
121 than POSIX, please don't ask me; real OS users can consult my example at
122 <ulink url="http://phdru.name/Software/dotfiles/mailcap.html">http://phdru.name/Software/dotfiles/mailcap.html</ulink>).
123 The decoding process uses the first copiousoutput filter it can find. If
124 there are no filters the body just passed as is.
128 Then Content-Type header is consulted for charset. If it is not equal to the
129 current locale charset and recoding is allowed the body text is recoded.
130 Finally message headers and the body are flushed to stdout.
136 <title>OPTIONS</title>
143 Print brief usage help and exit.
150 <term>--version</term>
153 Print version and exit.
162 Recode different character sets in message bodies to the current
163 default charset; this is the default.
172 Do not recode character sets in message bodies.
178 <term>-f charset</term>
181 Force this charset to be the current default charset instead of
188 <term>-H hostname</term>
189 <term>--host=hostname</term>
192 Use this hostname in X-MIME-Autoconverted headers instead of the
199 <term>-d header</term>
202 Add the header to a list of headers to decode; initially the list
203 contains headers "From", "To", "Cc", "Reply-To", "Mail-Followup-To"
213 Clear the list of headers to decode (make it empty).
219 <term>-p header:param</term>
222 Add the pair (header, param) to a list of headers parameters to
223 decode; initially the list contains header "Content-Type",
224 parameter "name" and header "Content-Disposition", parameter
234 Clear the list of headers parameters to decode (make it empty).
240 <term>-r header</term>
243 Add the header to a list of headers to remove completely; initially
250 <term>-R header:param</term>
253 Add the pair (header, param) to a list of headers parameters to
254 remove; initially the list is empty.
263 Append mask to the list of binary content types; if the message to
264 decode has a part of this type the program will pass the part as is,
265 without any additional processing.
274 Append mask to the list of error content types; if the message to
275 decode has a part of this type the program fails with ValueError.
284 Append mask to the list of content types to ignore; if the message to
285 decode has a part of this type the program will not pass it, instead
286 a line "Message body of type `%s' skipped." will be issued.
295 Append mask to the list of content types to convert to text; if the
296 message to decode has a part of this type the program will consult
297 mailcap database, find first copiousoutput filter and convert the
304 <term>-o output_file</term>
307 Useful to set the output file in case of redirected stdin:
308 <programlisting language="sh">mimedecode.py -o output_file < input_file
309 cat input_file | mimedecode.py -o output_file</programlisting>
316 The 4 list options (-beit) require more explanation. They allow a user to
317 control body decoding with great flexibility. Think about said mail archive;
318 for example, its maintainer wants to put there only texts, convert
319 Postscript/PDF to text, pass HTML and images as is, and ignore everything
325 mimedecode.py -t application/postscript -t application/pdf -b text/html
326 -b 'image/*' -i '*/*'
331 When the program decodes a message (non-MIME or a non-multipart subpart of a
332 MIME message), it consults Content-Type header. The content type is searched
333 in all 4 lists, in order "text-binary-ignore-error". If found, appropriate
334 action performed. If not found, the program search the same lists for
335 "type/*" mask (the type of "text/html" is just "text"). If found,
336 appropriate action performed. If not found, the program search the same
337 lists for "*/*" mask. If found, appropriate action performed. If not found,
338 the program uses default action, which is to decode everything to text (if
339 mailcap specifies a filter).
343 Initially all 4 lists are empty, so without any additional parameters
344 the program always uses the default decoding.
350 <title>ENVIRONMENT</title>
352 <varlistentry><term>LANG</term></varlistentry>
353 <varlistentry><term>LC_ALL</term></varlistentry>
354 <varlistentry><term>LC_CTYPE</term></varlistentry>
357 Define current locale settings. Used to determine current default charset (if
358 your Python is properly installed and configured).
366 The program may produce incorrect MIME message. The purpose of the program
367 is to decode whatever it is possible to decode, not to produce absolutely
368 correct MIME output. The incorrect parts are obvious - decoded
369 From/To/Cc/Reply-To/Mail-Followup-To/Subject headers and filenames. Other
370 than that output is correct MIME message. The program does not try to guess
371 whether the headers are correct. For example, if a message header states
372 that charset is iso8859-5, but the body is actually in utf-8 the program
373 will recode the message with the wrong charset.
379 <title>AUTHOR</title>
381 <firstname>Oleg</firstname>
382 <surname>Broytman</surname>
383 <email>phd@phdru.name</email>
389 <title>COPYRIGHT</title>
391 Copyright (C) 2001-2014 PhiloSoft Design.
397 <title>LICENSE</title>
405 <title>NO WARRANTIES</title>
407 This program is distributed in the hope that it will be useful, but WITHOUT
408 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
409 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
416 <title>SEE ALSO</title>
418 mimedecode.py home page:
419 <ulink url="http://phdru.name/Software/Python/#mimedecode">http://phdru.name/Software/Python/#mimedecode</ulink>