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>-beit mask</option>
60 <option>-o output_file</option>
62 <arg choice="opt">input_file
63 <arg choice="opt">output_file</arg>
70 <title>DESCRIPTION</title>
72 Mail users, especially in non-English countries, often find that mail
73 messages arrived in different formats, with different content types, in
74 different encodings and charsets. Usually it is good because it allows to use
75 an appropriate format/encoding/whatever. Sometimes, though, some unification is
76 desirable. For example, one may want to put mail messages into an archive,
77 make HTML indices, run search indexer, etc. In such situations converting
78 messages to text in one character set and skipping some binary attachments is
83 Here is the solution - mimedecode.py!
87 This is a program to decode MIME messages. The program expects one input
88 file (either on command line or on stdin) which is treated as an RFC822
89 message, and decodes to stdout or an output file. If the file is not an RFC822
90 message it is just copied to the output one-to-one. If the file is a simple
91 RFC822 message it is decoded as one part. If it is a MIME message with multiple
92 parts ("attachments") all parts are decoded. Decoding can be controlled by
97 First, Subject and Content-Disposition headers are examined. If any of those
98 exists, it is decoded according to RFC2047. Content-Disposition header is
99 not decoded - only its "filename" parameter. Encoded header parameters
100 violate the RFC, but widely deployed anyway by ignorant coders who never
101 even heard about RFCs. Correct parameter encoding specified by RFC2231. This
102 program decodes RFC2231-encoded parameters, too.
106 Then the body of the message (or the current part) is decoded. Decoding
107 starts with looking at header Content-Transfer-Encoding. If the header
108 specifies non-8bit encoding (usually base64 or quoted-printable), the body
109 converted to 8bit. Then, if its content type is multipart (multipart/related
110 or multipart/mixed, e.g) every part is recursively decoded. If it is not
111 multipart, mailcap database is consulted to find a way to convert the body
112 to plain text. (I have no idea how mailcap can be configured on OSes other
113 than POSIX, please don't ask me; real OS users can consult my example at
114 <ulink url="http://phdru.name/Software/dotfiles/mailcap.html">http://phdru.name/Software/dotfiles/mailcap.html</ulink>).
115 The decoding process uses the first copiousoutput filter it can find. If
116 there are no filters the body just passed as is.
120 Then Content-Type header is consulted for charset. If it is not equal to the
121 current locale charset and recoding is allowed the body text is recoded.
122 Finally message headers and the body are flushed to stdout.
128 <title>OPTIONS</title>
135 Print brief usage help and exit.
142 <term>--version</term>
145 Print version and exit.
154 Recode different character sets in message bodies to the current
155 default charset; this is the default.
164 Do not recode character sets in message bodies.
170 <term>-f charset</term>
173 Force this charset to be the current default charset instead of
180 <term>-H hostname</term>
181 <term>--host=hostname</term>
184 Use this hostname in X-MIME-Autoconverted headers instead of the
191 <term>-d header</term>
194 Add the header to a list of headers to decode; initially the list
195 contains headers "From", "To", "Cc", "Reply-To", "Mail-Followup-To"
205 Clear the list of headers to decode (make it empty).
211 <term>-p header:param</term>
214 Add the pair (header, param) to a list of headers' parameters to
215 decode; initially the list contains header "Content-Type",
216 parameter "name" and header "Content-Disposition", parameter
226 Clear the list of headers' parameters to decode (make it empty).
235 Append mask to the list of binary content types; if the message to
236 decode has a part of this type the program will pass the part as is,
237 without any additional processing.
246 Append mask to the list of error content types; if the message to
247 decode has a part of this type the program fails with ValueError.
256 Append mask to the list of content types to ignore; if the message to
257 decode has a part of this type the program will not pass it, instead
258 a line "Message body of type `%s' skipped." will be issued.
267 Append mask to the list of content types to convert to text; if the
268 message to decode has a part of this type the program will consult
269 mailcap database, find first copiousoutput filter and convert the
276 <term>-o output_file</term>
279 Useful to set the output file in case of redirected stdin:
280 <programlisting language="sh">mimedecode.py -o output_file < input_file
281 cat input_file | mimedecode.py -o output_file</programlisting>
288 The 4 list options (-beit) require more explanation. They allow a user
289 to control body decoding with great flexibility. Think about said mail
290 archive; for example, its maintainer wants to put there only texts, convert
291 Postscript/PDF to text, pass HTML and images as is, and ignore everything
297 mimedecode.py -t application/postscript -t application/pdf -b text/html
298 -b 'image/*' -i '*/*'
303 When the program decodes a message (non-MIME or a non-multipart subpart of a
304 MIME message), it consults Content-Type header. The content type is searched
305 in all 4 lists, in order "text-binary-ignore-error". If found, appropriate
306 action performed. If not found, the program search the same lists for
307 "type/*" mask (the type of "text/html" is just "text"). If found,
308 appropriate action performed. If not found, the program search the same
309 lists for "*/*" mask. If found, appropriate action performed. If not found,
310 the program uses default action, which is to decode everything to text (if
311 mailcap specifies a filter).
315 Initially all 4 lists are empty, so without any additional parameters
316 the program always uses the default decoding.
322 <title>ENVIRONMENT</title>
324 <varlistentry><term>LANG</term></varlistentry>
325 <varlistentry><term>LC_ALL</term></varlistentry>
326 <varlistentry><term>LC_CTYPE</term></varlistentry>
329 Define current locale settings. Used to determine current default charset (if
330 your Python is properly installed and configured).
338 The program may produce incorrect MIME message. The purpose of the program
339 is to decode whatever it is possible to decode, not to produce absolutely
340 correct MIME output. The incorrect parts are obvious - decoded
341 From/To/Cc/Reply-To/Mail-Followup-To/Subject headers and filenames. Other
342 than that output is correct MIME message. The program does not try to guess
343 whether the headers are correct. For example, if a message header states
344 that charset is iso8859-5, but the body is actually in utf-8 the program
345 will recode the message with the wrong charset.
351 <title>AUTHOR</title>
353 <firstname>Oleg</firstname>
354 <surname>Broytman</surname>
355 <email>phd@phdru.name</email>
361 <title>COPYRIGHT</title>
363 Copyright (C) 2001-2014 PhiloSoft Design.
369 <title>LICENSE</title>
377 <title>NO WARRANTIES</title>
379 This program is distributed in the hope that it will be useful, but WITHOUT
380 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
381 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
388 <title>SEE ALSO</title>
390 mimedecode.py home page:
391 <ulink url="http://phdru.name/Software/Python/#mimedecode">http://phdru.name/Software/Python/#mimedecode</ulink>