X-Git-Url: https://git.phdru.name/?p=mimedecode.git;a=blobdiff_plain;f=mimedecode.docbook;h=0129709532dca754b56d05efe16293cca83f9af3;hp=29a02e08b95831c7cca7b917dc0e65c906826a56;hb=bbdea6e26c82a925377da981f42b27653621a5a7;hpb=e817999a63e6187e7c1dbf04a05cb83db4be0505 diff --git a/mimedecode.docbook b/mimedecode.docbook index 29a02e0..0129709 100644 --- a/mimedecode.docbook +++ b/mimedecode.docbook @@ -1,9 +1,24 @@ - + + + mimedecode.py + mimedecode.docbook + + Oleg + Broytman + phd@phdru.name + + + + 2001-2017 + PhiloSoft Design. + + + mimedecode.py 1 @@ -30,13 +45,58 @@ - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + - + - + + + + + + + + + + + + + + + + @@ -52,59 +112,69 @@ DESCRIPTION Mail users, especially in non-English countries, often find that mail -messages arrived in different formats, with different content types, in -different encodings and charsets. Usually it is good because it allows to use -an appropriate format/encoding/whatever. Sometimes, though, some unification is -desirable. For example, one may want to put mail messages into an archive, -make HTML indices, run search indexer, etc. In such situations converting -messages to text in one character set and skipping some binary attachments is -much desirable. + messages arrived in different formats, with different content types, in + different encodings and charsets. Usually it is good because it allows to + use an appropriate format/encoding/whatever. Sometimes, though, some + unification is desirable. For example, one may want to put mail messages + into an archive, make HTML indices, run search indexer, etc. In such + situations converting messages to text in one character set and skipping + some binary attachments is much desirable. - Here is the solution - mimedecode.py! + Here is a solution - mimedecode.py! - It is a program to decode MIME messages. The program expects one input file -(either on the command line or on stdin) which is treated as an RFC822 message, -and decoded to stdout. If the file is not an RFC822 message it is just piped to -stdout as is. If the file is a simple RFC822 message it is just decoded as one -part. If it is a MIME message with multiple parts ("attachments") all parts are -decoded recursively. Decoding can be controlled by the command-line options. + This is a program to decode MIME messages. The program expects one input + file (either on command line or on stdin) which is treated as an RFC822 + message, and decodes to stdout or an output file. If the file is not an + RFC822 message it is just copied to the output one-to-one. If the file is a + simple RFC822 message it is decoded as one part. If it is a MIME message + with multiple parts ("attachments") all non-multipart subparts are decoded. + Decoding can be controlled by the command-line options. - First, Subject and Content-Disposition headers are examined. If any of those -exists, it is decoded according to RFC2047. Content-Disposition header is not -decoded - only its "filename" parameter. Encoded header parameters violate -the RFC, but widely deployed anyway, especially in the M$ Ophice GUI (often -referred as "Windoze") world, where programmers are often ignorant lamers who -never even heard about RFCs. Correct parameter encoding specified by RFC2231. -This program decodes RFC2231-encoded parameters, too. + First, for every part the program removes headers and parameters listed with + -r and -R options. Then, Subject and Content-Disposition headers (and all + headers listed with -d and -p options) are examined. If any of those exists, + they are decoded according to RFC2047. Content-Disposition header is not + decoded (if it was not listed in option -d) - only its "filename" parameter. + Encoded header parameters violate the RFC, but widely deployed anyway by + ignorant coders who never even heard about RFCs. Correct parameter encoding + specified by RFC2231. This program decodes RFC2231-encoded parameters, too. Then the body of the message (or the current part) is decoded. Decoding -starts with looking at header Content-Transfer-Encoding. If the header -specifies non-8bit encoding (usually base64 or quoted-printable), the body -converted to 8bit. Then, if its content type is multipart (multipart/related or -multipart/mixed, e.g) every part is recursively decoded. If it is not -multipart, mailcap database is consulted to find a way to convert the body to -plain text. (I have no idea how mailcap could be configured on said M$ Ophice -GUI, please don't ask me; real OS users can consult my example at -http://phdru.name/Software/dotfiles/mailcap.html). The decoding process uses -first copiousoutput filter it can find. If there is no any filter the body just -passed unconverted. + starts with looking at header Content-Transfer-Encoding. If the header + specifies non-8bit encoding (usually base64 or quoted-printable), the body + is converted to 8bit (can be prevented with -B). Then if its content type + is multipart (multipart/related or multipart/mixed, e.g) every part is + recursively decoded. If it is not multipart, mailcap database is consulted + to find a way to convert the body to plain text (can be prevented with + options -Bbei). (The author has no idea how mailcap can be configured on + OSes other than POSIX, please don't ask; users can consult an example at + http://phdru.name/Software/dotfiles/mailcap.html). + The decoding process uses the first copiousoutput filter it can find. If + there are no filters the body just passed as is. - Then Content-Type header consulted for charset. If it is not equal to -current default charset the body text recoded. Finally message headers and body -flushed to stdout. + Then Content-Type header is consulted for charset. If it is not equal to the + current locale charset and recoding is allowed (see options -Cc) the body + text is recoded. Finally message headers and the body are flushed to stdout. + + + Please be reminded that in the following options asterisk is a shell + metacharacter and should be escaped or quoted. Either write -d \*,-h1,-h2 + or -d '*,-h1,-h2' or such. + + OPTIONS @@ -133,8 +203,8 @@ flushed to stdout. -c - Recode different character sets in message body to current default - charset; this is the default. + Recode different character sets in message bodies to the current + default charset; this is the default. @@ -143,7 +213,7 @@ flushed to stdout. -C - Do not recode character sets in message body. + Do not recode character sets in message bodies. @@ -152,18 +222,43 @@ flushed to stdout. -f charset - Force this charset to be the current default charset instead of - sys.getdefaultencoding(). + Force this charset to be used for recoding instead of charset from + the current locale. + + + + + + -H hostname + --host=hostname + + + Use this hostname in X-MIME-Autoconverted headers instead of the + current hostname. + + + + + + -d header1[,header2,header3...] + + + Add the header(s) to a list of headers to decode; initially the + list contains headers "From", "To", "Cc", "Reply-To", + "Mail-Followup-To" and "Subject". - -d header + -d *[,-header1,-header2,-header3...] - Add the header to a list of headers to decode; initially the list - contains headers "From" and "Subject". + This variant completely changes headers decoding. First, the list of + headers to decode is cleared (as with -D). Then all the headers are + decoded except the given list of exceptions (headers listed with + '-'). In this mode it would be meaningless to give more than one -d + options but the program doesn't enforce the limitation. @@ -178,12 +273,42 @@ flushed to stdout. - -p header:param + -p header1[,header2,header3,...]:param1[,param2,param3,...] - Add the (header, param) pair to a list of headers' parameters to - decode; initially the list contains header "Content-Disposition", - parameter "filename". + Add the parameter(s) to a list of headers parameters to decode; + the parameter(s) will be decoded only for the given header(s). + Initially the list contains header "Content-Type", parameter "name"; + and header "Content-Disposition", parameter "filename". + + + + + + -p *[,-header1,-header2,-header3,...]:param1[,param2,param3,...] + + + Add the parameter(s) to a list of headers parameters to decode; + the parameter(s) will be decoded for all headers except the given + ones. + + + + + + -p header1[,header2,header3,...]:*[,-param1,-param2,-param3,...] + + + Decode all parameters except listed for the given list of headers. + + + + + + -p *[,-header1,-header2,-header3,...]:*[,-param1,-param2,-param3,...] + + + Decode all parameters except listed for all headers (except listed). @@ -192,7 +317,85 @@ flushed to stdout. -P - Clear the list of headers' parameters to decode (make it empty). + Clear the list of headers parameters to decode (make it empty). + + + + + + -r header1[,header2,header3...] + + + Add the header(s) to a list of headers to remove completely; + initially the list is empty. + + + + + + -r *[,-header1,-header2,-header3...] + + + Remove all headers except listed. + + + + + + -R header1[,header2,header3,...]:param1[,param2,param3,...] + + + Add the parameter(s) to a list of headers parameters to remove; + the parameter(s) will be removed only for the given header(s). + Initially the list is empty. + + + + + + -R *[,-header1,-header2,-header3,...]:param1[,param2,param3,...] + + + + -R header1[,header2,header3,...]:*[,-param1,-param2,-param3,...] + + + + -R *[,-header1,-header2,-header3,...]:*[,-param1,-param2,-param3,...] + + + Remove listed parameters (or all parameters except listed) from + these headers (or from all headers except listed). + + + + + + --set-header header:value + + + The program sets or changes value for the header to the given value + (only at the top-level message). + + + + + + --set-param header:param=value + + + The program sets or changes value for the header's parameter to the + given value (only at the top-level message). The header must exist. + + + + + + -B mask + + + Append mask to the list of binary content types that will be not + content-transfer-decoded (will be left as base64 or such). @@ -202,8 +405,9 @@ flushed to stdout. Append mask to the list of binary content types; if the message to - decode has a part of this type the program will pass the part as is, - without any additional processing. + decode has a part of this type the program content-transfer-decodes + (base64 or whatever to 8bit binary) it and outputs the decoded part + as is, without any further processing. @@ -213,7 +417,18 @@ flushed to stdout. Append mask to the list of error content types; if the message to - decode has a part of this type the program will raise ValueError. + decode has a part of this type the program fails with ValueError. + + + + + + -I mask + + + Append mask to the list of content types to completely ignore. + There will be no output - no headers, no body, no warning. For a + multipart part the entire subtree is removed. @@ -222,9 +437,10 @@ flushed to stdout. -i mask - Append mask to the list of content types to ignore; if the message to - decode has a part of this type the program will not pass it, instead - a line "Message body of type `%s' skipped." will be issued. + Append mask to the list of content types to ignore; if the message + to decode has a part of this type the program outputs headers but + skips the body. Instead a line "Message body of type %s skipped." + will be issued. @@ -234,18 +450,50 @@ flushed to stdout. Append mask to the list of content types to convert to text; if the - message to decode has a part of this type the program will consult - mailcap database, find first copiousoutput filter and convert the - part. + message to decode has a part of this type the program consults + mailcap database, find the first copiousoutput filter and, if any + filter is found, converts the part. + + + + + + --save-headers mask + + + + --save-body mask + + + + --save-message mask + + + Append mask to lists of content types to save to files; + --save-headers saves only decoded headers of the message (or + the current subpart); --save-body saves only decoded body; + --save-message saves the entire message or subpart (headers + + body). + + -O dest_dir + + + Set destination directory for the output files; if the directory + doesn't exist it will be created. Default is the current directory. + + + + -o output_file - Useful to set the output file in case of redirected stdin: + Save output to the file related to the destination directory from + option -O. Also useful in case of redirected stdin: mimedecode.py -o output_file < input_file cat input_file | mimedecode.py -o output_file @@ -254,47 +502,86 @@ cat input_file | mimedecode.py -o output_file - The last 4 options (-beit) require more explanation. They allow a user -to control body decoding with great flexibility. Think about said mail -archive; for example, its maintainer wants to put there only texts, convert -Postscript/PDF to text, pass HTML and images as is, and ignore everything -else. Easy: + The 5 list options (-Bbeit) require more explanation. They allow a user to + control body decoding with great flexibility. Think about said mail archive; + for example, its maintainer wants to put there only texts, convert + PDF/Postscript to text, pass HTML and images decoding base64 to html but + leaving images encoded, and ignore everything else. This is how it could be + done: - - mimedecode.py -t application/postscript -t application/pdf -b text/html - -b 'image/*' -i '*/*' + + mimedecode.py -t application/pdf -t application/postscript -t text/plain + -b text/html -B 'image/*' -i '*/*' - When the program decodes a message (or its part), it consults -Content-Type header. The content type is searched in all 4 lists, in order -"text-binary-ignore-error". If found, appropriate action performed. If not -found, the program search the same lists for "type/*" mask (the type of -"text/html" is just "text"). If found, appropriate action performed. If not -found, the program search the same lists for "*/*" mask. If found, -appropriate action performed. If not found, the program uses default -action, which is to decode everything to text (if mailcap specifies -a filter). + When the program decodes a message (non-MIME or a non-multipart subpart of a + MIME message), it consults Content-Type header. The content type is searched + in all 5 lists, in order "text-binary-ignore-error". If found, appropriate + action is performed. If not found, the program searches the same lists for + "type/*" mask (the type of "text/html" is just "text"). If found, + appropriate action is performed. If not found, the program searches the same + lists for "*/*" mask. If found, appropriate action is performed. If not + found, the program uses the default action, which is to decode everything to + text (if mailcap specifies a filter). This algorithm allows more specific + content types to override less specific: -b image/* will be processed + earlier than -B */*. + + + + Options -e/-I/-i can also work with multipart subparts of a MIME message. In + case of -I/-i the entire subtree of that multipart is removed; with -i it's + replaced with ignore warning. + + + + Initially all 5 lists are empty, so without any additional parameters + the program always uses the default decoding (as -t */*). + + + + The 3 save options (--save-headers/body/message) are similar. They make the + program to save every non-multipart subpart (only headers, or body, or the + entire subpart: headers + body) that corresponds to the given mask to a file. + Before saving the message (or the subpart) is decoded according to all other + options and is placed to the output stream as usual. Filename for the file is + created using "filename" parameter from the Content-Disposition header, or + "name" parameter from the Content-Type header if one of those exist; a serial + counter is prepended to the filename to avoid collisions; if there are no + name/filename parameters, or the name/filename parameters contain forbidden + characters (null, slash, backslash) the filename is just the serial counter. - Initially all 4 lists are empty, so without any additional parameters -the program always uses the default decoding. + If the file doesn't have any extensions (no dots in the value of the + name/filename parameters, or the name is just the counter) the program tries + to guess an extension by looking up the content type in mime.types files + including .mime.types file in the user's home directory (if it exists). If + the file has an extension the program doesn't try to verify that it + corresponds to the content type. + + + + The file is saved in the directory set with -O (default is the current + directory). The save options are proceeded before -e options so the user can + save the message that causes an error. ENVIRONMENT + + LANG + LC_ALL + LC_CTYPE + - LANG - LC_ALL - LC_CTYPE - Define current locale settings. Used to determine current default - charset (if your Python is properly installed and configured). + Define current locale settings. Used to determine current default charset (if + your Python is properly installed and configured). @@ -303,12 +590,13 @@ the program always uses the default decoding. BUGS The program may produce incorrect MIME message. The purpose of the program -is to decode whatever it is possible to decode, not to produce absolutely -correct MIME output. The incorrect parts are obvious - decoded Subject headers -and filenames. Other than that output is correct MIME message. The program does -not try to guess whether the headers are correct. For example, if a message -header states that charset is iso8859-5, but the body is actually in koi8-r - -the program will recode the message to the wrong charset. + is to decode whatever it is possible to decode, not to produce absolutely + correct MIME output. The incorrect parts are obvious - decoded + From/To/Cc/Reply-To/Mail-Followup-To/Subject headers and filenames. Other + than that output is correct MIME message. The program does not try to guess + whether the headers are correct. For example, if a message header states + that charset is iso8859-1, but the body (HTML, for example) is actually in + utf-8 the program will recode the message with the wrong charset. @@ -316,7 +604,9 @@ the program will recode the message to the wrong charset. AUTHOR - Oleg Broytman <phd@phdru.name> + Oleg + Broytman + phd@phdru.name @@ -324,7 +614,7 @@ the program will recode the message to the wrong charset. COPYRIGHT - Copyright (C) 2001-2014 PhiloSoft Design + Copyright (C) 2001-2017 PhiloSoft Design. @@ -351,7 +641,8 @@ the program will recode the message to the wrong charset. SEE ALSO - mimedecode.py home page: http://phdru.name/Software/Python/#mimedecode + mimedecode.py home page: + http://phdru.name/Software/Python/#mimedecode