X-Git-Url: https://git.phdru.name/?p=mimedecode.git;a=blobdiff_plain;f=mimedecode.docbook;h=0129709532dca754b56d05efe16293cca83f9af3;hp=02ee7a5b3ccfaddacdbb87bd1c4eb1e7b51b330b;hb=bbdea6e26c82a925377da981f42b27653621a5a7;hpb=d7aac25395b00e62c5c79160b81dbfcb58f14bcd diff --git a/mimedecode.docbook b/mimedecode.docbook index 02ee7a5..0129709 100644 --- a/mimedecode.docbook +++ b/mimedecode.docbook @@ -14,7 +14,7 @@ - 2001-2014 + 2001-2017 PhiloSoft Design. @@ -90,7 +90,7 @@ - + @@ -122,7 +122,7 @@ - Here is the solution - mimedecode.py! + Here is a solution - mimedecode.py! @@ -131,8 +131,8 @@ 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 parts are decoded. Decoding can be - controlled by command-line options. + with multiple parts ("attachments") all non-multipart subparts are decoded. + Decoding can be controlled by the command-line options. @@ -140,21 +140,22 @@ -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 - 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. + 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 can be configured on OSes other - than POSIX, please don't ask me; real OS users can consult my example at + 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. @@ -162,14 +163,14 @@ Then Content-Type header is consulted for charset. If it is not equal to the - current locale charset and recoding is allowed the body text is recoded. - Finally message headers and the body are flushed to stdout. + 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 warned that in the following options asterisk is a shell + 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. @@ -221,7 +222,7 @@ -f charset - Force this charset to be the current default charset instead of + Force this charset to be used for recoding instead of charset from the current locale. @@ -254,10 +255,10 @@ This variant completely changes headers decoding. First, the list of - headers to decode is cleared. 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 it. + 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. @@ -275,8 +276,8 @@ -p header1[,header2,header3,...]:param1[,param2,param3,...] - Add the parameters(s) to a list of headers parameters to decode; - the parameters will be decoded only for the given header(s). + 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". @@ -287,8 +288,8 @@ -p *[,-header1,-header2,-header3,...]:param1[,param2,param3,...] - Add the parameters(s) to a list of headers parameters to decode; - the parameters will be decoded for all headers except the given + 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. @@ -344,8 +345,8 @@ -R header1[,header2,header3,...]:param1[,param2,param3,...] - Add the parameters(s) to a list of headers parameters to remove; - the parameters will be decoded only for the given header(s). + 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. @@ -363,7 +364,7 @@ -R *[,-header1,-header2,-header3,...]:*[,-param1,-param2,-param3,...] - Remove listed parameters (or all parameters except listed) frome + Remove listed parameters (or all parameters except listed) from these headers (or from all headers except listed). @@ -421,6 +422,17 @@ + + -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. + + + + -i mask @@ -457,10 +469,11 @@ --save-message mask - Append mask to a list of content types to save to a file; + Append mask to lists of content types to save to files; --save-headers saves only decoded headers of the message (or - subpart); --save-body saves only decoded body; --save-message saves - the entire message or subpart (headers + body). + the current subpart); --save-body saves only decoded body; + --save-message saves the entire message or subpart (headers + + body). @@ -492,14 +505,15 @@ cat input_file | mimedecode.py -o output_file 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 as is (decoding base64 to html - but left images in base64), and ignore everything else. Easy: + 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/pdf -t application/postscript -b text/html - -B 'image/*' -i '*/*' + mimedecode.py -t application/pdf -t application/postscript -t text/plain + -b text/html -B 'image/*' -i '*/*' @@ -507,17 +521,25 @@ cat input_file | mimedecode.py -o output_file 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 performed. If not found, the program search the same lists for + 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 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). + 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. + the program always uses the default decoding (as -t */*). @@ -525,14 +547,27 @@ the program always uses the default decoding. 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 placed to the output stream as usual. Filename for the file is + 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. + + + + 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). + directory). The save options are proceeded before -e options so the user can + save the message that causes an error. @@ -560,8 +595,8 @@ the program always uses the default decoding. 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 iso8859-5, but the body is actually in utf-8 the program - will recode the message with the wrong charset. + 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. @@ -579,7 +614,7 @@ the program always uses the default decoding. COPYRIGHT - Copyright (C) 2001-2014 PhiloSoft Design. + Copyright (C) 2001-2017 PhiloSoft Design.