MIME::EncWords - deal with RFC 2047 encoded words (improved)
the MIME::EncWords manpage is aimed to be another implimentation
of the MIME::Words manpage so that it will achieve more exact conformance with
RFC 2047 (formerly RFC 1522) specifications. Additionally, it contains
some improvements.
Following synopsis and descriptions are inherited from its inspirer,
then added descriptions on improvements (**) or changes and
clarifications (*).
Before reading further, you should see the MIME::Tools manpage to make sure that
you understand where this module fits into the grand scheme of things.
Go on, do it now. I'll wait.
Ready? Ok...
use MIME::EncWords qw(:all);
### Decode the string into another string, forgetting the charsets:
$decoded = decode_mimewords(
'To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>',
);
### Split string into array of decoded [DATA,CHARSET] pairs:
@decoded = decode_mimewords(
'To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>',
);
### Encode a single unsafe word:
$encoded = encode_mimeword("\xABFran\xE7ois\xBB");
### Encode a string, trying to find the unsafe words inside it:
$encoded = encode_mimewords("Me and \xABFran\xE7ois\xBB in town");
Fellow Americans, you probably won't know what the hell this module
is for. Europeans, Russians, et al, you probably do. :-).
For example, here's a valid MIME header you might get:
From: =?US-ASCII?Q?Keith_Moore?= <moore@cs.utk.edu>
To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>
CC: =?ISO-8859-1?Q?Andr=E9_?= Pirard <PIRARD@vm1.ulg.ac.be>
Subject: =?ISO-8859-1?B?SWYgeW91IGNhbiByZWFkIHRoaXMgeW8=?=
=?ISO-8859-2?B?dSB1bmRlcnN0YW5kIHRoZSBleGFtcGxlLg==?=
=?US-ASCII?Q?.._cool!?=
The fields basically decode to (sorry, I can only approximate the
Latin characters with 7 bit sequences /o and 'e):
From: Keith Moore <moore@cs.utk.edu>
To: Keld J/orn Simonsen <keld@dkuug.dk>
CC: Andr'e Pirard <PIRARD@vm1.ulg.ac.be>
Subject: If you can read this you understand the example... cool!
Supplement: Fellow Americans, Europeans, you probably won't know
what the hell this module is for. East Asians, et al, you probably do.
(^_^).
For example, here's a valid MIME header you might get:
Subject: =?EUC-KR?B?sNTAuLinKGxhemluZXNzKSwgwvzB9ri7seIoaW1w?=
=?EUC-KR?B?YXRpZW5jZSksILGzuLgoaHVicmlzKQ==?=
The fields basically decode to (sorry, I cannot approximate the
non-Latin multibyte characters with any 7 bit sequences):
Subject: ???(laziness), ????(impatience), ??(hubris)
- decode_mimewords ENCODED, [OPTS...]
-
Function.
Go through the string looking for RFC 2047-style ``Q''
(quoted-printable, sort of) or ``B'' (base64) encoding, and decode them.
In an array context, splits the ENCODED string into a list of decoded
[DATA, CHARSET] pairs, and returns that list. Unencoded
data are returned in a 1-element array [DATA], giving an effective
CHARSET of undef.
$enc = '=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>';
foreach (decode_mimewords($enc)) {
print "", ($_[1] || 'US-ASCII'), ": ", $_[0], "\n";
}
**
However, adjacent encoded-words with same charset will be concatenated
to handle multibyte sequences safely.
**
Language information defined by RFC2231, section 5 will be additional
third element, if any.
*
Whitespaces surrounding unencoded data will not be stripped so that
compatibility with the MIME::Words manpage will be ensured.
In a scalar context, joins the ``data'' elements of the above
list together, and returns that. Warning: this is information-lossy,
and probably not what you want, but if you know that all charsets
in the ENCODED string are identical, it might be useful to you.
(Before you use this, please see unmime in the MIME::WordDecoder manpage,
which is probably what you want.)
**
See also ``Charset'' option below.
In the event of a syntax error, $@ will be set to a description
of the error, but parsing will continue as best as possible (so as to
get something back when decoding headers).
$@ will be false if no error was detected.
*
Malformed encoded-words will be kept encoded.
In this case $@ will be set.
Any arguments past the ENCODED string are taken to define a hash of options.
**
When Unicode/multibyte support is disabled
(see USE_ENCODE in the MIME::Charset manpage),
these options will not have any effects.
- Charset
B<**>
-
Name of character set by which data elements in scalar context
will be converted.
The default is no conversion.
If this option is specified as special value
"_UNICODE_",
returned value will be Unicode string.
Note:
This feature is still information-lossy, except when "_UNICODE_" is
specified.
- Detect7bit
B<**>
-
Try to detect 7-bit charset on unencoded portions.
Default is
"YES".
- Mapping
B<**>
-
In scalar context, specify mappings actually used for charset names.
"EXTENDED" uses extended mappings.
"STANDARD" uses standardized strict mappings.
Default is "EXTENDED".
- encode_mimeword RAW, [ENCODING], [CHARSET]
-
Function.
Encode a single RAW ``word'' that has unsafe characters.
The ``word'' will be encoded in its entirety.
### Encode "<<Franc,ois>>":
$encoded = encode_mimeword("\xABFran\xE7ois\xBB");
You may specify the ENCODING ("Q" or "B"), which defaults to "Q".
**
You may also specify it as ``special'' value: "S" to choose shorter
one of either "Q" or "B".
You may specify the CHARSET, which defaults to iso-8859-1.
*
Spaces will be escaped with ``_'' by "Q" encoding.
- encode_mimewords RAW, [OPTS]
-
Function.
Given a RAW string, try to find and encode all ``unsafe'' sequences
of characters:
### Encode a string with some unsafe "words":
$encoded = encode_mimewords("Me and \xABFran\xE7ois\xBB");
Returns the encoded string.
**
RAW may be a Unicode string when Unicode/multibyte support is enabled
(see USE_ENCODE in the MIME::Charset manpage).
Furthermore, RAW may be a reference to that returned
by decode_mimewords on array context. In latter case ``Charset''
option (see below) will be overridden (see also a note below).
Note:
*
When RAW is an arrayref,
adjacent encoded-words (i.e. elements having non-ASCII charset element)
are concatenated. Then they are split taking
care of character boundaries of multibyte sequences when Unicode/multibyte
support is enabled.
Portions for unencoded data should include surrounding whitespace(s), or
they will be merged into adjoining encoded-word(s).
Any arguments past the RAW string are taken to define a hash of options:
- Charset
-
Encode all unsafe stuff with this charset. Default is 'ISO-8859-1',
a.k.a. ``Latin-1''.
- Detect7bit
**Detect7bit
B<**>
-
When ``Encoding'' option (see below) is specified as
"a" and ``Charset''
option is unknown, try to detect 7-bit charset on given RAW string.
Default is "YES".
When Unicode/multibyte support is disabled,
this option will not have any effects
(see USE_ENCODE in the MIME::Charset manpage).
- Encoding
-
The encoding to use,
"q" or "b".
**
You may also specify ``special'' values: "a" will automatically choose
recommended encoding to use (with charset conversion if alternative
charset is recommended: see the MIME::Charset manpage);
"s" will choose shorter one of either "q" or "b".
Note:
*
As of release 1.005, The default was changed from "q"
(the default on MIME::Words) to "a".
- Field
-
Name of the mail field this string will be used in.
**
Length of mail field name will be considered in the first line of
encoded header.
- Folding
B<**>
-
A Sequence to fold encoded lines. The default is
"\n".
If empty string "" is specified, encoded-words exceeding line length
(see MaxLineLen below) will be split by SPACE.
Note:
*
Though RFC 5322 (formerly RFC 2822) states that the lines in
Internet messages are delimited by CRLF ("\r\n"),
this module chose LF ("\n") as a default to keep backward compatibility.
When you use the default, you might need converting newlines
before encoded headers are thrown into session.
- Mapping
**Mapping
B<**>
-
Specify mappings actually used for charset names.
"EXTENDED" uses extended mappings.
"STANDARD" uses standardized strict mappings.
The default is "EXTENDED".
When Unicode/multibyte support is disabled,
this option will not have any effects
(see USE_ENCODE in the MIME::Charset manpage).
- MaxLineLen
B<**>
-
Maximum line length excluding newline.
The default is 76.
Negative value means unlimited line length (as of release 1.012.3).
- Minimal
B<**>
-
Takes care of natural word separators (i.e. whitespaces)
in the text to be encoded.
If
"NO" is specified, this module will encode whole text
(if encoding needed) not regarding whitespaces;
encoded-words exceeding line length will be split based only on their
lengths.
Default is "YES" by which minimal portions of text are encoded.
If "DISPNAME" is specified, portions including special characters
described in RFC5322 (formerly RFC2822, RFC822) address specification
(section 3.4) are also encoded.
This is useful for encoding display-name of address fields.
Note:
As of release 0.040, default has been changed to "YES" to ensure
compatibility with MIME::Words.
On earlier releases, this option was fixed to be "NO".
Note:
"DISPNAME" option was introduced at release 1.012.
- Replacement
B<**>
-
See Error Handling in the MIME::Charset manpage.
Built-in defaults of option parameters for decode_mimewords
(except 'Charset' option) and
encode_mimewords can be overridden by configuration files:
MIME/Charset/Defaults.pm and MIME/EncWords/Defaults.pm.
For more details read MIME/EncWords/Defaults.pm.sample.
Consult $VERSION variable.
Development versions of this module may be found at
http://hatuka.nezumi.nu/repos/MIME-EncWords/.
the MIME::Charset manpage,
the MIME::Tools manpage
The original version of function decode_mimewords() is derived from
the MIME::Words manpage module that was written by:
Eryq (eryq@zeegee.com), ZeeGee Software Inc (http://www.zeegee.com).
David F. Skoll (dfs@roaringpenguin.com) http://www.roaringpenguin.com
Other stuff are rewritten or added by:
Hatuka*nezumi - IKEDA Soji <hatuka(at)nezumi.nu>.
This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself.
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