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MIME::EncWords(3) |
User Contributed Perl Documentation |
MIME::EncWords(3) |
MIME::EncWords - deal with RFC 2047 encoded words (improved)
MIME::EncWords is aimed to be another implimentation of MIME::Words 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 MIME::Tools 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 additonal third element, if any.
* Whitespaces surrounding unencoded data will not be
stripped so that compatibility with MIME::Words 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
MIME::WordDecoder, 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 MIME::Charset), these options will not
have any effects.
- Charset **
- 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 **
- Try to detect 7-bit charset on unencoded portions. Default is
"YES".
- Mapping **
- 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 MIME::Charset).
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 **
- 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 MIME::Charset).
- 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 MIME::Charset);
"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 **
- 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 **
- 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 MIME::Charset).
- MaxLineLen **
- Maximum line length excluding newline. The default is 76. Negative value
means unlimited line length (as of release 1.012.3).
- Minimal **
- 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 **
- See "Error Handling" in MIME::Charset.
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/>.
MIME::Charset, MIME::Tools
The original version of function decode_mimewords() is derived from
MIME::Words 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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