sam-t2/devtools/v9/man/man3/Encode::MIME::Header.3

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.\" ========================================================================
.\"
.IX Title "Encode::MIME::Header 3"
.TH Encode::MIME::Header 3 "2001-09-21" "perl v5.8.8" "Perl Programmers Reference Guide"
.SH "NAME"
Encode::MIME::Header \-\- MIME 'B' and 'Q' header encoding
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 3
\&    use Encode qw/encode decode/;
\&    $utf8   = decode('MIME-Header', $header);
\&    $header = encode('MIME-Header', $utf8);
.Ve
.SH "ABSTRACT"
.IX Header "ABSTRACT"
This module implements \s-1RFC\s0 2047 Mime Header Encoding.  There are 3
variant encoding names; \f(CW\*(C`MIME\-Header\*(C'\fR, \f(CW\*(C`MIME\-B\*(C'\fR and \f(CW\*(C`MIME\-Q\*(C'\fR.  The
difference is described below
.PP
.Vb 5
\&              decode()          encode()
\&  ----------------------------------------------
\&  MIME-Header Both B and Q      =?UTF-8?B?....?=
\&  MIME-B      B only; Q croaks  =?UTF-8?B?....?=
\&  MIME-Q      Q only; B croaks  =?UTF-8?Q?....?=
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
When you decode(=?\fIencoding\fR?\fIX\fR?\fI\s-1ENCODED\s0 \s-1WORD\s0\fR?=), \fI\s-1ENCODED\s0 \s-1WORD\s0\fR
is extracted and decoded for \fIX\fR encoding (B for Base64, Q for
Quoted\-Printable). Then the decoded chunk is fed to
decode(\fIencoding\fR).  So long as \fIencoding\fR is supported by Encode,
any source encoding is fine.
.PP
When you encode, it just encodes \s-1UTF\-8\s0 string with \fIX\fR encoding then
quoted with =?UTF\-8?\fIX\fR?....?= .  The parts that \s-1RFC\s0 2047 forbids to
encode are left as is and long lines are folded within 76 bytes per
line.
.SH "BUGS"
.IX Header "BUGS"
It would be nice to support encoding to non\-UTF8, such as =?ISO\-2022\-JP?
and =?ISO\-8859\-1?= but that makes the implementation too complicated.
These days major mail agents all support =?UTF\-8? so I think it is
just good enough.
.PP
Due to popular demand, 'MIME\-Header\-ISO_2022_JP' was introduced by
Makamaka.  Thre are still too many MUAs especially cellular phone
handsets which does not grok \s-1UTF\-8\s0.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Encode
.PP
\&\s-1RFC\s0 2047, <http://www.faqs.org/rfcs/rfc2047.html> and many other
locations.