MIME::WordDecoder(3pm)User Contributed Perl DocumentatioMIME::WordDecoder(3pm)
NAME
MIME::WordDecoder - decode RFC 2047 encoded words to a local
representation
WARNING: Most of this module is deprecated and may disappear. The only
function you should use for MIME decoding is "mime_to_perl_string".
SYNOPSIS
See MIME::Words for the basics of encoded words. See "DESCRIPTION" for
how this class works.
use MIME::WordDecoder;
### Get the default word-decoder (used by unmime()):
$wd = default MIME::WordDecoder;
### Get a word-decoder which maps to ISO-8859-1 (Latin1):
$wd = supported MIME::WordDecoder "ISO-8859-1";
### Decode a MIME string (e.g., into Latin1) via the default decoder:
$str = $wd->decode('To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld>');
### Decode a string using the default decoder, non-OO style:
$str = unmime('To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld>');
### Decode a string to an internal Perl string, non-OO style
### The result is likely to have the UTF8 flag ON.
$str = mime_to_perl_string('To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld>');
DESCRIPTION
WARNING: Most of this module is deprecated and may disappear. It
duplicates (badly) the function of the standard 'Encode' module. The
only function you should rely on is mime_to_perl_string.
A MIME::WordDecoder consists, fundamentally, of a hash which maps a
character set name (US-ASCII, ISO-8859-1, etc.) to a subroutine which
knows how to take bytes in that character set and turn them into the
target string representation. Ideally, this target representation
would be Unicode, but we don't want to overspecify the translation that
takes place: if you want to convert MIME strings directly to Big5,
that's your own decision.
The subroutine will be invoked with two arguments: DATA (the data in
the given character set), and CHARSET (the upcased character set name).
For example:
### Keep 7-bit characters as-is, convert 8-bit characters to '#':
sub keep7bit {
local $_ = shift;
tr/\x00-\x7F/#/c;
$_;
}
Here's a decoder which uses that:
### Construct a decoder:
$wd = MIME::WordDecoder->new({'US-ASCII' => "KEEP", ### sub { $_[0] }
'ISO-8859-1' => \&keep7bit,
'ISO-8859-2' => \&keep7bit,
'Big5' => "WARN",
'*' => "DIE"});
### Convert some MIME text to a pure ASCII string...
$ascii = $wd->decode('To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld>');
### ...which will now hold: "To: Keld J#rn Simonsen <keld>"
The UTF-8 built-in decoder decodes everything into Perl's internal
string format, possibly turning on the internal UTF8 flag. Use it like
this:
$wd = supported MIME::WordDecoder 'UTF-8';
$perl_string = $wd->decode('To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld>');
# perl_string will be a valid UTF-8 string with the "UTF8" flag set.
Generally, you should use the UTF-8 decoder in preference to "unmime".
PUBLIC INTERFACE
default [DECODER]
Class method. Get/set the default DECODER object.
supported CHARSET, [DECODER]
Class method. If just CHARSET is given, returns a decoder object
which maps data into that character set (the character set is
forced to all-uppercase).
$wd = supported MIME::WordDecoder "ISO-8859-1";
If DECODER is given, installs such an object:
MIME::WordDecoder->supported("ISO-8859-1" =>
(new MIME::WordDecoder::ISO_8859 "1"));
You should not override this method.
new [\@HANDLERS]
Class method, constructor. If \@HANDLERS is given, then @HANDLERS
is passed to handler() to initialize the internal map.
handler CHARSET=>\&SUBREF, ...
Instance method. Set the handler SUBREF for a given CHARSET, for
as many pairs as you care to supply.
When performing the translation of a MIME-encoded string, a given
SUBREF will be invoked when translating a block of text in
character set CHARSET. The subroutine will be invoked with the
following arguments:
DATA - the data in the given character set.
CHARSET - the upcased character set name, which may prove useful
if you are using the same SUBREF for multiple CHARSETs.
DECODER - the decoder itself, if it contains configuration information
that your handler function needs.
For example:
$wd = new MIME::WordDecoder;
$wd->handler('US-ASCII' => "KEEP");
$wd->handler('ISO-8859-1' => \&handle_latin1,
'ISO-8859-2' => \&handle_latin1,
'*' => "DIE");
Notice that, much as with %SIG, the SUBREF can also be taken from a
set of special keywords:
KEEP Pass data through unchanged.
IGNORE Ignore data in this character set, without warning.
WARN Ignore data in this character set, with warning.
DIE Fatal exception with "can't handle character set" message.
The subroutine for the special CHARSET of 'raw' is used for raw
(non-MIME-encoded) text, which is supposed to be US-ASCII. The
handler for 'raw' defaults to whatever was specified for 'US-ASCII'
at the time of construction.
The subroutine for the special CHARSET of '*' is used for any
unrecognized character set. The default action for '*' is WARN.
decode STRING
Instance method. Decode a STRING which might contain MIME-encoded
components into a local representation (e.g., UTF-8, etc.).
unmime STRING
Function, exported. Decode the given STRING using the default()
decoder. See default().
You should consider using the UTF-8 decoder instead. It decodes
MIME strings into Perl's internal string format.
mime_to_perl_string
Function, exported. Decode the given STRING into an internal Perl
Unicode string. You should use this function in preference to all
others.
The result of mime_to_perl_string is likely to have Perl's UTF8
flag set.
SUBCLASSES
MIME::WordDecoder::ISO_8859
A simple decoder which keeps US-ASCII and the 7-bit characters of
ISO-8859 character sets and UTF8, and also keeps 8-bit characters
from the indicated character set.
### Construct:
$wd = new MIME::WordDecoder::ISO_8859 2; ### ISO-8859-2
### What to translate unknown characters to (can also use empty):
### Default is "?".
$wd->unknown("?");
### Collapse runs of unknown characters to a single unknown()?
### Default is false.
$wd->collapse(1);
According to http://czyborra.com/charsets/iso8859.html (ca.
November 2000):
ISO 8859 is a full series of 10 (and soon even more) standardized
multilingual single-byte coded (8bit) graphic character sets for
writing in alphabetic languages:
1. Latin1 (West European)
2. Latin2 (East European)
3. Latin3 (South European)
4. Latin4 (North European)
5. Cyrillic
6. Arabic
7. Greek
8. Hebrew
9. Latin5 (Turkish)
10. Latin6 (Nordic)
The ISO 8859 charsets are not even remotely as complete as the
truly great Unicode but they have been around and usable for quite
a while (first registered Internet charsets for use with MIME) and
have already offered a major improvement over the plain 7bit US-
ASCII.
Characters 0 to 127 are always identical with US-ASCII and the
positions 128 to 159 hold some less used control characters: the
so-called C1 set from ISO 6429.
MIME::WordDecoder::US_ASCII
A subclass of the ISO-8859-1 decoder which discards 8-bit
characters. You're probably better off using ISO-8859-1.
SEE ALSO
MIME::Tools
AUTHOR
Eryq (eryq@zeegee.com), ZeeGee Software Inc (http://www.zeegee.com).
Dianne Skoll (dianne@skoll.ca)
perl v5.34.0 2022-07-10 MIME::WordDecoder(3pm)
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