MIME::Charset • man page

MIME::Charset (3)

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NAME

MIME::Charset - Charset Information for MIME

SYNOPSIS

    use MIME::Charset:

    $charset = MIME::Charset->new("euc-jp");

Getting charset information:

    $benc = $charset->body_encoding; # e.g. "Q"
    $cset = $charset->as_string; # e.g. "US-ASCII"
    $henc = $charset->header_encoding; # e.g. "S"
    $cset = $charset->output_charset; # e.g. "ISO-2022-JP"

Translating text data:

    ($text, $charset, $encoding) =
        $charset->header_encode(
           "\xc9\xc2\xc5\xaa\xc0\xde\xc3\xef\xc5\xaa".
           "\xc7\xd1\xca\xaa\xbd\xd0\xce\xcf\xb4\xef",
           Charset => 'euc-jp');
    # ...returns e.g. (<converted>, "ISO-2022-JP", "B").

    ($text, $charset, $encoding) =
        $charset->body_encode(
            "Collectioneur path\xe9tiquement ".
            "\xe9clectique de d\xe9chets",
            Charset => 'latin1');
    # ...returns e.g. (<original>, "ISO-8859-1", "QUOTED-PRINTABLE").

    $len = $charset->encoded_header_len(
        "Perl\xe8\xa8\x80\xe8\xaa\x9e",
        Charset => 'utf-8',
        Encoding => "b");
    # ...returns e.g. 28.

Manipulating module defaults:

    MIME::Charset::alias("csEUCKR", "euc-kr");
    MIME::Charset::default("iso-8859-1");
    MIME::Charset::fallback("us-ascii");

Non-OO functions (may be deprecated in near future):

    use MIME::Charset qw(:info);

    $benc = body_encoding("iso-8859-2"); # "Q"
    $cset = canonical_charset("ANSI X3.4-1968"); # "US-ASCII"
    $henc = header_encoding("utf-8"); # "S"
    $cset = output_charset("shift_jis"); # "ISO-2022-JP"

    use MIME::Charset qw(:trans);

    ($text, $charset, $encoding) =
        header_encode(
           "\xc9\xc2\xc5\xaa\xc0\xde\xc3\xef\xc5\xaa".
           "\xc7\xd1\xca\xaa\xbd\xd0\xce\xcf\xb4\xef",
           "euc-jp");
    # ...returns (<converted>, "ISO-2022-JP", "B");

    ($text, $charset, $encoding) =
        body_encode(
            "Collectioneur path\xe9tiquement ".
            "\xe9clectique de d\xe9chets",
            "latin1");
    # ...returns (<original>, "ISO-8859-1", "QUOTED-PRINTABLE");

    $len = encoded_header_len(
        "Perl\xe8\xa8\x80\xe8\xaa\x9e", "b", "utf-8"); # 28

DESCRIPTION

MIME::Charset provides information about character sets used for

MIME

messages on Internet.

Definitions

The charset is ``character set'' used in

MIME

to refer to a method of converting a sequence of octets into a sequence of characters. It includes both concepts of ``coded character set'' (

CCS

) and ``character encoding scheme'' (

CES

) of

ISO/IEC.

The encoding is that used in

MIME

to refer to a method of representing a body part or a header body as sequence(s) of printable US-ASCII characters.

Constructor

$charset = MIME::Charset->new([ CHARSET [, OPTS ]])

Create charset object.

OPTS

may accept following key-value pair.

NOTE

: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), conversion will not be performed. So this option do not have any effects.

Mapping => MAPTYPE: Whether to extend mappings actually used for charset names or not. "EXTENDED" uses extended mappings. "STANDARD" uses standardized strict mappings. Default is "EXTENDED".

Getting Information of Charsets

$charset->body_encoding
body_encoding CHARSET: Get recommended transfer-encoding of
CHARSET
for message body.
Returned value will be one of "B" (
BASE64
), "Q" (QUOTED-PRINTABLE), "S" (shorter one of either) or "undef" (might not be transfer-encoded; either 7BIT or 8BIT). This may not be same as encoding for message header.
$charset->as_string
canonical_charset CHARSET: Get canonical name for charset.
$charset->decoder: Get ``Encode::Encoding'' object to decode strings to Unicode by charset. If charset is not specified or not known by this module, undef will be returned.
$charset->dup: Get a copy of charset object.
$charset->encoder([ CHARSET ]): Get ``Encode::Encoding'' object to encode Unicode string using compatible charset recommended to be used for messages on Internet.
If optional
CHARSET
is specified, replace encoder (and output charset name) of $charset object with those of
CHARSET,
therefore, $charset object will be a converter between original charset and new
CHARSET.
$charset->header_encoding
header_encoding CHARSET: Get recommended encoding scheme of
CHARSET
for message header.
Returned value will be one of "B", "Q", "S" (shorter one of either) or "undef" (might not be encoded). This may not be same as encoding for message body.
$charset->output_charset
output_charset CHARSET: Get a charset which is compatible with given
CHARSET
and is recommended to be used for
MIME
messages on Internet (if it is known by this module).
When Unicode/multibyte support is disabled (see ``
USE_ENCODE''
), this function will simply return the result of ``canonical_charset''.

Translating Text Data

$charset->body_encode( STRING [, OPTS ])

body_encode STRING, CHARSET [, OPTS ]

Get converted (if needed) data of

STRING

and recommended transfer-encoding of that data for message body.

CHARSET

is the charset by which

STRING

is encoded.

OPTS

may accept following key-value pairs.

NOTE

: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), conversion will not be performed. So these options do not have any effects.

Detect7bit => YESNO: Try auto-detecting 7-bit charset when
CHARSET
is not given. Default is "YES".
Replacement => REPLACEMENT: Specifies error handling scheme. See ``Error Handling''.

: 3-item list of (converted string, charset for output, transfer-encoding) will be returned. Transfer-encoding will be either "BASE64", "QUOTED-PRINTABLE", "7BIT" or "8BIT". If charset for output could not be determined and converted string contains non-ASCII byte(s), charset for output will be "undef" and transfer-encoding will be "BASE64". Charset for output will be "US-ASCII" if and only if string does not contain any non-ASCII bytes.

$charset->decode( STRING [,CHECK])

Decode

STRING

to Unicode.

Note: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), this function will die.

detect_7bit_charset STRING

Guess 7-bit charset that may encode a string

STRING.

STRING

contains any 8-bit bytes, "undef" will be returned. Otherwise, Default Charset will be returned for unknown charset.

$charset->encode( STRING [, CHECK ])

Encode

STRING

(Unicode or non-Unicode) using compatible charset recommended to be used for messages on Internet (if this module knows it). Note that string will be decoded to Unicode then encoded even if compatible charset was equal to original charset.

Note: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), this function will die.

$charset->encoded_header_len( STRING [, ENCODING ])

encoded_header_len STRING, ENCODING, CHARSET

Get length of encoded

STRING

for message header (without folding).

ENCODING

may be one of "B", "Q" or "S" (shorter one of either "B" or "Q").

$charset->header_encode( STRING [, OPTS ])

header_encode STRING, CHARSET [, OPTS ]

Get converted (if needed) data of

STRING

and recommended encoding scheme of that data for message headers.

CHARSET

is the charset by which

STRING

is encoded.

OPTS

may accept following key-value pairs.

NOTE

: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), conversion will not be performed. So these options do not have any effects.

Detect7bit => YESNO: Try auto-detecting 7-bit charset when
CHARSET
is not given. Default is "YES".
Replacement => REPLACEMENT: Specifies error handling scheme. See ``Error Handling''.

: 3-item list of (converted string, charset for output, encoding scheme) will be returned. Encoding scheme will be either "B", "Q" or "undef" (might not be encoded). If charset for output could not be determined and converted string contains non-ASCII byte(s), charset for output will be "8BIT" (this is not charset name but a special value to represent unencodable data) and encoding scheme will be "undef" (should not be encoded). Charset for output will be "US-ASCII" if and only if string does not contain any non-ASCII bytes.

$charset->undecode( STRING [,CHECK])

Encode Unicode string

STRING

to byte string by input charset of $charset. This is equivalent to "$charset->decoder->encode()".

Note: When Unicode/multibyte support is disabled (see ``

USE_ENCODE''

), this function will die.

Manipulating Module Defaults

alias ALIAS [, CHARSET ]

Get/set charset alias for canonical names determined by ``canonical_charset''.

CHARSET

is given and isn't false,

ALIAS

will be assigned as an alias of

CHARSET.

Otherwise, alias won't be changed. In both cases, current charset name that

ALIAS

is assigned will be returned.

default [ CHARSET ]

Get/set default charset.

Default charset is used by this module when charset context is unknown. Modules using this module are recommended to use this charset when charset context is unknown or implicit default is expected. By default, it is "US-ASCII".

CHARSET

is given and isn't false, it will be set to default charset. Otherwise, default charset won't be changed. In both cases, current default charset will be returned.

NOTE

: Default charset should not be changed.

fallback [ CHARSET ]

Get/set fallback charset.

Fallback charset is used by this module when conversion by given charset is failed and "FALLBACK" error handling scheme is specified. Modules using this module may use this charset as last resort of charset for conversion. By default, it is "UTF-8".

CHARSET

is given and isn't false, it will be set to fallback charset. If

CHARSET

is "NONE", fallback charset will be undefined. Otherwise, fallback charset won't be changed. In any cases, current fallback charset will be returned.

NOTE

: It is useful that "US-ASCII" is specified as fallback charset, since result of conversion will be readable without charset information.

recommended CHARSET [, HEADERENC, BODYENC [, ENCCHARSET ]]

Get/set charset profiles.

If optional arguments are given and any of them are not false, profiles for

CHARSET

will be set by those arguments. Otherwise, profiles won't be changed. In both cases, current profiles for

CHARSET

will be returned as 3-item list of (

HEADERENC, BODYENC, ENCCHARSET

HEADERENC

is recommended encoding scheme for message header. It may be one of "B", "Q", "S" (shorter one of either) or "undef" (might not be encoded).

BODYENC

is recommended transfer-encoding for message body. It may be one of "B", "Q", "S" (shorter one of either) or "undef" (might not be transfer-encoded).

ENCCHARSET

is a charset which is compatible with given

CHARSET

and is recommended to be used for

MIME

messages on Internet. If conversion is not needed (or this module doesn't know appropriate charset),

ENCCHARSET

is "undef".

NOTE

: This function in the future releases can accept more optional arguments (for example, properties to handle character widths, line folding behavior, ...). So format of returned value may probably be changed. Use ``header_encoding'', ``body_encoding'' or ``output_charset'' to get particular profile.

Constants

USE_ENCODE: Unicode/multibyte support flag. Non-empty string will be set when Unicode and multibyte support is enabled. Currently, this flag will be non-empty on Perl 5.7.3 or later and empty string on earlier versions of Perl.

Error Handling

``body_encode'' and ``header_encode'' accept following "Replacement" options:

DEFAULT: Put a substitution character in place of a malformed character. For UCM-based encodings, <subchar> will be used.
FALLBACK: Try "DEFAULT" scheme using fallback charset (see ``fallback''). When fallback charset is undefined and conversion causes error, code will die on error with an error message.
CROAK: Code will die on error immediately with an error message. Therefore, you should trap the fatal error with eval{} unless you really want to let it die on error. Synonym is "STRICT".
PERLQQ
HTMLCREF
XMLCREF: Use "FB_PERLQQ", "FB_HTMLCREF" or "FB_XMLCREF" scheme defined by Encode module.
numeric values: Numeric values are also allowed. For more details see ``Handling Malformed Data'' in Encode.

If error handling scheme is not specified or unknown scheme is specified, "DEFAULT" will be assumed.

Configuration File

Built-in defaults for option parameters can be overridden by configuration file: MIME/Charset/Defaults.pm. For more details read MIME/Charset/Defaults.pm.sample.

VERSION

Consult $VERSION variable.

Development versions of this module may be found at <hatuka.nezumi.nu/repos/MIME-Charset>.

Incompatible Changes

Release 1.001

*: new() method returns an object when
CHARSET
argument is not specified.

Release 1.005

*: Restrict characters in encoded-word according to
RFC 2047
section 5 (3). This also affects return value of encoded_header_len() method.

Release 1.008.2

*: body_encoding() method may also returns "S".
*: Return value of body_encode() method for
UTF-8
may include "QUOTED-PRINTABLE" encoding item that in earlier versions was fixed to "BASE64".

AUTHOR

Hatuka*nezumi -

IKEDA

Soji <hatuka(at)nezumi.nu>

COPYRIGHT

IKEDA

Soji. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

MIME::Charset • man page

MIME::Charset • man page

MIME::Charset (3)

Leading comments

NAME

SYNOPSIS

DESCRIPTION

Definitions

Constructor

Getting Information of Charsets

Translating Text Data

Manipulating Module Defaults

Constants

Error Handling

Configuration File

VERSION

Incompatible Changes

SEE ALSO

AUTHOR

COPYRIGHT

Man Section

extra • Version

extra • Source

extra • Book