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Mail::Message::Field::UseriContributed PerMail::Message::Field::Attribute(3pm)



NAME
       Mail::Message::Field::Attribute - one attribute of a full field

INHERITANCE
        Mail::Message::Field::Attribute
          is a Mail::Reporter

SYNOPSIS
        my $field    = $msg->head->get('Content-Disposition') or return;
        my $full     = $field->study;   # full understanding in unicode
        my $filename = $full->attribute('filename')           or return;

        print ref $filename;     # this class name
        print $filename;         # the attributes content in utf-8
        print $filename->value;  # same
        print $filename->string; # print string as was found in the file
        $filename->print(\*OUT); # print as was found in the file

DESCRIPTION
       Attributes within MIME fields can be quite complex, and therefore be
       slow and consumes a lot of memory.  The Mail::Message::Field::Fast and
       Mail::Message::Field::Flex simplify them the attributes a lot, which
       may result in erroneous behavior in rare cases.  With the increase of
       non-western languages on Internet, the need for the complex headers
       becomes more and more in demand.

       A "Mail::Message::Field::Attribute" can be found in any structured
       Mail::Message::Field::Full header field.

METHODS
       Constructors

       Mail::Message::Field::Attribute->new((NAME, [VALUE] | STRING), OPTIONS)

           Create a new attribute NAME with the optional VALUE.  If no VALUE
           is specified, the first argument of this method is inspected for an
           equals sign '='.  If that character is present, the argument is
           taken as STRING, containing a preformatted attribute which is
           processed.  Otherwise, the argument is taken as name without VALUE:
           set the value later with value().

           Whether encoding takes place depends on the OPTIONS and the
           existence of non-ascii characters in the VALUE.  The NAME can only
           contain ascii characters, hence is never encoded.

           To speed things up, attributes are not derived from the
           Mail::Reporter base-class.

            Option           --Defined in     --Default
            charset                             'us-ascii'
            language                            undef
            log                Mail::Reporter   'WARNINGS'
            trace              Mail::Reporter   'WARNINGS'
            use_continuations                   <true>

           . charset => STRING

               The VALUE is translated from utf-8 (Perl internal) to this
               character set, and the resulting string is encoded if required.
               "us-ascii" is the normal encoding for e-mail.  Valid character
               sets can be found with Encode::encodings(':all').

           . language => STRING

               RFC2231 adds the possiblity to specify a language with the
               field.  When no language is specified, none is included in the
               encoding.  Valid language names are defined by RFC2130.  This
               module has only limited support for this feature.

           . log => LEVEL

           . trace => LEVEL

           . use_continuations => BOOLEAN

               Continuations are used to break-up long parameters into pieces
               which are no longer than 76 characters. Encodings are specified
               in RFC2231, but not supported by some Mail User Agents.

           example:

            my $fn    = Mail::Message::Field::Attribute
                           ->new(filename => 'xyz');

            my $fattr = 'Mail::Message::Field::Attribute';  # abbrev
            my $fn    = $fattr->new
                ( filename => "Re\xC7u"
                , charset  => 'iso-8859-15'
                , language => 'nl-BE'
                );
            print $fn;
              # -->  filename*=iso-8859-15'nl-BE'Re%C7u

       Error handling

       $obj->AUTOLOAD

           See "Error handling" in Mail::Reporter

       $obj->addReport(OBJECT)

           See "Error handling" in Mail::Reporter

       $obj->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

       Mail::Message::Field::Attribute->defaultTrace([LEVEL]|[LOGLEVEL,
       TRACELEVEL]|[LEVEL, CALLBACK])

           See "Error handling" in Mail::Reporter

       $obj->errors

           See "Error handling" in Mail::Reporter

       $obj->log([LEVEL [,STRINGS]])

       Mail::Message::Field::Attribute->log([LEVEL [,STRINGS]])

           See "Error handling" in Mail::Reporter

       $obj->logPriority(LEVEL)

       Mail::Message::Field::Attribute->logPriority(LEVEL)

           See "Error handling" in Mail::Reporter

       $obj->logSettings

           See "Error handling" in Mail::Reporter

       $obj->notImplemented

           See "Error handling" in Mail::Reporter

       $obj->report([LEVEL])

           See "Error handling" in Mail::Reporter

       $obj->reportAll([LEVEL])

           See "Error handling" in Mail::Reporter

       $obj->trace([LEVEL])

           See "Error handling" in Mail::Reporter

       $obj->warnings

           See "Error handling" in Mail::Reporter

       Cleanup

       $obj->DESTROY

           See "Cleanup" in Mail::Reporter

       $obj->inGlobalDestruction

           See "Cleanup" in Mail::Reporter

       The attribute

       $obj->addComponent(STRING)

           A component is a parameter as defined by RFC2045, optionally using
           encoding or continuations as defined by RFC2231.  Components of an
           attribute are found when a field is being parsed.  The RFCs are
           very strict on valid characters, but we cannot be: you have to
           accept what is coming in if you can.

           example:

            my $param = Mail::Message::Field::Attribute->new;
            $param->addComponent("filename*=iso10646'nl-BE'%Re\47u");

       $obj->charset

           Returns the character set which is used for this parameter.  If any
           component is added which contains character set information, this
           is directly available.  Be warned that a character-set is case
           insensitive.

       $obj->language

           Returns the language which is defined in the argument.  If no
           language is defined "undef" is returned, which should be
           interpreted as "ANY"

       $obj->name

           Returns the name of this attribute.

       $obj->string

           Returns the parameter as reference to an array of lines.  When only
           one line is returned, it may be short enough to fit on the same
           line with other components of the header field.

       $obj->value([STRING])

           Returns the value of this parameter, optionally after setting it
           first.

       Attribute encoding

       $obj->decode

           Translate all known continuations into a value.  The produced value
           is returned and may be utf-8 encoded or a plain string.

       $obj->encode

       Internals

       $obj->mergeComponent(ATTRIBUTE)

           Merge the components from the specified attribute in this
           attribute.  This is needed when components of the same attribute
           are created separately.  Merging is required by the field parsing.

DIAGNOSTICS
       Warning: Illegal character in parameter name '$name'

           The specified parameter name contains characters which are not
           permitted by the RFCs.  You can better change the name into
           something which is accepted, or risk applications to corrupt or
           ignore the message.

       Error: Package $package does not implement $method.

           Fatal error: the specific package (or one of its superclasses) does
           not implement this method where it should. This message means that
           some other related classes do implement this method however the
           class at hand does not.  Probably you should investigate this and
           probably inform the author of the package.

       Error: Too late to merge: value already changed.

SEE ALSO
       This module is part of Mail-Box distribution version 2.082, built on
       April 28, 2008. Website: http://perl.overmeer.net/mailbox/

LICENSE
       Copyrights 2001-2008 by Mark Overmeer. For other contributors see
       ChangeLog.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.  See
       http://www.perl.com/perl/misc/Artistic.html



perl v5.10.0                      2008-04-Mail::Message::Field::Attribute(3pm)