phpman > perldoc > Mail::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.

    Extends "DESCRIPTION" in Mail::Reporter.

OVERLOADED
    overload: comparison
        When the second argument is a field, then both attribute name (case-sensitive) and the
        decoded value must be the same. Otherwise, the value is compared.

    overload: stringification
        Returns the decoded content of the attribute.

METHODS
    Extends "METHODS" in Mail::Reporter.

  Constructors
    Extends "Constructors" in Mail::Reporter.

    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 possibility 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
    Extends "Error handling" in Mail::Reporter.

    $obj->AUTOLOAD()
        Inherited, see "Error handling" in Mail::Reporter

    $obj->addReport($object)
        Inherited, see "Error handling" in Mail::Reporter

    $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
    Mail::Message::Field::Attribute->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level,
    $callback] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->errors()
        Inherited, see "Error handling" in Mail::Reporter

    $obj->log( [$level, [$strings]] )
    Mail::Message::Field::Attribute->log( [$level, [$strings]] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->logPriority($level)
    Mail::Message::Field::Attribute->logPriority($level)
        Inherited, see "Error handling" in Mail::Reporter

    $obj->logSettings()
        Inherited, see "Error handling" in Mail::Reporter

    $obj->notImplemented()
        Inherited, see "Error handling" in Mail::Reporter

    $obj->report( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->reportAll( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->trace( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->warnings()
        Inherited, see "Error handling" in Mail::Reporter

  Cleanup
    Extends "Cleanup" in Mail::Reporter.

    $obj->DESTROY()
        Inherited, 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 into 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-Message distribution version 3.012, built on February 11, 2022.
    Website: http://perl.overmeer.net/CPAN/

LICENSE
    Copyrights 2001-2022 by [Mark Overmeer <markov AT cpan.org>]. 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://dev.perl.org/licenses/