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

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

 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

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

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 CW'='. 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                             C<'us-ascii'>
 language                            undef        
 log                L<Mail::Reporter>  C<'WARNINGS'>
 trace              L<Mail::Reporter>  C<'WARNINGS'>
 use_continuations                   <true>

 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

$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 CWundef 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.

$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

$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.

This class does not extend Mail::Reporter for obvious performance reasons: there is no logging or tracing available.

$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

$obj->DESTROY See Cleanup in Mail::Reporter

$obj->inGlobalDestruction See Cleanup in Mail::Reporter

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 CW$package does not implement CW$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 the MailBox website at <http://perl.overmeer.net/mailbox/> for more details.

Distribution version 2.063. Written by Mark Overmeer (mark@overmeer.net). See the ChangeLog for other contributors.

Copyright (c) 2001-2003 by the author(s). All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.