NAME

       Mail::Header - manipulate MIME headers

SYNOPSIS

        use Mail::Header;

        my $head = Mail::Header->new;
        my $head = Mail::Header->new( \*STDIN );
        my $head = Mail::Header->new( [<>], Modify => 0);

DESCRIPTION

       Read, write, create, and manipulate MIME headers, the leading part of each modern e-mail message, but
       also used in other protocols like HTTP.  The fields are kept in Mail::Field objects.

       Be aware that the header fields each have a name part, which shall be treated case-insensitive, and a
       content part, which may be folded over multiple lines.

       Mail::Header does not always follow the RFCs strict enough, does not help you with character encodings.
       It does not use weak references where it could (because those did not exist when the module was written)
       which costs some performance and make the implementation a little more complicated.  The
       Mail::Message::Head implementation is much newer and therefore better.

METHODS

   Constructors
       $obj->dup()
           Create a duplicate of the current object.

       $obj->new([ARG], [OPTIONS])
       Mail::Header->new([ARG], [OPTIONS])
           ARG  may  be  either a file descriptor (reference to a GLOB) or a reference to an array. If given the
           new object will be initialized with headers either from the array of read from the file descriptor.

           OPTIONS is a list of options given in the form of key-value pairs, just  like  a  hash  table.  Valid
           options are

            -Option    --Default
             FoldLength  79
             MailFrom    'KEEP'
             Modify      false

           FoldLength => INTEGER
             The default length of line to be used when folding header lines.  See fold_length().

           MailFrom => 'IGNORE'|'COERCE'|'KEEP'|'ERROR'
             See method mail_from().

           Modify => BOOLEAN
             If  this  value  is  true then the headers will be re-formatted, otherwise the format of the header
             lines will remain unchanged.

   "Fake" constructors
       Be warned that the next constructors all require an already created header object, of which the  original
       content will be destroyed.

       $obj->empty()
           Empty an existing "Mail::Header" object of all lines.

       $obj->extract(ARRAY)
           Extract  a  header  from  the given array into an existing Mail::Header object. "extract" will modify
           this array.  Returns the object that the method was called on.

       $obj->header([ARRAY])
           "header" does multiple operations. First it will extract a header from the ARRAY, if given.  It  will
           then  reformat  the header (if reformatting is permitted), and finally return a reference to an array
           which contains the header in a printable form.

       $obj->header_hashref([HASH])
           As header(), but it will eventually set headers from a hash reference, and it will return the headers
           as a hash reference.

           example:

            $fields->{From} = 'Tobias Brox <tobix@cpan.org>';
            $fields->{To}   = ['you@somewhere', 'me@localhost'];
            $head->header_hashref($fields);

       $obj->read(FILEHANDLE)
           Read a header from the given file descriptor into an existing Mail::Header object.

   Accessors
       $obj->fold_length([TAG], [LENGTH])
           Set the default fold length for all tags or just one. With no arguments the default  fold  length  is
           returned.  With  two  arguments  it  sets  the fold length for the given tag and returns the previous
           value. If only "LENGTH" is given it sets the default fold length for the current object.

           In the two argument form "fold_length" may be called as a static method, setting default fold lengths
           for tags that will be used by all "Mail::Header" objects. See the "fold" method for a description  on
           how "Mail::Header" uses these values.

       $obj->mail_from('IGNORE'|'COERCE'|'KEEP'|'ERROR')
           This specifies what to do when a `From ' line is encountered.  Valid values are "IGNORE" - ignore and
           discard  the  header,  "ERROR"  - invoke an error (call die), "COERCE" - rename them as Mail-From and
           "KEEP" - keep them.

       $obj->modify([VALUE])
           If "VALUE" is false then "Mail::Header" will not do any automatic reformatting of the headers,  other
           than to ensure that the line starts with the tags given.

   Processing
       $obj->add(TAG, LINE [, INDEX])
           Add  a  new line to the header. If TAG is "undef" the tag will be extracted from the beginning of the
           given line. If INDEX is given, the new line will be inserted into the  header  at  the  given  point,
           otherwise the new line will be appended to the end of the header.

       $obj->as_string()
           Returns the header as a single string.

       $obj->cleanup()
           Remove any header line that, other than the tag, only contains whitespace

       $obj->combine(TAG [, WITH])
           Combine  all  instances of TAG into one. The lines will be joined together WITH, or a single space if
           not given. The new item will be positioned in the header where the  first  instance  was,  all  other
           instances of TAG will be removed.

       $obj->count(TAG)
           Returns the number of times the given atg appears in the header

       $obj->delete(TAG [, INDEX ])
           Delete  a  tag  from  the  header.  If an INDEX id is given, then the Nth instance of the tag will be
           removed. If no INDEX is given, then all instances of tag will be removed.

       $obj->fold([LENGTH])
           Fold the header. If LENGTH is not given, then "Mail::Header" uses the following  rules  to  determine
           what length to fold a line.

       $obj->get(TAG [, INDEX])
           Get  the  text from a line. If an INDEX is given, then the text of the Nth instance will be returned.
           If it is not given the return value depends on the context in which "get" was  called.  In  an  array
           context  a  list  of  all  the  text  from all the instances of the TAG will be returned. In a scalar
           context the text for the first instance will be returned.

           The lines are unfolded, but still terminated with a new-line (see "chomp")

       $obj->print([FILEHANDLE])
           Print the header to the given file descriptor, or "STDOUT" if no file descriptor is given.

       $obj->replace(TAG, LINE [, INDEX ])
           Replace a line in the header.  If TAG is "undef" the tag will be extracted from the beginning of  the
           given  line.  If INDEX is given the new line will replace the Nth instance of that tag, otherwise the
           first instance of the tag is replaced. If the tag does not appear in the header then a new line  will
           be appended to the header.

       $obj->tags()
           Returns  an  array  of  all  the tags that exist in the header. Each tag will only appear in the list
           once. The order of the tags is not specified.

       $obj->unfold([TAG])
           Unfold all instances of the given tag so that they do not spread across multiple lines. If  "TAG"  is
           not given then all lines are unfolded.

           The  unfolding  process is wrong but (for compatibility reasons) will not be repaired: only one blank
           at the start of the line should be removed, not all of them.

SEE ALSO

       This module is part of the MailTools distribution, http://perl.overmeer.net/mailtools/.

AUTHORS

       The MailTools bundle was developed by Graham Barr.  Later, Mark Overmeer took  over  maintenance  without
       commitment to further development.

       Mail::Cap   by   Gisle  Aas  <aas@oslonett.no>.   Mail::Field::AddrList  by  Peter  Orbaek  <poe@cit.dk>.
       Mail::Mailer and Mail::Send by Tim Bunce <Tim.Bunce@ig.co.uk>.  For other contributors see ChangeLog.

LICENSE

       Copyrights 1995-2000 Graham Barr <gbarr@pobox.com> and 2001-2007 Mark Overmeer <perl@overmeer.net>.

       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 v5.20.0                                       2014-01-05                                  Mail::Header(3pm)