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Mail::Header(3pm)     User Contributed Perl Documentation    Mail::Header(3pm)

       Mail::Header - manipulate MIME headers

        use Mail::Header;

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

       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 writ-
       ten) which costs some performance and make the implementation a little
       more complicated.  The Mail::Message::Head implementation is much newer
       and therefore better.



           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 ref-
           erence to an array. If given the new object will be initialized
           with headers either from the array of read from the file descrip-

           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      true

           . 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.


           Empty an existing "Mail::Header" object of all lines.


           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.


           "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.


           As header(), but it will eventually set headers from a hash refer-
           ence, and it will return the headers as a hash reference.


            $fields->{From} = 'Tobias Brox <tobixATcpan.org>';
            $fields->{To}   = ['you@somewhere', 'me@localhost'];


           Read a header from the given file descriptor into an existing
           Mail::Header object.


       $obj->fold_length([TAG], [LENGTH])

           Set the default fold length for all tags or just one. With no argu-
           ments 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.


           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.


           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.


       $obj->add(TAG, LINE [, INDEX])

           Add a new line to the header. If TAG is "undef" the 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.


           Returns the header as a single string.


           Remove any header line that, other than the tag, only contains

       $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.


           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.


           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


           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 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, oth-
           erwise 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


           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


           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

           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.

       This module is part of the MailTools distribution, http://perl.over-

       The MailTools bundle was developed by Graham Barr.  Later, Mark Over-
       meer took over maintenance without development.

       Mail::Cap by Gisle Aas <aasAToslonett.no>.  Mail::Field::AddrList by
       Peter Orbaek <poeATcit.dk>.  Mail::Mailer and Mail::Send by Tim Bunce
       <Tim.BunceATig.uk>.  For other contributors see ChangeLog.

       Copyrights 1995-2000 Graham Barr <gbarrATpobox.com> and 2001-2007 Mark
       Overmeer <perlATovermeer.net>.

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

perl v5.8.8                       2008-04-14                 Mail::Header(3pm)