phpman > man > Mail::Header(3pm)

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.

    $obj->new( [$source], [%options] )
    Mail::Header->new( [$source], [%options] )
        The $source 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 AT cpan.org>';
         $fields->{To}   = ['you@somewhere', 'me@localhost'];
         $head->header_hashref($fields);

    $obj->read($fh)
        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")

    $obj->print( [$fh] )
        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 AT oslonett.no>. Mail::Field::AddrList by Peter Orbaek <poe AT cit.dk>.
    Mail::Mailer and Mail::Send by Tim Bunce <Tim.Bunce AT ig.uk>. For other contributors see
    ChangeLog.

LICENSE
    Copyrights 1995-2000 Graham Barr <gbarr AT pobox.com> and 2001-2017 Mark Overmeer
    <perl AT 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