=head1 NAME
Mail::Header - manipulate MIME headers
=head1 SYNOPSIS
my
$head
= Mail::Header->new;
my
$head
= Mail::Header->new( \
*STDIN
);
my
$head
= Mail::Header->new( [<>],
Modify
=> 0);
=head1 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 L<Mail::Field|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.
=head1 METHODS
=head2 Constructors
$obj
-E<gt>B<dup>
=over 4
Create a duplicate of the current object.
=back
$obj
-E<gt>B<new>([ARG], [OPTIONS])
Mail::Header-E<gt>B<new>([ARG], [OPTIONS])
=over 4
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 true
.
FoldLength
=> INTEGER
=over 4
The
default
length
of line to be used
when
folding header lines.
See L<fold_length()|Mail::Header/
"Accessors"
>.
=back
.
MailFrom
=>
'IGNORE'
|
'COERCE'
|
'KEEP'
|
'ERROR'
=over 4
See method L<mail_from()|Mail::Header/
"Accessors"
>.
=back
.
Modify
=> BOOLEAN
=over 4
If this value is I<true> then the headers will be re-formatted,
otherwise the
format
of the header lines will remain unchanged.
=back
=back
=head2
"Fake"
constructors
Be warned that the
next
constructors all
require
an already created
header object, of which the original content will be destroyed.
$obj
-E<gt>B<empty>
=over 4
Empty an existing C<Mail::Header> object of all lines.
=back
$obj
-E<gt>B<extract>(ARRAY)
=over 4
Extract a header from the
given
array into an existing Mail::Header
object. C<extract> B<will modify> this array.
Returns the object that the method was called on.
=back
$obj
-E<gt>B<header>([ARRAY])
=over 4
C<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.
=back
$obj
-E<gt>B<header_hashref>([HASH])
=over 4
As L<header()|Mail::Header/
""
Fake
" constructors"
>, 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
);
=back
$obj
-E<gt>B<
read
>(FILEHANDLE)
=over 4
Read a header from the
given
file descriptor into an existing Mail::Header
object.
=back
=head2 Accessors
$obj
-E<gt>B<fold_length>([TAG], [LENGTH])
=over 4
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 C<LENGTH>
is
given
it sets the
default
fold
length
for
the current object.
In the two argument form C<fold_length> may be called as a static method,
setting
default
fold lengths
for
tags that will be used by B<all>
C<Mail::Header> objects. See the C<fold> method
for
a description on how C<Mail::Header> uses these
values
.
=back
$obj
-E<gt>B<mail_from>(
'IGNORE'
|
'COERCE'
|
'KEEP'
|
'ERROR'
)
=over 4
This specifies what to
do
when
a C<`From '> line is encountered.
Valid
values
are C<IGNORE> - ignore and discard the header,
C<ERROR> - invoke an error (call
die
), C<COERCE> -
rename
them as Mail-From
and C<KEEP> - keep them.
=back
$obj
-E<gt>B<modify>([VALUE])
=over 4
If C<VALUE> is I<false> then C<Mail::Header> will not
do
any automatic
reformatting of the headers, other than to ensure that the line
starts
with
the tags
given
.
=back
=head2 Processing
$obj
-E<gt>B<add>(TAG, LINE [, INDEX])
=over 4
Add a new line to the header. If TAG is C<
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.
=back
$obj
-E<gt>B<as_string>
=over 4
Returns the header as a single string.
=back
$obj
-E<gt>B<cleanup>
=over 4
Remove any header line that, other than the tag, only contains whitespace
=back
$obj
-E<gt>B<combine>(TAG [, WITH])
=over 4
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.
=back
$obj
-E<gt>B<count>(TAG)
=over 4
Returns the number of
times
the
given
atg appears in the header
=back
$obj
-E<gt>B<
delete
>(TAG [, INDEX ])
=over 4
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.
=back
$obj
-E<gt>B<fold>([LENGTH])
=over 4
Fold the header. If LENGTH is not
given
, then C<Mail::Header> uses the
following rules to determine what
length
to fold a line.
=back
$obj
-E<gt>B<get>(TAG [, INDEX])
=over 4
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 C<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 C<
chomp
>)
=back
$obj
-E<gt>B<
print
>([FILEHANDLE])
=over 4
Print the header to the
given
file descriptor, or C<STDOUT>
if
no
file descriptor is
given
.
=back
$obj
-E<gt>B<replace>(TAG, LINE [, INDEX ])
=over 4
Replace a line in the header. If TAG is C<
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, 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.
=back
$obj
-E<gt>B<tags>
=over 4
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.
=back
$obj
-E<gt>B<unfold>([TAG])
=over 4
Unfold all instances of the
given
tag so that they
do
not spread across
multiple lines. If C<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.
=back
=head1 SEE ALSO
This module is part of the MailTools distribution,
=head1 AUTHORS
The MailTools bundle was developed by Graham Barr. Later, Mark
Overmeer took over maintenance without development.
Mail::Cap by Gisle Aas E<lt>aas
@oslonett
.noE<gt>.
Mail::Field::AddrList by Peter Orbaek E<lt>poe
@cit
.dkE<gt>.
Mail::Mailer and Mail::Send by Tim Bunce E<lt>Tim.Bunce
@ig
.co.ukE<gt>.
For other contributors see ChangeLog.
=head1 LICENSE
Copyrights 1995-2000 Graham Barr E<lt>gbarr
@pobox
.comE<gt> and
2001-2007 Mark Overmeer E<lt>perl
@overmeer
.netE<gt>.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.