package Net::hostent;
use strict;
use 5.006_001;
our $VERSION = '1.01';
our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS);
BEGIN {
use Exporter ();
@EXPORT = qw(gethostbyname gethostbyaddr gethost);
@EXPORT_OK = qw(
$h_name @h_aliases
$h_addrtype $h_length
@h_addr_list $h_addr
);
%EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] );
}
use vars @EXPORT_OK;
# Class::Struct forbids use of @ISA
sub import { goto &Exporter::import }
use Class::Struct qw(struct);
struct 'Net::hostent' => [
name => '$',
aliases => '@',
addrtype => '$',
'length' => '$',
addr_list => '@',
];
sub addr { shift->addr_list->[0] }
sub populate (@) {
return unless @_;
my $hob = new();
$h_name = $hob->[0] = $_[0];
@h_aliases = @{ $hob->[1] } = split ' ', $_[1];
$h_addrtype = $hob->[2] = $_[2];
$h_length = $hob->[3] = $_[3];
$h_addr = $_[4];
@h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ];
return $hob;
}
sub gethostbyname ($) { populate(CORE::gethostbyname(shift)) }
sub gethostbyaddr ($;$) {
my ($addr, $addrtype);
$addr = shift;
require Socket unless @_;
$addrtype = @_ ? shift : Socket::AF_INET();
populate(CORE::gethostbyaddr($addr, $addrtype))
}
sub gethost($) {
if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) {
require Socket;
&gethostbyaddr(Socket::inet_aton(shift));
} else {
&gethostbyname;
}
}
1;
__END__
=head1 NAME
Net::hostent - by-name interface to Perl's built-in gethost*() functions
=head1 SYNOPSIS
use Net::hostent;
=head1 DESCRIPTION
This module's default exports override the core gethostbyname() and
gethostbyaddr() functions, replacing them with versions that return
"Net::hostent" objects. This object has methods that return the similarly
named structure field name from the C's hostent structure from F<netdb.h>;
namely name, aliases, addrtype, length, and addr_list. The aliases and
addr_list methods return array reference, the rest scalars. The addr
method is equivalent to the zeroth element in the addr_list array
reference.
You may also import all the structure fields directly into your namespace
as regular variables using the :FIELDS import tag. (Note that this still
overrides your core functions.) Access these fields as variables named
with a preceding C<h_>. Thus, C<$host_obj-E<gt>name()> corresponds to
$h_name if you import the fields. Array references are available as
regular array variables, so for example C<@{ $host_obj-E<gt>aliases()
}> would be simply @h_aliases.
The gethost() function is a simple front-end that forwards a numeric
argument to gethostbyaddr() by way of Socket::inet_aton, and the rest
to gethostbyname().
To access this functionality without the core overrides,
pass the C<use> an empty import list, and then access
function functions with their full qualified names.
On the other hand, the built-ins are still available
via the C<CORE::> pseudo-package.
=head1 EXAMPLES
use Net::hostent;
use Socket;
@ARGV = ('netscape.com') unless @ARGV;
for $host ( @ARGV ) {
unless ($h = gethost($host)) {
warn "$0: no such host: $host\n";
next;
}
printf "\n%s is %s%s\n",
$host,
lc($h->name) eq lc($host) ? "" : "*really* ",
$h->name;
print "\taliases are ", join(", ", @{$h->aliases}), "\n"
if @{$h->aliases};
if ( @{$h->addr_list} > 1 ) {
my $i;
for $addr ( @{$h->addr_list} ) {
printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr);
}
} else {
printf "\taddress is [%s]\n", inet_ntoa($h->addr);
}
if ($h = gethostbyaddr($h->addr)) {
if (lc($h->name) ne lc($host)) {
printf "\tThat addr reverses to host %s!\n", $h->name;
$host = $h->name;
redo;
}
}
}
=head1 NOTE
While this class is currently implemented using the Class::Struct
module to build a struct-like class, you shouldn't rely upon this.
=head1 AUTHOR
Tom Christiansen
Mini Shell