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   1  package Net::servent;
   2  use strict;
   3  
   4  use 5.006_001;
   5  our $VERSION = '1.01';
   6  our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS);
   7  BEGIN {
   8      use Exporter   ();
   9      @EXPORT      = qw(getservbyname getservbyport getservent getserv);
  10      @EXPORT_OK   = qw( $s_name @s_aliases $s_port $s_proto );
  11      %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] );
  12  }
  13  use vars      @EXPORT_OK;
  14  
  15  # Class::Struct forbids use of @ISA
  16  sub import { goto &Exporter::import }
  17  
  18  use Class::Struct qw(struct);
  19  struct 'Net::servent' => [
  20     name        => '$',
  21     aliases    => '@',
  22     port        => '$',
  23     proto    => '$',
  24  ];
  25  
  26  sub populate (@) {
  27      return unless @_;
  28      my $sob = new();
  29      $s_name      =    $sob->[0]              = $_[0];
  30      @s_aliases     = @{ $sob->[1] } = split ' ', $_[1];
  31      $s_port     =    $sob->[2]          = $_[2];
  32      $s_proto     =    $sob->[3]          = $_[3];
  33      return $sob;
  34  }
  35  
  36  sub getservent    (   ) { populate(CORE::getservent()) }
  37  sub getservbyname ($;$) { populate(CORE::getservbyname(shift,shift||'tcp')) }
  38  sub getservbyport ($;$) { populate(CORE::getservbyport(shift,shift||'tcp')) }
  39  
  40  sub getserv ($;$) {
  41      no strict 'refs';
  42      return &{'getservby' . ($_[0]=~/^\d+$/ ? 'port' : 'name')}(@_);
  43  }
  44  
  45  1;
  46  
  47  __END__
  48  
  49  =head1 NAME
  50  
  51  Net::servent - by-name interface to Perl's built-in getserv*() functions
  52  
  53  =head1 SYNOPSIS
  54  
  55   use Net::servent;
  56   $s = getservbyname(shift || 'ftp') || die "no service";
  57   printf "port for %s is %s, aliases are %s\n",
  58      $s->name, $s->port, "@{$s->aliases}";
  59  
  60   use Net::servent qw(:FIELDS);
  61   getservbyname(shift || 'ftp') || die "no service";
  62   print "port for $s_name is $s_port, aliases are @s_aliases\n";
  63  
  64  =head1 DESCRIPTION
  65  
  66  This module's default exports override the core getservent(),
  67  getservbyname(), and
  68  getnetbyport() functions, replacing them with versions that return
  69  "Net::servent" objects.  They take default second arguments of "tcp".  This object has methods that return the similarly
  70  named structure field name from the C's servent structure from F<netdb.h>;
  71  namely name, aliases, port, and proto.  The aliases
  72  method returns an array reference, the rest scalars.
  73  
  74  You may also import all the structure fields directly into your namespace
  75  as regular variables using the :FIELDS import tag.  (Note that this still
  76  overrides your core functions.)  Access these fields as variables named
  77  with a preceding C<s_>.  Thus, C<$serv_obj-E<gt>name()> corresponds to
  78  $s_name if you import the fields.  Array references are available as
  79  regular array variables, so for example C<@{ $serv_obj-E<gt>aliases()}>
  80  would be simply @s_aliases.
  81  
  82  The getserv() function is a simple front-end that forwards a numeric
  83  argument to getservbyport(), and the rest to getservbyname().
  84  
  85  To access this functionality without the core overrides,
  86  pass the C<use> an empty import list, and then access
  87  function functions with their full qualified names.
  88  On the other hand, the built-ins are still available
  89  via the C<CORE::> pseudo-package.
  90  
  91  =head1 EXAMPLES
  92  
  93   use Net::servent qw(:FIELDS);
  94  
  95   while (@ARGV) {
  96       my ($service, $proto) = ((split m!/!, shift), 'tcp');
  97       my $valet = getserv($service, $proto);
  98       unless ($valet) {
  99           warn "$0: No service: $service/$proto\n"
 100           next;
 101       }
 102       printf "service $service/$proto is port %d\n", $valet->port;
 103       print "alias are @s_aliases\n" if @s_aliases;
 104   }
 105  
 106  =head1 NOTE
 107  
 108  While this class is currently implemented using the Class::Struct
 109  module to build a struct-like class, you shouldn't rely upon this.
 110  
 111  =head1 AUTHOR
 112  
 113  Tom Christiansen