=head1 NAME
-perlfaq9 - Networking ($Revision: 1.24 $, $Date: 2005/10/13 19:43:13 $)
+perlfaq9 - Networking ($Revision: 6309 $)
=head1 DESCRIPTION
=head2 How do I decode or create those %-encodings on the web?
-
If you are writing a CGI script, you should be using the CGI.pm module
that comes with perl, or some other equivalent module. The CGI module
automatically decodes queries for you, and provides an escape()
function to handle encoding.
-
The best source of detailed information on URI encoding is RFC 2396.
Basically, the following substitutions do it:
s/([^\w()'*~!.-])/sprintf '%%%02x', ord $1/eg; # encode
- s/%([A-Fa-f\d]{2})/chr hex $1/eg; # decode
+ s/%([A-Fa-f\d]{2})/chr hex $1/eg; # decode
+ s/%([[:xdigit:]]{2})/chr hex $1/eg; # same thing
However, you should only apply them to individual URI components, not
the entire URI, otherwise you'll lose information and generally mess
To enable authentication for your web server, you need to configure
your web server. The configuration is different for different sorts
-of web servers---apache does it differently from iPlanet which does
+of web servers--apache does it differently from iPlanet which does
it differently from IIS. Check your web server documentation for
the details for your particular server.
will not bounce). Modules like Mail::CheckUser and Mail::EXPN
try to interact with the domain name system or particular
mail servers to learn even more, but their methods do not
-work everywhere---especially for security conscious administrators.
+work everywhere--especially for security conscious administrators.
Many are tempted to try to eliminate many frequently-invalid
mail addresses with a simple regex, such as
$msg[$msgno] .= $_;
END { print @msg[ sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msg) ] }
-=head2 How do I find out my hostname/domainname/IP address?
+=head2 How do I find out my hostname, domainname, or IP address?
+X<hostname, domainname, IP address, host, domain, hostfqdn, inet_ntoa,
+gethostbyname, Socket, Net::Domain, Sys::Hostname>
-The normal way to find your own hostname is to call the C<`hostname`>
-program. While sometimes expedient, this has some problems, such as
-not knowing whether you've got the canonical name or not. It's one of
-those tradeoffs of convenience versus portability.
+(contributed by brian d foy)
-The Sys::Hostname module (part of the standard perl distribution) will
-give you the hostname after which you can find out the IP address
-(assuming you have working DNS) with a gethostbyname() call.
+The Net::Domain module, which is part of the standard distribution starting
+in perl5.7.3, can get you the fully qualified domain name (FQDN), the host
+name, or the domain name.
- use Socket;
- use Sys::Hostname;
- my $host = hostname();
- my $addr = inet_ntoa(scalar gethostbyname($host || 'localhost'));
+ use Net::Domain qw(hostname hostfqdn hostdomain);
+
+ my $host = hostfqdn();
+
+The C<Sys::Hostname> module, included in the standard distribution since
+perl5.6, can also get the hostname.
+
+ use Sys::Hostname;
-Probably the simplest way to learn your DNS domain name is to grok
-it out of /etc/resolv.conf, at least under Unix. Of course, this
-assumes several things about your resolv.conf configuration, including
-that it exists.
+ $host = hostname();
-(We still need a good DNS domain name-learning method for non-Unix
-systems.)
+To get the IP address, you can use the C<gethostbyname> built-in function
+to turn the name into a number. To turn that number into the dotted octet
+form (a.b.c.d) that most people expect, use the C<inet_ntoa> function
+from the <Socket> module, which also comes with perl.
+
+ use Socket;
+
+ my $address = inet_ntoa(
+ scalar gethostbyname( $host || 'localhost' )
+ );
=head2 How do I fetch a news article or the active newsgroups?
Use one of the RPC modules you can find on CPAN (
http://search.cpan.org/search?query=RPC&mode=all ).
+=head1 REVISION
+
+Revision: $Revision: 6309 $
+
+Date: $Date: 2006-05-18 07:44:45 +0200 (jeu, 18 mai 2006) $
+
+See L<perlfaq> for source control details and availability.
+
=head1 AUTHOR AND COPYRIGHT
-Copyright (c) 1997-2005 Tom Christiansen, Nathan Torkington, and
+Copyright (c) 1997-2006 Tom Christiansen, Nathan Torkington, and
other authors as noted. All rights reserved.
This documentation is free; you can redistribute it and/or modify it
projects / p5sagit/p5-mst-13.2.git / blobdiff