CGI Programming on the World Wide Web

Previous Chapter 10
Gateways to Internet Information Servers

10.4 Socket Library

To make the whole task of creating clients and servers easier, a socket library was developed that encapsulates the various socket and network information functions. Here is the same finger client using the library:

require "";
$service = "finger";
chop ($hostname = `/bin/hostname`);
$input = shift (@ARGV);
($username, $remote_host) = split (/@/, $input, 2);
unless ($remote_host) {
        $remote_host = $hostname;

Most of the code here is the same as that used in the previous example, with one exception. The require command includes the library.

&open_connection (FINGER, $remote_host, $service) 
    || die "Cannot open connection to: $remote_host", "\n";

The open_connection library subroutine performs the following tasks:

Now, here is the rest of the program.

print FINGER $username, "\n";
while (<FINGER>) {
&close_connection (FINGER);
exit (0);

The close_connection subroutine flushes the socket so that all the remaining information in the socket is released, and then closes it. As you can see, this library makes the whole process of communicating with network servers much easier. Now, let's look at a simple example that interacts with an HTTP server.

Previous Home Next
Socket I/O in Perl Book Index Checking Hypertext (HTTP) Links

HTML: The Definitive Guide CGI Programming JavaScript: The Definitive Guide Programming Perl WebMaster in a Nutshell
Hosted by uCoz