Using Sockets in PHP

Using sockets in PHP : Get articles from Usenet

PHP can open sockets on remote or local hosts. Here is a hands-on example of using
such a socket: getting connected to a Usenet News Server, talking to this server,
and downloading some articles for a precise newsgroup.

Opening a socket in PHP

Sockets are opened using fsockopen(). This function is both available in PHP3 and
PHP4. It uses the following prototype :

<?php
int fsockopen 
    (string hostname, 
        int port [, 
        int errno [, 
        string errstr [, 
        double timeout]]])
?>

For the Internet domain, it will open a TCP socket connection to hostname on port port.
hostname may in this case be either a fully qualified domain name or an IP address. For UDP
connections, you need to explicitly specify the protocol: udp://hostname. For
the Unix domain, hostname will be used as the path to the socket, port must be set to 0 in
this case. The optional timeout can be used to set a timeout in seconds for the connect system call.

More information about fsockopen() :
http://www.php.net/manual/function.fsockopen.php

Network News Transfer Protocol

Accessing a Usenet News Server requires using a specific protocol, called NNTP and standing for Network News Transfer Protocol.

This protocol is higly detailed in RFC977 (Request For Comment number 977), which is available at : http://www.w3.org/Protocols/rfc977/rfc977.html

This document described precisely how to connect to and then dialog with the NNTP server thanks to the various commands available for the task.

Connecting

Connecting to the NNTP server requires knowing its hostname (or IP address) and the port it is listening on. You should include a timeout so that an unsuccessful attempt at connecting does not “freeze” the application.

<?php
$cfgServer    = "your.news.host";
$cfgPort    = 119;
$cfgTimeOut    = 10;
// open a socket
if(!$cfgTimeOut)
    // without timeout
    $usenet_handle = fsockopen($cfgServer, $cfgPort);
else
    // with timeout
    $usenet_handle = fsockopen($cfgServer, $cfgPort, &$errno, &$errstr, $cfgTimeOut);
if(!$usenet_handle) {
    echo "Connexion failedn";
    exit();
}    
else {
    echo "Connectedn";
    $tmp = fgets($usenet_handle, 1024);
}
?>