PHP can open Socket ports on remote or local hosts. This article is a small example of using Socket: connect
to a Usenet news group server, talk to the server, and download some articles from the news group.
Open a socket in php
Use fsockopen() to open a socket. This function can be used in both php3 and php4. The function declaration
is like this:
int fsockopen (string hostname, int port [, int errno [, string errstr [, double timeout]]])
This function will open a port connected to the host hostname Port of the TCP connection. hostname can be a
valid domain name or an IP address. For udp connections, you must specify the protocol: udp://hostname.
For unix domains, the hostname uses the path to the socket. In this case, the port must be set to 0. The optional
timeout parameter is used to set the time to wait to open a socket, in seconds.
For more information about fsockopen(), please refer to: h
ttp://www.php.net/manual/function.fsockopen.php
Network News Transfer Protocol
Access the news group server This needs to be done through a protocol called NNTP (Network News Transfer Protocol). This protocol
is detailed in rfc977, available at http://www.w3.org/Protocols/rfc977/rfc977.html
. This document describes how to connect to an NNTP server, how to talk to the server, and the different commands to accomplish these tasks.
Connect
Connecting to an NNTP server requires knowing its hostname (or IP address) and the port it is listening on. To
avoid a failed connection attempt causing the program to hang, you should use the timeout parameter.
$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 "Connection failed.n";
exit();
}
else {
echo "Connected.n";
$tmp = fgets($usenet_handle, 1024);
}
?>
Talk to the server
Now that we are connected to the server, You can talk to the server through the socket opened earlier. For example,
says we want to get the latest 10 articles from a certain news group. RFC977 points out that the first step is to use the GROUP command to select the
correct newsgroup:
GROUP ggg