I need your help.
Please I need to understand some lines in this code which about handling multiple connections and how they effect the code.
error_reporting(~E_NOTICE);
set_time_limit (0);
$address = "0.0.0.0";
$port = 5000;
$max_clients = 10;
if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Couldn't create socket: [$errorcode] $errormsg \n");
}
echo "Socket created \n";
if( !socket_bind($sock, $address , 5000) )
{
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Could not bind socket : [$errorcode] $errormsg \n");
}
echo "Socket bind OK \n";
if(!socket_listen ($sock , 10))
{
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Could not listen on socket : [$errorcode] $errormsg \n");
}
echo "Socket listen OK \n";
echo "Waiting for incoming connections... \n";
$client_socks = array();
$read = array();
while (true)
{
$read = array();
$read[0] = $sock;
for ($i = 0; $i < $max_clients; $i++)
{
if($client_socks[$i] != null)
{
$read[$i+1] = $client_socks[$i];
}
}
if(socket_select($read , $write , $except , null) === false)
{
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Could not listen on socket : [$errorcode] $errormsg \n");
}
if (in_array($sock, $read))
{
for ($i = 0; $i < $max_clients; $i++)
{
if ($client_socks[$i] == null)
{
$client_socks[$i] = socket_accept($sock);
if(socket_getpeername($client_socks[$i], $address, $port))
{
echo "Client $address : $port is now connected to us. \n";
}
$message = "Welcome to php socket server version 1.0 \n";
$message .= "Enter a message and press enter, and i shall reply back \n";
socket_write($client_socks[$i] , $message);
break;
}
}
}
for ($i = 0; $i < $max_clients; $i++)
{
if (in_array($client_socks[$i] , $read))
{
$input = socket_read($client_socks[$i] , 1024);
if ($input == null)
{
unset($client_socks[$i]);
socket_close($client_socks[$i]);
}
$n = trim($input);
$output = "OK ... $input";
echo "Sending output to client \n";
socket_write($client_socks[$i] , $output);
}
}
}
the lines which I can't understand are:
the first line is $read[0] = $sock; here I can't understand why the coder store the master socket in the read array.
the second line is if (in_array($sock, $read)) here I can't understand how he/she check for a new connection using this line and how he/she check for the master socket if it is exist in the read array while he/she store it already in the read array.
the last line is if (in_array($client_socks[$i] , $read)) here I can't understand why the coder check for the client socket if it is exist in the read array while he/she want to write for it.
thanks every body.