Can't Create Client Server Socket Program in Php

Question

I am working on Client Server Socket Program for chat like application, but it is giving following error message

Warning: socket_bind(): unable to bind address [98]: Address already in use.... Could not bind to address on line 15

I have seen various tutorials, but i want Server to listen to client request continuously. I have seen port number it is open also but still the same message. I am stuck at this point for several days could not get proper solutions. Please help to solve it thanks.....

Server.php:

 <?php
    error_reporting(E_ALL);

    /* Allow the script to hang around waiting for connections. */
    set_time_limit(0);

    /* Turn on implicit output flushing so we see what we're getting
     * as it comes in. */
    ob_implicit_flush();

    $address = 'XXX.XX.XX.XXX';
    $port = 15213;

    if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
        echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
    }

    if (socket_bind($sock, $address, $port) === false) {
        echo "socket_bind() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
    }

    if (socket_listen($sock, 5) === false) {
        echo "socket_listen() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
    }

    do {
        if (($msgsock = socket_accept($sock)) === false) {
            echo "socket_accept() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
            break;
        }
        /* Send instructions. */
        $msg = "\nWelcome to the PHP Test Server. \n" .
            "To quit, type 'quit'. To shut down the server type 'shutdown'.\n";
        socket_write($msgsock, $msg, strlen($msg));

        do {
            if (false === ($buf = socket_read($msgsock, 2048, PHP_NORMAL_READ))) {
                echo "socket_read() failed: reason: " . socket_strerror(socket_last_error($msgsock)) . "\n";
                break 2;
            }
            if (!$buf = trim($buf)) {
                continue;
            }
            if ($buf == 'quit') {
                break;
            }
            if ($buf == 'shutdown') {
                socket_close($msgsock);
                break 2;
            }
            $talkback = "PHP: You said '$buf'.\n";
            socket_write($msgsock, $talkback, strlen($talkback));
            echo "$buf\n";
        } while (true);
        socket_close($msgsock);
    } while (true);

    socket_close($sock);
    ?>

Client.php

    <?php
error_reporting(E_ALL);

echo "<h2>TCP/IP Connection</h2>\n";

/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');

/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');

/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
    echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
} else {
    echo "OK.\n";
}

echo "Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
    echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\n";
} else {
    echo "OK.\n";
}

$in = "HEAD / HTTP/1.1\r\n";
$in .= "Host: www.example.com\r\n";
$in .= "Connection: Close\r\n\r\n";
$out = '';

echo "Sending HTTP HEAD request...";
socket_write($socket, $in, strlen($in));
echo "OK.\n";

echo "Reading response:\n\n";
while ($out = socket_read($socket, 2048)) {
    echo $out;
}

echo "Closing socket...";
socket_close($socket);
echo "OK.\n\n";
?>

Answer 1

In both php files you create a Socket on the same port. That is the problem.

The Server has to create the Socket while the client has to use the Socket (not creating it, too)

Two applications can not create the same socket and listen on the same port.

EDIT: I have tested your script with xampp at localhost. so IP was 127.0.0.1. The Server listened properly on port 15213 and the client connected properly on this port. That the port was open i saw with the xampp controll panel.

If you use your scripts like you posted here, then you have to replace in Server.php

$address = 'XXX.XX.XX.XXX';

with

$address = '127.0.0.1';

and in Client.php

$address = gethostbyname('www.example.com');

with

$address = gethostbyname('localhost');
or
$address = '127.0.0.1';