Front End Script for Setting HP Printer LCD Status

<?php

$msg =  "Your first line     "; // first line (20 chars max)
$msg .= "                    "; // second line, comment this out if your display is one line only

if(isset($_GET['firstLine'])) {
    $firstLine = $_GET['firstLine'];
    $len  = strlen($firstLine);
    if($len > 20) {
        $firstLine = substr($firstLine, 0, 19);
     } else {
        for ($i=$len; $i <= 20; $i++) {
            $firstLine .= " ";
        }
    }
    $msg = $firstLine;

    if(isset($_GET['secondLine'])) {
        $secondLine = $_GET['secondLine'];
        $len  = strlen($secondLine);
        if($len > 20) {
            $secondLine = substr($secondLine, 0, 19);
        }
        $msg .= $secondLine;
    }

    $msg = preg_replace("/[^A-Za-z0-9?![:space:]]/","",$msg); // strip any ASCII commands (eg newlines because they will break the command and print a page) use this if accepting user input.
    $msg = substr($msg,0,40); // (optional) truncate message to 40 characters (2 lines)

    $printerIP = '127.0.0.1'; // IPV4 (a.b.c.d) obviously change to your printer IP

    $socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
    socket_connect($socket,$printerIP,9100) or die("Could not connect to printer.");
    $data = chr(27) . "%-12345X@PJL JOB" . chr(13) . chr(10) .
    "@PJL RDYMSG DISPLAY=\"$msg\"" . chr(13) . chr(10) .
    "@PJL EOJ" . chr(13) . chr(10) .
    chr(27) . "%-12345X";
    socket_write($socket, $data) or die("Could not write to printer. Check connections.");

    echo "<strong>Printer status set to:<br>" . $firstLine . "<br>" . $secondLine . "</strong><br>";
}

?>
<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Set HP Printer LCD Status</title>
</head>
<body>
    <form method="GET">
        <table>
            <tr>
                <td><label for="firstLine">First line (20 chars max):</label></td>
                <td><input type="text" id="firstLie" name="firstLine" size="20"></td>
            </tr>
            <tr>
                <td><label for="secondLine">Second line (20 chars max):</label></td>
                <td><input type="text" id="secondLie" name="secondLine" size="20"></td>
            </tr>
            <tr>
                <td></td>
                <td><input type="submit" value="Submit"></td>
            </tr>
    </form>
</body>
</html>