Captcha

[lostprophetpunk]

I am trying to use captcha to make my registration form safer.

 

The only thing that is going wrong is that the captcha image is not showing...

 

My host has a GD2 library, so it should work...shouldn't it?

 

This is the code in a seperate file...

<?php
session_start();
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); 
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
header("Cache-Control: no-store, no-cache, must-revalidate"); 
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache"); 

function _generateRandom($length=6)
{
    $_rand_src = array(
        array(48,57) //digits
        , array(97,122) //lowercase chars
//        , array(65,90) //uppercase chars
    );
    srand ((double) microtime() * 1000000);
    $random_string = "";
    for($i=0;$i<$length;$i++){
        $i1=rand(0,sizeof($_rand_src)-1);
        $random_string .= chr(rand($_rand_src[$i1][0],$_rand_src[$i1][1]));
    }
    return $random_string;
}

$im = @imagecreatefromjpeg("captcha.jpg"); 
$rand = _generateRandom(3);
$_SESSION['captcha'] = $rand;
ImageString($im, 5, 2, 2, $rand[0]." ".$rand[1]." ".$rand[2]." ", ImageColorAllocate ($im, 0, 0, 0));
$rand = _generateRandom(3);
ImageString($im, 5, 2, 2, " ".$rand[0]." ".$rand[1]." ".$rand[2], ImageColorAllocate ($im, 255, 0, 0));
Header ('Content-type: image/jpeg');
imagejpeg($im,NULL,100);
ImageDestroy($im);
?>

 

This is my test page...

<?php session_start() ?>
<form method="post" action="">
<table bgcolor="#CCCCCC">
<tr><th>Contact us (Post new message):</th></tr>
<tr><td><textarea cols="30" rows="5" name="message"></textarea></td></tr>
<tr><td align="center">CAPTCHA:<br>
    (antispam code, 3 black symbols)<br>
    <table><tr><td><img src="captcha.php" alt="captcha image"></td>
    <td><input type="text" name="captcha" size="3" maxlength="3"></td></tr></table>
</td></tr>
<tr><th align="center"><input type="submit" value="Submit"></th></tr>    
</table>
</form>
<?php
if(isset($_POST["captcha"]))
if($_SESSION["captcha"]==$_POST["captcha"])
{
    //CAPTHCA is valid; proceed the message: save to database, send by e-mail ...
    echo 'CAPTHCA is valid; proceed the message';
}
else
{
    echo 'CAPTHCA is not valid; ignore submission';
}
?>

[DarkWater]

If you navigate directly to captcha.php, does it show any errors?

[Xurion]

Do a phpinfo() just to check the GD is there.

[DarkWater]

He'd get a Fatal error: Call to undefined function image_jpeg().

[Xurion]

Only if he navigates to the captcha.php file and errors are turned on.

[lostprophetpunk]

The page loads fine just the image doesn't show.