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  1. #1
    New to the CF scene
    Join Date
    Dec 2010
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    Birmingham (UK)
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    CAPTCHA issue setting session variable

    I have a form with a CAPTCHA image.

    The image is is displayed fine in the browser with the following HTML but I need to set a session variable set to the characters generated in the image. The session variable is set in the php file CaptchasecurityImages.php

    HTML CODE
    <td align="right"><p><img src="CaptchaSecurityImages.php?width=100&height=40&characters=6" /></p> </td>

    The line $_SESSION['security_code'] = $code; (near the end of the php below) does not set the session variable. Any help or guidance would be much appreciated - Many thanks Dambuster

    THE PHP CODE CaptchaSecurityImages.php is:
    <?php
    class CaptchaSecurityImages {

    var $font = 'monofont.ttf';

    function generateCode($characters) {
    /* list all possible characters, similar looking characters and vowels have been removed */
    $possible = '23456789bcdfghjkmnpqrstvwxyz';
    $code = '';
    $i = 0;
    while ($i < $characters) {
    $code .= substr($possible, mt_rand(0, strlen($possible)-1), 1);
    $i++;
    }
    return $code;
    }

    function CaptchaSecurityImages($width='120',$height='40',$characters='6') {
    $code = $this->generateCode($characters);
    /* font size will be 75% of the image height */
    $font_size = $height * 0.75;
    $image = @imagecreate($width, $height) or die('Cannot initialize new GD image stream');
    /* set the colours */
    $background_color = imagecolorallocate($image, 255, 255, 255);
    $text_color = imagecolorallocate($image, 20, 40, 100);
    $noise_color = imagecolorallocate($image, 100, 120, 180);
    /* generate random dots in background */
    for( $i=0; $i<($width*$height)/3; $i++ ) {
    imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $noise_color);
    }
    /* generate random lines in background */
    for( $i=0; $i<($width*$height)/150; $i++ ) {
    imageline($image, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $noise_color);
    }
    /* create textbox and add text */
    $textbox = imagettfbbox($font_size, 0, $this->font, $code) or die('Error in imagettfbbox function');
    $x = ($width - $textbox[4])/2;
    $y = ($height - $textbox[5])/2;
    imagettftext($image, $font_size, 0, $x, $y, $text_color, $this->font , $code) or die('Error in imagettftext function');
    /* output captcha image to browser */
    header('Content-Type: image/jpeg');
    imagejpeg($image);
    imagedestroy($image);
    $_SESSION['security_code'] = $code;
    }

    }

    $width = isset($_GET['width']) ? $_GET['width'] : '120';
    $height = isset($_GET['height']) ? $_GET['height'] : '40';
    $characters = isset($_GET['characters']) && $_GET['characters'] > 1 ? $_GET['characters'] : '6';
    $captcha = new CaptchaSecurityImages($width,$height,$characters);

    ?>

  • #2
    Master Coder
    Join Date
    Jun 2003
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    Cottage Grove, Minnesota
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    Thanked 1,089 Times in 1,080 Posts
    The very top of EVERY script that uses SESSION ... should look like this ...

    <?php
    session_start();


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