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Snippets tagged "verification"

Simple Captcha with GD

Ever wanted to have a captcha image verification, but didn't want to go through the trouble of using the jgraph lib? Me too! Here's what I came up with.

sfCaptcha.class.php in /lib

class sfCaptcha 
  public $securityCode;
  private $codeLength=6;
  private $imageFile= 'captchaImg.jpg';
  public $fontSize  = 12;           
  public $fontColor  = array("252525","8b8787","550707");
  public function simpleRandString($length, $list="23456789ABDEFGHJKLMNQRTYabdefghijkmnqrty") {
     * Generates a random string with the specified length
     * Chars are chosen from the provided [optional] list
    $newstring = "";
    if ($length > 0) {
        while (strlen($newstring) < $length) {
            $newstring .= $list[mt_rand(0, strlen($list)-1)];
    return $newstring;
  public function generateImage()
    $this->securityCode = $this->simpleRandString($this->codeLength);
    $img_path = dirname(__FILE__)."/../web/uploads/";
    if(!is_writable($img_path) && !is_dir($img_path)){
      $error = "The image path $img_path does not appear to be writable or the folder does not exist. Please verify your settings";
      throw new Exception($error);
    $this->img = ImageCreateFromJpeg($img_path.$this->imageFile);
    $img_size = getimagesize($img_path.$this->imageFile);
    foreach($this->fontColor as $fcolor)
        $color[] = imagecolorallocate($this->img,
                hexdec(substr($fcolor, 1, 2)),
                hexdec(substr($fcolor, 3, 2)), 
                hexdec(substr($fcolor, 5, 2))
    $line = imagecolorallocate($this->img,255,255,255);
    $line2 = imagecolorallocate($this->img,200,200,200);
    $fw = imagefontwidth($this->fontSize)+3;
    $fh = imagefontheight($this->fontSize);
    // create a new string with a blank space between each letter so it looks better
    $newstr = "";
    for ($i = 0; $i < strlen($this->securityCode); $i++) {
        $newstr .= $this->securityCode[$i] ." ";
    // remove the trailing blank
    $newstr = trim($newstr);
    // center the string 
    $x = ($img_size[0] - strlen($newstr) * $fw ) / 2;
    $font[0] = 'arial.ttf';
    $font[1] = 'TIMES.ttf';
    $font[2] = 'COURI.ttf';
    // create random lines over text
    for($i=0; $i <3;$i++){
        $s_x = rand(40,180);
        $s_y = rand(5,35);
        $e_x = rand(($s_x-50), ($s_x+50));
        $e_y = rand(5,35);
        $c = rand(0, (count($color)-1));
      imageline($this->img, $s_x,$s_y, $e_x,$e_y, $color[$c]);
    // random bg ellipses
    imageellipse($this->img, $s_x, $s_y, $e_x, $e_y, $line);
    imageellipse($this->img, $e_x, $e_y, $s_x, $s_y, $line2);
    // output each character at a random height and standard horizontal spacing
    for ($i = 0; $i < strlen($newstr); $i++) {
        $hz = mt_rand( 10, $img_size[1] - $fh - 5);
        // randomize rotation
        $rotate = rand(-35, 35);
        // randomize font size
        $this->fontSize =  rand(14, 18);
        // radomize color
        $c = rand(0, (count($color)-1));
        // imagechar( $this->img, $this->fontSize, $x + ($fw*$i), $hz, $newstr[$i], $color);
        imagettftext($this->img, $this->fontSize,$rotate , $x + ($fw*$i), $hz + 12, $color[0], $font[$c], $newstr[$i]);

in the moduleyou want to use, in my case the user module add the following to your actions.

// replace XXX with the name of the action that is calling the form, like validateRegistration if your action is executeRegistration.
// This function validates the stored captcha against the users input and returns true if they match, or returns an error back to the form if they don't.
 public function validateXXX()
    if($this->getRequest()->getMethod() == sfRequest::POST)
      $captcha = $this->getRequestParameter('captcha');
      $session_captcha = $this->getUser()->getAttribute('captcha');
      if($captcha != $session_captcha)
        $this->getRequest()->setError('captcha', 'The code you entered did not match the one provided, please try again.');
        return false;
    return true;
// action that executes the actual image
public function executeGetImage()
    $captcha = new sfCaptcha();
    $this->getUser()->setAttribute('captcha', $captcha->securityCode);

and the in the view showing the image and form

<div class='error'><?php echo form_error('captcha') ?></div>
    <img src='<?php echo url_for('user/getimage'); ?>'><br>
    <?php echo input_tag('captcha') ?>

Note that the image source user/getimage refers to my user module and the executeGetImage() function we added above.

You'll need to add a JPG to your /web/uploads/ directory with the size of 200px w x 40px h and the name "captchaImg.jpg" (you can change the name in the sfCaptcha.classs.php file too). This is used to generate the captcha image and if you choose so you can create a background in the image that will be used. Otherwise, just leave it blank.

by Jason Ibele on 2006-06-13, tagged captcha  image  verification