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captcha
Derek Jones edited this page Jul 4, 2012
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9 revisions
Category:Plugin::Data Presentation
In the new Code Igniter the older plugin for generate captcha don't exist; i have simply transform this old plugin in a library: The code of captcha library
<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
* Code Igniter
*
* An open source application development framework for PHP 4.3.2 or newer
*
* @package CodeIgniter
* @author Rick Ellis
* @copyright Copyright (c) 2006, pMachine, Inc.
* @license http://www.codeignitor.com/user_guide/license.html
* @link http://www.codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/*
Instructions:
Load the plugin using:
$this->load->plugin('captcha');
Once loaded you can generate a captcha like this:
$vals = array(
'word' => 'Random word',
'img_path' => './captcha/',
'img_url' => 'http://www.your-site.com/captcha/',
'font_path' => './system/texb.ttf',
'img_width' => '150',
'img_height' => 30,
'expiration' => 7200
);
$cap = create_captcha($vals);
echo $cap['image'];
NOTES:
The captcha function requires the GD image library.
Only the img_path and img_url are required.
If a "word" is not supplied, the function will generate a random
ASCII string. You might put together your own word library that
you can draw randomly from.
If you do not specify a path to a TRUE TYPE font, the native ugly GD
font will be used.
The "captcha" folder must be writable (666, or 777)
The "expiration" (in seconds) signifies how long an image will
remain in the captcha folder before it will be deleted. The default
is two hours.
RETURNED DATA
The create_captcha() function returns an associative array with this data:
[array]
(
'image' => IMAGE TAG
'time' => TIMESTAMP (in microtime)
'word' => CAPTCHA WORD
)
The "image" is the actual image tag:
<img src="http://your-site.com/captcha/12345.jpg" width="140" height="50" />
The "time" is the micro timestamp used as the image name without the file
extension. It will be a number like this: 1139612155.3422
The "word" is the word that appears in the captcha image, which if not
supplied to the function, will be a random string.
ADDING A DATABASE
In order for the captcha function to prevent someone from posting, you will need
to add the information returned from create_captcha() function to your database.
Then, when the data from the form is submitted by the user you will need to verify
that the data exists in the database and has not expired.
Here is a table prototype:
CREATE TABLE captcha (
captcha_id bigint(13) unsigned NOT NULL auto_increment,
captcha_time int(10) unsigned NOT NULL,
ip_address varchar(16) default '0' NOT NULL,
word varchar(20) NOT NULL,
PRIMARY KEY (captcha_id),
KEY (word)
)
Here is an example of usage with a DB.
On the page where the captcha will be shown you'll have something like this:
$this->load->plugin('captcha');
$vals = array(
'img_path' => './captcha/',
'img_url' => 'http://www.your-site.com/captcha/'
);
$cap = create_captcha($vals);
$data = array(
'captcha_id' => '',
'captcha_time' => $cap['time'],
'ip_address' => $this->input->ip_address(),
'word' => $cap['word']
);
$query = $this->db->insert_string('captcha', $data);
$this->db->query($query);
echo 'Submit the word you see below:';
echo $cap['image'];
echo '<input type="text" name="captcha" value="" />';
Then, on the page that accepts the submission you'll have something like this:
// First, delete old captchas
$expiration = time()-7200; // Two hour limit
$DB->query("DELETE FROM captcha WHERE captcha_time < ".$expiration);
// Then see if a captcha exists:
$sql = "SELECT COUNT(*) AS count FROM captcha WHERE word = ? AND ip_address = ? AND date > ?";
$binds = array($_POST['captcha'], $this->input->ip_address(), $expiration);
$query = $this->db->query($sql, $binds);
$row = $query->row();
if ($row->count == 0)
{
echo "You must submit the word that appears in the image";
}
*/
class Captcha {
/**
|==========================================================
| Create Captcha
|==========================================================
|
*/
function create_captcha($data = '', $img_path = '', $img_url = '', $font_path = '')
{
$defaults = array('word' => '', 'img_path' => '', 'img_url' => '', 'img_width' => '100', 'img_height' => '30', 'font_path' => '', 'expiration' => 7200);
foreach ($defaults as $key => $val)
{
if ( ! is_array($data))
{
if ( ! isset($$key) OR $$key == '')
{
$$key = $val;
}
}
else
{
$$key = ( ! isset($data[$key])) ? $val : $data[$key];
}
}
if ($img_path == '' OR $img_url == '')
{
return FALSE;
}
if ( ! @is_dir($img_path))
{
return FALSE;
}
if ( ! is_writable($img_path))
{
return FALSE;
}
if ( ! extension_loaded('gd'))
{
return FALSE;
}
// -----------------------------------
// Remove old images
// -----------------------------------
list($usec, $sec) = explode(" ", microtime());
$now = ((float)$usec + (float)$sec);
$current_dir = @opendir($img_path);
while($filename = @readdir($current_dir))
{
if ($filename != "." and $filename != ".." and $filename != "index.html")
{
$name = str_replace(".jpg", "", $filename);
if (($name + $expiration) < $now)
{
@unlink($img_path.$filename);
}
}
}
@closedir($current_dir);
// -----------------------------------
// Do we have a "word" yet?
// -----------------------------------
if ($word == '')
{
$pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$str = '';
for ($i = 0; $i < 8; $i++)
{
$str .= substr($pool, mt_rand(0, strlen($pool) -1), 1);
}
$word = $str;
}
// -----------------------------------
// Determine angle and position
// -----------------------------------
$length = strlen($word);
$angle = ($length >= 6) ? rand(-($length-6), ($length-6)) : 0;
$x_axis = rand(6, (360/$length)-16);
$y_axis = ($angle >= 0 ) ? rand($img_height, $img_width) : rand(6, $img_height);
// -----------------------------------
// Create image
// -----------------------------------
$im = ImageCreate($img_width, $img_height);
// -----------------------------------
// Assign colors
// -----------------------------------
$bg_color = ImageColorAllocate($im, 255, 255, 255);
$border_color = ImageColorAllocate($im, 153, 102, 102);
$text_color = ImageColorAllocate($im, 110, 110, 110);
$grid_color = imagecolorallocate($im, 255, 182, 182);
$shadow_color = imagecolorallocate($im, 255, 240, 240);
/*$bg_color = ImageColorAllocate($im, 255, 255, 255);
$border_color = ImageColorAllocate($im, 153, 102, 102);
$text_color = ImageColorAllocate($im, 204, 153, 153);
$grid_color = imagecolorallocate($im, 255, 182, 182);
$shadow_color = imagecolorallocate($im, 255, 240, 240);
*/
// -----------------------------------
// Create the rectangle
// -----------------------------------
ImageFilledRectangle($im, 0, 0, $img_width, $img_height, $bg_color);
// -----------------------------------
// Create the spiral pattern
// -----------------------------------
$theta = 1;
$thetac = 7;
$radius = 16;
$circles = 20;
$points = 32;
for ($i = 0; $i < ($circles * $points) - 1; $i++)
{
$theta = $theta + $thetac;
$rad = $radius * ($i / $points );
$x = ($rad * cos($theta)) + $x_axis;
$y = ($rad * sin($theta)) + $y_axis;
$theta = $theta + $thetac;
$rad1 = $radius * (($i + 1) / $points);
$x1 = ($rad1 * cos($theta)) + $x_axis;
$y1 = ($rad1 * sin($theta )) + $y_axis;
imageline($im, $x, $y, $x1, $y1, $grid_color);
$theta = $theta - $thetac;
}
// -----------------------------------
// Write the text
// -----------------------------------
$use_font = ($font_path != '' AND file_exists($font_path) AND function_exists('imagettftext')) ? TRUE : FALSE;
if ($use_font == FALSE)
{
$font_size = 12;
$x = rand(0, $img_width/($length/3));
$y = 0;
echo "NO";
}
else
{
$font_size = 16;
$x = rand(0, $img_width/($length/1.5));
$y = $font_size+2;
}
for ($i = 0; $i < strlen($word); $i++)
{
if ($use_font == FALSE)
{
$y = rand(0 , $img_height/2);
imagestring($im, $font_size, $x, $y, substr($word, $i, 1), $text_color);
$x += ($font_size*2);
}
else
{
$y = rand($img_height/2, $img_height-3);
imagettftext($im, $font_size, $angle, $x, $y, $text_color, $font_path, substr($word, $i, 1));
$x += $font_size;
}
}
// -----------------------------------
// Create the border
// -----------------------------------
imagerectangle($im, 0, 0, $img_width-1, $img_height-1, $border_color);
// -----------------------------------
// Generate the image
// -----------------------------------
$img_name = $now.'.jpg';
ImageJPEG($im, $img_path.$img_name);
$img = "<img src=\"$img_url$img_name\" width=\"$img_width\" height=\"$img_height\" style=\"border:0;\" alt=\" \" />";
ImageDestroy($im);
return array('word' => $word, 'time' => $now, 'image' => $img);
}
}
?>For us ethe librarie (put it in the application librarie) create a db table as this code
CREATE TABLE captcha (
captcha_id bigint(13) unsigned NOT NULL auto_increment,
captcha_time int(10) unsigned NOT NULL,
ip_address varchar(16) default '0' NOT NULL,
word varchar(20) NOT NULL,
PRIMARY KEY (captcha_id),
KEY (word)
)In the controller:
function prova(){
$this->load->library('captcha');
$this->load->library('validation');
$rules['user'] = "required";
$rules['captcha'] = "required|callback_captcha_check";
$this->validation->set_rules($rules);
$fields['user'] = 'Username';
$fields['captcha'] = 'codice';
$this->validation->set_fields($fields);
if ($this->validation->run() == FALSE)
{
$expiration = time()-300; // Two hour limit
$this->db->query("DELETE FROM captcha WHERE captcha_time < ".$expiration);
$vals = array(
//'word' => 'Random word',
'img_path' => './uploads/',
'img_url' => base_url().'uploads/',
'font_path' => './system/fonts/texb.ttf',
'img_width' => '100',
'img_height' => '30',
'expiration' => '3600'
);
$cap = $this->captcha->create_captcha($vals);
//
$dati['image']= $cap['image'];
//mette nel db
$data = array(
'captcha_id' => '',
'captcha_time' => $cap['time'],
'ip_address' => $this->input->ip_address(),
'word' => $cap['word']
);
$query = $this->db->insert_string('captcha', $data);
$this->db->query($query);
$this->load->view('captcha',$dati);
}else{
echo "OK";
}
}
function captcha_check()
{
// Then see if a captcha exists:
$exp=time()-600;
$sql = "SELECT COUNT(*) AS count FROM captcha WHERE word = ? AND ip_address = ? AND captcha_time > ?";
$binds = array($this->input->post('captcha'), $this->input->ip_address(), $exp);
$query = $this->db->query($sql, $binds);
$row = $query->row();
if ($row->count == 0)
{
$this->validation->set_message('_captcha_check', 'Codice di controllo non valido');
return FALSE;
}else{
return TRUE;
}
}and the view as
<html>
<head>
<title>My Form</title>
</head>
<body>
<?=$this->validation->error_string; ?>
<?=form_open('XXXXXXXXX type your controller'); ?>
<h5>Username</h5>
<?=$this->validation->user_error; ?>
<input type="text" name="user" value="<?php echo ($this->validation->user) ;?>" size="50" />
<br/>
<?=$image;?>
<br/>
<?=$this->validation->captcha_error; ?>
<input type="text" name="captcha" value="" />
<br/>
<div><input type="submit" value="Submit" /></div>
</form>
</body>
</html>