- - -

CAPTCHA Helper

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The CAPTCHA Helper file contains functions that assist in creating CAPTCHA images.

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Loading this Helper

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This helper is loaded using the following code:

-$this->load->helper('captcha'); - -

The following functions are available:

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create_captcha(`$data`)

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Takes an array of information to generate the CAPTCHA as input and creates the image to your specifications, returning an array of associative data about the image.

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[array]

-(

-  'image' => IMAGE TAG

-  'time'	=> TIMESTAMP (in microtime)

-  'word'	=> CAPTCHA WORD

-)

- -

The "image" is the actual image tag: -<img src="http://example.com/captcha/12345.jpg" width="140" height="50" />

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The "time" is the micro timestamp used as the image name without the file - extension. It will be a number like this: 1139612155.3422

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The "word" is the word that appears in the captcha image, which if not - supplied to the function, will be a random string.

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Using the CAPTCHA helper

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Once loaded you can generate a captcha like this:

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$vals = array(

-    'word'		 => 'Random word',

-    'img_path'	 => './captcha/',

-    'img_url'	 => 'http://example.com/captcha/',

-    'font_path'	 => './path/to/fonts/texb.ttf',

-    'img_width'	 => '150',

-    'img_height' => 30,

-    'expiration' => 7200

-    );

-

-$cap = create_captcha($vals);

-echo $cap['image'];

- -

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.

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Adding a Database

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In order for the captcha function to prevent someone from submitting, 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.

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Here is a table prototype:

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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` (`captcha_id`),

- KEY `word` (`word`)

-);

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Here is an example of usage with a database. On the page where the CAPTCHA will be shown you'll have something like this:

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$this->load->helper('captcha');

-$vals = array(

-    'img_path'	 => './captcha/',

-    'img_url'	 => 'http://example.com/captcha/'

-    );

-

-$cap = create_captcha($vals);

-

-$data = array(

-    '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="" />';

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Then, on the page that accepts the submission you'll have something like this:

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// First, delete old captchas

-$expiration = time()-7200; // Two hour limit

-$this->db->query("DELETE FROM captcha WHERE captcha_time < ".$expiration);	

-

-// Then see if a captcha exists:

-$sql = "SELECT COUNT(*) AS count FROM captcha WHERE word = ? AND ip_address = ? AND captcha_time > ?";

-$binds = array($_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";

-}

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CodeIgniter User Guide Version 2.0.3

CAPTCHA Helper

Loading this Helper

create_captcha($data)

Using the CAPTCHA helper

Adding a Database

create_captcha(`$data`)