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diff --git a/user_guide/helpers/captcha_helper.html b/user_guide/helpers/captcha_helper.html new file mode 100644 index 000000000..297e47e2a --- /dev/null +++ b/user_guide/helpers/captcha_helper.html @@ -0,0 +1,195 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> + +<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> +<title>CAPTCHA Helper : CodeIgniter User Guide</title> + +<style type='text/css' media='all'>@import url('../userguide.css');</style> +<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' /> + +<script type="text/javascript" src="../nav/nav.js"></script> +<script type="text/javascript" src="../nav/prototype.lite.js"></script> +<script type="text/javascript" src="../nav/moo.fx.js"></script> +<script type="text/javascript" src="../nav/user_guide_menu.js"></script> + +<meta http-equiv='expires' content='-1' /> +<meta http-equiv= 'pragma' content='no-cache' /> +<meta name='robots' content='all' /> +<meta name='author' content='ExpressionEngine Dev Team' /> +<meta name='description' content='CodeIgniter User Guide' /> + +</head> +<body> + +<!-- START NAVIGATION --> +<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div> +<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div> +<div id="masthead"> +<table cellpadding="0" cellspacing="0" border="0" style="width:100%"> +<tr> +<td><h1>CodeIgniter User Guide Version 1.7.2</h1></td> +<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td> +</tr> +</table> +</div> +<!-- END NAVIGATION --> + + +<!-- START BREADCRUMB --> +<table cellpadding="0" cellspacing="0" border="0" style="width:100%"> +<tr> +<td id="breadcrumb"> +<a href="http://codeigniter.com/">CodeIgniter Home</a> › +<a href="../index.html">User Guide Home</a> › +CAPTCHA Helper +</td> +<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td> +</tr> +</table> +<!-- END BREADCRUMB --> + +<br clear="all" /> + + +<!-- START CONTENT --> +<div id="content"> + + +<h1>CAPTCHA Helper</h1> + +<p>The CAPTCHA Helper file contains functions that assist in creating CAPTCHA images.</p> + + +<h2>Loading this Helper</h2> + +<p>This helper is loaded using the following code:</p> +<code>$this->load->helper('captcha');</code> + +<p>The following functions are available:</p> + +<h2>captcha_create(<var>$data</var>)</h2> + +<p>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.</p> + +<code>[array]<br /> +(<br /> + 'image' => IMAGE TAG<br /> + 'time' => TIMESTAMP (in microtime)<br /> + 'word' => CAPTCHA WORD<br /> +)</code> + + <p>The "image" is the actual image tag: +<code><img src="http://example.com/captcha/12345.jpg" width="140" height="50" /></code></p> + + <p>The "time" is the micro timestamp used as the image name without the file + extension. It will be a number like this: 1139612155.3422</p> + + <p>The "word" is the word that appears in the captcha image, which if not + supplied to the function, will be a random string.</p> + + <h3>Using the CAPTCHA plugin</h3> + + <p>Once loaded you can generate a captcha like this:</p> + +<code>$vals = array(<br /> + 'word' => 'Random word',<br /> + 'img_path' => './captcha/',<br /> + 'img_url' => 'http://example.com/captcha/',<br /> + 'font_path' => './path/to/fonts/texb.ttf',<br /> + 'img_width' => '150',<br /> + 'img_height' => 30,<br /> + 'expiration' => 7200<br /> + );<br /> +<br /> +$cap = create_captcha($vals);<br /> +echo $cap['image'];</code> + + <ul> + <li>The captcha function requires the GD image library.</li> + <li>Only the img_path and img_url are required.</li> + <li>If a "word" is not supplied, the function will generate a random + ASCII string. You might put together your own word library that + you can draw randomly from.</li> + <li>If you do not specify a path to a TRUE TYPE font, the native ugly GD + font will be used.</li> + <li>The "captcha" folder must be writable (666, or 777)</li> + <li>The "expiration" (in seconds) signifies how long an image will + remain in the captcha folder before it will be deleted. The default + is two hours.</li> + </ul> + + <h3>Adding a Database</h3> + + <p>In order for the captcha function to prevent someone from submitting, you will need + to add the information returned from <kbd>create_captcha()</kbd> function to your database. + Then, when the data from the form is submitted by the user you will need to verify + that the data exists in the database and has not expired.</p> + + <p>Here is a table prototype:</p> + +<code>CREATE TABLE captcha (<br /> + captcha_id bigint(13) unsigned NOT NULL auto_increment,<br /> + captcha_time int(10) unsigned NOT NULL,<br /> + ip_address varchar(16) default '0' NOT NULL,<br /> + word varchar(20) NOT NULL,<br /> + PRIMARY KEY `captcha_id` (`captcha_id`),<br /> + KEY `word` (`word`)<br /> +)</code> + + <p>Here is an example of usage with a database. On the page where the CAPTCHA will be shown you'll have something like this:</p> + +<code>$this->load->plugin('captcha');<br /> +$vals = array(<br /> + 'img_path' => './captcha/',<br /> + 'img_url' => 'http://example.com/captcha/'<br /> + );<br /> +<br /> +$cap = create_captcha($vals);<br /> +<br /> +$data = array(<br /> + 'captcha_time' => $cap['time'],<br /> + 'ip_address' => $this->input->ip_address(),<br /> + 'word' => $cap['word']<br /> + );<br /> +<br /> +$query = $this->db->insert_string('captcha', $data);<br /> +$this->db->query($query);<br /> +<br /> +echo 'Submit the word you see below:';<br /> +echo $cap['image'];<br /> +echo '<input type="text" name="captcha" value="" />';</code> + + <p>Then, on the page that accepts the submission you'll have something like this:</p> + +<code>// First, delete old captchas<br /> +$expiration = time()-7200; // Two hour limit<br /> +$this->db->query("DELETE FROM captcha WHERE captcha_time < ".$expiration); <br /> +<br /> +// Then see if a captcha exists:<br /> +$sql = "SELECT COUNT(*) AS count FROM captcha WHERE word = ? AND ip_address = ? AND date > ?";<br /> +$binds = array($_POST['captcha'], $this->input->ip_address(), $expiration);<br /> +$query = $this->db->query($sql, $binds);<br /> +$row = $query->row();<br /> +<br /> +if ($row->count == 0)<br /> +{<br /> + echo "You must submit the word that appears in the image";<br /> +}</code> + +</div> +<!-- END CONTENT --> + + +<div id="footer"> +<p> +Previous Topic: <a href="url_helper.html">URL Helper</a> + · +<a href="#top">Top of Page</a> · +<a href="../index.html">User Guide Home</a> +</p> +<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2010 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p> +</div> + +</body> +</html>
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