Scott Nellé.com

Just a quick post to keep my CodeIgniter unique field validation extension up to date. When EllisLab released CodeIgniter 1.7.0, they included a new form validation class which is meant to replace the old validation class. The old class still exists in the code for now but it’s been deprecated, so developers are urged to use the new form validation class instead. Only very minor updates are needed to my validation extension in order to make it work with the new code. These were suggested to me by commenter libre before I even had a chance to look at implementing them myself. (Thanks libre!) For everyone’s benefit, here’s the updated version of the library (and remember, use this if you’re running CodeIgniter 1.7.0 or later:)

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * MY_Form_validation Class
 *
 * Extends Form_Validation library
 *
 * Adds one validation rule, "unique" and accepts a
 * parameter, the name of the table and column that
 * you are checking, specified in the forum table.column
 *
 * Note that this update should be used with the
 * form_validation library introduced in CI 1.7.0
 */
class MY_Form_validation extends CI_Form_validation {

	function My_Form_validation()
	{
	    parent::CI_Form_validation();
	}

	// --------------------------------------------------------------------

	/**
	 * Unique
	 *
	 * @access	public
	 * @param	string
	 * @param	field
	 * @return	bool
	 */
	function unique($str, $field)
	{
		$CI =& get_instance();
		list($table, $column) = split("\.", $field, 2);

		$CI->form_validation->set_message('unique', 'The %s that you requested is unavailable.');

		$query = $CI->db->query("SELECT COUNT(*) dupe FROM $table WHERE $column = '$str'");
		$row = $query->row();
		return ($row->dupe > 0) ? FALSE : TRUE;
	}
}
?>

You’ll want to save this file as system/application/libraries/MY_Form_validation.php (instead of MY_Validation.php.)

When you load the library, don’t forget that it’s now called form_validation instead of just validation. There have also been some changes to the way you set your rules for the new form validation class. You can read all about this in the class documentation. Here’s the basic format, including usage of the “unique” rule from the extension:

$this->form_validation->set_rules('username','User Name','required|min_length[5]|unique[users.username]');
$this->form_validation->set_rules('emailaddress','Email Address','required|valid_email|unique[users.email]');

Updated November 4, 2008: This extension has been updated slightly to work with CI’s new form validation class, added with version 1.7.0. If you’re using an older version of CI you should still use the extension on this page. If you’re using 1.7.0 or later, you should check out the updated extension.

I’m working on small web application and I’m building it with CodeIgniter. Like most web applications, mine requires user registration and login. And like most login systems, mine is happiest if each user has a unique username. While the CodeIgniter validation library is pretty robust, it doesn’t come with a function for checking a value to see if it is unique or if it already exists in the database. Fortunately there are a couple of ways to remedy that.

The first way is outlined in the documentation for the validation library under the heading “Callbacks: Your own Validation Functions.” I tried this and it works well, but it requires you to write the functions in your controller or model. I thought that looked messy and I wanted something a little more streamlined, so I decided to extend the validation library with my own function. Extending CodeIgniter’s libraries is pretty easy. Here’s what I came up with–I’ll explain the important lines afterward:

(more…)