How to load form validation rules from a database

Sometimes I would rather load my form validation rules from a database, instead of from a config file, or hard coding them into the controller. This is a short tutorial on how to do that.

First thing to do is add a database table like so:

CREATE TABLE `form_validation` (                                     
   `pk_form_validation_id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,  
   `form_key` VARCHAR(20) DEFAULT NULL,                               
   `field` VARCHAR(50) DEFAULT NULL,                                  
   `title` VARCHAR(50) DEFAULT NULL,                                  
   `rules` TEXT,                                                      
   PRIMARY KEY (`pk_form_validation_id`)                              
);

Then create a MY_Form_validation.php file in system/application/libraries. Paste the following code into that file:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class MY_Form_validation extends CI_Form_validation {

    /**
     * Checks to see if we need to load rules from the database,
     * then runs the CI_Form_validation library's run method.
     *
     * @access    public
     * @param    string
     * @return
     */

    function run($group = '')
    {
        // Is there a validation rule for the particular URI being accessed?
        $uri = ($group == '') ? trim($this->CI->uri->ruri_string(), '/') : $group;

        if ($uri != '' AND !isset($this->_config_rules[$uri]))
        {
            $this->load_rules_from_database($uri);
        }

        return parent::run($group);
    }

    /**
     * Loads rules from a database for a given form key
     *
     * @access    public
     * @param    string
     * @return    
     */

    function load_rules_from_database($form_key)
    {
        $this->CI->load->database();
        $qry = $this->CI->db->get_where('form_validation',         
                array('form_key'=>$form_key)); 

        foreach ($qry->result() as $row)
        {
            $this->set_rules($row->field, $row->title, $row->rules);
        }
    }
}

Then if you were going to make a contact form, you could put the following rows into your table:

INSERT INTO `form_validation` (`form_key`, `field`, `title`, `rules`) VALUES ("contact", "name", "Your Name", "required");
INSERT INTO `form_validation` (`form_key`, `field`, `title`, `rules`) VALUES ("contact", "phone", "Phone Number", "required");

Then in your Controller, you call the form validation run method just as you would if you put the rules into a config file:

$this->form_validation->run('contact') == FALSE