Pagination Automated a Little More

This pagination library builds upon JoostV's MY_Pagination library which offers a nice automated way of dealing with pagination. For my own needs I ended up adding more pagination configuration variables and adding an additional function to generate a brief "viewing X to Y of Z items" message. I separated out the pagination link area into a separate view making everything very easy to customize.

Here's the library file:

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

/**
 * Extends CI's pagination class (http://codeigniter.com/user_guide/libraries/pagination.html)
 * It sets some variables for configuration of the pagination class dynamically,
 * depending on the URI, so we don't have to substract the offset from the URI,
 * or set $config['base_url'] and $config['uri_segment'] manually in the controller
 * 
 * Here is what is set by this extension class:
 * 1. $this->offset - the current offset
 * 2. $this->uri_segment - the URI segment to be used for pagination
 * 3. $this->base_url - the base url to be used for pagination
 * (where $this refers to the pagination class)
 *
 * The way this works is simple:
 * Drop this library in folder application/libraries
 * If we use pagination, it must ALWAYS follow the following syntax and be
 * located at the END of the URI:
 * PAGINATION_SELECTOR/offset
 * E.g. http://www.example.com/controller/action/Page/2
 *
 * The PAGINATION_SELECTOR is a special string which we know will ONLY be in the
 * URI when paging is set. Let's say the PAGINATION_SELECTOR is 'Page' (since most
 * coders never use any capitals in the URI, most of the times any string with
 * a single capital character in it will suffice). The PAGINATION_SELECTOR is
 * set in the general config file,
 * in the following index: $CI->config->item('pagination_selector')
 *
 * Example use (in controller):
 * // Set pagination and get pagination HTML
 * $this->data['pagination'] = $this->pagination->get_pagination($this->db->count_all_results('my_table'), 10);
 *
 * // Retrieve paginated results, using the dynamically determined offset
 * $this->db->limit($config['per_page'], $this->pagination->offset);
 * $query = $this->db->get('my_table');
 * 
 * @name MY_Pagination.php
 * @version 1.0
 * @author Joost van Veen
 * @extended a little by Joseph R. B. Taylor
 */
class MY_Pagination extends CI_Pagination
{
    
    /**
     * Pagination offset.
     * @var integer
     */
    public $offset = 0;
    public $num_links = 8;
    public $per_page = 20;
    
    /**
     * Pagination selector to be used in URI. Make sure to set this to a value 
     * that is never used elsewhere in the URI.
     * @var string
     */
    public $pagination_selector = '';
    
    //Customizing the First Link
        public $first_link = 'First'; //The text you would like shown in the "first" link on the left.
        public $first_tag_open = '<span class="first_link">'; //The opening tag for the "first" link.
        public $first_tag_close = '</span> '; //The closing tag for the "first" link.
        
        //Customizing the Last Link
        public $last_link = 'Last'; //The text you would like shown in the "last" link on the right.
        public $last_tag_open = '<span class="last_link">'; //The opening tag for the "last" link.
        public $last_tag_close = '</span> '; //The closing tag for the "last" link.
        
        //Customizing the "Next" Link
        public $next_link = 'Next'; //The text you would like shown in the "next" page link.
        public $next_tag_open = '<span class="next_link">'; //The opening tag for the "next" link.
        public $next_tag_close = '</span> '; //The closing tag for the "next" link.
        
        //Customizing the "Previous" Link
        public $prev_link = 'Prev'; //The text you would like shown in the "previous" page link.
        public $prev_tag_open = '<span class="prev_link">'; //The opening tag for the "previous" link.
        public $prev_tag_close = '</span> '; //The closing tag for the "previous" link.
        
        //Customizing the "Current Page" Link
        public $cur_tag_open = '<span class="current_link">'; //The opening tag for the "current" link.
        public $cur_tag_close = '</span> '; //The closing tag for the "current" link.
        
        //Customizing the "Digit" Link
        public $num_tag_open = '<span>'; //The opening tag for the "digit" link.
        public $num_tag_close = '</span> '; //The closing tag for the "digit" link.
   
       // wrapping the pagination links in a div for safekeeping
    public $full_tag_open = '<div class="pagination_links">'; //The opening tag placed on the left side of the entire result.
        public $full_tag_close = '</div>'; //The closing tag placed on the right side of the entire result.   

    function MY_Pagination()
    {
        parent::CI_Pagination();
        
        $CI = & get_instance();
        
        log_message('debug', "MY_Pagination Class Initialized");
        
        if ($CI->config->item('pagination_selector') == '') 
        {
            show_error('config->item(\'pagination_selector\') is not set. Set config->item(\'pagination_selector\') in a config file, or $this->pagination->$this->pagination_selector');
        }
        else 
        {
            $this->pagination_selector = $CI->config->item('pagination_selector');
        }
        
        $this->_set_pagination_offset();
    }

    /**
     * Return HTML for pagination, based on count ($total_rows) and limit ($per_page)
     * @param integer $total_rows
     * @param integer $per_page
     * @return string
     */
    public function get_pagination($total_rows, $per_page)
    {
        if ($total_rows > $per_page) 
        {
            $CI = & get_instance();
            $this->initialize(array('total_rows' => $total_rows, 'per_page' => $per_page));
            return $this->create_links();
        }
    }
    
    // Build a results string (e.g. viewing 1 to 20 of 100 items)
    public function get_results_message($results, $total)
    {                
            $str = FALSE;
            
                $from = ($this->offset + 1);
                $to = ($this->per_page > $results) ? ($this->offset + $results) : ($this->offset + $this->per_page);

                if ($from)
            {
                    $str = "Viewing $from to $to of $total";
            }

            return $str;        
    }

    /**
     * Set dynamic pagination variables in $CI->data['pagvars']
     * @return void
     */
    private function _set_pagination_offset()
    {     
        // Instantiate the CI super object so we can use the uri class
        $CI = & get_instance();
        
        // Store pagination offset if it is set
        if (strstr($CI->uri->uri_string(), $this->pagination_selector)) {
            
            // Get the segment offset for the pagination selector
            $segments = $CI->uri->segment_array();
            
            // Loop through segments to retrieve pagination offset
            foreach ($segments as $key => $value) {
                
                // Find the pagination_selector and work from there
                if ($value == $this->pagination_selector) {
                    
                    // Store pagination offset
                    $this->offset = $CI->uri->segment($key + 1);
                    
                    // Store pagination segment
                    $this->uri_segment = $key + 1;
                    
                    // Set base url for paging. This only works if the
                    // pagination_selector and paging offset are AT THE END of
                    // the URI!
                    $uri = $CI->uri->uri_string();
                    $pos = strpos($uri, $this->pagination_selector);
                    $this->base_url = $CI->config->item('base_url') . substr($uri, 0, $pos + strlen($this->pagination_selector));
                }
            }
        }
        else 
        {
            // Pagination selector was not found in URI string. So offset is 0
            $this->offset = 0;
            $this->uri_segment = 0;
            $this->base_url = $CI->config->item('base_url') . substr($CI->uri->uri_string(), 1) . '/' . $this->pagination_selector;
        }
    }

}  


/* End of File: my_pagination.php */
/* Location: ./system/application/libraries/MY_pagination.php */

Using the library is very easy. Here's some example code to help you understand how everything works.

First we have our controller (I've already autoloaded the pagination library (see User Guide or just peek into application/config/autoload.php and look for the libraries section and add in "pagination".

function index()
{
        // load the pagination library
        $this->load->library('pagination');

        // get total results            
        $data['total_items'] = $this->Items_model->get_total_items();        
        
        // our actual records for the screen        
        $data['items'] = $this->Items_model->get_all_items(), $this->pagination->per_page, $this->pagination->offset);
        
        // set up pagination links
        $data['pagination_links'] = $this->pagination->get_pagination($data['total_items'], $this->pagination->per_page);
                                    
        // build our results message
        $data['results_message'] = $this->pagination->get_results_message($data['items']->num_rows(), $data['total_items']);
        
        // load and go!
        $this->load->view('items_list', $data);
}        

The view file "items_list" spits out our items into a basic table and has pagination links at both the top and bottom of the table:

<?php
if ($items)
{
        if ($items->num_rows() > 0)
        {
                $this->load->view('pagination');
                
                echo '<table id="items" class="list">';
                    echo '<thead>';
                        echo '<tr>';
                            echo '<th>Field A</th>';
                            echo '<th>Field B</th>';
                            echo '<th>Field C</th>';
                            echo '<th>Field D</th>';
                        echo '</tr>';
                    echo '</thead>';
                    echo '<tbody>';
                        foreach ($items->result() as $items)
                        {
                                echo '<tr>';
                                echo '<td>' . $item->field_a . '</td>';
                                echo '<td>' . $item->field_b . '</td>';
                                echo '<td>' . $item->field_c . '</td>';
                                echo '<td>' . $item->field_d . '</td>';
                                echo '</tr>';
                        }
                    echo '</tbody>';
                echo '</table>';
                
                $this->load->view('pagination');
        }
}
else
{
        echo '<p>No items found.</p>';
}
?&gt;

The "items_list" view loads the "pagination" view twice, which contains:

echo '<div class="results_info">';
echo '<p class="results_message">';
echo $results_message;
echo '.</p>';
echo $pagination_links;
echo '</div>';

It seems like a nice compact solution to an annoying problem.