Which is the best way to display 'flash messages' in kohana v3?

Question

I would like to know the best way to display flash messages in Kohana v3?

Some tutorials or examples would be helpful.

Answer 1

Do you mean like Kohana 2.x's flash session variables?

The latest Kohana supports get_once() which is pretty similar to the old flash session variables.

$session = Session::instance();

$session->set('test', 'Hello, World!');

// The session variable is returned and removed.
$test = $session->get_once('test');

Answer 2

I think the get_once is a great function, but what if you want to keep the data actually separate from the regular data, here's a basic class that overloads "Session" so that you can use "codeigniter" style flashdata calls with any data-store.

<?php defined('SYSPATH') or die('No direct script access.');
abstract class Session extends Kohana_Session {

/**
 * This calls the parent Kohana_Session constructor and processes 
 * new flashdata to flashdata, and flashdata to old flashdata
 *
 * @param   array   configuration
 * @param   string  session id
 * @return  void
 * @uses    Kohana_Session::__construct
 */
public function __construct(array $config = NULL, $id = NULL)
{
    parent::__construct($config,$id);

    if(array_key_exists('___of',$this->_data)){
        //Remove old Flash data
        unset($this->_data['___of']);
    }

    if(array_key_exists('___flash',$this->_data)){
        //Move current last requests flash data to old flash data
        $this->_data['___of'] = $this->_data['___flash'];
        unset($this->_data['___flash']);
    }

    if(array_key_exists('___nf',$this->_data)){
        //Move Last Requests added data to the flash data
        $this->_data['___flash'] = $this->_data['___nf'];
        unset($this->_data['___nf']);
    }
}

/**
 * keeps a variable set in the sessions flashdata array.
 *
 *     $session->set_flashdata('foo', 'bar');
 *
 * @param   string   variable name
 * @param   ...
 * @return  $this
 */
public function keep_flashdata($k)
{
    $args = func_get_args();

    if(array_key_exists('___of',$this->_data)){
        foreach($args as $key){
            if(array_key_exists($key,$this->_data['___of'])){
                //So we were going to trash it...
                $this->set_flashdata($k,$this->_data['___of'][$key],true);
            }
        }
    }

    $this->_data['___nf'][$key] = $value;

    return $this;
}

/**
 * Set a variable in the sessions flashdata array.
 *
 *     $session->set_flashdata('foo', 'bar');
 *
 * @param   string   variable name
 * @param   mixed    value
 * @return  $this
 */
public function set_flashdata($key, $value, $current=false)
{
    if(!array_key_exists('___nf',$this->_data)){
        $this->_data['___nf'] = array();
    }

    $this->_data['___nf'][$key] = $value;

    if($current){
        if(!array_key_exists('___flash',$this->_data)){
            $this->_data['___flash'] = array();
        }
        $this->_data['flash'][$key] = $value;
    }

    return $this;
}

/**
 * Set a variable by reference in the sessions flashdata array.
 *
 *     $session->bind_flashdata('foo', $foo);
 *
 * @param   string  variable name
 * @param   mixed   referenced value
 * @return  $this
 */
public function bind_flashdata($key, & $value)
{
    if(!array_key_exists('___nf',$this->_data)){
        $this->_data['___nf'] = array();
    }

    $this->_data['___nf'][$key] =& $value;

    return $this;
}

/**
 * Removes a variable in the session array.
 *
 *     $session->delete_flashdata('foo');
 *
 * @param   string  variable name
 * @param   ...
 * @return  $this
 */
public function delete_flashdata($key)
{
    $args = func_get_args();

    if(array_key_exists('___nf',$this->_data)){
        foreach ($args as $key)
        {
            if(array_key_exists($key,$this->_data['___nf'])){
                unset($this->_data['___nf'][$key]);
            }
        }
    }
    return $this;
}

/**
 * Get a variable from the sessions flashdata array.
 *
 *     $foo = $session->get_flashdata('foo');
 *
 * @param   string   variable name
 * @param   mixed    default value to return
 * @return  mixed
 */
public function get_flashdata($key, $default = NULL)
{
    if(array_key_exists('___flash',$this->_data) && array_key_exists($key,$this->_data['___flash'])){
        return $this->_data['___flash'][$key];
    } else if(array_key_exists('___nf',$this->_data) && array_key_exists($key,$this->_data['___nf'])){
        return $this->_data['___nf'][$key];
    }

    return $default;
}

/**
 * Get and delete a variable from the session array.
 *
 *     $bar = $session->get_once('bar');
 *
 * @param   string  variable name
 * @param   mixed   default value to return
 * @return  mixed
 */
public function get_flashdata_once($key, $default = NULL)
{
    $value = $this->get_flashdata($key, $default);

    if(array_key_exists($key, $this->_data['___flash'])){
        unset($this->_data['___flash'][$key]);
    }

    if(array_key_exists($key, $this->_data['___nf'])){
        unset($this->_data['___nf'][$key]);
    }

    return $value;
}
}
?>

I realize there was an answer to this, and like i stated before, the get_once method is great and all, but i enjoy auto garbage collection much more.

If you have any improvements on this code, let me know, its been great to me so far.