Kohana Tutorial: For the beginners

Kohana is the framework I liked best among other PHP framework. Its an easy one also . To me it is organized, highly object oriented, having clear separation of model, view & controller.  Autoloading of classes is nice feature here also. Here is the tutorial I prepared. In a simple and short…

• It is going to be a 3 or 4 part series
• All series will have around 10+/- steps
• I will be creating a simple blog with this example

Probably you have downloaded the zip file from here. Below are the steps one by one. So lets start…

Installation

• Extract the zip file in htdocs folder
• Rename it to kohana-blog
• Now hit the url: http://localhost/kohana-blog/
• You should see your installation info
• If you are using linux, make kohana-blog/application/logs & kohana-blog/application/cache folder writable
• You are done

Initial configuration

• Now remove/rename kohana-blog/install.php.
• Change kohana-blog/application/bootstrap.php as same as below.

Kohana::init(array(
	'base_url'   => '/kohana-blog',
));

• Now try accessing any of the URLs listed below
  • http://localhost/kohana-blog
  • http://localhost/kohana-blog/index.php/welcome
  • http://localhost/kohana-blog/index.php/welcome/index

Get introduce with action & controller

By default URL format for koahna is like http://<base_url>/index.php/<controller>/<action>. So for an example http://localhost/kohana/index.php/article/new means it will be looking for article controller (Controller_Article) and execute new action (action_new()). If action part is empty, index action will be executed .

• controller & action in Kohana:

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Welcome extends Controller {

 	public function action_index() {
 		$this->response->body('hello, world!');
	}

} // End Welcome

1. Here Controller_ is the prefix for welcome controller & it extends Controller
2. Here action_ is the prefix for an action
3. $this->response->body(‘hello, world!’); sets hello, world! as the response for the request.

• Lets add an action as highlighted below

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Welcome extends Controller {

  	public function action_index() {
  		$this>response->body('hello, world!');
	}

	public function action_another() {
		$this->response->body('added another action...');
	}

} // End Welcome

Now try this url: http://localhost/kohana-blog/index.php/welcome/another

• Lets create an article controller for our blog as below.

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Article extends Controller {

 	public function action_index() {
 		$this->response->body("Kohana Blog");
	}

}

Now try this url: http://localhost/kohana-blog/index.php/article/index

Render a view with Kohana

• Create the kohana-blog/application/views/article/index.php file under application/view folder as shown below

<?php defined('SYSPATH') or die('No direct script access.'); ?>

<h1>Kohana Blog Homepage</h1>

• Modify the Controller_Article‘s method action_index() as below to load the view

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Article extends Controller {

	public function action_index() {
		$view = new View('article/index'); // loads the 'article/index.php' file under 'application/view' folder
		$this->response->body($view); // render the  view as response
	}

}

Now try this url again: http://localhost/kohana-blog/index.php/article/index

Now prepare database configuration

• Run following sql script. It will create simple articles table in the database.

CREATE SCHEMA `kohana_blog`;

use `kohana_blog`;

CREATE TABLE `kohana_blog`.`articles` (
  `id` int unsigned NOT NULL AUTO_INCREMENT,
  `title` varchar(200) DEFAULT NULL,
  `content` text,
  PRIMARY KEY (`id`)
);

We will use Kohana ORM to communicate with database. So both database & orm module is needed to be enabled. we can do so modifying kohana-blog/application/bootstrap.php as shown below.

/**
 * Enable modules. Modules are referenced by a relative or absolute path.
 */
Kohana::modules(array(
	// 'auth'       => MODPATH.'auth',       // Basic authentication
	// 'cache'      => MODPATH.'cache',      // Caching with multiple backends
	// 'codebench'  => MODPATH.'codebench',  // Benchmarking tool
	'database'   => MODPATH.'database',   // Database access
	// 'image'      => MODPATH.'image',      // Image manipulation
	'orm'        => MODPATH.'orm',        // Object Relationship Mapping
	// 'unittest'   => MODPATH.'unittest',   // Unit testing
	// 'userguide'  => MODPATH.'userguide',  // User guide and API documentation
	));

Create the kohana-blog/application/config/database.php configuration file under kohana-blog/application/config folder like as below. Change username & password accordingly.

<?php defined('SYSPATH') or die('No direct access allowed.');

return array
(
	'default' => array
	(
		'type'       => 'mysql',
		'connection' => array(
			'hostname'   => 'localhost',
			'database'   => 'kohana_blog',
			'username'   => 'root',
			'password'   => 'root',
			'persistent' => FALSE,
		),
		'table_prefix' => '',
		'charset'      => 'utf8',
		'caching'      => FALSE,
		'profiling'    => TRUE,
	)
);

Congratulation!!! You are done with configuring your database.

Create a model

It is just easy. Create a article.php file under application/classes/model as shown below. Here, our Model_Article object extends ORM. By default it will assume table name from the model name (so cool). For article model table name is be articles. You can also change it, using $_table_name property. But this is not important now.

<?php defined('SYSPATH') or die('No direct script access.');

class Model_Article extends ORM {
	
}

This step is just easy, huh? We have few more steps to play with this article model.

Create the form to create/edit an article

Create a view file kohana-blog/application/views/article/edit.php under application/views folder as shown below.

<?php defined('SYSPATH') or die('No direct script access.'); ?>

<h1>Create new article</h1>

<?php echo Form::open('article/post/'.$article->id); ?>
	<?php echo Form::label("title", "Title"); ?>
	<br />
	<?php echo Form::input("title", $article->title); ?>
	<br />
	<br />
	<?php echo Form::label("content", "Content"); ?>
	<br />
	<?php echo Form::textarea("content", $article->content); ?>
	<br />
	<br />
	<?php echo Form::submit("submit", "Submit"); ?>
<?php echo Form::close(); ?>

• Create new action to load the form
• Create post action to post & save the article

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Article extends Controller {
	
	public function action_index() {
		$view = new View('article/index');
		
		$this->response->body($view);
	}

	// loads the new article form
	public function action_new() {
		$article = new Model_Article();
		
		$view = new View('article/edit');
		$view->set("article", $article);
		
		$this->response->body($view);
	}

	// save the article
	public function action_post() {
		$article_id = $this->request->param('id');
		$article = new Model_Article($article_id);
		$article->values($_POST); // populate $article object from $_POST array
		$article->save(); // saves article to database
		
		$this->request->redirect('index.php/article'); // redirects to article page after saving
	}

}

Now hit the url: http://localhost/kohana-blog/index.php/article/new and try creating some article.

Show list of articles

Lets improve our view to show all the articles.

• Load all the articles. It is shown below changing article’s index action.

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Article extends Controller {
	
	public function action_index() {
		$articles = ORM::factory('article')->find_all(); // loads all article object from table
		
		$view = new View('article/index');
		$view->set("articles", $articles); // set "articles" object to view
		
		$this->response->body($view);
	}
	....

• Change article/index.php as below to load all the articles.

<?php defined('SYSPATH') or die('No direct script access.'); ?>

<h1>Kohana Blog Homepage</h1>

<?php echo HTML::anchor("article/new", "New Article"); ?>

<?php foreach ($articles as $article) : ?>
<div style="background-color: #dddddd; margin: 0px 2px 0px 2px">
	<h2><?php echo $article->title; ?></h2>
	<pre><?php echo $article->content; ?></pre>
	<?php echo HTML::anchor("article/edit/".$article->id, "Edit"); ?>
	<?php echo HTML::anchor("article/delete/".$article->id, "Delete"); ?>
</div>
<?php endforeach; ?>

Now hit the url: http://localhost/kohana-blog/index.php/article/index to see all created articles.

Update & delete an article

You can skip it, but this is to add the final touch of this part. Two more actions, edit & delete action, are added to the article controller.

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Article extends Controller {
	
	const INDEX_PAGE = 'index.php/article';
	
	public function action_index() {
		$articles = ORM::factory('article')->find_all(); // loads all article object from table
		
		$view = new View('article/index');
		$view->set("articles", $articles); // set "articles" object to view
		
		$this->response->body($view);
	}
	
	// loads the new article form
	public function action_new() {
		$article = new Model_Article();
		
		$view = new View('article/edit');
		$view->set("article", $article);
		
		$this->response->body($view);
	}
	
	// edit the article
	public function action_edit() {
		$article_id = $this->request->param('id');
		$article = new Model_Article($article_id);

		$view = new View('article/edit');
		$view->set("article", $article);
		
		$this->response->body($view);
	}

	// delete the article
	public function action_delete() {
		$article_id = $this->request->param('id');
		$article = new Model_Article($article_id);

		$article->delete();
		$this->request->redirect(self::INDEX_PAGE);
	}
	
	// save the article
	public function action_post() {
		$article_id = $this->request->param('id');
		$article = new Model_Article($article_id);
		$article->values($_POST); // populate $article object from $_POST array
		$article->save(); // saves article to database
		
		$this->request->redirect(self::INDEX_PAGE);
	}

}

Now you can edit/delete an article also.

So this is it. I have tried to demonstrate the followings here

• Configure an kohana application
• Create a controller & action in kohana
• Render view in kohana. Thogh this is pretty basic concept.
• Working with ORM model
• CRUD (create, read, update & delete) operation using Kohana ORM

Let me know what do u think. Any kind of suggestion is appreciable.