4.8 KiB
Controller
Controller is one of the key parts of the application. It determines how to handle incoming request and creates a response.
Most often a controller takes HTTP request data and returns HTML, JSON or XML as a response.
Basics
Controller resides in application's controllers
directory is is named like SiteController.php
where Site
part could be anything describing a set of actions it contains.
The basic web controller is a class that extends \yii\web\Controller and could be very simple:
namespace app\controllers;
use yii\web\Controller;
class SiteController extends Controller
{
public function actionIndex()
{
// will render view from "views/site/index.php"
return $this->render('index');
}
public function actionTest()
{
// will just print "test" to the browser
return 'test';
}
}
As you can see, typical controller contains actions that are public class methods named as actionSomething
.
Routes
Each controller action has a corresponding internal route. In our example above actionIndex
has site/index
route
and actionTest
has site/test
route. In this route site
is referred to as controller ID while test
is referred to
as action ID.
By default you can access specific controller and action using the http://example.com/?r=controller/action
URL. This
behavior is fully customizable. For details refer to URL Management.
If controller is located inside a module its action internal route will be module/controller/action
.
In case module, controller or action specified isn't found Yii will return "not found" page and HTTP status code 404.
Defaults
If user isn't specifying any route i.e. using URL like http://example.com/
, Yii assumes that default route should be
used. It is determined by \yii\web\Application::defaultRoute method and is site
by default meaning that SiteController
will be loaded.
A controller has a default action. When the user request does not specify which action to execute by usign an URL such as
http://example.com/?r=site
, the default action will be executed. By default, the default action is named as index
.
It can be changed by setting the \yii\base\Controller::defaultAction property.
Action parameters
It was already mentioned that a simple action is just a public method named as actionSomething
. Now we'll review
ways that an action can get parameters from HTTP.
Action parameters
You can define named arguments for an action and these will be automatically populated from corresponding values from
$_GET
. This is very convenient both because of the short syntax and an ability to specify defaults:
namespace app\controllers;
use yii\web\Controller;
class BlogController extends Controller
{
public function actionView($id, $version = null)
{
$post = Post::find($id);
$text = $post->text;
if($version) {
$text = $post->getHistory($version);
}
return $this->render('view', array(
'post' => $post,
'text' => $text,
));
}
}
The action above can be accessed using either http://example.com/?r=blog/view&id=42
or
http://example.com/?r=blog/view&id=42&version=3
. In the first case version
isn't specified and default parameter
value is used instead.
Getting data from request
If your action is working with data from HTTP POST or has too many GET parameters you can rely on request object that
is accessible via \Yii::$app->request
:
namespace app\controllers;
use yii\web\Controller;
use yii\web\HttpException;
class BlogController extends Controller
{
public function actionUpdate($id)
{
$post = Post::find($id);
if(!$post) {
throw new HttpException(404);
}
if(\Yii::$app->request->isPost)) {
$post->load($_POST);
if($post->save()) {
$this->redirect(array('view', 'id' => $post->id));
}
}
return $this->render('update', array(
'post' => $post,
));
}
}
Standalone actions
If action is generic enough it makes sense to implement it in a separate class to be able to reuse it.
Create actions/Page.php
namespace \app\actions;
class Page extends \yii\base\Action
{
public $view = 'index';
public function run()
{
$this->controller->render($view);
}
}
The following code is too simple to implement as a separate action but gives an idea of how it works. Action implemented can be used in your controller as following:
public SiteController extends \yii\web\Controller
{
public function actions()
{
return array(
'about' => array(
'class' => '@app/actions/Page',
'view' => 'about',
),
),
);
}
}
After doing so you can access your action as http://example.com/?r=site/about
.