Controllers

A controller is where CakePHP brings a request together with your data. Once routing has decided which controller and action should run, the controller takes over: reading input, talking to models, and choosing what gets rendered back to the user.

Naming and Location

Controllers live in src/Controller/ and are named after the resource (plural) they handle, with a Controller suffix. A controller for articles is named ArticlesController and lives at:

src/Controller/ArticlesController.php

Every controller you write extends AppController, which in turn extends CakePHP's own base Controller class. AppController is a good place to put behavior shared across your whole application.

Actions Are Just Public Methods

An action is nothing more than a public method on a controller. Common action names follow REST-ish conventions: index() for a listing, view($id) for a single record, add() for creating a new one, and so on. Whichever method matches the routed action name is the one that runs.

The Model Is Loaded Automatically

Thanks to convention over configuration — the same idea introduced on the CakePHP Tutorial home page — ArticlesController gets a ready-to-use $this->Articles property pointing at the ArticlesTable model, with no manual wiring required.

Passing Data to the View

Once a controller action has the data it needs, it hands it off to the view with $this->set(), giving the value a variable name the template can use:

$this->set('articles', $articles);

Inside the matching template, that data is then available simply as $articles.

A Full Worked Example

Here's a small but complete ArticlesController with an index() action that lists all articles, and a view($id) action that loads one:

<?php
namespace App\Controller;

class ArticlesController extends AppController
{
    // Lists every article
    public function index()
    {
        $articles = $this->Articles->find()->all();
        $this->set('articles', $articles);
    }

    // Shows a single article by id
    public function view($id = null)
    {
        $article = $this->Articles->get($id);
        $this->set('article', $article);
    }
}

With this in place, a request to /articles runs index(), and a request to /articles/view/5 runs view(5) — routing, the model, and the controller all working together exactly as described in the previous two lessons.