Controllers

Introduction

Every defined route requires a callable to invoke when dispatched, something that could be described as a controller in MVC. By default, Route only imposes that the callable is defined with a specific signature, it is given a request object as the first argument, an associative array of wildcard route arguments as the second argument, and expects a response object to be returned. Read more about this in HTTP.

This behaviour can be changed by creating/using a different strategy, read more about strategies here.

Defining Controllers

Defining what controller is invoked when a route is matched is as easy as padding a callable as the the third argument of the map method or the second argument of the proxy methods for different request verbs, get, post etc.

<?php declare(strict_types=1);

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

$router = new League\Route\Router;

$router->map('GET', '/route', function (ServerRequestInterface $request): ResponseInterface {
    // ...
});

$router->get('/another-route', function (ServerRequestInterface $request): ResponseInterface {
    // ...
});

Types of Controllers

As mentioned above, Route will dispatch any callable when a route is matched.

For performance reasons, Route also allows you to define controllers as a type of proxy, there are two of these proxies that will allow you to define strings and the actually callable will be built when Route dispatches it.

Closure

A controller can be defined as a simple \Closure anonymous function.

<?php declare(strict_types=1);

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

$router = new League\Route\Router;

$router->map('GET', '/', function (ServerRequestInterface $request): ResponseInterface {
    // ...
});

Lazy Loaded Class Method (Proxy)

You can define a class method as a controller where the callable is to be lazy loaded when it is dispatched by defining a string and separating the class name and method name like so ClassName::methodName.

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class SomeController
{
    /**
     * Controller.
     *
     * @param \Psr\Http\Message\ServerRequestInterface $request
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function someMethod(ServerRequestInterface $request): ResponseInterface
    {
        // ...
    }
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', 'Acme\SomeController::someMethod');

Lazy Loaded Class Implementing __invoke (Proxy)

You can define the name of a class that implements the magic __invoke method and the object will not be instantiated until it is dispatched.

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class SomeController
{
    /**
     * Controller.
     *
     * @param \Psr\Http\Message\ServerRequestInterface $request
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function __invoke(ServerRequestInterface $request): ResponseInterface
    {
        // ...
    }
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', Acme\SomeController::class);

Lazy Loaded Array Based Callable (Proxy)

A controller can be defined as an array based callable where the class element will not be instantiated until it is dispatched.

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class SomeController
{
    /**
     * Controller.
     *
     * @param \Psr\Http\Message\ServerRequestInterface $request
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function someMethod(ServerRequestInterface $request): ResponseInterface
    {
        // ...
    }
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', [Acme\SomeController::class, 'someMethod']);

Object Implementing __invoke

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class SomeController
{
    /**
     * Controller.
     *
     * @param \Psr\Http\Message\ServerRequestInterface $request
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function __invoke(ServerRequestInterface $request): ResponseInterface
    {
        // ...
    }
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', new Acme\SomeController);

Array Based Callable

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class SomeController
{
    /**
     * Controller.
     *
     * @param \Psr\Http\Message\ServerRequestInterface $request
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function someMethod(ServerRequestInterface $request): ResponseInterface
    {
        // ...
    }
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', [new Acme\SomeController, 'someMethod']);

Named Function

<?php declare(strict_types=1);

namespace Acme;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

/**
 * Controller.
 *
 * @param \Psr\Http\Message\ServerRequestInterface $request
 *
 * @return \Psr\Http\Message\ResponseInterface
 */
function controller(ServerRequestInterface $request): ResponseInterface
{
    // ...
}

<?php declare(strict_types=1);

$router = new League\Route\Router;

$router->map('GET', '/', 'Acme\controller');

Dependency Injection

Where Route is instantiating the objects for your defined controller, a dependency injection container can be used to resolve those objects. Read more on dependency injection here.