Routing Adapters

Using zend-router

zend-router provides several router implementations used for ZF2+ applications; the default is Zend\Router\Http\TreeRouteStack, which can compose a number of different routes of differing types in order to perform routing.

The ZF2 bridge we provide, Zend\Expressive\Router\ZendRouter, uses the TreeRouteStack, and injects Segment routes to it; these are in turn injected with Method routes, and a special "method not allowed" route at negative priority to enable us to distinguish between failure to match the path and failure to match the HTTP method.

The TreeRouteStack offers some unique features:

• Route "prototypes". These are essentially like child routes that must also match in order for a given route to match. These are useful for implementing functionality such as ensuring the request comes in over HTTPS, or over a specific subdomain.
• Base URL functionality. If a base URL is injected, comparisons will be relative to that URL. This is mostly unnecessary with Stratigility-based middleware, but could solve some edge cases.

To specify these, you need access to the underlying TreeRouteStack instance, however, and the RouterInterface does not provide an accessor!

The answer, then, is to use dependency injection. This can be done in two ways: programmatically, or via a factory to use in conjunction with your container instance.

Installing the ZF2 Router

To use the ZF2 router, you will need to install the zend-mvc router integration:

$ composer require zendframework/zend-expressive-zendrouter

The package provides both a factory for the router, and a ConfigProvider that wires the router with your application.

Advanced configuration

If you want to provide custom setup or configuration, you can do so. In this example, we will be defining two factories:

• A factory to register as and generate an Zend\Router\Http\TreeRouteStack instance.
• A factory registered as Zend\Expressive\Router\RouterInterface, which creates and returns a Zend\Expressive\Router\ZendRouter instance composing the Zend\Mvc\Router\Http\TreeRouteStack instance.

The factories might look like the following:

// in src/App/Container/TreeRouteStackFactory.php:
namespace App\Container;

use Psr\Container\ContainerInterface;
use Zend\Http\Router\TreeRouteStack;

class TreeRouteStackFactory
{
    /**
     * @param ContainerInterface $container
     * @return TreeRouteStack
     */
    public function __invoke(ContainerInterface $container)
    {
        $router = new TreeRouteStack();
        $router->addPrototypes(/* ... */);
        $router->setBaseUrl(/* ... */);

        return $router;
    }
}

// in src/App/Container/RouterFactory.php
namespace App\Container;

use Psr\Container\ContainerInterface;
use Zend\Expressive\Router\ZendRouter as Zf2Bridge;

class RouterFactory
{
    /**
     * @param ContainerInterface $container
     * @return Zf2Bridge
     */
    public function __invoke(ContainerInterface $container)
    {
        return new Zf2Bridge($container->get(Zend\Mvc\Router\Http\TreeRouteStack::class));
    }
}

From here, you will need to register your factories with your IoC container.

// in a config/autoload/ file, or within a ConfigProvider class:
return [
    'factories' => [
        \Zend\Router\Http\TreeRouteStack::class => App\Container\TreeRouteStackFactory::class,
        \Zend\Expressive\Router\RouterInterface::class => App\Container\RouterFactory::class,
    ],
];