rwarasaurus/broker

A conditional dispatcher for PSR-15 middleware

Northwoods Broker

Broker is a PSR-15 middleware dispatcher that uses conditional matching. As opposed to most middleware dispatcher, Broker verifies each middleware can be applied to the request before executing it. This allows for a centralized configuration of middleware without compromising flexibility.

Attempts to be PSR-1, PSR-2, PSR-4, and PSR-15 compliant.

Install

composer require northwoods/broker

Usage

Broker works best when combined with a PSR-11 container. When a container is provided middleware can be added by class name. Without the container middleware must be fully constructed.

use Northwoods\Broker\Broker;

$broker = new Broker($container);

Broker operates on conditions. The middleware will not be executed unless the condition returns true. Because some middleware is not conditional the always() method makes it easy to add middleware that must be executed on every request. The when() method accepts a condition and a list of middleware to execute if the condition passes. All middleware is executed in the order added.

// Always execute these middleware
$broker->always([
    Acme\HandleErrors::class,
    Acme\DetectClientIp::class,
]);

// Do we need to redirect to a secure connection?
$broker->when(
    function (ServerRequestInterface $request) {
        $scheme = $request->getUri()->getScheme();
        return $scheme !== 'https';
    },
    Acme\RedirectHttps::class,
);

// Add more middleware to be executed
$broker->always([
    Acme\ParseBody::class,
    Acme\HandleRequest::class,
]);

To dispatch the middleware call the handle() method with a request instance and a callable $default that returns the response, typically a 404 Not Found, if no middleware can handle the request.

// Define the callable to create a 404 response
$default = [Acme\ResponseFactor::class, 'notFound'];

// Execute the middleware as a dispatcher
$response = $broker->handle($request, $default);

Broker also implements MiddlewareInterface and can be used as a middleware:

// Execute the broker like any other PSR-15 middleware
$response = $broker->process($request, $delegate);

License

MIT