README

Guardian provides an adapter between an authentication backend and your PSR-15 middleware stack

• Compatible to the PSR-15 middleware interface
• Adaptable to your authentication backend with a simple interface

<?php

// create a new authentication backend which implements the AuthenticationInterface
$authenticationBackend = new AuthenticationBackend();

// using e.g. mindplay-dk/middleman as a dispatcher for the middleware stack
$response = (new Dispatcher(
    [   
        // inject Guardian with the authentication backend instance
        new Guardian($authenticationBackend),
        // ... more middlwares e.g. a router
        new Router()
    ]
))->dispatch($request);

Authentication Backend

The focus of Guardian is on the adaptation of an authentication backend with a PSR-15 middleware stack.

This means that Guardian itself is not capable of providing authentication e.g. Basic access authentication. But Guardian ships with a simple interface that can be implemented by the authentication backend. The interface consists of two methods.

<?php

interface AuthenticationInterface
{

    /**
     * @param ServerRequestInterface $request
     * @return bool
     */
    public function authenticate(ServerRequestInterface $request);
    
    /**
    * @return ResponseInterface
    */
    public function getAuthenticationFailedResponse();

}

authenticate

The authenticate method receives the current request as a parameter and must return a boolean (which stands for access approved respectively access denied) .

getAuthenticationFailedResponse

The getAuthenticationFailedResponse method must return a ResponseInterface instance. It's called by Guardian in case of access denied to return a ResponseInterface instance to the middleware pipeline. The fact that the authentication backend is in charge to provide a proper ResponseInterface instance is due to the need of custom properties.

E.g. an authentication backend, which supports the Basic access authentication, "should return a response whose header contains a HTTP 401 Unauthorized status and a WWW-Authenticate field. The WWW-Authenticate field for basic authentication (used most often) is constructed as following: WWW-Authenticate: Basic realm="User Visible Realm"" [WIKI]