Slim 3.0 Getting Route Params in Middleware

[bradynpoulsen]

I am creating a controller class and trying to add a method on my controller to load a object based on its route ID. I've got that all written and ready to work EXCEPT I don't know how to grab the route parameters from the request. There's also no documented way for middleware to access those parameters.

$app->group('/users', function () {
    $controller = new MyController();
    $this->get('/', [$controller, 'index']);
    $this->get('/{id}', [$controller, 'show'])->add($controller);
});

class MyController
{
    // Fulfills invoke status for Middleware, see http://www.slimframework.com/docs/concepts/middleware.html#invokable-class-middleware-example
    public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
    {
        // how do I get $routeParams???
        $userId = $routeParams['id'];
        $user = $userMapper->findById($userId);
        if ($user) {
           $request = $request->withAttribute('user', $user);
           return $next($request, $response);
        } else {
            // setup $response to contain a 404 response, don't call $next
            return $response;
        }
    }

    public function show(ServerRequestInterface $request, ResponseInterface $response, array $args)
    {
        $user = $request->getAttribute('user');  // already loaded by middleware
        return $response->getBody()->write(json_encode($user)); // varies, but for example
    }

[bradynpoulsen]

I think I've figured out a solution to my problem; however, I still would like to know how a middleware would access router parameters or what people think on that being poor middleware design

For now I'm just doing the __call() magic method on my controller and making my show action private. Something like:

$app->group('/users', function () {
    $controller = new MyController();
    $this->get('/', [$controller, 'index']);
    $this->get('/{id}', [$controller, 'show']);
});

class MyController
{
    public function __call($name, array $arguments)
    {
        list($request, $response, $args) = $arguments;
        $user = $userMapper->findById($args['id']);
        if ($user) {
            $request = $request->withAttribute('user', $user);
            return call_user_func([$this, $name], $request, $response, $args);
        } else {
            // $response now contains 404 response, don't call method
            return $response;
        }
    }

    private function show(ServerRequestInterface $request, ResponseInterface $response, array $args)
    {
        $user = $request->getAttribute('user');  // already loaded by middleware
        return $response->getBody()->write(json_encode($user)); // varies, but for example
    }
}

[akrabat]

You'll find the route parameters in the third element of the 'routeInfo' attribute. We'd love a PR documenting this :)

$routeParams = $request->getAttribute('routeInfo')[2];

[bradynpoulsen]

As a side note, this option does not work for application middleware

[kevinmlong]

Agree with @bradynpoulsen that it doesn't work for middleware. Would also be able to access route arguments from within middleware

[akrabat]

By default, the route hasn't been worked out when app middleware is running, which is why it's not working for you.

If you need this, then you can enable this setting:

$settings = [
    'settings' => [
        'determineRouteBeforeAppMiddleware' => true,
    ],
];
$app = new Slim\App($settings);

[kevinmlong]

@akrabat - this does solve the problem. Thanks!

[akrabat]

This works @kevinmlong:

$settings = [
    'settings' => [
        'determineRouteBeforeAppMiddleware' => true,
    ],
];
$app = new \Slim\App($settings);

$app->get("/{name}", function ($request, $response, $args) {
    return $response->write("Hello {$args['name']}");
});

$app->add(function ($request, $response, $next) {
    var_dump($request->getAttribute('routeInfo')[2]);

    return $next($request, $response);
});

Navigating to http://develop-testbed.slim3.dev/rob gives me:

/www/dev/slim3/develop-testbed/public/index-scratch.php:23:
array (size=1)
  'name' => string 'rob' (length=3)
Hello rob

[kevinmlong]

@akrabat - I sent the other comment to quickly. I suppose I deleted it after you saw it. Thanks!

A related issue ....

In my middleware, I am calling

$next($request,$response);
-- doing stuff --

As it goes through the routing methods, it returns a response. In some cases it changes the status to a different code (e.g. 400) like below:

$newResponse = $this->response->withStatus(404)
                                     ->withHeader('Content-Type', 'application/json')
                                     ->write(...stuff...);
return $newResponse;

when the application returns to the middleware, the response object has a code of 200. When returned, it has the right body, but the wrong status. Thoughts?

[silentworks]

@kevinmlong $this->response is probably stale. Where is that coming from?

[kevinmlong]

It's in the route method

$app->get('path to route', function ($request, $response, $args) {
    do some stuff
    $newResponse = $this->response->withStatus(404)
                                     ->withHeader('Content-Type', 'application/json')
                                     ->write(...stuff...);
return $newResponse;
}

The code then returns to the middleware. The code response here is 200 instead of 404. If I return the response, I get the right body from the write(..stuff..) but the code is not 404.

[silentworks]

@kevinmlong you need to use $response instead of $this->response. $this->response is a stale response object while $response is the current one from this request. You can even do exactly what @akrabat did in his example.

$app->get('path to route', function ($request, $response, $args) {
    return $response->withStatus(404)
                   ->withHeader('Content-Type', 'application/json')
                   ->write(...stuff...);
});

[kevinmlong]

@silentworks - that doesn't work. it still returns to the middleware with a 200 code.

[kevinmlong]

@silentworks - the response object is getting updated, since the body is being updated correctly.

[kevinmlong]

@silentworks - I figured it out. Need to change the middleware to:

public function __invoke($request, $response, $next){
// do some stuff
$newResponse = $next($request,$response);
// do more stuff
return $newResponse;
}

[HarshVarshney]

Add following line in configuration
$config['determineRouteBeforeAppMiddleware'] = true;

In middleware
$route = $request->getAttribute('route');
$arguments = $route->getArguments();
print_r($arguments);