# \#not instantiable#

**URL:** <https://discourse.slimframework.com/t/not-instantiable/4598>\
**Category:** Questions\
**Created:** [January 7, 2021, 6:17pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598 "2021-01-07T18:17:23Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![poldee](https://avatars.discourse-cdn.com/v4/letter/p/bbce88/32.png) [@poldee](https://discourse.slimframework.com/u/poldee)\
**Post date:** [January 7, 2021, 6:17pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598/1 "2021-01-07T18:17:23Z")

</div>

Hey SlimPeople,

I’m fairly new new to PHP/Slim.

I’ve got pretty much everything going the way I want. Except for one thing I can’t wrap my brain around.  
Middleware…

I’ve managed to get the routing middleware to work the way I want… YEAH!

Now I’d like to block the whole execution from happening on routes the logged in user doesn’t have access to.

I’m able to change the response’s status code

> $response = $handler-\>handle($request);  
> if(SOME\_CONDITION) {  
> $response = $response-\>withStatus(403);//Forbidden  
> }
> 
> return $response;

The trouble is I’m still running and returning the forbidden data.

So I tried:

> ```
> if(!$path_is_not_protected && !$session && !$is_option) {
> $response = new ResponseInterface();
> $response = $response->withStatus(403);//Forbidden
> return $response;
> }
> 
> ```
> 
> $response = $handler-\>handle($request);  
> return $response;

But I get the following error (using Postman for simplicity)

> Details
> 
> **Type:** Error
> 
> **Code:** 0
> 
> **Message:** Cannot instantiate interface Psr\Http\Message\ResponseInterface
> 
> **File:** /var/www/src/Middleware/Auth.php
> 
> **Line:** 51

Here’s the complete Auth.php file

```
<?php
namespace App\Middleware;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Slim\Routing\RouteContext;
/**
* CORS middleware.
*/
final class Auth implements MiddlewareInterface
{
  /**
  * Invoke middleware.
  *
  * @param ServerRequestInterface $request The request
  * @param RequestHandlerInterface $handler The handler
  *
  * @return ResponseInterface The response
  */
  public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface {
    $request_path = $request->getUri()->getPath();

    $unprotected_paths = [
      '/users/login',
      '/access/request',
    ];
    $admin_only_paths = [
      '/users/login',
      '/access/request',
    ];
    $clinician_only_paths = [
      '/users/login',
      '/access/request',
    ];

    $path_is_not_protected = in_array($request_path, $unprotected_paths);

    $qrit_auth = $request->getHeaders()['QRIT-AUTH'][0] ?? '';

    session_start();

    $_SESSION['UUID'] = $qrit_auth;
    $_SESSION['USER_ROLE'] = 'unknown';

    $has_qrit_auth = ($qrit_auth != '');
    $is_option = ($request->getMethod() == 'OPTIONS');

    if(!$path_is_not_protected && !$session && !$is_option) {
      $response = new ResponseInterface();
      $response = $response->withStatus(403);//Forbidden
      return $response;
    }

    $response = $handler->handle($request);
    return $response;
  }

  private function retrieve_session(string $uuid) {
    $query = $this->queryFactory->newSelect('sessions');
    $query->select('*');
    $query->andWhere(['uuid' => $uuid]);

    return $query->execute()->fetch('assoc');
  }
}

```

---

<div class="post-metadata">

**Author:** ![odan](https://avatars.discourse-cdn.com/v4/letter/o/9de053/32.png) [@odan](https://discourse.slimframework.com/u/odan)\
**Post date:** [January 7, 2021, 8:31pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598/2 "2021-01-07T20:31:42Z")

</div>

Hi @poldee

It’s not possible in PHP to create an instance from an interface.

> $response = new ResponseInterface();

You need an implementation of that interface instead.  
The `slim/psr7` package provides such an implementation and a ResponseFactory for Slim.

---

<div class="post-metadata">

**Author:** ![poldee](https://avatars.discourse-cdn.com/v4/letter/p/bbce88/32.png) [@poldee](https://discourse.slimframework.com/u/poldee)\
**Post date:** [January 7, 2021, 8:35pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598/3 "2021-01-07T20:35:04Z")

</div>

Thanks for the quick reply.

Being new to PHP/Slim can you point me to a tutorial or a couple of examples to help understand you suggestion?

I purchased you eBook yesterday. Maybe you have an example in there?

Thanks

---

<div class="post-metadata">

**Author:** ![odan](https://avatars.discourse-cdn.com/v4/letter/o/9de053/32.png) [@odan](https://discourse.slimframework.com/u/odan)\
**Post date:** [January 7, 2021, 8:59pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598/4 "2021-01-07T20:59:37Z")

</div>

There is are some middleware examples in the eBook, for example in the “Error handling” chapter. Take a look at the `HttpExceptionMiddleware` example how to define a `ResponseInterface` containter entry and how to use it within a middleware to create a new response object.

---

<div class="post-metadata">

**Author:** ![poldee](https://avatars.discourse-cdn.com/v4/letter/p/bbce88/32.png) [@poldee](https://discourse.slimframework.com/u/poldee)\
**Post date:** [January 7, 2021, 9:01pm UTC](https://discourse.slimframework.com/t/not-instantiable/4598/5 "2021-01-07T21:01:26Z")

</div>

THANK YOU!!!

I’ll check it out tomorrow am.

Energy level going down drastically after 16:00 😉

I just had a quick look… I think I get it! 🙂

Thanks again!