Passing variable from middleware to controllers __construct to prevent repeating myself - php

Question

I'm doing an existence check within a middleware, by checking a route-parameter.
If the check succeeds, I'm attaching it's model to the request to make it available throughout the rest of the request-cycle, application.
// App\Http\Middleware\CheckForExistence.php:
...
public function handle($request, Closure $next)
{
// some checks...
// success
$request->attributes->add([
'company' => $someModel
]);
}
I now have a controller which 'needs' this information in a couple of methods. So my thought was to add it to the construct of the controller and add it as a protected var in the whole controller:
// App\Http\Controllers\MyController.php
<?php
use Illuminate\Http\Request;
class MyController extends Controller
{
protected $company;
public function __construct(Request $request)
{
$this->company = $request->attributes->get('company');
}
public function index()
{
dd($this->company); // returns null
}
}
This controllers index() returns null instead of the give model.
If I change the index() method to:
public function index(Request $request)
{
return $request->attributes->get('company');
}
This returns the model; as expected.
Why is this happening? It looks like the middleware is not run when the controller is constructed.... Is there a way to circumvent it?
Or am I missing the obvious here.....
I could off course repeat myself in each method; but that is not very DRY ;)

Answer 1

You can't access the session or authenticated user in your controller's constructor because the middleware has not run yet, So you can do it like this :
public function __construct()
{
$this->middleware(function ($request, $next) {
$this->company = $request->attributes->get('company');
return $next($request);
});
}

Answer 2

For reasons currently unclear to me, the controller object is constructed before the request changes are reflected in the request object. In short the request is not considered properly constructed when a controller is constructed. This post seems to imply that.
There's two ways to work around this (if for a second we ignore what you're trying to do).
Use request dependency injection
public function index(Request $request)
{
$compary = $request->attributes->get('company');
}
This is not really WET because you're just swapping $this->company with $request->attributes->get('company') it's just a refactor. You should be injecting the request in the controller action anyway and if you don't want to do that you can use the request() helper.
Use a callback middleware in the constructor (Maraboc's answer explains how)
Now if you want a more case specific solution though you can use case specific dependency injection:
If you need to bind a model to a specific route parameter you can use route model binding and add the following in your RouteServiceProvider (or any provider).
Route::bind("companyAsARouteVarName", function () {
// this is why more details in the question are invaluable. I don't know if this is the right way for you.
//checks
// success
return $someModel;
});
Then you will register your route as:
Route::get("/something/{companyAsARouteVarName}", "SomeController#index");
and your controller will be:
public function index(Company $companyAsARouteVarName) {
//Magic
}

Answer 3

Controller constructor will be initialized before middleware execution.
You can get data from Injected $request object in controller functions.