Examples for presentation.

sources/Example/Bad/Controller.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Example\Bad;
+
+use Psr\Http\Message\RequestInterface;
+
+class Controller
+{
+    private CalculatorService  $calculator;
+
+    public function __construct(CalculatorService $calculator)
+    {
+        $this->calculator = $calculator;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(RequestInterface $request) : array {
+        $params = $request->getBody();
+        return $this->calculator->getProducts($params);
+    }
+}