Test

app/Http/Controllers/CsvExport.php

@@ -1,14 +1,44 @@
 <?php
+
 declare(strict_types=1);
 
 namespace App\Http\Controllers;
 
-class CsvExport extends Controller {
+use App\Http\Requests\GenerateCSVRequest;
+use Symfony\Component\HttpFoundation\StreamedResponse;
+
+class CsvExport extends Controller
+{
     /**
      * Converts the user input into a CSV file and streams the file back to the user
      */
-    public function convert()
+    public function convert(GenerateCSVRequest $request): StreamedResponse
     {
-        return ['success' => false];
+        $tableItems = $request->get('tableItems');
+
+        $filename = 'items.csv';
+
+        $headers = [
+            "Content-type" => "text/csv",
+            "Content-Disposition" => "attachment; filename=$filename",
+            "Pragma" => "no-cache",
+            "Cache-Control" => "must-revalidate, post-check=0, pre-check=0",
+            "Expires" => "0"
+        ];
+
+        $columns = array_keys($tableItems[0]);
+
+        $callback = function () use ($tableItems, $columns) {
+            $file = fopen('php://output', 'w');
+            fputcsv($file, $columns);
+
+            foreach ($tableItems as $item) {
+                fputcsv($file, $item);
+            }
+
+            fclose($file);
+        };
+
+        return response()->stream($callback, 200, $headers);
     }
 }

app/Http/Requests/GenerateCSVRequest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class GenerateCSVRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     *
+     * @return bool
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array
+     */
+    public function rules(): array
+    {
+        return [
+            'tableItems' => ['required', 'array'],
+            'tableItems.0' => ['required', 'array']
+        ];
+    }
+}

composer.json

@@ -11,7 +11,8 @@
         "php": "^7.2",
         "fideloper/proxy": "^4.0",
         "laravel/framework": "^6.2",
-        "laravel/tinker": "^2.0"
+        "laravel/tinker": "^2.0",
+        "league/csv": "^9.7"
     },
     "require-dev": {
         "facade/ignition": "^1.4",