Cambio a la forma de obtener los indices

common/Controller/Web/Documentos.php

@@ -0,0 +1,25 @@
+<?php
+namespace ProVM\NotariaRaby\Common\Controller\Web;
+
+use Psr\Container\ContainerInterface as Container;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Http\Message\ResponseInterface as Response;
+
+class Documentos {
+  public function existe(Request $request, Response $response, Container $container, $documento) {
+    $filename = implode(DIRECTORY_SEPARATOR, [
+      $container->get('folders.upload'),
+      $documento . '.pdf'
+    ]);
+    $existe = file_exists($filename);
+    $output = [
+      'informacion' => $documento,
+      'archivo' => $filename,
+      'existe' => $existe
+    ];
+    $response->getBody()->write(json_encode($output));
+    return $response
+      ->withHeader('Content-Type', 'application/json')
+      ->withStatus(201);
+  }
+}