expo qr code to get visitors email

web/modules/custom/materio_expo/materio_expo.module

@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * @file
+ * Contains materio_expo.module.
+ */
+
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function materio_expo_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    // Main module help for the materio_expo module.
+    case 'help.page.materio_expo':
+      $output = '';
+      $output .= '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('My Awesome Module') . '</p>';
+      return $output;
+
+    default:
+  }
+}
+
+/**
+* Implements hook_mail().
+*/
+function materio_expo_mail($key, &$message, $params) {
+  switch ($key) {
+    case 'expo_getmail_submitted':
+      $message['from'] = \Drupal::config('system.site')->get('mail');
+      $message['subject'] = t('[EXPO] mail submitted: @mail', array('@mail' => $params['mail']));
+      $message['body'][] = $params['message'];
+      break;
+  }
+ }