Add JSON whitelist mask (TheSoftwareHouse#8)

src/Fogger/Mask/JSONWhitelistMask.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Fogger\Mask;
+
+final class JSONWhitelistMask extends AbstractMask
+{
+    public function apply(?string $value, array $options = []): ?string
+    {
+        if ((null === $value) or ("" === $value )) {
+            return $value;
+        }
+
+        $whitelist = $options['whitelist'] ?? [];
+
+        $result = [];
+        $jsonArray = json_decode($value, true);
+
+        foreach ($whitelist as $field) {
+            if (array_key_exists($field, $jsonArray)) {
+                $result[$field] = $jsonArray[$field];
+            }
+        }
+        return json_encode($result);
+    }
+
+    protected function getMaskName(): string
+    {
+        return 'jsonwhitelist';
+    }
+}