Add user detector (#7)

Author: zepfietje

config/localizer.php

@@ -13,6 +13,7 @@
      */
     'detectors' => [
         CodeZero\Localizer\Detectors\UrlDetector::class,
+        CodeZero\Localizer\Detectors\UserDetector::class,
         CodeZero\Localizer\Detectors\SessionDetector::class,
         CodeZero\Localizer\Detectors\CookieDetector::class,
         CodeZero\Localizer\Detectors\BrowserDetector::class,
@@ -34,6 +35,12 @@
      */
     'url-segment' => 1,
 
+    /**
+     * The attribute on the user model that holds the locale,
+     * when using the UserDetector.
+     */
+    'user-attribute' => 'locale',
+
     /**
      * The session key that holds the locale,
      * when using the SessionDetector and SessionStore.

src/Detectors/UserDetector.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace CodeZero\Localizer\Detectors;
+
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\Config;
+
+class UserDetector implements Detector
+{
+    /**
+     * Detect the locale.
+     *
+     * @return string|array|null
+     */
+    public function detect()
+    {
+        $user = Auth::user();
+
+        if ($user === null) {
+            return null;
+        }
+
+        $attribute = Config::get('localizer.user-attribute');
+
+        return $user->getAttributeValue($attribute);
+    }
+}