Added ability for date format strings to be localized by back-end

Requires the locale to be installed on the system-side.
Closes #1214

app/Http/Middleware/Localization.php

@@ -7,8 +7,40 @@ use Illuminate\Http\Request;
 class Localization
 {
 
+    /**
+     * Array of right-to-left locales
+     * @var array
+     */
     protected $rtlLocales = ['ar'];
 
+    /**
+     * Map of BookStack locale names to best-estimate system locale names.
+     * @var array
+     */
+    protected $localeMap = [
+        'ar' => 'ar',
+        'de' => 'de_DE',
+        'de_informal' => 'de_DE',
+        'en' => 'en_GB',
+        'es' => 'es_ES',
+        'es_AR' => 'es_AR',
+        'fr' => 'fr_FR',
+        'it' => 'it_IT',
+        'ja' => 'ja',
+        'kr' => 'ko_KR',
+        'nl' => 'nl_NL',
+        'pl' => 'pl_PL',
+        'pt_BR' => 'pt_BR',
+        'pt_BR' => 'pt_BR',
+        'ru' => 'ru',
+        'sk' => 'sk_SK',
+        'sv' => 'sv_SE',
+        'uk' => 'uk_UA',
+        'uk' => 'uk_UA',
+        'zh_CN' => 'zh_CN',
+        'zh_TW' => 'zh_TW',
+    ];
+
     /**
      * Handle an incoming request.
      *
@@ -31,8 +63,11 @@ class Localization
             config()->set('app.rtl', true);
         }
 
+
+
         app()->setLocale($locale);
         Carbon::setLocale($locale);
+        $this->setSystemDateLocale($locale);
         return $next($request);
     }
 
@@ -53,4 +88,18 @@ class Localization
         }
         return $default;
     }
+
+    /**
+     * Set the system date locale for localized date formatting.
+     * Will try both the standard locale name and the UTF8 variant.
+     * @param string $locale
+     */
+    protected function setSystemDateLocale(string $locale)
+    {
+        $systemLocale = $this->localeMap[$locale] ?? $locale;
+        $set = setlocale(LC_TIME, $systemLocale);
+        if ($set === false) {
+            setlocale(LC_TIME, $systemLocale . '.utf8');
+        }
+    }
 }

resources/views/pages/revisions.blade.php

@@ -34,7 +34,7 @@
                                     @endif
                                 </td>
                                 <td> @if($revision->createdBy) {{ $revision->createdBy->name }} @else {{ trans('common.deleted_user') }} @endif</td>
-                                <td><small>{{ $revision->created_at->format('jS F, Y H:i:s') }} <br> ({{ $revision->created_at->diffForHumans() }})</small></td>
+                                <td><small>{{ $revision->created_at->formatLocalized('%e %B %Y %H:%M:%S') }} <br> ({{ $revision->created_at->diffForHumans() }})</small></td>
                                 <td>{{ $revision->summary }}</td>
                                 <td class="actions">
                                     <a href="{{ $revision->getUrl('changes') }}" target="_blank">{{ trans('entities.pages_revisions_changes') }}</a>