Warning (2): Undefined array key "HTTP_REFERER" [APP/Controller/ContentController.php, line 206]

Code Context

        $language_id=$language['Language']['id'];
        echo $lang_code.'<br>';
        echo $_SERVER['HTTP_REFERER'].'<br>';

ContentController::lang() - APP/Controller/ContentController.php, line 206
ReflectionMethod::invokeArgs() - [internal], line ??
Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 499
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 193
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 167
[main] - APP/webroot/index.php, line 117

Warning (2): Undefined array key "HTTP_REFERER" [APP/Controller/ContentController.php, line 207]

Code Context

        echo $lang_code.'<br>';
        echo $_SERVER['HTTP_REFERER'].'<br>';
        $urls = explode('/', $_SERVER['HTTP_REFERER']);

ContentController::lang() - APP/Controller/ContentController.php, line 207
ReflectionMethod::invokeArgs() - [internal], line ??
Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 499
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 193
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 167
[main] - APP/webroot/index.php, line 117