Gracefully catches Twig exceptions and displays error messages

MAILPOET-667 #time 3h

lib/Config/Initializer.php

@@ -146,8 +146,9 @@ class Initializer {
   }
 
   function setupRenderer() {
-    $renderer = new Renderer();
-    $this->renderer = $renderer->init();
+    $caching = !WP_DEBUG;
+    $debugging = WP_DEBUG;
+    $this->renderer = new Renderer($caching, $debugging);
   }
 
   function setupLocalizer() {
@@ -210,4 +211,4 @@ class Initializer {
   function handleFailedInitialization($message) {
     return WPNotice::displayError($message);
   }
-}
+}

lib/Config/Menu.php

@@ -16,6 +16,7 @@ use MailPoet\Subscribers\ImportExport\ImportExportFactory;
 use MailPoet\Listing;
 use MailPoet\Util\License\Features\Subscribers as SubscribersFeature;
 use MailPoet\WP\DateTime;
+use MailPoet\WP\Notice as WPNotice;
 
 if(!defined('ABSPATH')) exit;
 
@@ -215,7 +216,7 @@ class Menu {
       'redirect_url' => $redirect_url,
       'sub_menu' => 'mailpoet-newsletters'
     );
-    echo $this->renderer->render('welcome.html', $data);
+    $this->displayPage('welcome.html', $data);
   }
 
   function update() {
@@ -241,7 +242,7 @@ class Menu {
       'sub_menu' => 'mailpoet-newsletters'
     );
 
-    echo $this->renderer->render('update.html', $data);
+    $this->displayPage('update.html', $data);
   }
 
   function settings() {
@@ -263,7 +264,7 @@ class Menu {
       )
     );
 
-    echo $this->renderer->render('settings.html', $data);
+    $this->displayPage('settings.html', $data);
   }
 
   private function _getFlags() {
@@ -315,7 +316,7 @@ class Menu {
     $data['date_formats'] = Block\Date::getDateFormats();
     $data['month_names'] = Block\Date::getMonthNames();
 
-    echo $this->renderer->render('subscribers/subscribers.html', $data);
+    $this->displayPage('subscribers/subscribers.html', $data);
   }
 
   function segments() {
@@ -323,7 +324,7 @@ class Menu {
 
     $data = array();
     $data['items_per_page'] = $this->getLimitPerPage('segments');
-    echo $this->renderer->render('segments.html', $data);
+    $this->displayPage('segments.html', $data);
   }
 
   function forms() {
@@ -334,7 +335,7 @@ class Menu {
     $data['items_per_page'] = $this->getLimitPerPage('forms');
     $data['segments'] = Segment::findArray();
 
-    echo $this->renderer->render('forms.html', $data);
+    $this->displayPage('forms.html', $data);
   }
 
   function newsletters() {
@@ -364,7 +365,7 @@ class Menu {
     wp_enqueue_script('jquery-ui');
     wp_enqueue_script('jquery-ui-datepicker');
 
-    echo $this->renderer->render('newsletters.html', $data);
+    $this->displayPage('newsletters.html', $data);
   }
 
   function newletterEditor() {
@@ -377,7 +378,7 @@ class Menu {
     wp_enqueue_media();
     wp_enqueue_script('tinymce-wplink', includes_url('js/tinymce/plugins/wplink/plugin.js'));
     wp_enqueue_style('editor', includes_url('css/editor.css'));
-    echo $this->renderer->render('newsletter/editor.html', $data);
+    $this->displayPage('newsletter/editor.html', $data);
   }
 
   function import() {
@@ -389,14 +390,14 @@ class Menu {
       'month_names' => Block\Date::getMonthNames(),
       'sub_menu' => 'mailpoet-subscribers'
     ));
-    echo $this->renderer->render('subscribers/importExport/import.html', $data);
+    $this->displayPage('subscribers/importExport/import.html', $data);
   }
 
   function export() {
     $export = new ImportExportFactory('export');
     $data = $export->bootstrap();
     $data['sub_menu'] = 'mailpoet-subscribers';
-    echo $this->renderer->render('subscribers/importExport/export.html', $data);
+    $this->displayPage('subscribers/importExport/export.html', $data);
   }
 
   function formEditor() {
@@ -417,7 +418,7 @@ class Menu {
       'sub_menu' => 'mailpoet-forms'
     );
 
-    echo $this->renderer->render('form/editor.html', $data);
+    $this->displayPage('form/editor.html', $data);
   }
 
   function setPageTitle($title) {
@@ -428,6 +429,13 @@ class Menu {
     );
   }
 
+  function displaySubscriberLimitExceededTemplate() {
+    $this->displayPage('limit.html', array(
+      'limit' => SubscribersFeature::SUBSCRIBERS_LIMIT
+    ));
+    exit;
+  }
+
   private function getLimitPerPage($model = null) {
     if($model === null) {
       return Listing\Handler::DEFAULT_LIMIT_PER_PAGE;
@@ -441,10 +449,12 @@ class Menu {
       : Listing\Handler::DEFAULT_LIMIT_PER_PAGE;
   }
 
-  function displaySubscriberLimitExceededTemplate() {
-    echo $this->renderer->render('limit.html', array(
-      'limit' => SubscribersFeature::SUBSCRIBERS_LIMIT
-    ));
-    exit;
+  private function displayPage($template, $data) {
+    try {
+      echo $this->renderer->render($template, $data);
+    } catch (\Exception $e) {
+      $notice = new WPNotice(WPNotice::TYPE_ERROR, $e->getMessage());
+      $notice->displayWPNotice();
+    }
   }
-}
+}

lib/Config/Renderer.php

@@ -8,19 +8,26 @@ use \MailPoet\Twig;
 if(!defined('ABSPATH')) exit;
 
 class Renderer {
-  function __construct() {
+  protected $cache_path;
+  protected $caching_enabled;
+  protected $debugging_enabled;
+  protected $renderer;
+
+  function __construct($caching_enabled = false, $debugging_enabled = false) {
+    $this->caching_enabled = $caching_enabled;
+    $this->debuggin_enabled = $debugging_enabled;
+    $this->cache_path = Env::$temp_path . '/cache';
+
     $file_system = new TwigFileSystem(Env::$views_path);
     $this->renderer = new TwigEnv(
       $file_system,
       array(
         'cache' => $this->detectCache(),
-        'debug' => WP_DEBUG,
+        'debug' => $this->debugging_enabled,
         'auto_reload' => true
       )
     );
-  }
 
-  function init() {
     $this->setupDebug();
     $this->setupTranslations();
     $this->setupFunctions();
@@ -28,8 +35,6 @@ class Renderer {
     $this->setupHelpscout();
     $this->setupGlobalVariables();
     $this->setupSyntax();
-
-    return $this->renderer;
   }
 
   function setupTranslations() {
@@ -66,16 +71,30 @@ class Renderer {
   }
 
   function detectCache() {
-    $cache_path = Env::$temp_path . '/cache';
-    if(WP_DEBUG === false) {
-      return $cache_path;
-    }
-    return false;
+    return $this->caching_enabled ? $this->cache_path : false;
   }
 
   function setupDebug() {
-    if(WP_DEBUG === true) {
+    if($this->debugging_enabled) {
       $this->renderer->addExtension(new \Twig_Extension_Debug());
     }
   }
+
+  function render($template, $context = array()) {
+    try {
+      return $this->renderer->render($template, $context);
+    } catch(\RuntimeException $e) {
+      throw new \Exception(sprintf(
+        __('Failed to render template "%s". Please ensure the template cache folder "%s" exists and has write permissions. Terminated with error: "%s"'),
+        $template,
+        $this->cache_path,
+        $e->getMessage()
+      ));
+    }
+  }
+
+
+  function addGlobal($key, $value) {
+    return $this->renderer->addGlobal($key, $value);
+  }
 }

lib/Config/Widget.php

@@ -73,7 +73,11 @@ class Widget {
           )
         );
 
-        echo $this->renderer->render('form/iframe.html', $data);
+        try {
+          echo $this->renderer->render('form/iframe.html', $data);
+        } catch(\Exception $e) {
+          echo $e->getMessage();
+        }
       }
       exit();
     }

lib/Form/Widget.php

@@ -165,9 +165,12 @@ class Widget extends \WP_Widget {
 
         // render form
         $renderer = new Renderer();
-        $renderer = $renderer->init();
-        $output = $renderer->render('form/widget.html', $data);
-        $output = do_shortcode($output);
+        try {
+          $output = $renderer->render('form/widget.html', $data);
+          $output = do_shortcode($output);
+        } catch(\Exception $e) {
+          $output = $e->getMessage();
+        }
       }
 
       if($form_type === 'widget') {

lib/WP/Notice.php

@@ -11,7 +11,7 @@ class Notice {
   private $type;
   private $message;
 
-  protected function __construct($type, $message) {
+  function __construct($type, $message) {
     $this->type = $type;
     $this->message = $message;
   }

tests/unit/Config/RendererTest.php

@@ -1,9 +1,10 @@
 <?php
+use Codeception\Util\Stub;
 use \MailPoet\Config\Renderer;
 
 class RendererTest extends MailPoetTest {
   function _before() {
-    $this->renderer = new Renderer();
+    $this->renderer = new Renderer($caching = false, $debugging = false);
   }
 
   function testItWillNotEnableCacheWhenWpDebugIsOn() {
@@ -11,6 +12,47 @@ class RendererTest extends MailPoetTest {
     expect($result)->equals(false);
   }
 
+  function testItDelegatesRenderingToTwig() {
+    $renderer = Stub::construct(
+      $this->renderer,
+      array(),
+      array(
+        'renderer' => Stub::makeEmpty('Twig_Environment',
+          array(
+            'render' => Stub::atLeastOnce(function() { return 'test render'; }),
+          )
+        ),
+      )
+    );
+
+    expect($renderer->render('non-existing-template.html', array('somekey' => 'someval')))->equals('test render');
+  }
+
+  function testItRethrowsTwigCacheExceptions() {
+    $exception_message = 'this is a test error';
+    $renderer = Stub::construct(
+      $this->renderer,
+      array(true, false),
+      array(
+        'renderer' => Stub::makeEmpty('Twig_Environment',
+          array(
+            'render' => Stub::atLeastOnce(function() use ($exception_message) {
+              throw new \RuntimeException($exception_message);
+            }),
+          )
+        ),
+      )
+    );
+
+    try {
+      $renderer->render('non-existing-template.html', array('somekey' => 'someval'));
+      self::fail('Twig exception was not rethrown');
+    } catch(\Exception $e) {
+      expect($e->getMessage())->contains($exception_message);
+      expect($e->getMessage())->notEquals($exception_message);
+    }
+  }
+
   function _after() {
   }
 }