Fix #105

* configured tags can access request.attributes with simple expression vars (id)
* response is no longer available as a value for expressions; but there’s no use case
  for that anyway
* update docs

EventListener/TagSubscriber.php

@@ -15,7 +15,6 @@
 use FOS\HttpCacheBundle\Configuration\Tag;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
@@ -78,10 +77,7 @@ public function onKernelResponse(FilterResponseEvent $event)
                 $tags[] = $tag;
             }
             foreach ($configuredTags['expressions'] as $expression) {
-                $tags[] = $this->expressionLanguage->evaluate($expression, array(
-                    'request' => $request,
-                    'response' => $response,
-                ));
+                $tags[] = $this->evaluateTag($expression, $request);
             }
         }
 
@@ -98,6 +94,16 @@ public function onKernelResponse(FilterResponseEvent $event)
         }
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public static function getSubscribedEvents()
+    {
+        return array(
+            KernelEvents::RESPONSE => 'onKernelResponse'
+        );
+    }
+
     /**
      * Get the tags from the annotations on the controller that was used in the
      * request.
@@ -118,9 +124,9 @@ private function getAnnotationTags(Request $request)
         $tags = array();
         foreach ($tagConfigurations as $tagConfiguration) {
             if (null !== $tagConfiguration->getExpression()) {
-                $tags[] = $this->expressionLanguage->evaluate(
+                $tags[] = $this->evaluateTag(
                     $tagConfiguration->getExpression(),
-                    $request->attributes->all()
+                    $request
                 );
             } else {
                 $tags = array_merge($tags, $tagConfiguration->getTags());
@@ -131,12 +137,19 @@ private function getAnnotationTags(Request $request)
     }
 
     /**
-     * {@inheritdoc}
+     * Evaluate a tag that contains expressions
+     *
+     * @param string  $expression
+     * @param Request $request
+     *
+     * @return string Evaluaated tag
      */
-    public static function getSubscribedEvents()
+    private function evaluateTag($expression, Request $request)
     {
-        return array(
-            KernelEvents::RESPONSE => 'onKernelResponse'
+        return $this->expressionLanguage->evaluate(
+            $expression,
+            $request->attributes->all()
         );
     }
+
 }

Resources/doc/reference/annotations.rst

@@ -114,7 +114,7 @@ response::
      */
     public function showAction($id)
     {
-        // Assume $id equals 123
+        // Assume request parameter $id equals 123
     }
 
 Or, using a `param converter`_::

Resources/doc/reference/configuration/tags.rst

@@ -2,7 +2,8 @@ tags
 ====
 
 Create tag rules in your application configuration to set tags on responses
-and invalidate them.
+and invalidate them. See the :doc:`tagging feature chapter </features/tagging>`
+for an introduction.
 
 .. include:: /includes/enabled.rst
 
@@ -40,6 +41,14 @@ invalidated instead.
 
 .. include:: /includes/match.rst
 
+tags
+^^^^
+
+**type**: ``array``
+
+Tags that should be set on responses to safe requests; or invalidated for
+unsafe requests.
+
 .. code-block:: yaml
 
     # app/config/config.yml
@@ -51,14 +60,27 @@ invalidated instead.
                         path: ^/news
                     tags: [news-section]
 
-.. note::
-
-    See further the :doc:`tagging feature description </features/tagging>`.
 
-tags
-^^^^
+tag_expressions
+~~~~~~~~~~~~~~~
 
 **type**: ``array``
 
-Tags that should be set on responses to safe requests; or invalidated for
-unsafe requests.
+You can dynamically refer to request attributes using
+:ref:`expressions <expression language requirement>`. Assume a route
+``/articles/{id}``. A request to path ``/articles/123`` will set/invalidate
+tag ``articles-123`` with the following configuration:
+
+.. code-block:: yaml
+
+    # app/config/config.yml
+    fos_http_cache:
+        tags:
+            rules:
+                -
+                    match:
+                        path: ^/articles
+                    tags: [articles]
+                    tag_expressions: ["article-"~id]
+
+You can combine ``tags`` and ``tag_expression`` in one rule.

Tests/Unit/EventListener/TagSubscriberTest.php

@@ -68,7 +68,7 @@ public function testOnKernelResponseGet()
         ;
         $this->listener->addRule($mockMatcher, array(
             'tags' => array('configured-tag'),
-            'expressions' => array('"item-" ~ request.attributes.get("id")'),
+            'expressions' => array('"item-" ~ id'),
         ));
         $this->listener->onKernelResponse($event);
 
@@ -123,7 +123,7 @@ public function testOnKernelResponsePost()
         ;
         $this->listener->addRule($mockMatcher, array(
             'tags' => array('configured-tag'),
-            'expressions' => array('"item-" ~ request.attributes.get("id")'),
+            'expressions' => array('"item-" ~ id'),
         ));
         $this->listener->onKernelResponse($event);
     }