also provide request itself in expressions

EventListener/InvalidationSubscriber.php

@@ -202,14 +202,19 @@ private function invalidatePaths(array $pathConfigurations)
      */
     private function invalidateRoutes(array $routes, Request $request)
     {
+        $values = $request->attributes->all();
+        // if there is an attribute called "request", it needs to be accessed through the request.
+        $values['request'] = $request;
+        $expressionLanguage = $this->getExpressionLanguage();
+
         foreach ($routes as $route) {
             $params = array();
 
             if (null !== $route->getParams()) {
                 // Iterate over route params and try to evaluate their values
                 foreach ($route->getParams() as $key => $value) {
                     if (is_array($value)) {
-                        $value = $this->getExpressionLanguage()->evaluate($value['expression'], $request->attributes->all());
+                        $value = $expressionLanguage->evaluate($value['expression'], $values);
                     }
 
                     $params[$key] = $value;

EventListener/TagSubscriber.php

@@ -146,10 +146,11 @@ private function getAnnotationTags(Request $request)
      */
     private function evaluateTag($expression, Request $request)
     {
-        return $this->getExpressionLanguage()->evaluate(
-            $expression,
-            $request->attributes->all()
-        );
+        $values = $request->attributes->all();
+        // if there is an attribute called "request", it needs to be accessed through the request.
+        $values['request'] = $request;
+
+        return $this->getExpressionLanguage()->evaluate($expression, $values);
     }
 
     /**

Resources/doc/reference/annotations.rst

@@ -59,6 +59,9 @@ route ``articles`` with the ``number`` parameter set to ``123``, do::
         // Assume $request->attributes->get('id') returns 123
     }
 
+The expression has access to all request attributes and the request itself
+under the name ``request``.
+
 See :doc:`/features/invalidation` for more information.
 
 .. _tag:

Resources/doc/reference/configuration/tags.rst

@@ -83,4 +83,7 @@ tag ``articles-123`` with the following configuration:
                     tags: [articles]
                     tag_expressions: ["'article-'~id"]
 
+The expression has access to all request attributes and the request itself
+under the name ``request``.
+
 You can combine ``tags`` and ``tag_expression`` in one rule.