remove validation related headers when needed

src/Symfony/Component/HttpKernel/HttpCache/EsiResponseCacheStrategy.php

@@ -29,13 +29,12 @@ use Symfony\Component\HttpFoundation\Response;
 class EsiResponseCacheStrategy implements EsiResponseCacheStrategyInterface
 {
     private $cacheable = true;
+    private $embeddedResponses = 0;
     private $ttls = array();
     private $maxAges = array();
 
     /**
-     * Adds a Response.
-     *
-     * @param Response $response
+     * {@inheritdoc}
      */
     public function add(Response $response)
     {
@@ -45,26 +44,38 @@ class EsiResponseCacheStrategy implements EsiResponseCacheStrategyInterface
             $this->ttls[] = $response->getTtl();
             $this->maxAges[] = $response->getMaxAge();
         }
+
+        $this->embeddedResponses++;
     }
 
     /**
-     * Updates the Response HTTP headers based on the embedded Responses.
-     *
-     * @param Response $response
+     * {@inheritdoc}
      */
     public function update(Response $response)
     {
-        // if we only have one Response, do nothing
-        if (1 === count($this->ttls)) {
+        // if we have no embedded Response, do nothing
+        if (0 === $this->embeddedResponses) {
             return;
         }
 
+        // Remove validation related headers in order to avoid browsers using
+        // their own cache, because some of the response content comes from
+        // at least one embedded response (which likely has a different caching strategy).
+        if ($response->isValidateable()) {
+            $response->setEtag(null);
+            $response->setLastModified(null);
+            $this->cacheable = false;
+        }
+
         if (!$this->cacheable) {
             $response->headers->set('Cache-Control', 'no-cache, must-revalidate');
 
             return;
         }
 
+        $this->ttls[] = $response->getTtl();
+        $this->maxAges[] = $response->getMaxAge();
+
         if (null !== $maxAge = min($this->maxAges)) {
             $response->setSharedMaxAge($maxAge);
             $response->headers->set('Age', $maxAge - min($this->ttls));

src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php

@@ -204,10 +204,10 @@ class HttpCache implements HttpKernelInterface, TerminableInterface
         }
 
         if (null !== $this->esi) {
-            $this->esiCacheStrategy->add($response);
-
             if (HttpKernelInterface::MASTER_REQUEST === $type) {
                 $this->esiCacheStrategy->update($response);
+            } else {
+                $this->esiCacheStrategy->add($response);
             }
         }
 

src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php

@@ -1075,4 +1075,32 @@ class HttpCacheTest extends HttpCacheTestCase
 
         $this->assertEquals('10.0.0.1', $this->kernel->getBackendRequest()->headers->get('X-Forwarded-For'));
     }
+
+    public function testEsiCacheRemoveValidationHeadersIfEmbeddedResponses()
+    {
+        $time = new \DateTime;
+
+        $responses = array(
+            array(
+                'status'  => 200,
+                'body'    => '<esi:include src="/hey" />',
+                'headers' => array(
+                    'Surrogate-Control' => 'content="ESI/1.0"',
+                    'ETag' => 'hey',
+                    'Last-Modified' => $time->format(DATE_RFC2822),
+                ),
+            ),
+            array(
+                'status'  => 200,
+                'body'    => 'Hey!',
+                'headers' => array(),
+            ),
+        );
+
+        $this->setNextResponses($responses);
+
+        $this->request('GET', '/', array(), array(), true);
+        $this->assertNull($this->response->getETag());
+        $this->assertNull($this->response->getLastModified());
+    }
 }