From 96df6b984cdf2bc7df50e028e92fe27abb8826f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonatan=20M=C3=A4nnchen?= <jonatan.maennchen@ibrows.ch>
Date: Wed, 20 Jul 2016 17:11:46 +0000
Subject: [PATCH] [HttpFoundation] HttpCache refresh stale responses containing
 an ETag

---
 .../HttpKernel/HttpCache/HttpCache.php        |  3 +++
 .../Tests/HttpCache/HttpCacheTest.php         | 25 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
index f794d94e29..1b86ddd3c0 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
@@ -600,6 +600,9 @@ class HttpCache implements HttpKernelInterface, TerminableInterface
      */
     protected function store(Request $request, Response $response)
     {
+        if (!$response->headers->has('Date')) {
+            $response->setDate(\DateTime::createFromFormat('U', time()));
+        }
         try {
             $this->store->write($request, $response);
 
diff --git a/src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php b/src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
index b6164dd678..4eb1437144 100644
--- a/src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/HttpCache/HttpCacheTest.php
@@ -181,6 +181,31 @@ class HttpCacheTest extends HttpCacheTestCase
         $this->assertEquals(304, $this->response->getStatusCode());
     }
 
+    public function testIncrementsMaxAgeWhenNoDateIsSpecifiedEventWhenUsingETag()
+    {
+        $this->setNextResponse(
+            200,
+            array(
+                'ETag' => '1234',
+                'Cache-Control' => 'public, s-maxage=60',
+            )
+        );
+
+        $this->request('GET', '/');
+        $this->assertHttpKernelIsCalled();
+        $this->assertEquals(200, $this->response->getStatusCode());
+        $this->assertTraceContains('miss');
+        $this->assertTraceContains('store');
+
+        sleep(2);
+
+        $this->request('GET', '/');
+        $this->assertHttpKernelIsNotCalled();
+        $this->assertEquals(200, $this->response->getStatusCode());
+        $this->assertTraceContains('fresh');
+        $this->assertEquals(2, $this->response->headers->get('Age'));
+    }
+
     public function testValidatesPrivateResponsesCachedOnTheClient()
     {
         $this->setNextResponse(200, array(), '', function ($request, $response) {