Add withSharedMaxAge()

src/Network/Response.php

@@ -1331,6 +1331,24 @@ public function sharedMaxAge($seconds = null)
         return null;
     }
 
+    /**
+     * Create a new instance with the Cache-Control s-maxage directive.
+     *
+     * The max-age is the number of seconds after which the response should no longer be considered
+     * a good candidate to be fetched from a shared cache (like in a proxy server).
+     *
+     * @param int $seconds The number of seconds for shared max-age
+     * @return static
+     */
+    public function withSharedMaxAge($seconds)
+    {
+        $new = clone $this;
+        $new->_cacheDirectives['s-maxage'] = $seconds;
+        $new->_setCacheControl();
+
+        return $new;
+    }
+
     /**
      * Sets the Cache-Control max-age directive.
      * The max-age is the number of seconds after which the response should no longer be considered

tests/TestCase/Network/ResponseTest.php

@@ -980,6 +980,23 @@ public function testSharedMaxAge()
         $this->assertEquals('s-maxage=3600, public', $response->getHeaderLine('Cache-Control'));
     }
 
+    /**
+     * Tests setting of s-maxage Cache-Control directive
+     *
+     * @return void
+     */
+    public function testWithSharedMaxAge()
+    {
+        $response = new Response();
+        $new = $response->withSharedMaxAge(3600);
+
+        $this->assertFalse($response->hasHeader('Cache-Control'));
+        $this->assertEquals('s-maxage=3600', $new->getHeaderLine('Cache-Control'));
+
+        $new = $response->withSharedMaxAge(3600)->withSharable(true);
+        $this->assertEquals('s-maxage=3600, public', $new->getHeaderLine('Cache-Control'));
+    }
+
     /**
      * Tests setting of must-revalidate Cache-Control directive
      *