Implementing mustRevaidate()

lib/Cake/Network/CakeResponse.php

@@ -767,6 +767,29 @@ class CakeResponse {
 		return null;
 	}
 
+/**
+ * Sets the Cache-Control must-revalidate directive.
+ * must-revalidate indicates that the response should not be served 
+ * stale by a cache under any cirumstance without first revalidating 
+ * with the origin.
+ * If called with no parameters, this function will return wheter must-revalidate is present.
+ *
+ * @param int $seconds if null, the method will return the current 
+ * must-revalidate value
+ * @return boolean
+ */
+	public function mustRevalidate($enable = null) {
+		if ($enable !== null) {
+			if ($enable) {
+				$this->_cacheDirectives['must-revalidate'] = null;
+			} else {
+				unset($this->_cacheDirectives['must-revalidate']);
+			}
+			$this->_setCacheControl();
+		}
+		return array_key_exists('must-revalidate', $this->_cacheDirectives);
+	}
+
 /**
  * Helper method to generate a valid Cache-Control header from the options set
  * in other methods

lib/Cake/Test/Case/Network/CakeResponseTest.php

@@ -733,4 +733,34 @@ class CakeResponseTest extends CakeTestCase {
 			->method('_sendHeader')->with('Cache-Control', 's-maxage=3600, public');
 		$response->send();
 	}
+
+/**
+ * Tests setting of must-revalidate Cache-Control directive
+ *
+ * @return void
+ */
+	public function testMustRevalidate() {
+		$response = $this->getMock('CakeResponse', array('_sendHeader', '_sendContent'));
+		$this->assertFalse($response->mustRevalidate());
+		$response->mustRevalidate(true);
+		$this->assertTrue($response->mustRevalidate());
+		$headers = $response->header();
+		$this->assertEquals('must-revalidate', $headers['Cache-Control']);
+		$response->expects($this->at(1))
+			->method('_sendHeader')->with('Cache-Control', 'must-revalidate');
+		$response->send();
+		$response->mustRevalidate(false);
+		$this->assertFalse($response->mustRevalidate());
+
+		$response = $this->getMock('CakeResponse', array('_sendHeader', '_sendContent'));
+		$response->sharedMaxAge(3600);
+		$response->mustRevalidate(true);
+		$headers = $response->header();
+		$this->assertEquals('s-maxage=3600, must-revalidate', $headers['Cache-Control']);
+		$response->expects($this->at(1))
+			->method('_sendHeader')->with('Cache-Control', 's-maxage=3600, must-revalidate');
+		$response->send();
+
+	}
+
 }