feat(datafile management): Added Config Update Notification Listener

Author: rashidsp

README.md

@@ -14,7 +14,7 @@ Optimizely Rollouts is free feature flags for development teams. Easily roll out
 
 ### Installing the SDK
 
-The Optimizely PHP SDK can be installed through [Composer](https://getcomposer.org/). Please use the following command: 
+The Optimizely PHP SDK can be installed through [Composer](https://getcomposer.org/). Please use the following command:
 
 ```
 php composer.phar require optimizely/optimizely-sdk
@@ -61,6 +61,8 @@ $configManager = new HTTPProjectConfigManager(<<SDK_KEY>>);
 ##### SDK key
 Optimizely project SDK key; required unless source URL is overridden.
 
+A notification signal will be triggered whenever a _new_ datafile is fetched and Project Config is updated. To subscribe to these notifications, use the `$notificationCenter->addNotificationListener(NotificationType::OPTIMIZELY_CONFIG_UPDATE, $updateCallback)`.
+
 #### Documentation
 See the Optimizely Full Stack [developer documentation](https://developers.optimizely.com/x/solutions/sdks/reference/?language=php) to learn how to set up your first Full Stack project and use the SDK.
 

src/Optimizely/Notification/NotificationType.php

@@ -32,11 +32,17 @@ class NotificationType
      */
     const DECISION = "DECISION:type, user_id, attributes, decision_info";
 
+    /*
+     * Notification triggered when Project Config is updated.
+     */
+    const OPTIMIZELY_CONFIG_UPDATE = "optimizely_config_update";
+
     /*
      * Notification triggered when a conversion event is sent to Optimizely.
      */
     const TRACK = "TRACK:event_key, user_id, attributes, event_tags, event";
 
+
     public static function isNotificationTypeValid($notification_type)
     {
         $oClass = new \ReflectionClass(__CLASS__);

src/Optimizely/ProjectConfigManager/HTTPProjectConfigManager.php

@@ -24,6 +24,8 @@
 use Optimizely\Enums\ProjectConfigManagerConstants;
 use Optimizely\ErrorHandler\NoOpErrorHandler;
 use Optimizely\Logger\NoOpLogger;
+use Optimizely\Notification\NotificationCenter;
+use Optimizely\Notification\NotificationType;
 use Optimizely\Utils\Validator;
 
 class HTTPProjectConfigManager implements ProjectConfigManagerInterface
@@ -63,6 +65,11 @@ class HTTPProjectConfigManager implements ProjectConfigManagerInterface
      */
     private $_errorHandler;
 
+    /**
+     * @var NotificationCenter NotificationCenter instance.
+     */
+    private $_notificationCenter;
+
     public function __construct(
         $sdkKey = null,
         $url = null,
@@ -71,11 +78,16 @@ public function __construct(
         $datafile = null,
         $skipJsonValidation = false,
         $logger = null,
-        $errorHandler = null
+        $errorHandler = null,
+        $notificationCenter = null
     ) {
         $this->_skipJsonValidation = $skipJsonValidation;
-        $this->_logger = $logger;
-        $this->_errorHandler = $errorHandler;
+        $this->_logger = $logger ?: new NoOpLogger();
+        $this->_errorHandler = $errorHandler ?: new NoOpErrorHandler();
+        $this->_notificationCenter = $notificationCenter;
+        if (!($this->_notificationCenter instanceof NotificationCenter)) {
+            $this->_notificationCenter = new NotificationCenter($this->_logger, $this->_errorHandler);
+        }
         $this->httpClient = new HttpClient();
 
         if ($this->_logger === null) {
@@ -231,6 +243,10 @@ protected function handleResponse($datafile)
         }
 
         $this->_config = $config;
+
+        $this->_notificationCenter->sendNotifications(NotificationType::OPTIMIZELY_CONFIG_UPDATE);
+        $this->_logger->log(Logger::DEBUG, sprintf('Received new datafile and updated config. Old revision number: "%s". New revision number: "%s".', $previousRevision, $this->_config->getRevision()));
+
         return true;
     }
 

tests/ProjectConfigManagerTests/HTTPProjectConfigManagerTest.php

@@ -27,6 +27,8 @@
 use Optimizely\ErrorHandler\NoOpErrorHandler;
 use Optimizely\Exceptions\InvalidDatafileVersionException;
 use Optimizely\Logger\NoOpLogger;
+use Optimizely\Notification\NotificationCenter;
+use Optimizely\Notification\NotificationType;
 use Optimizely\ProjectConfigManager\HTTPProjectConfigManager;
 
 class HTTPProjectConfigManagerTest extends \PHPUnit_Framework_TestCase
@@ -48,6 +50,12 @@ public function setUp()
             ->setMethods(array('handleError'))
             ->getMock();
 
+        // Mock Notification Center
+        $this->notificationCenterMock = $this->getMockBuilder(NotificationCenter::class)
+            ->setConstructorArgs(array($this->loggerMock, $this->errorHandlerMock))
+            ->setMethods(array('sendNotifications'))
+            ->getMock();
+
         $this->url = "https://cdn.optimizely.com/datafiles/QBw9gFM8oTn7ogY9ANCC1z.json";
         $this->template = "https://cdn.optimizely.com/datafiles/%s.json";
     }
@@ -254,18 +262,26 @@ public function testConfigNotUpdatedWhenDatafileIsNotModified()
         $this->assertEquals($config, $configAfterFetch);
     }
 
-    public function testGetConfigReturnsUpdatedDatafileWhenHttpClientReturnsValidDatafile()
+    public function testHandleResponseCallsConfigUpdateListenerWhenProjectConfigIsUpdated()
     {
         $configManagerMock = $this->getMockBuilder(HTTPProjectConfigManagerTester::class)
             ->setConstructorArgs(array(null, $this->url, null, true, DATAFILE_WITH_TYPED_AUDIENCES, false,
-                                     $this->loggerMock, $this->errorHandlerMock))
+                                     $this->loggerMock, $this->errorHandlerMock, $this->notificationCenterMock))
             ->setMethods(array('fetchDatafile'))
             ->getMock();
 
         $configManagerMock->expects($this->any())
             ->method('fetchDatafile')
             ->willReturn(DATAFILE);
 
+        $this->loggerMock->expects($this->once())
+            ->method('log')
+            ->with(Logger::DEBUG, 'Received new datafile and updated config. Old revision number: "3". New revision number: "15".');
+
+        $this->notificationCenterMock->expects($this->once())
+            ->method('sendNotifications')
+            ->with(NotificationType::OPTIMIZELY_CONFIG_UPDATE);
+
         $configManagerMock->handleResponse(DATAFILE);
 
         $config = DatafileProjectConfig::createProjectConfigFromDatafile(
@@ -333,13 +349,19 @@ public function testHandleResponseReturnsFalseForSameDatafilesRevisions()
     {
         $configManagerMock = $this->getMockBuilder(HTTPProjectConfigManagerTester::class)
             ->setConstructorArgs(array(null, $this->url, null, false, DATAFILE, false,
-                                    $this->loggerMock, $this->errorHandlerMock))
+                                    $this->loggerMock, $this->errorHandlerMock, $this->notificationCenterMock))
             ->setMethods(array('fetch'))
             ->getMock();
 
         $config = $configManagerMock->getConfig();
         $datafile = json_decode(DATAFILE, true);
 
+        $this->loggerMock->expects($this->never())
+            ->method('log');
+
+        $this->notificationCenterMock->expects($this->never())
+            ->method('sendNotifications');
+
         // handleResponse returns False when new Datafile's revision is equal
         // to previous revision.
         $this->assertSame($config->getRevision(), $datafile['revision']);