{"id":13341,"date":"2017-05-30T15:46:32","date_gmt":"2017-05-30T12:46:32","guid":{"rendered":"https:\/\/belvg.com\/blog\/?p=13341"},"modified":"2019-09-27T14:40:56","modified_gmt":"2019-09-27T12:40:56","slug":"flushing-data-output-in-magento-2","status":"publish","type":"post","link":"https:\/\/belvg.com\/blog\/flushing-data-output-in-magento-2.html","title":{"rendered":"Flushing Data (Output) in Magento 2"},"content":{"rendered":"\n

The physical process of rendering is conceptually the same as in Magento 1, but it differs from the code and architectural levels. <\/span>Data meant for output to the browser accumulates in the controller in the internal variable <\/span>Zend\\Stdlib\\Message::content<\/span><\/i>, and is displayed by calling <\/span>Magento\\Framework\\HTTP\\PhpEnvironment::appendBody<\/span><\/i>().<\/span><\/p>\n

In general terms, the following steps are taken during the rendering and flushing output process:<\/span><\/p>\n

    \n
  1. Custom controller returns an object of the required type.<\/span><\/li>\n
  2. The front controller (Magento\\Framework\\App-\\FrontController) dispatches a request and gets a result object.<\/span><\/li>\n
  3. The app (Magento\\Framework\\App\\Http) in the launch()<\/em> method copies HTML to the response object.<\/span><\/li>\n
  4. The bootstrap (Magento\\Framework\\App\\Bootstrap) flushes that HTML from the response objects to the browser.<\/span><\/li>\n<\/ol>\n

    \"Flushing<\/a><\/p>\n

    1.1<\/strong> PageObject can be injected into the controller, created, and returned from the execute() method:<\/p>\n

    \/Import page factory into constructor:\r\npublic function __construct(\\Magento\\Framework\\View\\Result\\PageFactory $pageFactory, ...)\r\n{\r\n   $this->pageFactory = $pageFactory;\r\n...\r\n}\r\n    \/\/Create and return object in execute method\r\n   $page = $this->pageFactory->create();\r\n   return $page;<\/pre>\n
    1.2<\/strong> JSON result object, created in the execute()<\/em> method, can be injected into a controller.<\/span><\/p>\n
    Usually a controller returns an object as the result of the call $result->setData($data)<\/em>, which is a $result<\/em> object. The setData()<\/em> method is used to assign the array to return as JSON.<\/span><\/p>\n
    \/\/Import json factory into constructor:\r\npublic function __construct(\\Magento\\Framework\\Controller\\Result\\JsonFactory $jsonFactory, ...)\r\n{\r\n   $this->jsonFactory = $jsonFactory;\r\n...\r\n} \r\n   \/\/Create json object in the execute method; set data into it, and return\r\n   $result = $this->jsonFactory->create();\r\n   return $result->setData($data);\r\n<\/pre>\n
    <\/a>
    Magento 2 Development<\/h3>
    Take your online store to the next level with BelVG Magento 2 Development<\/p>Visit the page<\/span><\/a><\/div><\/div><\/div>\n
    2.<\/strong> Result objects are got back to the FrontController<\/span><\/p>\n
     $result = $actionInstance->execute();):\r\n \r\npublic function dispatch(RequestInterface $request)\r\n{\r\n   \\Magento\\Framework\\Profiler::start('routers_match');\r\n   $routingCycleCounter = 0;\r\n   $result = null;\r\n   while (!$request->isDispatched() && $routingCycleCounter++ < 100) {\r\n       \/** @var \\Magento\\Framework\\App\\RouterInterface $router *\/\r\n       foreach ($this->_routerList as $router) {\r\n           try {\r\n               $actionInstance = $router->match($request);\r\n               if ($actionInstance) {\r\n                   $request->setDispatched(true);\r\n                   $this->response->setNoCacheHeaders();\r\n                   if ($actionInstance instanceof \\Magento\\Framework\\App\\Action\\AbstractAction) {\r\n                       $result = $actionInstance->dispatch($request);\r\n                   } else {\r\n                       $result = $actionInstance->execute();\r\n                   }\r\n                   break;\r\n               }\r\n....\r\nreturn $result;\r\n<\/pre>\n
    3.<\/strong> And then go to the App object (Magento\\Framework\\App\\Http), to the launch()<\/em> method:<\/span><\/p>\n
    public function launch()\r\n{\r\n   $areaCode = $this->_areaList->getCodeByFrontName($this->_request->getFrontName());\r\n   $this->_state->setAreaCode($areaCode);\r\n   $this->_objectManager->configure($this->_configLoader->load($areaCode));\r\n   \/** @var \\Magento\\Framework\\App\\FrontControllerInterface $frontController *\/\r\n   $frontController = $this->_objectManager->get('Magento\\Framework\\App\\FrontControllerInterface');\r\n   $result = $frontController->dispatch($this->_request);\r\n   \/\/ TODO: Temporary solution until all controllers return ResultInterface (MAGETWO-28359)\r\n   if ($result instanceof ResultInterface) {\r\n       $this->registry->register('use_page_cache_plugin', true, true);\r\n       $result->renderResult($this->_response);\r\n   } elseif ($result instanceof HttpInterface) {\r\n       $this->_response = $result;\r\n   } else {\r\n       throw new \\InvalidArgumentException('Invalid return type');\r\n   }\r\n   \/\/ This event gives possibility to launch something before sending output (allow cookie setting)\r\n   $eventParams = ['request' => $this->_request, 'response' => $this->_response];\r\n   $this->_eventManager->dispatch('controller_front_send_response_before', $eventParams);\r\n   return $this->_response;\r\n}\r\n<\/pre>\n
    The event controller_front_send_response_before<\/em> may contain additional headers or params.<\/span><\/p>\n
    \"Andrey_Dubina\"
    Partner With Us <\/h3>Let's discuss how to grow your business. Get a Free Quote.<\/span><\/div> Talk to Andrey<\/a><\/div>\n
    $result->renderResult($this->_response)<\/em> – the exact place where rendering output occurs.<\/span><\/p>\n
    4.<\/strong> Magento will generate HTML and append it to the response object. Response objects are then got back to the Bootstrap class (run() method)<\/em> before being flushed:<\/p>\n
    public function run(AppInterface $application)\r\n{\r\n   try {\r\n       try {\r\n           \\Magento\\Framework\\Profiler::start('magento');\r\n           $this->initErrorHandler();\r\n           $this->initObjectManager();\r\n           $this->assertMaintenance();\r\n           $this->assertInstalled();\r\n           $response = $application->launch();\r\n           $response->sendResponse();\r\n           \\Magento\\Framework\\Profiler::stop('magento');<\/pre>\n
    Magento\\Framework\\HTTP\\PhpEnvironment\\Response::sendResponse()<\/span><\/i><\/p>\n
    public function sendResponse()\r\n{\r\n   $this->send();\r\n}\r\n<\/pre>\n
    Let`s take a close look at <\/span>Zend\\Http\\PhpEnvironment::sent()<\/span><\/i> public function:<\/span><\/p>\n
    public function send()\r\n{\r\n   $this->sendHeaders()\r\n        ->sendContent();\r\n   return $this;\r\n}\r\n<\/pre>\n
    First, the function <\/span>sendHeaders()<\/span><\/i> applies all the standard headers accumulated through the call <\/span>Magento\\Framework\\HTTP\\PhpEnvironment\\Response::setHeader() <\/span><\/i>and <\/span>sendContent() <\/span><\/i>– display content body:<\/span><\/p>\n
    public function sendContent()\r\n{\r\n   if ($this->contentSent()) {\r\n       return $this;\r\n   }\r\n \r\n   echo $this->getContent();\r\n   $this->:contentSent = true;\r\n   return $this;\r\n}\r\n<\/pre>\n
    Redirect<\/b><\/p>\n
    Magento 2 offers more structure around the forward function and redirects than Magento 1.<\/span><\/p>\n
    There are two types of redirect:<\/span><\/p>\n