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2020-06-14 Magento2

Magento 2 Request Flow

Magento 2 Request Flow#

Request flow - sequence of steps an application takes to process and respond to requests

Required:

index.php -> Bootstrap -> App Class -> Routing

Sometimes:

Controller processing -> Rendering (Container and blocks) -> Output (HTML)

Initiation#

Init phase: Setting u pkey objects: bootstrap object, app object, dependency injection, object manager, log configs etc.

Multiple entry points: index.php, pub/cron.php, pub/static.php and shell commands (bin/magento)

Cron calls go through: ub/cron.php

Calls to satic files go through: pub/static.php

There are 2 index.php files:

  • <root>/index.php
  • <root>/pub/index.php

The Bootstrap.php file registers the autoloader

Bootstrap creats the ObjectManager factory: ObjectManager::create() - di initialisation happens in the same call

$app = $bootstrap->createApplication('Magento\Framework\App\Http');

create the application

PublicFunction::launch() are similar to $major->run() and $app->run() methods in magento 1.

Routing Phase#

routing - converts a request URL into a style magento can handle and finds class to process it

Goals:

  • Defining all available routers
  • Converting a URL to Magento style
  • Parsing request parameters
  • Identifying an action class that will process the URL

Controller - class that contains the execute() method

Router - class responsible for handling certain types of URL’s

Magento style URL: 3 parts + parameters

Eg. catalog/product/view/id/5

Route declaration#

route - declaration of set of pages belonging to a particular module

Defined in routes.xml

Controller Processing#

Controller does not manage data, it manages the parameters and exceptions. It may initiate a main class for category pages.

Launches the rendering process between view and data layers in production.

Steps in rendering and flushing output#

  • Front controller (Magento\Framework\App\FrontController) dispatches request and gets result object.
  • The app (Magento\Framework\App\Http) in the launch() method copies html to response object.
  • The bootstrap (Magento\Framework\App\Bootstrap) flushes html from response object to browser.

There are multiple result objects that a controller can return.

Best Practice: It is recommended to return a Magento\Framework\Controller\ResultInterface

Request Routing#

Front Controller#

front controllers are used to efficiently handle requests and direct work flows across all pages

responsibilities:

  • gathering all routers
  • finding matching controller/router
  • obtaining generated HTML to the response object

In magento 2, URL rewrites are implemented by a router

High level execution flow#

index.php -> Bootstrap::run() -> App::launch() -> FrontController::dispatch()

Dispatch:

router::match() -> Controler::execute() -> View::loadlayout() -> View->renderLayout() -> Response::sendResponse()

Routing Mechanism#

Router::match() most useful when looking for the list of routers.

Available routers:

  • Base router: Magento\Framework\App\Router\Base
  • Default router: Magento\Framework\App\Router\DefaultRouter
  • CMS router: Magento\Cms\Controller\Router
  • URL rewrite router: Magento\UrlRewrite\Controller\Router (new)

The Base router extends RouterInterface

Base router is located lib/internal/Magento/Framework/App/Router/Base.php (Not in the code)

The router interface is simple in structure; it contains a single method, Router::match()

The default router: Magento/Framework/App/Router/DefaultRouter.php handles Not Found pages. Magento 2 allows different handles for “Not Found” pages, eg. Sorry, this product does not exist or This category does not exist

UrlRewrite Controller#

In magento 1 URL rewrites is implemented in frontController. In magento 2 we have a separate router for processing URL rewrites.

Order of Routing#

  1. frontControler::dispatch()
  2. Base Router
  3. CMS Router
  4. URL Rewrite Router
  5. Default Router

Registering a new router#

  1. Add it as a parameter to class Magento\Framework\App\RouterList by using etc/frontend/di.xml of the module

URL Processing#

In magento 2 a single product can have multiple URL’s for SEO and human reading optimization

Structure of URl accepted by base router is:

$baseUrl/$frontName/$controllerName/$actionName/$otherParams

eg: http://magento.dev/catalog/product/view/id/1

CMS Router#

Pertinent code:

$request->setModuleName(‘cms’)
->setControllerName(‘page’)
->setActioName(‘view’)
->setParam(‘page_id’;$pageid);

Exercise: modify the not found page to forward to the home page#

Easiest way is to change /web/default/noroute

Controller Architecture#

Controller is a class specific to a URL or group of URL’s

A Controller can only process a single action. One class per action.

Eg. Magento\Catalog\Controller\Product\View

Action classes / Controllers#

Action classes include:

  • execute() method
  • Constructor (dependencies injected using DI)
  • Extra methods and variables

Usually extends Magento\Framework\App\Action\Action. Which itself extends Magento\Framework\App\Action\AbstractAction which implements Magento\Framework\App\ActionInterface

ActionInterface has two methods: dispatch() and getResponse()

Action\AbstractAction#

  • Obtains request and response objects using DI
  • Contains the method getRequest() and getResponse() - must call parent class

Action\Action#

  • Implements dispatch() method

High Level execution flow#

  • Router::match() -> Controller::dispatch() -> Controller::execute()

Action Wrappers#

If controller does not extend Action/Action but directly implements ActionInterface, it must implement dispatch() method with specific logic.

Key result objects#

  • Page: Html output $page = $this->pageFactory->create()
  • Json: For JSON database $result = $this->jsonFactory->create(); return $result->setData($data);
  • Forward: internal redirect to another controller $result = $this->forwardFactory->create(); $result->forward('some/new/route'); return $result;
  • Redirect: Physically redirect customers browser to another URL: $result = $this->redirectFactory->create(); $result->setUrl('some/new/url'); return $result;

Types controllers#

  • Frontend
  • Backend - must support ACL

Backend AbstractAction#

  • Constructor with extra objects injected
  • Contains the new dispatch() method
  • Contains the _isAllowed() method
  • own implementation of redirect() and forward()

Asigned Modules#

routerConfig is injected with DI

matchAction() will perform 2 calls:

  • Router\Base::matchModuleFrontName()
  • Router\Config::getModulesByFrontName()

Debugging the matching controller process#

  1. Check the frontName is correct
  2. Check the list of available modules
  3. Check path name for each module
  4. Check whether controlled being debugged is listed and whether class exists

Creating controllers#

  1. Create routes.xml
  2. Create the correct action class and implement an execute() method
  3. Test

routes.xml:

<?xml version="1.0"?>
<!--
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:App/etc/routes.xsd">
    <router id="standard">
        <route id="catalog" frontName="catalog">
            <module name="Magento_Catalog" />
        </route>
    </router>
</config>

specify the id of the router, the frontName and the module name

standard means the base router

Above tells magento it is ready to process URL that starts with catalog

  • frontName is connected to the module
  • ActionPath is connected to the folder/subfolder of Controller folder of module
  • Action is connected to the PHP class

Controller must extend Magento\Framework\App\Action\Action and must implement execute()

Testing#

Enter the URL: frontName/actionPath/action

Customize existing controllers#

Controllers are same as any other class in Magento 2. So customised in the same way using preferences or plugins

URL Rewrites#

Making complicated URL’s more user-friendly: shorter, more descriptive and easier to remember

Magento allows you to specify a URL key

Process Flow#

Browser sends request to server which requires Magento\UrlRewrite\Controller\Router

Then it accesses the database: url_rewrite

Url Finder is an instance of Magento\UrlRewrite\Model\Storage\DbStorage

Exercise: Add a rewrite for the ‘Hell World’ Controller#

INSERT INTO url_rewrite SET request_path=’testpage.html’, target_path=’test/action/index’,
redirect_type=0, store_id=1, is_autogenerated=0;