m2demo/module-m2-extension 1.0

Bare-bones demo extension

Demo Extension

Access extension at this url: /demo_extension/index/sayhello

Composer Deployment

To deploy the extension using composer, add the following line to the root composer.json->require: "m2demo/module-m2-extension": "*"

Then run composer update.

Integration with Magento

If the application is already installed, add the name of the module to the module array in app/etc/config.php as a key with the value of 1. The means the module is enabled.

If the application is re-installed while the module exist in app/code, it will recognize the module and put it in app/etc/config.php automatically.

If the module has any database scripts, the installer will have to run to incorporate them.

Components

composer.json

Root

To autoload classes in the module more quickly, the root composer.json must be updated. Place the following line in the autoload->psr-4 section: "M2Demo\": "app/code/M2Demo/"

For reference, see Composer's autoloading documentation.

Module

To integrate the module with composer, a composer.json file must be placed in the root of the extension.

Routing

A router takes the given request and determines which controller and action should handle it. Routing options are configured in "etc/routes.xml" (relative to extension root).

Router

The router element's id attribute determines which router to use for this module.

Route

The route element's id attribute provides a unique name for the router and module pair. Used for merging config information of multiple routers.

Frontname

The module element's frontname attribute is what will show up in the url corresponding to the module.

Area

During runtime, one of several areas is always active, depending on the type of user and code being executed. This module is meant for the frontend area. The directory structure is: Extension/etc/area/routes.xml

module.xml

The module.xml file defines the name of the module. If any of the module's dependencies need to be loaded in a particular sequence, this file can also store that sequence.

Controller

The controller class is in app/code/M2Demo/M2Extension/Controller/Index/SayHello.php.

URL

The controller is accessed at the URL /demo_extension/index/sayhello

• demo_extension is the frontname of the module
• index is the namespace of the controller (slightly different from the namespace of the class but related).
• sayhello is the action name.

Code

The controller class extends \Magento\Framework\App\Action\Action. It implements an execute() method, which contains the controller's business logic. In this case, it prints out a short message and a list of active modules. If it renders output, the output must go into the _response object.

Response

The _response object stores the information that is sent back to the client. It is a protected member of the class defined by a parent.

Parent

The parent's dispatch() method calls execute(), and then returns the _response back to the system, which delivers it to the client.