Forwarding decorators

This is the demo of the concept described in Sitepoint article - Achieving modular architecture with Forwarding Decorators.

This demo showcases the typical PHP app with the modular architecture. Modules can added and removed, and their files can modify core files on-the-fly. Decorator compiler (located inside Includes directory) is the stripped version of the X-Cart 5 decorator (Copyright © 2001-present Qualiteam software Ltd).

Installation and configuration

composer install
php rebuild.php

Some configuration can be made through modifying bootstrap.php:

• LC_DEVELOPER_MODE switches between development and production autoloader (true by default). Development autoloader tracks changes inside classes folder but not module installation.

Running the app

php app.php

What does it do?

The app runs some simple code which by default should output the example message:

Foo modified by Module1

App-specific code is located inside classes/DecoratorsDemo folder. Take a look at classes/DecoratorsDemo/Example/Foo.php class and classes/DecoratorsDemo/Module/Module1/Example/Foo.php class decorator.

Managing modules of the system

You can modify .decorator.modules.ini to add\enable\disable modules. Each module takes a line inside [modules_list] section. Key is the module folder and the value is the enabled state (1 for enabled and 0 for disabled). Example:

[modules_list]
Module1 = 1
OtherModule2 = 0

Module code should be placed inside classes/DecoratorsDemo/Module/ folder in a separate folder. Module1 is the example module, but you can add more. Each module is required to have Definition.php file inside its folder.

If you've added the new module, run php rebuild.php to compile the classes. Changes to the already installed module should be applied on-the-fly, no rebuild needed.

Modifying the classes (decorating)

To modify some class, you should extend it with another class inside module folder and add the marker interface - \Includes\DecoratorInterface. If several decorators are applied, you can control the order via this class annotations:

• Decorator\Before("ModuleName") -- puts decorator before some module decorator (ignored if the other module is not installed).
• Decorator\After("ModuleName") -- puts decorator after some module decorator (ignored if the other module is not installed).
• Decorator\Rely("ModuleName") -- enables this decorator only if some module is installed or not installed, if you specify module name as !ModuleName.
• Decorator\Depend("ModuleName") -- combines Rely and After.

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Thanks for checking this out.

– Eugene Dementjev, @drdaemos, X-Cart core developer