Yii2 Application Development Cookbook - Third Edition

Service locator

Instead of manually creating instances of different shared services (application components) we can get them from a special global object, which contains configurations and instances of all components.

A service locator is a global object that contains a list of components or definitions, uniquely identified by an ID, and allow us to retrieve any needed instance by its ID. The locator creates a single instance of the component on-the-fly at the first call and returns a previous instance at the subsequent calls.

In this recipe, we will create a shopping cart component and will write a cart controller for working with it.

Getting ready

Create a new application by using the Composer package manager, as described in the official guide ...