Book Image

Yii2 By Example

By : Fabrizio Caldarelli
Book Image

Yii2 By Example

By: Fabrizio Caldarelli

Overview of this book

Yii is a high-performance PHP framework best for developing Web 2.0 applications. It provides fast, secure, and professional features to create robust projects, however, this rapid development requires the ability to organize common tasks together to build a complete application. It's all too easy to get confused; this is where this book comes in. This book contains a series of practical project examples for developers starting from scratch. Each section contains the most relevant theories for every topic as you walk through developing each project, focusing on key aspects that commonly confuse users. The book starts with all the framework’s basic concepts, such as controllers and views, to introduce you to Yii and creating your first application, a simple news reader. You will be learn to configure URL rules to make a pretty URL, essential for search engine optimization. Next, you will walk through Model and ActiveRecord, key concepts in database interaction. The second application you will develop is a reservation system that allows you to manage rooms, customers, and reservations. For this, you will use database connection through SQL and ActiveRecord. More complex than the first one, this application will introduce you to the advanced template of Yii 2, splitting the app into two parts: a frontend for all visitors and a backend for the admin. Finally, you will move on to the last two applications: one that allows connections from remote clients, through RESTful components of Yii 2, and another that creates and organizes automatic tasks using the console application structure of Yii 2.
Table of Contents (20 chapters)
Yii2 By Example
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Creating components


A component is a reusable object that should contain only logic, and it is callable from every point of the app. In a component, we put all the functions that are usable in more than one place of the app.

Technically, a component extends yii\base\Component that implements the property, event and behavior features. We can have two kinds of component: component and application component. The only difference between them is that the second has to be also configured in the configuration file of the app in the components property and it is available as a property from the Yii::$app object. Examples of application components are db, user, and so on.

Usually, components are stored in the components folder starting from the root folder of the project.

Let's see how to create a simple custom component:

namespace app\components;
 
use Yii;
use yii\base\Component;
 
class MyComponent extends Component
{
..
..
}

We can instantiate this component as follows:

$myCmp = new \app\components...