Book Image

Scala Programming Projects

By : Mikael Valot, Nicolas Jorand
Book Image

Scala Programming Projects

By: Mikael Valot, Nicolas Jorand

Overview of this book

Scala Programming Projects is a comprehensive project-based introduction for those who are new to Scala. Complete with step-by-step instructions and easy-to-follow tutorials that demonstrate best practices when building applications, this Scala book will have you building real-world projects in no time. Starting with the fundamentals of software development, you’ll begin with simple projects, such as developing a financial independence calculator, and then advance to more complex projects, such as a building a shopping application and a Bitcoin transaction analyzer. You’ll explore a variety of Scala features, including its OOP and FP capabilities, and learn how to write concise, reactive, and concurrent applications in a type-safe manner. You’ll also understand how to use libraries such as Akka and Play. Furthermore, you’ll be able to integrate your Scala apps with Kafka, Spark, and Zeppelin, along with deploying applications on a cloud platform. By the end of the book, you’ll have a firm foundation in Java programming that’ll enable you to solve a variety of real-world problems, and you’ll have built impressive projects to add to your professional portfolio.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Implementing the client side


In the following sections, we will look at the client side. On the client side, we have to initiate the web socket connection with the server, send a CartEvent when a product is added or removed from the cart, and show alerts when other browsers make changes to the cart.

First, let's create the connection with the server using a web socket.

Adding the web socket

To add the web socket to the client, we are going to use the UIManager object, which is the entry point of the client. In Scala.js, WebSocket is part of the framework; edit the UIManager and add the web socket property to it, as follows:

val webSocket: WebSocket = getWebSocket

Some configuration is needed to create the WebSocket. We encapsulate all of the initializations into a function named getWebSocket, as follows:

private def getWebSocket: WebSocket = {
  val ws = new WebSocket(getWebsocketUri(dom.document, 
  "v1/cart/events"))
    
  ws.onopen = { (event: Event) ⇒
    println(s"webSocket.onOpen '${event...