Book Image

Opa Application Development

By : Li Wenbo
Book Image

Opa Application Development

By: Li Wenbo

Overview of this book

Opa is a full-stack Open Source web development framework for JavaScript that lets you write secure and scalable web applications. It generates standard Node.js/MongoDB applications, natively supports HTML5 and CSS and automates many aspects of modern web application programming. It handles all aspects of web programming written in one consistent language and compiled to web standards.Opa Application Development is a practical,hands-on guide that provides you with a number of step-by-step exercises. It covers almost all aspects of developing a web application with Opa, which will help you take advantage of the real power of Opa, as well as building a secure, powerful web application rapidly.Opa Application Development dives into all concepts and components required to build a web application with Opa. The first half of this book shows you all of the basic building blocks that you will need to develop an Opa application, including the syntax of Opa, web development aspects, client and server communication and slicing, plugin, database, and so on. By the end of the book you will have yourself created a complete web application along with a game: Pacman!
Table of Contents (18 chapters)
Opa Application Development
About the Author
About the Reviewers

A quick start to MongoDB

First, we need to download (, install, and run ( the MongoDB server. After MongoDB has been installed properly, let's get started with a simple example:

database int /counter = 0;
function page(){
    <h1 id="text">Hello {/counter}</h1>
    <input type="button" value="click" onclick={function(_){
          #text = "Hello {/counter}"	
Server.start(Server.http, {title:"Opa Packt", ~page})

In the first line of the preceding code, we define a /counter database path that holds an integer. A database path describes a position in the database, and we can read, write, update, and delete the data through a database path. Note that the data type of the path cannot be omitted.

The preceding database is unnamed; we can give a name to the database, for example:

database testdb {
    int /counter = 0;

In this way, we should read data from the path /testdb...