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

External approach

The internal approach suffers from one important problem, that is, it mixes the source code and the translations. The remedy for this problem is the external approach. Using it, we can separate the program code and the translations.

To use external translations, we use the same @i18n directive, but we provide it with a key string instead of a function. Thus, @i18n(hello) can be replaced by:


Here is an example of an external approach:

function page(){
  <div onready={function(_) { I18n.set_lang("fr") }}>
Server.start(Server.http, {title:"Opa Packt", ~page})

Save the file as 802.opa. If we do not provide any translation, @i18n("hello") will be replaced by the string "hello". How do we add the translation? The solution is to compile our source code with the translation switch --i18n-template-opa:

opa 802.opa --i18n-template-opa --i18n-pkg trans --i18n-dir langs

Make a directory named langs and...