To install Vert.x, you simply download and unpack a ZIP file. A Vert.x installation lives in a self-contained directory structure, which can be located anywhere on your machine.

It's also recommended that you include the path to the Vert.x executable in your PATH environment variable. This will make working with the Vert.x command line easier.

In the following pages, we'll go through these steps, after which you'll have everything up and running.

java –version

apt-get install openjdk-7-jdk

Let's verify that the Vert.x installation was successful by trying to run it. Go to a terminal (on OS X/Linux) or a Command Prompt (on Windows). Try running the vertx command:

vertx version

This should simply output the version of your Vert.x distribution. If you see the version, you have successfully installed Vert.x!

The vertx command has multiple uses, but the main one is to launch a Vert.x instance, which is something you'll be doing a lot.

If you want to see the different things that you can do with the vertx command, just run it without any arguments, and it will print out a description of all the different use cases:

vertx

Now that you have Vert.x installed and are able to run it, you're all set to write your first Vert.x application. This application will consist of a single verticle that prints out the classic "Hello world" message.

Verticles can be implemented in any of the supported Vert.x languages (JavaScript, CoffeeScript, Java, Ruby, Python, or Groovy). For this one, let's use JavaScript.

Create a file named hello.js (it doesn't matter where you put it). Open the file in an editor and add the following contents:

var console = require("vertx/console");
console.log("Hello world");

That's all the code you need for this simple application.

Now, let's launch a Vert.x instance and run hello.js in it as a verticle:

vertx run hello.js

This should print out the message. Even though there's nothing else to do, the Vert.x instance will keep running until we explicitly shut it down. Use Ctrl + C to shut down the Vert.x instance when you're done.

So, what just happened?

You have just gone through the basic process of writing and running a Vert.x application. Now, let's turn to something a bit more useful.

Our application is going to need a web server, which is used to serve all the HTML, CSS, and JavaScript files to web browsers.

Vert.x includes all the building blocks for setting up a web server, including the HTTP networking and filesystem access. However, there is also something more high-level we can use, that is, a publicly available web server module, which does file serving over HTTP for us out of the box.

First create a folder for the application we will be building for the duration of this book. You can just call it mindmap, and put it within your Home directory:

cd
mkdir mindmap
cd mindmap

In this folder, create a file named app.js. This will be the deployment verticle of our application. We will use it to deploy all the other verticles and modules that our application needs. As far as the Vert.x itself is concerned, there is nothing special about a deployment verticle; it is just a code organization practice.

We are going to deploy the mod-web-server module. The latest version of the module at the time of writing is 2.0.0-final, which we will be using here. Alternatively, you can look for the latest version in the Vert.x module registry.

Add the following code to app.js:

var container = require("vertx/container");
container.deployModule("io.vertx~mod-web-server~2.0.0-final", {
  port: 8080,
  host: "localhost"
});

Let's go through the contents of this file:

Now you can run this code as a verticle:

vertx run app.js

The first time a new module is deployed, Vert.x will automatically download and install it from the public module registry. You will see a subfolder named mods appearing in the project folder, and within it the contents of the installed modules. (In this case, the web server module.)

If you now point your web browser at http://localhost:8080/, you will see a 404 Resource not found message. This means that the web server is running, but there is nothing to serve. Let's fix that.

Create a subfolder named web in the project folder. By default, this is where the web server module looks for static files to serve the browsers (this folder is configurable through the web server's module configuration object).

mkdir web

In this folder, add a simple HTML document in a file named index.html, with the following contents:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
</head>
<body>
  Hello!
</body>
</html>

Now, as you point your browser at http://localhost:8080/, you will see the Hello! message. You are running a web server in Vert.x!

In this chapter, you have installed Vert.x and taken the very first steps towards building a real-time web application by configuring and running a web server.

You have already covered a lot of ground: