Hello, World

This section assumes you have installed Swift 3 and the Vapor CLI and have verified they are working.

New Project

Let's start by creating a new project called Hello, World

Shell

vapor new Hello

Folder Structure

Vapor's folder structure will probably look familiar to you if you have worked with other web frameworks.

Text

.
├── App
│   └── Controllers
│   └── Middleware
│   └── Models
│   └── main.swift
├── Public
├── Resources
│   └── Views
└── Package.swift

For our Hello, World project, we will be focusing on the main.swift file.

Text

.
└── App
    └── main.swift

Open main.swift in your favorite text editor.

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Example Project

The vapor new command creates a new project with examples and comments about how to use the framework. You can delete these if you want.

Droplet

Look for the following line in the main.swift file.

Swift

let drop = Droplet()

This is where the one and only Droplet for this example will be created. The Droplet class has a plethora of useful functions on it, and is used extensively.

Routing

Right after the creation of drop, add the following code snippet.

Swift

drop.get("hello") { request in
    return "Hello, world"
}

This creates a new route on the Droplet that will match all GET requests to /hello. All route closures are passed an instance of Request that contains information such as the URI requested and data sent. We will learn more about requests later.This route simply returns a string. We will learn more about what can be returned by route closures later.

Starting

At the bottom of the main file, make sure to start your application.

Swift

drop.serve()

Save the file, and switch back to the terminal.

Compiling

A big part of what makes Vapor so great is Swift's state of the art compiler. Let's fire it up. Make sure you are in the root directory of the project and run the following command.

Shell

vapor build

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Toolbox Shortcut

vapor build runs swift build in the background.

The Swift Package Manager will first start by downloading the appropriate dependencies from git. It will then compile and link these dependencies together.When the process has completed, you will see output similar to Linking .build/debug/App

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Process Killed

If you see a message like unable to execute command: Killed, you need to increase your swap space. This can happen if you are running on a machine with limited RAM.

Run

Boot up the server by running the following command.

Shell

vapor run serve

# Optionally specify port
vapor run serve --port=8080

You should see a message Server starting.... You can now visit http://localhost/hello in your browser.

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Permission Denied

Certain port numbers require super user access to bind. Simply run sudo vapor run to allow access. If you decide to run on a port besides 80, make sure to direct your browser accordingly.

Hello, World

You should see the following output in your browser window.

Text

Hello, world