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Hello, World

This section assumes you have installed Swift 3.1 and the Vapor Toolbox and have verified they are working.

Tip

Note: If you don't want to use the Toolbox, follow the manual guide.

New Project

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

vapor new Hello --template=api

Warning

Use vapor new Hello --template=api --branch=beta while Vapor 2 is in beta

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

Hello
├── Sources
│   └── 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.

Hello
└── Sources
    └── App
        └── main.swift

Tip

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.

Code

Droplet

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

let drop = try Droplet()

This is where the one and only Dropletfor 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.

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.

This route simply returns a string, but anything that is ResponseRepresentable can be returned. Learn more in the Routing section of the guide.

Tip

Xcode autocomplete may add extraneous type information to your closure's input arguments. This can be deleted to keep the code clean. If you'd like to keep the type information add import HTTP to the top of the file.

Serving

At the bottom of the main file, make sure to run your Droplet.

drop.run()

Save the file, and switch back to the terminal.

Compile & Run

Building

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.

vapor build

Note

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 Building Project [Done]

Tip

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 memory.

Release

Building your application in release mode takes longer, but increases performance.

vapor build --release

Serving

Boot up the server by running the following command.

vapor run serve

You should see a message Server starting.... You can now visit http://localhost:8080/hello in your browser.

Note

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.

Production

Serving your application in the production environment increases its security and performance.

vapor run serve --env=production

Debug errors will be silenced while in the production environment, so make sure to check your logs for errors.

Warning

If you compiled your application with --release, make sure to add that flag to the vapor run command as well. e.g., vapor run serve --env=production --release.

Hello, World

You should see the following output in your browser window.

Hello, world!

Success

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