helloexpress.md

Hello Express

This is a very basic application. Much simpler than one created with Express Command Line. Still it's good to understand the basic concepts by creating an app by hands. Keep in mind that you have to follow Installation instructions first. If you are doing it on a Mac, please, install Swift 2.2 latest development snapshot in addition.

If you don't want to create an app manually, just skip this tutorial and use Express Command Line tool instead.

Create a folder

Simple as that. We need a separate folder for the Hello Express app. Just run:

mkdir HelloExpress
cd HelloExpress

Package.swift

Package.swift is your project descriptor. Contains the name of the app and dependencies. Check reference for more info.

Create one right in the current dirctory and put the following text inside (we have just one dependency to Express):

import PackageDescription

let package = Package(
    name: "HelloExpress",
    dependencies: [
        .Package(url: "https://github.com/crossroadlabs/Express.git", majorVersion: 0, minor: 3),
    ]
)

The App

Create a folder app in current directory and put there a file named main.swift. The contents of the file should look like:

import Express

let app = express()

app.get("/") { request in
    return Action.ok("Hello Express!")
}

app.listen(9999).onSuccess { server in
    print("Express was successfully launched on port", server.port)
}

app.run()

This means that all the requests coming to the root will be responded with Hello Express! string. All other requests will get 404.

Build tool

Swift on Linux and Package Manager are early tools and are a bit complicated to use. We created a simple tool to build Swift on Linux. Get it using following commands:

wget https://raw.githubusercontent.com/crossroadlabs/utils/master/build
chmod a+x build

Build

Just type in terminal:

./build

Run

Run our new app with:

./.build/debug/app

In the console you should see something like this:

Express was successfully launched on port 9999

Test

Enter the following url in the browser: http://localhost:9999/. You should now see text:

http://localhost:9999/

Next tutorial: Express Command Line