Hello world application

Configuration

First, create a file called Package.swift. This is the file that tells swift compiler where the libraries are located. In this hello world example, we are using GitHub repos. We need Kitura and HeliumLogger. Put the following code inside Package.swift. It specified the name of the project as kitura-helloworld and also the dependency urls.

import PackageDescription
let package = Package(
    name: "kitura-helloworld",
        dependencies: [
            .Package(url: "https://github.com/IBM-Swift/HeliumLogger.git", majorVersion: 1, minor: 6),
            .Package(url: "https://github.com/IBM-Swift/Kitura.git", majorVersion: 1, minor: 6) ] )

Next, create a folder called Sources. Inside, create a file called main.swift. This is the file that we implement all the logic for this application. Enter the following code into this main file.

Import libraries and enable logging

import Kitura
import Foundation
import HeliumLogger

HeliumLogger.use()

Adding a router. Router specifies a path, type, etc of the HTTP request. Here we are adding a GET request handler which prints Hello world, and then a post request that reads plain text from the request and then send it back.

let router = Router()

router.get("/get") {
    request, response, next in
    response.send("Hello, World!")
    next()
}

router.post("/post") {
    request, response, next in
    var string: String?
    do{
        string = try request.readString()
        
    } catch let error {
        string = error.localizedDescription
    }
    response.send("Value \(string!) received.")
    next()
}

Specify a port to run the service

let port = 8080

Bind the router and port together and add them as HTTP service

Kitura.addHTTPServer(onPort: port, with: router)
Kitura.run()

Execute

Navigate to the root folder with Package.swift file and Resources folder. Run the following command. Swift compiler will automatically download the mentioned resources in Package.swift into Packages folder, and then compile these resources with main.swift

swift build

When the build is finished, executable will be placed at this location. Double click this executable to start the server.

.build/debug/kitura-helloworld

Validate

Open a browser, type in localhost:8080/get as url and hit enter. The hello world page should come out.

Open a HTTP request app, post plain text to localhost:8080/post. The respond string will show the entered text correctly.