Kotlin Intro & Starting the Koans

Tomás Hanley

17th Sept 2018

What is Ktor?

• Framework for creating Web applications in Kotlin

• Written in Kotlin

• Sponsored and developed by JetBrains

Git History

• First commit in Oct 2014

• Currently on version 0.94

"Ktor is a framework for building asynchronous servers and clients in connected systems using the powerful Kotlin language"

Kotlin Adoption

• Widely adopted for android development

• Somewhat more cautious adoption for server side development

Why use Kotlin?

• Kotlin is a better language for the JVM than Java
  • Really easy to get up and running
  • Simpler language than Java

  • Much safer than Java

    • No more NullPointerExceptions!

    • Streamlines the handling of null values

  • More more clean & concise than Java

  • 100% Interoperable with Java

    • Kotlin & Java classes can live side by side

Lots of web frameworks available

• Spring MVC/WebFlux, Vert.x

• Anything thats available on the JVM

Benefits of a Kotlin framework like Ktor

• Makes heavy use of Coroutines for high scalability

• Easy-to-use and idiomatic API

  • Type safe builders (DSLs)

Ktor

• Really Lightweight

• Extensible through features

  • Functionality that is injected into the request and response pipeline

Demo

Android Controller

• Control drone with existing android app

  • Take off, Land

  • Control pitch, yaw, roll, etc.

• Converted it to Kotlin & cleaned it up

Drone Controller

• Send higher level commands to drone

• • Move one unit in any direction

  • Fly to coordinate (x, y)

  • Experimented with Coroutines

Consumer Service

• Embedded Web Servers

• Handle http requests

• Experimenting with Ktor!