Backend Engineering for Android Developers

With Kotlin growing in popularity, it's about time we start looking at Kotlin as a language that has superpowers.
When we talk about backend technologies, we have a lot of languages/frameworks like Go, Java, Python, etc.
But when we talk about Kotlin as a backend language, it might raise a lot of eyebrows
But let me try to convince you that Kotlin is definitely a good choice for Backend! We will talk about Ktor (A framework for Kotlin) to build a fast backend that can be re-used on your client-side

Transcript

1. Backend for Android Engineers
2. 01. About me
3. 3 Himanshu Singh Android @Clue, GDE - Android,Kotlin
4. 4 Agenda: Backend for Android Engineers 01. Intro Kotlin Android? Backend Benefits 02. Kotlin Frameworks Ktor Spring Boot Vertx. Etc. 03. Ktor Why? How? Benefits 04. Tutorial Setting up Restful APIs Routing HTTP Verbs Features Location Status Pages 05. Why to use as Android Developer?
5. 01. Introduction
6. 6 Introduction 01. Kotlin?
7. 7 Introduction 01. Kotlin? Android?
8. 8 Introduction 01. Kotlin? Android? Backend
9. Benefits 1. 2. 3. 4. 5. Expressive Tooling Migration 6. Scalable! Community Support Ease of Learning
10. 02. Frameworks
11. Frameworks 1. 2. 3. 4. 5. Ktor Micronauts Vertx Spring Boot A lot more!
12. 03. Ktor
13. 13  Ktor Why?
14. Ktor 1. 2. 3. 4. 5. Light weighted Backed by Jetbrains Coroutine support Open sourced Scalable -> ∞
15. 04. Tutorial.
16. 16  Tutorial: Web https://start.ktor.io/
17. 17  Tutorial: Web
18. 18  Tutorial: Web Create Project
19. 19  Tutorial: Web Create Project
20. 20  Tutorial: Output
21. Code run through!
22. 22  fun main() { embeddedServer(Netty, port = 8080, host = "0.0.0.0") { configureRouting() }.start(wait = true) }
23. 23  fun main() { embeddedServer(Netty, port = 8080, host = "0.0.0.0") { configureRouting() }.start(wait = true) }
24. 24  fun main() { embeddedServer(Netty, port = 8080, host = "0.0.0.0") { configureRouting() }.start(wait = true) }
25. 05. Routing
26. 26  fun Application.configureRouting() { // Starting point for a Ktor app: routing { get("/") { call.respondText("Hello World!") } } }
27. 27  fun Application.configureRouting() { // Starting point for a Ktor app: routing { get("/") { call.respondText("Hello World!") } } }
28. 28  fun Application.configureRouting() { // Starting point for a Ktor app: routing { get("/") { call.respondText("Hello World!") } } }
29. 29  fun Application.configureRouting() { // Starting point for a Ktor app: routing { get("/") { call.respondText("Hello World!") } } }
30. 30  fun Application.configureRouting() { // Starting point for a Ktor app: routing { get("/") { call.respondText("Hello World!") } } }
31. HTTP Verbs
32. HTTP Verbs 1. 2. 3. 4. GET PUT/PATCH DELETE POST
33. 33  routing { get("/") { //code } post("/") { //code } delete("/") { //code } put("/") { //code } }
34. 06. Plugins
35. “ Set of pre-coded packages to help you ship/build faster
36. 36  fun Application.dummyPlugin(){ install(//the plugin) }
37. 37  fun main() { embeddedServer(Netty, port = 8080, host = "0.0.0.0") { configureRouting() dummyPlugin() }.start(wait = true) }
38. 38  fun Application.contentNegotiation(){ install(ConentNegotiation){ gson() } }
39. 07. Real world example.
40. 40  fun Application.configureRouting(){ post("/create-user"){ val user = call.receive<User>() //create user call.respond(user) } }
41. 41  fun Application.configureRouting(){ post("/create-user"){ val user = call.receive<User>() //create user call.respond(user) } }
42. 42  { "name":"Himanshu", "age":26, "job":"Clue" } data class User( val name:String, val age:Int, val job:String )
43. 43  https://www.google.com/search?q=droidcon+berlin
44. 44  https://www.google.com/search?q=droidcon+berlin
45. 45  fun Application.configureRouting(){ get("/search"){ val param = call.request.queryParameters[“q”] //code call.respond(result) } }
46. 08. Locations
47. “ A mechanism to create routes in a typed way, for both: constructing URLs and reading the parameters.
48. 48  fun Application.module() { install(Locations) // ... }
49. 49  @Location("/list/{name}/page/{page}") data class Listing(val name: String, val page: Int)
50. 50  routing { get<Listing> { listing -> call.respondText("Listing ${listing.name}, page ${listing.page}") } }
51. 09. Status Page
52. “ Response to any failure state/Exception.
53. 53  fun Application.module() { install(StatusPages) // ... }
54. 54  install(StatusPages) { exception<AuthenticationException> { cause -> call.respond(HttpStatusCode.Unauthorized) } exception<AuthorizationException> { cause -> call.respond(HttpStatusCode.Forbidden) } }
55. 10. Libraries Available for Awesomeness
56. Why? 1. 2. 3. 4. 5. KMongo/Expose In build Authentication/Auth Velocity / Kotlin HTML Gson/Jackson Swagger, ORM etc.
57. 10. Why use it as android Dev?
58. Why? 1. 2. 3. 4. 5. Uses our fav. Kotlin KMM support Easy learning curve. Supports JVM Libraries Makes you a full stack developer.
59. 11. Summary
60. Summary 1. 2. Use Kotlin to do anything Build your own backend
61. 12. Resources
62. 62  Resources https://ktor.io/ https://himanshoe.com
63. Danke Schön! Questions?