Hi, could someone recommend me something equivalent to akka-streams native to Kotlin, I need something lightweight that can handle backpressure and publish/subscribe patterns? thanks

I want to start server development using Kotlin. So i thought I wanted to use Ktor, but IntelliJ mentions its Obsolete? Am I missing something?

Any course to start learning server side Kotlin ...

For fun and exercise, to practice pair programming and TDD, our team has built a web application from scratch in Kotlin, including all necessary parts (web server, database, framework), all in one. The only production dependency is the standard library. https://github.com/7ep/r3z . Perhaps you will find it useful. Let me know.

My new team does a Kotlin micro-service with Vert.x (I just came into the Kotlin world from Java, loving it so far!) However, I couldn’t find any books on Vert.x with Kotlin (with coroutines). There are so many Vert.x books with Java. If anyone could let me know of a book, it would be super helpful. Thanks in advance!

Hi, guys! Recently started to develop full stack application using kotlin with ktor as backend. And now i have a problem with cors policy

Access to fetch at '<http://127.0.0.1:8080/api/run?userId=root&profile=test>' from origin '<http://localhost:3000>' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled

As i understand, i should add origin to list of allowed origins in my backend app, i do this that way

install(CORS){
        method(HttpMethod.Get)
        method(<http://HttpMethod.Post|HttpMethod.Post>, )
        method(HttpMethod.Delete)
        anyHost()
        host("localhost")
    }

But this dont work. This is headers of response from js clinet

'Origin': '<http://localhost:3000>',
                'Content-Type': 'application/json',
                'Accept': 'application/json',
                'Access-Control-Request-Headers': 'Content-Type, Authorization'

Can anyone help me please?

Hi guys, i use kx.ser and i'm stuck with my post request, the terminal say to me :

2021-05-24 17:50:38.841 [eventLoopGroupProxy-4-1] ERROR ktor.application - Unhandled: POST - /Music/Add
io.ktor.features.CannotTransformContentToTypeException: Cannot transform this request's content to Musics

What i have do wrong in my code ? 🥲 (I have do many research and soluce but he doesn't work)

post("/Add") {
        val post = call.receive<Musics>()
        aMusicDAO.addMusic(post)
        call.respondText("OK OK",ContentType.Text.Plain)
}

@Serializable
data class Musics(
    val tag:Int? =null,
    @JsonInclude(value=JsonInclude.Include.NON_NULL)
    val title:String?="",
    val artist:String?="",
    val duration: String?="",
    val tagU:Int? =null
)

 override fun addMusic(music: Musics){
        transaction {
                Music.insert{
                    it[title]= music.title ?:""
                    it[artist]=music.artist?:""
                    it[duration]=music.duration?:""
                    it[tagU]=music.tagU?:0
                }
            }
    }

Hi! I created a backend based on the Clean Architecture principles. Feedback would be very much appreciated! The application is separated into three modules: Domain, Usecases and Adapters • Domain module contains all entities, it's validation and repository interfaces • Usecases module performs actions on the domain entities and repositories and does authorization The domain and usecase modules do not have any external dependencies. • Adapter layer: each adapter is implemented as a standalone module, lowering dependence on specific frameworks and libraries and making them interchangable. The server module consumes all adapters (e.g. databases, (graphql) endpoints, authentication logic) GraphQL endpoints are auto-generated from the Usecases Used technologies: Ktor, JWT, Exposed, Flyway, KGraphQL/GraphQL generated endpoints. https://github.com/ESchouten/CleanArchitecture

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I am interested in kotlin for backend and server driven UI. Any idea how to do it?

I am try to set up a android client with ktor for websocket? Any idea on that?

Hey 👋 I'm developing a backend with Ktor, loving the framework so far! In some cases, I'll have to handle several (possibly large) responses from another backend, process them and forward them to my client. For now this is all rest, no web sockets. Is there anyway in Ktor to have a constant flow of responses to the client? Something like Spring WebFlux, I'd like to have a reactive flux of responses in Ktor. Have you ever implemented such thing with Ktor? Is it even possible as the framework stands today? Did you have success with any other framework? Thanks in advance 🙏

hi everyone, this is my first using ktor, I just cloned this repo https://github.com/ktorio/ktor-http-api-sample from ktor’s docs. after running the project, I see this in terminal window: Application - Responding at http://0.0.0.0:8080, but when I try to access it from browser, it gives me This 127.0.0.1 page can’t be found. does anyone know why, did I miss anything? I tried to use different port and host but still the same result

Hello friends, I have a client with a legacy Java backend project (Spring + Java 5). He is "open to Kotlin" but needs to be convinced. How would you make succintly the case for Kotlin on a server application?

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Hi there, I’m using ktor for communication between backend services (kinda rpc) and wonder is there h2c support? I obviously don’t need any tls facilities. My setup is ktor 1.6.0 on netty transport. So far I have found this 9 months old unanswered SO question.

Hi! Can someone please help me to solve this question? https://discuss.gradle.org/t/kotlin-dsl-jar-compile-error-exception-in-thread-main-java-lang-noclassdeffounderror/40210/1

Hello Guys I'm trying to deploy a sample ktor api project from intellijIdea, but not working can anybody help?

Hello there - Do You think is it idiomatic to use extension functions on data transfer objects in order to map to some other representation? I have doubts - as name suggests ‚extension function’ are for extending functionality of a class which already does something, while DTO should carry only data and no functions. On the other hand - extension function does not add methods to the extended object but are resolved statically - so DTO in its binary representation is still plain. It only lexically looks like you are messing with DTO. I would like to know your opinions.

Hello to all 😄 I have a question regarding of using Redis with Ktor Server Side Application, have some of you already tried: io.ktor.clients:ktor-client-redis ? -> Or you can suggest me something different to use? Thank you in advance for any answer 😄

Hello everyone! An Android developer with very little backend experience, I am interested to learn more of it. Kotlin seems to be getting more popular for backend development and to pair very well with KMP projects. Therefore I have several questions, mostly about how and where to start: 1. Is it reasonable/worth it to start learning Backend development with Kotlin? Or should I rather choose Java frameworks as they are more mature? Having lots to do with KMM not sure how happy I'll be learning backend from start in "experimental" mode 2. Which framework is good to choose for a beginner? Kotlin Spring probably benefits from the maturity of Java Spring, whereas I have seen and heard more about Ktor implementations. Also using Ktor in the client side in KMM may be a good addition to learning backend with Ktor. Or would you recommend a completely different option? 3. Any tutorials/starter projects/guides/learning kits you can recommend? 4. Speaking of completely different options, may be there is something different from Kotlin options you'd recommend? I've heard good things about Go backend developments - good for beginners. This being a kotlinglang slack, I totally understand the answers may be biased, still will appreciate any opinion and advise!

#code-coverage do this survey! https://twitter.com/kotlin/status/1405526653330104333?s=19

announcing Restaurant, a kotlin web server api with focus on testability and coroutine support: https://github.com/christophsturm/restaurant

HI there. I'm working on spring-boot-kotlin and trying to replace apache-http/okhttp to CIO. Can I get a performance comparison?

Hey all! Can someone share with me some experience creating a GraphQL server using kotlin?

Hey folks. I'm working on a realtime Chat System. I was Using Firebase previously. Now I need to switch to Custom backend. Can someone share his experience on NodeJs + Socket.io vs Ktor

Hey all, Can someone recommended a kotlin based state-machine library? Found one from Tinder but the license is restrictive, others are mostly old Java based.

Hello friends: a non-technical question. I want to work with Kotlin on the server-side, so I'm trying to figure out which companies use Kotlin there, but I'm flooded with offers for Kotlin. on Android. Any idea how to proceed? I'm in Europe

@antonarhipov maybe that question has been asked many times already so sorry about that - is there a Kotlin Multi-platform version of this wonderful tutorial with KotlinJS: https://github.com/kotlin-hands-on/kotlin-spring-chat  Thanks in advance!

Hi guys! I’ve been working on spring boot with kotlin recently. I have a question around architecting a complex stepwise process - might be more general software than kotlin/spring. I’ve got a endpoint for placing an ecommerce order that has several steps involved (say 1, 2, 3, 4), and a lot of params in the request as well. Each one of these steps ends up transforming the initial request in a way that gives a complex output as a result - which I’ve modelled into their own output

data class

es, like

Step1Output

, which becomes the input for step 2, and so on. I’ve managed to make the step functions are pure functions this way, which I believe is a best practice. My problem now is that in case I need to introduce anything new in the output that requires another piece of data from the input, I need to modify all my

StepXOutput

classes and keep passing on the data between them. This obviously makes doing any changes slow and painful. Any ideas on design patterns that can help with this? Or is there some well-architected, complex project that I can look at for reference? Thanks!