Is anyone using ktor + reaktive on native targets?...

# reaktive

[saket]

Is anyone using ktor + reaktive on native targets? What does your setup look like and have you run into any issues?

[Arkadii Ivanov]

Hey, you can check the notice about Ktor in the Readme: https://github.com/badoo/Reaktive/blob/master/README.md#coroutines-interop

[Arkadii Ivanov]

In general I tried Ktor multiple times, it's very easy to fall into the freezing trap and currently Ktor crashes in this case. The stack traces sometimes meaningless and overall it's hard to debug.

[Omar Mainegra]

This is a simplified version of what we do at Skip

@Serializable
data class Post(val id: Int, val title: String, val body: String)

typealias GetPostResult = (Post?) -> Unit

interface TodoApi {
    fun getPost(id: Int, callback: GetPostResult)
}

class TodoApiImpl : TodoApi {

    private val client: HttpClient =
        HttpClient(httpEngine) {
            install(JsonFeature) {
                serializer = KotlinxSerializer(Json(JsonConfiguration.Stable.copy(ignoreUnknownKeys = true, isLenient = true)))
            }
        }

    init {
        client.ensureNeverFrozen()
    }

    override fun getPost(id: Int, callback: GetPostResult) {
        GlobalScope.launch(Main) {
            callback(
                try {
                    client.get<Post>("<https://jsonplaceholder.typicode.com/posts/$id>")
                } catch (e: Throwable) {
                    null
                }
            )
        }
    }
}

[Omar Mainegra]

ensureNeverFrozen is from reaktive-utils

[Omar Mainegra]

httpEngine is an expected HttpClientEngine which resolves to OkHttp in Android and NSURLSession in iOS

[Arkadii Ivanov]

Yeah this will work. Except the returned Job is not used, so it is not possible to cancel. If you need cancellation, then you should care to not freeze the Job as well.

[Omar Mainegra]

That's right

[saket]

@Arkadii Ivanov Got it. The interop section in the readme was added a few months ago so I was wondering if anything has changed. I remember coming across mentions of a preview branch of ktor where native support has improved.

@Omar Mainegra This is useful, thank you!

[Arkadii Ivanov]

Multithreaded native coroutines are in a separate branch currently and are published separately. I'm not sure about Ktor, lastest information I remember is it still crashes. Anyway Reaktive uses stable version of coroutines, they not multithreaded.

[Arkadii Ivanov]

My personal opinion - I would avoid Ktor at the moment. They have 100+ open bugs and 500+ open issues. Is use simple expect/actual for jvm and Android when needed.

[Omar Mainegra]

We are using ktor with coroutines 1.3.5-native-mt , no crashes so far (beyond InvalidMutabilityException, etc), good point about their GH status tho

[Omar Mainegra]

Is important to enforce the right Ktor version for K/N, something like:

configurations.all {
    resolutionStrategy {
        force "org.jetbrains.kotlinx:kotlinx-coroutines-core-common:${versions.coroutines}"
        force "org.jetbrains.kotlinx:kotlinx-coroutines-core-native:${versions.coroutines}-native-mt"
    }
}