Hi everyone I’m trying to create kmp with ktor 1.4.0 similar to this sample <https://github.com/kto...

# multiplatform

[AG]

Hi everyone I’m trying to create kmp with ktor 1.4.0 similar to this sample https://github.com/ktorio/ktor-samples/tree/master/client-mpp and having issues with ktor, ios app keep crashing with kotlin
InvalidMutabilityException

class Api {

    private val client = HttpClient()

    var address = Url("<https://tools.ietf.org/rfc/rfc1866.txt>")

    fun request(callback: (String) -> Unit) {
        GlobalScope.apply {
            launch(ApplicationDispatcher) {
                val result: String = client.get {
                    url(address.toString())
                }
                callback(result)
            }
        }
    }
}

[John O'Reilly]

There's a couple of known issues with Ktor 1.4.0 running in Kotlin/Native env e.g
https://youtrack.jetbrains.com/issue/KTOR-915
https://youtrack.jetbrains.com/issue/KTOR-924

Firstly Ktor 1.4 now uses native-mt branch of Kotlinx Coroutines but this is only fully supported in Kotlin/Native using CIO engine I believe (and only for http endpoints). (EDIT: my previous statement about only being supported in CIO is not correct, see below!).....but that crash still occurs with that setup if logging is enabled ( @russhwolf identified that and created that 2nd issue).

[John O'Reilly]

fwiw I'm using it in following small project if you want to compare setup https://github.com/joreilly/PeopleInSpace

[AG]

Thanks 👍

[russhwolf]

CIO isn’t actually necessary. You can get the default engine working as well.

[John O'Reilly]

I thought I had issues with default engine on iOS and/or macOS but will double check

[russhwolf]

You still have to be careful about all the usual K/N threading, but we have it working in KaMPKit

[russhwolf]

And I was using the default engine in the sample for KTOR-924

[russhwolf]

Haven’t looked at macOS so it’s also possible the situation is different there but I think that would surprise me

[John O'Reilly]

at least prior to 1.4 I was seeing different behaviour on iOS and macOS

[John O'Reilly]

I'll check again now I'm rebased on 1.4 and see what works/doesn't work now

[John O'Reilly]

I may have misinterpreted "Partial support for CIO (native-mt) which includes Sockets and HTTP* from https://blog.jetbrains.com/ktor/2020/08/18/ktor-1-4-0-now-available/

[russhwolf]

Yeah I initially misinterpreted that to mean that was the only place where native-mt was.

[John O'Reilly]

yeah, confirmed default engine is fine....which also means there isn't same restriction on only using http endpoint that current CIO imlementation has

[John O'Reilly]

thanks @russhwolf for heads up on that