I have this simple class that I use as a model for a a GET call with ktor

@Serializable
data class MeasurementsEndpoint(
    @SerialName("measurements")
    val measurements: List<Measurement>,

    @SerialName("measurementGroups")
    val measurementGroups: Map<String, MeasurementGroup>,
)

the call is made like so

http.get<MeasurementsEndpoint>(…)

nothing fancy here, but for some reason I get the error

kotlinx.serialization.MissingFieldException: Fields [measurements, measurementGroups] are required for type with serial name ‘no.beiningbogen.snute.sharedlibrary.library.model.endpoint.MeasurementsEndpoint’, but they were missing

When I test my request locally I don’t get this error, it only happens when I run the request from android or iOS clients. Any idea what I’m doing wrong?

📣 Folks, would appreciate your feedback on this! https://twitter.com/JetBrainsKtor/status/1466061672481796103 📣

Hi, I'm trying to use ktor-network to send and receive some data over UDP. I have however run into a problem which I was able to break down to a few lines of code:

suspend fun main() {
    val socket = aSocket(ActorSelectorManager(<http://Dispatchers.IO|Dispatchers.IO>)).udp().connect(InetSocketAddress("localhost", 1111))

    val input = socket.openReadChannel()

    input.readByte() // This line causes the exception
}

This code always throws the following exception:

Exception in thread "main" java.lang.IllegalStateException: Handler for READ is already registered
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at io.ktor.utils.io.ExceptionUtilsJvmKt$createConstructor$$inlined$safeCtor$1.invoke(ExceptionUtilsJvm.kt:103)
	at io.ktor.utils.io.ExceptionUtilsJvmKt$createConstructor$$inlined$safeCtor$1.invoke(ExceptionUtilsJvm.kt:90)
	at io.ktor.utils.io.ExceptionUtilsJvmKt.tryCopyException(ExceptionUtilsJvm.kt:66)
	at io.ktor.utils.io.ByteBufferChannelKt.rethrowClosed(ByteBufferChannel.kt:2460)
	at io.ktor.utils.io.ByteBufferChannelKt.access$rethrowClosed(ByteBufferChannel.kt:1)
	at io.ktor.utils.io.ByteBufferChannel.setupStateForRead(ByteBufferChannel.kt:310)
	at io.ktor.utils.io.ByteBufferChannel.readByte(ByteBufferChannel.kt:2540)
	at com.example.TestKt.main(Test.kt:13) // Line with readByte()
	at com.example.TestKt$main$2.invoke(Test.kt)
	at com.example.TestKt$main$2.invoke(Test.kt)
	at kotlin.coroutines.intrinsics.IntrinsicsKt__IntrinsicsJvmKt$createCoroutineUnintercepted$$inlined$createCoroutineFromSuspendFunction$IntrinsicsKt__IntrinsicsJvmKt$1.invokeSuspend(IntrinsicsJvm.kt:205)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlin.coroutines.ContinuationKt.startCoroutine(Continuation.kt:115)
	at kotlin.coroutines.jvm.internal.RunSuspendKt.runSuspend(RunSuspend.kt:19)
	at com.example.TestKt.main(Test.kt)
Caused by: java.lang.IllegalStateException: Handler for READ is already registered
	at io.ktor.network.selector.InterestSuspensionsMap.addSuspension(InterestSuspensionsMap.kt:34)
	at io.ktor.network.selector.SelectorManagerSupport.select(SelectorManagerSupport.kt:40)
	at io.ktor.network.sockets.CIOReaderKt$attachForReadingImpl$1.invokeSuspend(CIOReader.kt:46)
	at io.ktor.network.sockets.CIOReaderKt$attachForReadingImpl$1.invoke(CIOReader.kt)
	at io.ktor.network.sockets.CIOReaderKt$attachForReadingImpl$1.invoke(CIOReader.kt)
	at io.ktor.utils.io.CoroutinesKt$launchChannel$job$1.invokeSuspend(Coroutines.kt:132)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:367)
	at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:30)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.startCoroutineImpl(Builders.common.kt:192)
	at kotlinx.coroutines.BuildersKt.startCoroutineImpl(Unknown Source)
	at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:134)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.launch(Builders.common.kt:56)
	at kotlinx.coroutines.BuildersKt.launch(Unknown Source)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.launch$default(Builders.common.kt:47)
	at kotlinx.coroutines.BuildersKt.launch$default(Unknown Source)
	at io.ktor.utils.io.CoroutinesKt.launchChannel(Coroutines.kt:123)
	at io.ktor.utils.io.CoroutinesKt.writer(Coroutines.kt:77)
	at io.ktor.network.sockets.CIOReaderKt.attachForReadingImpl(CIOReader.kt:27)
	at io.ktor.network.sockets.NIOSocketImpl$attachForReading$1.invoke(NIOSocketImpl.kt:43)
	at io.ktor.network.sockets.NIOSocketImpl$attachForReading$1.invoke(NIOSocketImpl.kt:41)
	at io.ktor.network.sockets.NIOSocketImpl.attachFor(NIOSocketImpl.kt:80)
	at io.ktor.network.sockets.NIOSocketImpl.attachForReading(NIOSocketImpl.kt:41)
	at io.ktor.network.sockets.SocketsKt.openReadChannel(Sockets.kt:108)
	at com.example.TestKt.main(Test.kt:11) // Line with .openReadChannel()
	... 7 more

Edit: The only dependency I have n the example project is ktor-network:1.6.6

It’s probably been asked before, but is there a reason why

MockEngine.create

doesn’t return

MockEngine

? At the moment we’re doing

MockEngine.create { … } as MockEngine

- will it be expected in the future that

MockEngine.create

might not return

MockEngine

?

Is there a way to disable ktor server from logging common errors? e.g. cancelling a download: https://www.toptal.com/developers/hastebin/noqucizoku.log

On Android, I’m using

io.ktor:ktor-client-okhttp

but need to support Android 4.2+, so I included OkHttp in version

3.12.0

as documented by OkHttp to support Android 4. Will bis cause problems when using Ktor together with OkHttp? Is compatibility between versions documented somewhere?

a(...) {
    attributes["download"] = "..."
}

is what you're looking for I think

Hello, does Ktor server support gRPC? I'm new to gRPC and would love to try it. Thanks

This message was deleted.

Hi, why am i getting 404 in test ?

withTestApplication {
    handleRequest(HttpMethod.Get, "/hello").apply {
        assertEquals(HttpStatusCode.OK, response.status())
    }
}

I do not think I understand

StatusPages

plugin correctly. I am trying to redirect the user to “/” if they try to navigate to a page that does not exist (say they go to “/invalid”, then the browser should redirect to “/” instead). I was under the impression that I would have to use StatusPages for this like so:

install(StatusPages) {
        status(HttpStatusCode.NotFound) {
            call.respondRedirect("/")
        }

but when I navigate to “/invalid” the browser displays a blank page and the console shows a 404 for “/invalid”. I set a breakpoint to the call but it is never triggered. Isn’t this what StatusPages are meant to handle? Would I need to use something else for this scenario? (I am thinking that maybe i could use just routing with wildcards)

Is there any roadmap for ktor to own certificate pinning for the client?

Has a general timeframe been announced for the 2.0 release? I found this ticket https://youtrack.jetbrains.com/issue/KTOR-3457, but there isn't any indication of general timeline that I can see. The native mode looks cool, and would work really well with a project I'm planning on starting in the future.

I have a RouteBuilder object that dynamically configures all the routes for my application, given a list of controller classes. However, when I run the project without the gradle shadow plugin, the object doesn't seem to cross into the embeddedServer context. The relevant code snippet and resulting log output is pasted below:

<http://log.info|log.info>("RouteTypeMap size: ")
		<http://log.info|log.info>(RouteBuilder.routeTypeMap.size.toString())

		embeddedServer(
				Netty
			, port = 11111
		) {
			<http://log.info|log.info>("RouteTypeMap size in configuration block: ")
			<http://log.info|log.info>(RouteBuilder.routeTypeMap.size.toString())

Log:

RouteTypeMap size:
870
RouteTypeMap size in configuration block:
0

My knowledge of kotlin isn't deep enough to really have a a clue as to why this is happening 😅

Hi guys, i want to setBody to handleRequest for test. How should i do?

handleRequest(<http://HttpMethod.Post|HttpMethod.Post>, "/login") {
    addHeader(HttpHeaders.ContentType, ContentType.Application.Json.toString())
    addHeader(HttpHeaders.Accept, ContentType.Application.Json.toString())
    //setBody("{\"username\": \"emirhan\", \"password\": \"1234\"}")
    setBody(listOf("username" to "emirhan", "password" to "1234").toString())
}

i'm receiving: io.ktor.features.CannotTransformContentToTypeException: Cannot transform this request's content to com.emirhan.model.UserRequest My data class UserRequest is like:

@Serializable
data class UserRequest(
    val username: String,
    var password: String
)

In route im receiving body like:

val userRequest = call.receive<UserRequest>()

Talk about guys! Do you happen to have any material on the differences between Spring and Ktor? Please

what’s the canonical way to create a URL string literal with encoded parameters?

I am facing a very strange behaviour with a download button and a video. I am not sure how to debug this so any help is welcome. I have a page with a href and a video (see the routing setup below). If the anchor is the only tag in the page clicking on it, then the file starts downloading, no problem here. When I have both the anchor tag and the video tag, clicking on the anchor doesn’t trigger the download… I also noticed that it will eventually start downloading, only if I click on the video 🤯

fun Application.configureRouting() {
    routing {
        static("/vid") {
            files("videos")
        }
        get("/download/*") {
            val file = File("./files/hello.txt")
            call.respondFile(file)
        }
        get("/") {
            call.respondHtml {
                body {
                    a(href = "/download/hello.txt") {
                        attributes["download"] = ""
                        +"Download"
                    }
                    video {
                        loop = true
                        controls = true
                        source {
                            src = "/vid/vid.mp4"
                            type = "video/mp4"
                        }
                    }
                }
            }
        }
    }
}

What is the css DSL counter part of the following css?

@font-face {
    src: url("/fonts/Urbanist.ttf");
    font-family: urbanist;
}

So far I got:

call.respondCss {
    fontFace {
        fontFamily = "urbanist"
    }
}

but I cannot find a way to populate the src value. (also, please let me know if this is not the right place to ask this)

Careful, log4j remote execution exploit. Posted in #feed

hi guys! can anyone can help me with multipart form data? i have a ktor server endpoint which expects a two parts form data: form item and form data. I can send form item without any problems, but a cant findout a way to send file as PartData.FileItem thx

How can I check the size of an uploaded file to ktor? Checked the documentation and searched here but surprised I couldn’t find something

I am using version 2.0.0-eap-278. It looks like

defaultRequest

was moved from features package to plugins package. However, now

attributes

in the

defaultRequest

block is unresolved. I think this is a bug as it was there previously. How to fix this?

I noticed that on https://ktor.io/learn/ Server-Sent Events are referred as Server-Side Events. I guess that's a typo.

Hi, is there a way to use Ktor 1.6.7 with Coroutines 1.6.0-RC2 on Kotlin/Native to take advantage of the new memory model? I get an error when I try to use the HttpClient on iOS, which is thrown by this function which is called in the init block of HttpClient. Looks like I’m not able to use a Coroutines version different than a

native-mt

one

Hello everyone, is there a guide on microservices for ktor or a sample project one can look at, preferably ktor 2.0 EAP?

I installed an SSL certificate on my ktor server (Let’s Encrypt) and the HttpsRedirect to automatically switch to https calls instead of http. Is there a way to hide the port number from the url without having to use a reverse proxy?

Hi 👋 was libcurl for Apple Silicon released? I can only find macos

x86_64

but not macos

arm64

https://mvnrepository.com/artifact/io.ktor/ktor-client-curl-macosx64 ✅ https://mvnrepository.com/artifact/io.ktor/ktor-client-curl-macosarm64 ❌ For the context: we use libcurl as a Ktor client engine for macos in Realm-Kotlin and we're in the process of adding support for

macosArm64

Hello there! A project I work on maintains multiple HTTP client-backed services for Java, JavaScript, Kotlin, and Swift that all basically do the same thing, so Ktor’s multiplatform support looks super attractive for reducing a lot of duplication and maintenance burdens. I made a simple service using Ktor that calls a GET method, and noticed my function needed to become a suspend function (or maybe wrap the call with

runBlocking

, but I doubt that’s a performant or even suggested approach, and it won’t work for JS or common). As far as working with the service using Kotlin goes, whether in my common, JVM, JS, or whatever source set, I had no issues. The problem I have is consuming the service from Java code of course adds the Continuation argument, which isn’t something I want to impose on consumers of these services. I’ve seen a few threads in this channel about this issue, but I’m still wondering if there is any documentation or examples on how to make consuming the suspend function from Java sources more friendly. I saw mention of transforming to Futures or RxJava Singles or some other equivalent type, which is totally fine, but I’m not sure where to look for examples on how to even achieve that. I also know I can create a JVM-specific implementation that uses

runBlocking

, but again I’m pretty sure that should be avoided. Am I correct that using

runBlocking

would actually be worse than making the service using a RestEasy blocking client, due to coroutines not wanting to be blocked? Or would the performance be similar to a traditional blocking client, and I’d just be giving up benefits from using coroutines? Any pointers or links to guides would be appreciated!

playing with ktor 2 eap, I’m confused with 2 things: • Why is the latest version for

ktor-server-core-macosx64

2.0.0-eap-272

instead of

2.0.0-eap-283

? Are we having any problems with the building mechanism, or is this discontinued? • How can I install

ktor-server-content-negotiation

? I can’t see this published for any platform, but without it I don’t know how to install the json serializer