Has anyone had success deploying to Heroku? I got it working by involving shadowJar gradle plugin, would like to know if I could get it to work without this workaround

hey there. Any chance to disable the json serialization for a single request? I have to deal with an api that is supposed to speak json but expects one serialized json object / line in the body when performing batch operations 😕

I wonder what I am doing wrong, but I have been unable to make a simple request from UI (kotlin React) to Ktor backend using the HttpClient. Any pointer to an example please, preferably one done with Ktor version 1.4.0 and above

I have a multiplatform project setup with ktor and I am having issues with running it through intellij. I set some jvm args in the application block of build.gradle.kts to fix errors I was getting, but IntelliJ completely ignores them. I also tried putting them in the gradle run configuration itself and it ignores those too. I've tried rebuilding, remaking the intellij project, invalidating the intellij caches, but nothing works. When I run

gradlew run

it sees the jvm args and starts just fine, it's only through intellij that theres a problem. Does anyone know how to fix this issue?

GraalVM + Ktor here's a good starting point for anyone interested: example utilising "kraal" gradle plugin I would like to get your input, whether it is of interest to ktor developers. Is this a worthwhile endeavour? Is the supposed performance boost, if any, worth the hassle? Does it depend entirely on the use-case?

i'm using a ktor client with

JsonFeature

, but I would like to wrap my return types with a

Result

sealed class type of thing instead of exceptions when a network error occurs - any suggestions for going forward with this?

kotlin.Error: Ktor native HttpClient requires kotlinx.coroutines version with `native-mt` suffix (like `1.3.9-native-mt`). Consider checking the dependencies.

Has anyone else experienced this? It happens on iOS with Ktor 1.4.1, 1.4.2; coroutines 1.3.9-native-mt, 1.3.9-native-mt-2

What’s your favourite Ktor + Frontend setup? Started with simple HTML/JS + Freemarker but it’s getting messy.

I’ve the problem with ktor-curl on macOS.

val response = <http://httpClient.post|httpClient.post><T>(url) {
                    contentType(ContentType.Application.Json)
                    body = "some json"
                }

This code executed on windows ~1 sec but on macOS - first request < 1 sec but next ~ 15 sec. kotlin 1.4.10, ktor 1.4.2,

io.ktor:ktor-client-curl

and others. How can I look up a problem?

is there any way to just write plain text into the body of a post request with the ktor client? I have the following code

val content = """
            {"identifier":"cdp_9055274"}
            {"identifier":"cdp_9111757"}
            {"identifier":"cdp_9135021"}
        """.trimIndent()

        val response = httpClient.patch<String> {
            url("/api/rest/v1/products")
            header("Authorization", "Bearer ${token.accessToken}")
            contentType(ContentType("application", "vnd.akeneo.collection+json"))
            body = content
        }

and it seems like regardless of what I'm writing into the body (the string, TextContent / ByteArrayContent), the body is always serialized into json again.

Hello all, I’m trying to write a file download method using Ktor on a native/mpp app. here’s my method so far:

suspend fun HttpClient.downloadFile(
    output: File,
    downloadUrl: Url,
    md5Hash: String
): Flow<DownloadResult> {
    return flow {
        try {
            val response = get<HttpResponse> { url(downloadUrl) }
            val data = ByteArray(response.contentLength()?.toInt() ?: 0)
            var offset = 0
            do {
                val progress = (offset.toDouble() / data.size) * 100
                emit(DownloadResult.Progress(progress))
                val currentRead = response.content.readAvailable(data, offset, data.size)
                offset += currentRead
            } while (currentRead > 0)

            if (response.status.isSuccess()) {
                if (data.md5().hex == md5Hash) {
                    output.write(data)
                    emit(DownloadResult.Success)
                } else {
                    emit(DownloadResult.ErrorCorruptFile)
                }
            } else {
                emit(DownloadResult.ErrorBadResponseCode(response.status.value))
            }
        } catch (e: TimeoutCancellationException) {
            emit(DownloadResult.ErrorRequestTimeout("Connection timed out", e))
        } catch (t: Throwable) {
            emit(DownloadResult.Error("Failed to connect", t))
        }
    }
}

The problem is that the 

response.content.readAvailable()

 method always seems to read the whole file at once without chunking it up, which means my progress emission only gets outputted once. I’m wondering if there’s something I’m doing wrong here? or if that’s normal behaviour? Also as a side note the file I’m testing on is 25MB so it should emit a few times I’d think.

Are there any guides on how to write and use ktor middleware (if it's even possible)

I am building an asynchronous web server using Flask and Celery. The latter is a task queue manager. In the screenshot below, I generate a task ID via a POST request to the web server and the actual task starts 10 seconds later. You can then check the status via an automated task id generated by Celery. I prefer coding with Ktor for obvious reasons but I am struggling to find out a way to do the same thing easily. Does anyone know how to address that? (asynchronous tasks triggered by a post and status easy to assess). I don’t mind adding external components (but not too complex ones 🙂 )

Hi! I would like to create webserver to send data to frontend via websocket. I found example (below) how to make list of connections and sync data to all. Is there some more efficient way to do this? Something like multicast? Can someone tell me how many clients is possible to connect to such websocket? In real case I need to sync position of 100 cars to 10000 clients every second... What would be the best way with ktor?

routing {
    val wsConnections = Collections.synchronizedSet(LinkedHashSet<DefaultWebSocketSession>())

    webSocket("/chat") { // this: DefaultWebSocketSession
        wsConnections += this
        try {
            while (true) {
                val frame = incoming.receive()
                when (frame) {
                    is Frame.Text -> {
                        val text = frame.readText()
                        // Iterate over all the connections
                        for (conn in wsConnections) {
                            conn.outgoing.send(Frame.Text(text))
                        }
                    }
                }
            }
        } finally {
            wsConnections -= this
        }
    }
}

I don’t know how I managed to delete my last message. Here it goes, can anyone help me please ? Using ktor (server side) = 1.4.2, coroutines = 1.3.9, jdk14, kotlin = 1.4.10 and proemtheus java client = 0.9.0, this code throws :

get("/") {
    call.respondTextWriter {
        withContext(IO) {    TextFormat.write004(this@respondTextWriter, CollectorRegistry.defaultRegistry.metricFamilySamples()) } 
    }
}

Exception in thread "eventLoopGroupProxy-3-1" kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation[UnsafeBlockingTrampoline@381151be, Continuation at io.ktor.utils.io.jvm.javaio.OutputAdapter$loop$1.loop(Blocking.kt:311)@33f7436b]. Please read KDoc to 'handleFatalException' method and report this incident to maintainers
	at kotlinx.coroutines.DispatchedTask.handleFatalException$kotlinx_coroutines_core(DispatchedTask.kt:144)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:115)
	at io.ktor.utils.io.jvm.javaio.UnsafeBlockingTrampoline.dispatch(Blocking.kt:296)
	at kotlinx.coroutines.internal.DispatchedContinuation.resumeWith(DispatchedContinuation.kt:184)
	at io.ktor.utils.io.jvm.javaio.BlockingAdapter$end$1.resumeWith(Blocking.kt:163)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:46)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at io.ktor.utils.io.jvm.javaio.UnsafeBlockingTrampoline.dispatch(Blocking.kt:296)
	at kotlinx.coroutines.internal.DispatchedContinuation.resumeWith(DispatchedContinuation.kt:184)
	at io.ktor.utils.io.internal.CancellableReusableContinuation.resumeWith(CancellableReusableContinuation.kt:93)
	at io.ktor.utils.io.ByteBufferChannel.resumeWriteOp(ByteBufferChannel.kt:2258)
	at io.ktor.utils.io.ByteBufferChannel.bytesRead(ByteBufferChannel.kt:929)
	at io.ktor.utils.io.ByteBufferChannel.consumed(ByteBufferChannel.kt:1953)
	at io.ktor.server.netty.cio.NettyResponsePipeline$processBodyFlusher$2.invokeSuspend(NettyResponsePipeline.kt:305)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.ktor.server.netty.EventLoopGroupProxy$Companion$create$factory$1$1.run(NettyApplicationEngine.kt:215)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.ClassCastException: class kotlin.coroutines.jvm.internal.CompletedContinuation cannot be cast to class kotlinx.coroutines.internal.DispatchedContinuation (kotlin.coroutines.jvm.internal.CompletedContinuation and kotlinx.coroutines.internal.DispatchedContinuation are in unnamed module of loader 'app')
	at kotlinx.coroutines.CoroutineDispatcher.releaseInterceptedContinuation(CoroutineDispatcher.kt:104)
	at kotlin.coroutines.jvm.internal.ContinuationImpl.releaseIntercepted(ContinuationImpl.kt:118)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:39)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:104)
	... 22 more
`

As

kotlinx-coroutines-1.4.1-native-mt

has just been released, when can we expect new Ktor release, with coroutines 1.4 and the fix for KTOR-1286?

I am using ktor client in a mpp project and I am trying to post form-data:

client.submitFormWithBinaryData {
    url { encodedPath = "my_url" }
    formData {
        append("my_key", "my_key_value")
    }
}

Bu then get an error from kotlinx serialization:

kotlinx.serialization.SerializationException: Serializer for class 'MultiPartFormDataContent' is not found.

What am I missing here?

[Client] Hello everyone, I’m configuring my client with a

defaultRequest { }

and I want a parameter to be used only for some path, what’s the best way? Details in thread

Hi everyone, is it possible to override features? For example: I have a feature that allows actions from a user (GET/PUT/Whatever) based on a role, but also based on an exception in this rule. I want all my routes to default that you would need to be logged in as ADMIN, except if I override it (which could be route specific) For example:

routing {
    withRole(ADMIN) {
         route("admin_only_route") {
         }

         withRole(USER) {
             route("special_route") {
             }
         }
           
    }
}

Is there any websocket ktor client example, in which the entry object is available so it can be used to cancel or start the websocket session. So far, there is that example where you manage the websocket session within a scoped block of code and it isn't available to the outside world.

I’ve found some strange problem with the latest kotlin+coroutinues+ktor and macOS CURL request slowly - 2-3 seconds instead if 400-500ms. The fix is weird - remove

app.run()

https://github.com/alekseytomin/coroutines-problem/pull/1 It’s a ktor’s bug? Or coroutinue’s bug?

How do I access properties from

application.conf

from a non-Ktor object class?

Hi guys, how would we use mockengine for mocking the response from an endpoint, if some one could give an example or some kind of explanation would be good

Hi! How can I send a 204 No content response without content ?

call.respond(HttpStatusCode.NoContent, Unit)

I have

{}

in the content.

Is it standard for Ktor or KotlinxSerialization to chop a request? I was trying to understand what was happening and after inspecting into the

@Deprecated("This is going to become internal. Use Pipeline.execute() instead.")
public fun <TSubject : Any, TContext : Any> pipelineExecutorFor(
    context: TContext,
    interceptors: List<PipelineInterceptor<TSubject, TContext>>,
    subject: TSubject
): @Suppress("DEPRECATION") PipelineExecutor<TSubject> {
    return SuspendFunctionGun(subject, context, interceptors)
}

I found that my body is being sent in half

Hi! please help! 🙂 We are a few days from our release and stupid me upgraded to kotlin 1.4.20 and ktor 1.4.2 .. very simple handler:

get("/test") {
            call.respondTextWriter(contentType = ContentType.Text.CSV) {
                repeat(100000) {
                    write("bla")
                }
            }
        }

result:

Exception in thread "eventLoopGroupProxy-3-2" kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation[UnsafeBlockingTrampoline@28448af8, Continuation at io.ktor.utils.io.jvm.javaio.OutputAdapter$loop$1.loop(Blocking.kt:311)@4245d158]. Please read KDoc to 'handleFatalException' method and report this incident to maintainers
	at kotlinx.coroutines.DispatchedTask.handleFatalException$kotlinx_coroutines_core(DispatchedTask.kt:93)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:64)
	at io.ktor.utils.io.jvm.javaio.UnsafeBlockingTrampoline.dispatch(Blocking.kt:296)
	at kotlinx.coroutines.DispatchedContinuation.resumeWith(DispatchedContinuation.kt:184)
	at io.ktor.utils.io.jvm.javaio.BlockingAdapter$end$1.resumeWith(Blocking.kt:163)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:46)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56)
	at io.ktor.utils.io.jvm.javaio.UnsafeBlockingTrampoline.dispatch(Blocking.kt:296)
	at kotlinx.coroutines.DispatchedContinuation.resumeWith(DispatchedContinuation.kt:184)
	at io.ktor.utils.io.internal.CancellableReusableContinuation.resumeWith(CancellableReusableContinuation.kt:93)
	at io.ktor.utils.io.ByteBufferChannel.resumeWriteOp(ByteBufferChannel.kt:2258)
	at io.ktor.utils.io.ByteBufferChannel.bytesRead(ByteBufferChannel.kt:929)
	at io.ktor.utils.io.ByteBufferChannel.consumed(ByteBufferChannel.kt:1953)
	at io.ktor.server.netty.cio.NettyResponsePipeline$processBodyFlusher$2.invokeSuspend(NettyResponsePipeline.kt:305)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.ktor.server.netty.EventLoopGroupProxy$Companion$create$factory$1$1.run(NettyApplicationEngine.kt:215)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.ClassCastException: class kotlin.coroutines.jvm.internal.CompletedContinuation cannot be cast to class kotlinx.coroutines.DispatchedContinuation (kotlin.coroutines.jvm.internal.CompletedContinuation and kotlinx.coroutines.DispatchedContinuation are in unnamed module of loader 'app')
	at kotlinx.coroutines.CoroutineDispatcher.releaseInterceptedContinuation(CoroutineDispatcher.kt:103)
	at kotlin.coroutines.jvm.internal.ContinuationImpl.releaseIntercepted(ContinuationImpl.kt:118)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:39)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:55)
	... 22 more

can i run ktor 1.4.1 with kotlin 1.4.20 and serialization 1.4.20?

Hey 👋 I’m using ktor client with Json feature installed. Some of my requests are downloading json files via

ByteReadChannel

(I just need to save them in local file storage) but looks like ktor is running those through json parsing as well (probably because content type is

application/json

). This results in an exception, because there’s not enough information to deserialize response data. Any hints? Or should I just file a github issue? Thanks!

Hello, I am using a Ktor client with the Json feature to receive some Json objects, but I also need to access the response headers. I can see them if I get the HttpResponse object, but then I don't have my deserialized Json object. How do I retrieve both the Json object and the response headers?