Hi, I'm having trouble with CIO in Android I'm getting weird timeout errors, if I switch to OkHttp everything is fine ...

Hello, I am writing a REST service that serves aggregated statistics of multicast message flow. It listens to a multicast socket and keeps track of the messages it receives. In response to some REST operations it also needs to send a multicast message (to a different group). Right now, I've structured it as two

launch

-ed coroutines on the IO dispatcher, using blocking

receive()

and

send()

with timeout, one draining an outbound channel, the other directly updating a map with statistics (guarded by

synchronized

section). Is this the idiomatic way? Am I supposed to use one of the

Flow

implementations? Can I somehow plug my I/O into Ktor's selector?

the gradle plugin for the Docker stuff doesn't seem to expose a port and I can't find anything to specify it. am I missing something?

I have a problem with the new

testApplication

functionality where the application initialization is not called. Please look at my issue https://youtrack.jetbrains.com/issue/KTOR-4819/testApplication-application-initialization-block-not-called

Hi @everyone, I have a couple of microservices written in Ktor(2.0.2). I want to ensure that there is a way that microservice communication happens inorder to share the data among them via REST API's. What is the best and secure way to make this communication happen. I have time constraint so gPRC is out of implementation for now. Any other recommendations?

Hi. We are trying to bump Kotlin to 1.7.10 and ktor to 2.0.3. We have a library LibA where we include ktor like this:

val ktorVersion = "2.0.3"
implementation("io.ktor:ktor-client:$ktorVersion")
implementation("io.ktor:ktor-client-core:$ktorVersion")
implementation("io.ktor:ktor-client-apache:$ktorVersion")
implementation("io.ktor:ktor-client-json:$ktorVersion")
implementation("io.ktor:ktor-client-jackson:$ktorVersion")
implementation("io.ktor:ktor-client-logging-jvm:$ktorVersion")
implementation("io.ktor:ktor-client-auth:$ktorVersion")
implementation("io.ktor:ktor-client-websockets:$ktorVersion")
implementation("io.ktor:ktor-client-okhttp:$ktorVersion")
implementation("io.ktor:ktor-client-content-negotiation:$ktorVersion")
implementation("io.ktor:ktor-serialization-jackson:$ktorVersion")

In another lib, LibB we include this lib.

implementation("ourgroup:ourapp:version")

When compiling LibB we get this error:

Cannot access class 'io.ktor.client.statement.HttpResponse'. Check your module classpath for missing or conflicting dependencies

We don't reference anything from ktor directly in LibB

is there a way to set every json field name to snake_case with Content Negotiation? I know it’s possible using

@JsonNames

but I don’t wanna do it for each one of the fields

Hi. While receiving multipart uploads, do I need to close any of the resources? Basically my routing looks like this:

post("/fileimport") {
                val multipartData = call.receiveMultipart()
                val parts = multipartData.readAllParts()
                    .filterIsInstance<PartData.FileItem>()
                    .mapIndexed { index, item ->
                        UploadedContent(
                            name = item.name ?: "unnamed$index",
                            filename = item.originalFileName ?: "unnamed$index",
                            contentType = item.contentType,
                            bytes = item.provider.invoke().readBytes()
                        )
                    }
                doSomething(parts)
                call.respond("OK")
            }

so the questions is - do I need to somehow close resources created by

call.receiveMultipart()

or

item.provider.invoke().readBytes()

?

Why we don't have 2 channels (client side channel and server side channel) for Ktor

I'm trying to write a plugin that alters HTML files served by Ktor. In

onCallRespond

/

transformBody

, the

data

argument I get is

Any

. When printing its type when a static HTML file is served, I get a

io.ktor.server.http.content.PreCompressedResponse

(I don't have compression configured on this server). Is there a way to get the actual body?

I'm hitting the same issue as asked in https://stackoverflow.com/q/64369594/775894 - with a routing defined like this:

routing {
  static("/") {
    staticRootFolder = dataDir
    files(".")
    default("index.html")
  }
}

Ktor serves the top-level

index.html

, but when requesting a subdirectory, Ktor returns a 404 (but requesting explicitly

index.html

in this subdirectory works fine). I also tried

default(File(dataDir, "index.html"))

, assuming it would at least serve the top-level

index.html

, which isn't the case. Is there any way to serve those index files in subdirectories?

Hi, all. I'm a new user of ktor client. And I found the Blob() class in Js can't be recognized by ktor Js and throw "unserializeable exception". The official documentation of ktor didn't mentions how to send binary data request in Js. Can anyone give me some advise? Thank you for your attention.

Apologies about the repost, but I sent this message on a weekend and it got zero replies and was quickly buried under Monday chatter. I'm trying one more time. Looking for advice please :-)

Hi, I am trying to use ktor client with kotlin native and cio engine, but when i run the application i get

Uncaught Kotlin exception: kotlin.native.IncorrectDereferenceException: Trying to access top level value not marked as @ThreadLocal or @SharedImmutable from non-main thread

The code looks like this

import io.ktor.client.*
import io.ktor.client.engine.cio.*

fun main() {
    val client = HttpClient(CIO)
}

This is just a simple new instance. I think it should work but it does not 😐. Just in case it is important i am on

linuxX64

with dependencies

implementation("io.ktor:ktor-client-core:2.1.0")
implementation("io.ktor:ktor-client-cio:2.1.0")

Looking into using Ktor Server for websockets. While playing around with them I was testing how the coroutine scope works. WebSocketSession implements CoroutineScope so I assumed calling

close

on the websocket would cancel the coroutine scope and clean up children jobs. This doesn't seem to be the case, which I can work around, but I was wondering if this is the behavior for a specific reason?

Is it possible to have a set of endpoints/routes with one content-types (and content negotiation) and some other routes with another content-types? I’d like to work on xmls in some application modules and jsons in some other module, and regular form-data -> html in the last module.

Hi. We upgraded Ktor from version 1 to 2. We use OkHttp engine. After the upgrade post/put with large JSON data is sent as

Transfer-Encoding: chunked

. Are there any ways to prevent this? The server we communicate with doesn't support it

Is there a way to receive serialized objects of different types from the same websocket? The example shows creating one socket per type, is that best practise?

I'm having issues with the CORS feature. With the following:

install(CORS) {
    anyHost()
  }

A

GET

request works just fine, but a

POST

doesn't. Trying to be a bit more explicit with this:

install(CORS) {
    anyHost()
    allowHeader(HttpHeaders.ContentType)
    allowMethod(HttpMethod.Get)
    allowMethod(<http://HttpMethod.Post|HttpMethod.Post>)
  }

results in the

GET

not working either now. What's the minimum to get both

GET

and

POST

working from any host?

I’m receiving this

java.lang.IllegalStateException: No request transformation found:

when running Integration Tests for my endpoint. If I just run the application it works fine, no exceptions or whatsoever. Any ideas?

Hi, is there any way to send kotlin object over ktor http client to ktor server without serialization/deserialization?

I am developing a small ktor application using Freemarker to render HTML-pages, which works as expected. But, I also need to set up a few API endpoints which serve JSON data to the client. To that end I install ContentNegotion with JSON serializer. It works splendidly and JOSN is produced by the api. But, now when I try one of the Freemarker pages I get:

2022-09-02 14:38:46.137 [eventLoopGroupProxy-4-1] ERROR Application - Unhandled: GET - /tak/6/producers
kotlinx.serialization.SerializationException: Serializer for class 'FreeMarkerContent' is not found.
Mark the class as @Serializable or provide the serializer explicitly.

How can I solve that so that my server both can support Freemarker pages and JSON responses?

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I’m trying out KMM using Ktor as client, with OkHttp engine for Android and Darwin for iOS. I am making a request like below

suspend fun getUpcomingLaunches(): List<Launch> =
    client.get {
        url {
            protocol = URLProtocol.HTTPS
            host = "<http://api.spacexdata.com/v4|api.spacexdata.com/v4>"
            encodedPath = "launches/upcoming"
        }
    }.body()

This works fine on Android, however on iOS it is failing with 404 not found. From the logs it looks like the correct url is being built (https://api.spacexdata.com/v4/launches/upcoming) although obviously it is not calling that url exactly. However, f I change the code though to

suspend fun getUpcomingLaunches(): List<Launch> =
    client.get("<https://api.spacexdata.com/v4/launches/upcoming>").body()

it works as expected. I’m guessing it is a bug in Darwin engine, but just wanted to check I’m not doing something stupid or if it’s a known issue. TIA!

How do I log exceptions? I know about StatusPages but I don't really want to change the returned data, I want to log the exception for monitoring purposes.

Is there any way to automatically add defined routes at compile-time (or runtime) without having to explicitly add them in the application module definition? Not only does it get tedious, it's also error prone if you forget to register a defined route. I assume it should be possible with code-generation or annotation processing such as kapt, but I'm wondering if anyone has already done something like this?

in ktor-server-html-builder-jvm, there’s an interesting Kotlin detail that I’m wondering if anyone here knows more about:

respondHtml(status) { with(template) { apply() } }

is used as just doing

template.apply()

triggers the built in scope function

apply

. What is it about the use of

with

that makes Kotlin invoke the

apply

method on

HTML<T>

rather than the scope function? Is it something about member functions taking presedence in the parser/compiler when it’s called without an explicit receiver, or something like that? If I try and change it to

with(resp.body) { this.apply() }

, i.e. explicitly using

this

inside

with

, it tries to call the scope function again.

Is there any way to use ktor as backend and vue as frontend? I foiund the singlePageApplication but it didn't seem to take a route argument, and it also seemed to require compiled files rather than being able to reload quickly.