I made a sample REST API with Ktor coupled with a Postgres database running on a docker compose 🙂 I tried to showcase several Ktor Feature such as StatusPage, Locations, DataConversion... and other very cool external library like Valiktor, Exposed, HikariCP, Flyway...). I am also using swagger to generate my front models (that can be shared with Android apps). This is a tiny cooking API and you can fork it as you want 🙂 Feedback appreciated 🙂 Enjoy! If you have any questions feel free to ask 🙂 https://github.com/Oleur/swcook-ktor-api

I have a request with rest assured and want to Transfer it to ktor but no Solution worked. I hope somebody can help me. MultiPartSpecification multiPartSpec = new MultiPartSpecBuilder(zipBytes(„fileinput.xml", bodyXmlAsString.getBytes())) .controlName("file") .fileName("myfile.zip") .mimeType("application/zip") .charset(StandardCharsets.UTF_8) .build(); I don‘t know how to do this with ktor.

Hi all! I have a Ktor server with a Netty engine. On requests, I just call

delay

for some time (say 20 seconds) and then respond with a string. I thought that when I call

delay

, I can serve other requests while previous requests are suspended, but instead, I have to wait until those requests are done and only then I'm able to serve new requests. How can I serve new requests when my previous requests are suspended? I thought it works like that by default, but now I really don't understand.

Hey! Is the only way to get a HttpResponse from a call to set expectSuccess to false?

I guess nobody have built a custom swagger codegen generator that can output a ktor client? 😄

Hey folks. I'm getting a rather unhelpful exception from ktor (with okhttp) on Android:

java.io.IOException: 
  at sun.nio.ch.IOUtil.makePipe (Native Method)
  at sun.nio.ch.PollSelectorImpl.<init> (PollSelectorImpl.java:57)
  at sun.nio.ch.PollSelectorProvider.openSelector (PollSelectorProvider.java:36)
  at io.ktor.network.selector.ActorSelectorManager$1.invokeSuspend (ActorSelectorManager.kt:41)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:106)
  at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely (CoroutineScheduler.kt:571)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask (CoroutineScheduler.kt:750)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker (CoroutineScheduler.kt:678)
  at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run (CoroutineScheduler.kt:665)

And to make matters worse, the user who experienced it sent the crash report to Google Play Store anonymously, so I can't contact them to ask for more info. I can't reproduce it either (even though I coincidentally have the same phone). Any thoughts on how to get to the bottom of this? It seems like it's happened 5 times to the same user (we're running a beta right now, so it may be a big issue when we eventually launch). I'm using Ktor via a library. Behind the scenes, that library keeps a WebSocket open and makes some

POST

requests when certain events happen. I can see that the library is properly handling `IOException`s in WebSocket and HTTP connections.

sorry if this is basic question but couldn't find answer in docs.....basicaly in a SPA setup I want any requests that would normally return a 404 to redirect to say main index.html....is there way to configure this in Ktor?

Hey guys.. how can i get the remote address of a caller in ktor?

ResponseException

has an

HttpResponse

on it, but it looks like by the time I

catch

that exception, the response has already been consumed. I want to parse the json on the response, what’s the best way to do that?

Is there a way to uninstall a module/routes so that I can create something like a servlet container? In other words, I'd watch for jar changes and reload an 'app' without shutting down the ktor process?

Hi, I keep getting this error

Could not get unknown property 'kotlin_serialization' for object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

while importing this dependency

implementation "org.jetbrains.kotlinx:kotlinx-serialization-core:$kotlin_serialization"

How do I store large strings in SQL? I am working with H2 database in Exposed

I’m not sure if I understand how to use Ktor properly. Unless I get an HTTP 200 Ok, it throws an exception unless I set

expectSuccess

to

false

. But if I do that, I can’t get the deserialized body. This means that when I get a valid response, like

302 Found

, I still get an exception. How is this meant to be used?

Hi, friends. I’m working on a ktor server and am having trouble refactoring this bit of code. I want to move this bit of Authentication code into another file/class, specifically the validate credentials call. But I’m having a bit of trouble with the kotlin syntax. Any tips to point me in the right direction? Or more generally, is there a way to move the install features calls into separate files?

/** Application.main() */
val db: SqlDelightDatabase by inject()
val orgDb: OrgDb by inject()

install(Authentication) {
    basic(name = "orgtoken") {
        validate { credentials ->
            if (credentials.name.isEmpty() or credentials.name.isEmpty()) return@validate null
            val org = db.organizationQueries.selectByHttpAuthUsername(credentials.name)
                .executeAsOneOrNull() ?: return@validate null
            val orgQueries = orgDb.instance(org) ?: return@validate null
            val activeToken = orgQueries.tokenQueries.validToken(credentials.password).executeAsOne()

            if (activeToken) {
                return@validate OrganizationPrincipal(org)
            } else {
                return@validate null
            }
        }
    }
}

When I create new project with ktor in IntelliJ IDE, I encountered issue like below. It doesn't work properly even though I tried to create project in many times. Anyone knows why it's happening? My environment 1. IntelliJ IDE 211.4961.33 (Latest version) 2. ktor_version : 1.5.1 3. kotlin_version : 1.4.21 4. Project SDK : Java 15

I made a fairly small ktor project and am now trying to add Locations, but the second it's on the classpath (doesn't change if I install or don't) I get the following:

Exception in thread "main" java.lang.AbstractMethodError: io.ktor.server.engine.ApplicationEngineEnvironmentReloading.getDevelopmentMode()Z
	at io.ktor.application.Application.<init>(Application.kt:20)
	at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.instantiateAndConfigureApplication(ApplicationEngineEnvironmentReloading.kt:269)
	at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.createApplication(ApplicationEngineEnvironmentReloading.kt:125)
	at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.start(ApplicationEngineEnvironmentReloading.kt:245)
	at io.ktor.server.netty.NettyApplicationEngine.start(NettyApplicationEngine.kt:126)
	at io.ktor.server.netty.EngineMain.main(EngineMain.kt:26)

not sure where to go from here? This error isn't that descriptive

Where do I deploy my REST APIs in Ktor? Google cloud has so many hidden charges and its very confusing, and Heroku gets expensive rapidly as we scale. Are there any other options? Thanks.

so how do I structure a KTor app in a reasonable way with a DI? I seems I'm currently fighting the framework due it's heavy use of extension methods (I am also highly skeptical of that design choice, but for now I will go with the flow and give it a chance to grow). Say I have a

FooRoute

and want to make use of the

FooService

interface, what is a reasonable way to do that? Currently I'm around:

class FooRoute @Inject constructor(application: Application, foo: FooService) {
    init {
        // do "magic" here
    }
}

but I also want to structure my code in nicely designed methods etc. so there's a clear structure to it and all that

I tried to turn a python request RESTFul code to ktor, it's upload file with form data, but there's an error in ktor, please help https://paste.ubuntu.com/p/rmMM3W82HR/

I'm trying to use an object (singleton) to share state between a JavaFX application and a ktor netty embedded server. Two instances of the singleton are being created: one when the netty server accesses the "singleton" and one when the main application accesses it. Can you help me understand why that is happening?

Hi what is the suggested way to implement a schedule task in ktor ?

has anyone used Espresso to test Android UX that’s backed by a multiplatform ktor client? I’m trying to use Espresso to verify that a response is rendered on the screen, my test starts and I call

ktorClient.get<Something>

and see the request logged, but the ktor client gets blocked and the ktor function never returns. As such the test hangs forever. The application runs fine normally.

HttpResponseValidator{}

doesn't work anymore in 1.5.0, why? It doesn't get called at all https://ktor.io/docs/response-validation.html

📣 New EAP Program open, along with new plugin and plans moving forward with IDE support 📣 https://blog.jetbrains.com/ktor/2021/02/03/say-hello-to-ktor-early-access-program-and-new-plugin/

I'm at a complete loss with this random problem I'm facing (google didn't provide anything useful). I'm working on a fullstack project which has: • ktor-client-js & ktor-client-serialization @ 1.5.1 (js) • kotlinx.serialization-json @1.0.1 (common) The following class in commonMain:

import kotlinx.serialization.*

@Serializable
data class PagedResponse<T>(
  val data: List<T>,
  val total: Int,
  val next: String?,
  val prev: String?,
)

And when I fetch something from the backed via ktor client I get this (request itself is successful and that same class is serialized on the backand fine):

ERROR[]: Can't find a method to construct serializer for type PagedResponse. Make sure this class is marked as @Serializable or provide serializer explicitly.

Any ideas anyone?? I'm completely lost...

For folks that were wondering why we stopped publishing to JCenter, here’s one of the reasons https://jfrog.com/blog/into-the-sunset-bintray-jcenter-gocenter-and-chartcenter/

On Android, what engine do you guys use for your ktor client? I'm currently using the Android engine, but thinking about switching to CIO. Curious what people generally like to use.

Hi Anyone know about a server feature for cache functionality ?

Hello, the code below for Ktor MockEngine for 1.5.1

val client = HttpClient(MockEngine) {
            engine {
                addHandler { request ->
                    val body = request.body
                    val req = body.toByteArray().decodeToString()
                    println(req)
                    respond("Testing", headers = responseHeaders)
                }
           }
}

val res = client.get<String>("/")
expect(res).toBe("test")

throws

io.ktor.utils.io.ByteChannelCtorKt.ByteReadChannel([B)Lio/ktor/utils/io/ByteReadChannel;
java.lang.NoSuchMethodError: io.ktor.utils.io.ByteChannelCtorKt.ByteReadChannel([B)Lio/ktor/utils/io/ByteReadChannel;
	at io.ktor.client.engine.mock.MockUtilsKt.respond(MockUtils.kt:74)
	at io.ktor.client.engine.mock.MockUtilsKt.respond$default(MockUtils.kt:72)
	at CreateEndpointTest$should_have_a_valid_path$1$client$1$1$1.invokeSuspend(CreateEndpointTest.kt:35)
	at CreateEndpointTest$should_have_a_valid_path$1$client$1$1$1.invoke(CreateEndpointTest.kt)
	at CreateEndpointTest$should_have_a_valid_path$1$client$1$1$1.invoke(CreateEndpointTest.kt)
	at io.ktor.client.engine.mock.MockEngine.execute(MockEngine.kt:61)

When executed on JVM And throws

e: java.lang.IllegalStateException: Deserializer for declaration public <http://io.ktor.utils.io/ByteReadChannel%7C8179199761482737139[0]|io.ktor.utils.io/ByteReadChannel|8179199761482737139[0]> is not found
        at org.jetbrains.kotlin.backend.common.serialization.KotlinIrLinker.handleNoModuleDeserializerFound(KotlinIrLinker.kt:471)
        at org.jetbrains.kotlin.backend.common.serialization.KotlinIrLinker$IrDeserializerForFile.findModuleDeserializer(KotlinIrLinker.kt:359)
        at org.jetbrains.kotlin.backend.common.serialization.KotlinIrLinker$IrDeserializerForFile.deserializeIrSymbolData(KotlinIrLinker.kt:388)
        at org.jetbrains.kotlin.backend.common.serialization.KotlinIrLinker$IrDeserializerForFile.deserializeIrSymbol(KotlinIrLinker.kt:404)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeIrSymbolAndRemap(IrFileDeserializer.kt:144)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeCall(IrFileDeserializer.kt:387)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeOperation(IrFileDeserializer.kt:897)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeExpression(IrFileDeserializer.kt:938)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeMemberAccessCommon(IrFileDeserializer.kt:345)
        at org.jetbrains.kotlin.backend.common.serialization.IrFileDeserializer.deserializeCall(IrFileDeserializer.kt:404)

When executed on jsBrowser Am I missing a dependency?