How can I setup my build script correctly and re-import project

Support
1

I am tring to do a simple back-end for one aplication and I am recivend
kotlinx.serialization compiler plugin is not applied to the module, so this annotation would not be processed. Make sure that you’ve setup your buildscript correctly and re-import project.
in this file:

package com.example.data.model

import kotlinx.serialization.Serializable

@Serializable
data class Rabbit (
val name: String,
val description: String,
val imageUrl: String,
)

When i make a request this a menssage that appers in my terminal 2023-07-28 23:30:53.218 [eventLoopGroupProxy-4-1] TRACE io.ktor.routing.Routing - Trace for
/, segment:0 → SUCCESS @ /
/, segment:0 → SUCCESS @ /
/(method:GET), segment:0 → SUCCESS @ /(method:GET)
/{…}, segment:0 → FAILURE “Better match was already found” @ /{…}
Matched routes:
“” → “” → “(method:GET)”
Route resolve result:
SUCCESS @ /(method:GET)
2023-07-28 23:30:53.308 [eventLoopGroupProxy-4-1] ERROR ktor.application - 200 OK: GET - /
kotlinx.serialization.SerializationException: Serializer for class ‘Rabbit’ is not found.
Please ensure that class is marked as ‘@Serializable’ and that the serialization compiler plugin is applied.

at kotlinx.serialization.internal.Platform_commonKt.serializerNotRegistered(Platform.common.kt:92)
at kotlinx.serialization.SerializersKt__SerializersKt.serializer(Serializers.kt:285)
at kotlinx.serialization.SerializersKt.serializer(Unknown Source)
at io.ktor.serialization.kotlinx.SerializerLookupKt.guessSerializer(SerializerLookup.kt:50)
at io.ktor.serialization.kotlinx.KotlinxSerializationConverter.serializeNullable(KotlinxSerializationConverter.kt:66)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1$2.invokeSuspend(ResponseConverter.kt:66)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1$2.invoke(ResponseConverter.kt)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1$2.invoke(ResponseConverter.kt)
at io.ktor.server.application.OnCallRespondContext.transformBody(KtorCallContexts.kt:86)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1.invokeSuspend(ResponseConverter.kt:39)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1.invoke(ResponseConverter.kt)
at io.ktor.server.plugins.contentnegotiation.ResponseConverterKt$convertResponseBody$1.invoke(ResponseConverter.kt)
at io.ktor.server.application.PluginBuilder$onDefaultPhase$1.invokeSuspend(PluginBuilder.kt:215)
at io.ktor.server.application.PluginBuilder$onDefaultPhase$1.invoke(PluginBuilder.kt)
at io.ktor.server.application.PluginBuilder$onDefaultPhase$1.invoke(PluginBuilder.kt)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1$1.invokeSuspend(PluginBuilder.kt:198)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1$1.invoke(PluginBuilder.kt)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1$1.invoke(PluginBuilder.kt)
at io.ktor.util.debug.ContextUtilsKt.addToContextInDebugMode(ContextUtils.kt:30)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1.invokeSuspend(PluginBuilder.kt:194)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1.invoke(PluginBuilder.kt)
at io.ktor.server.application.PluginBuilder$onDefaultPhaseWithMessage$1$1.invoke(PluginBuilder.kt)
at io.ktor.util.pipeline.SuspendFunctionGun.loop(SuspendFunctionGun.kt:120)
at io.ktor.util.pipeline.SuspendFunctionGun.proceed(SuspendFunctionGun.kt:78)
at io.ktor.util.pipeline.SuspendFunctionGun.execute$ktor_utils(SuspendFunctionGun.kt:98)
at io.ktor.util.pipeline.Pipeline.execute(Pipeline.kt:77)
at com.example.routes.RabbitRouteKt$randomRabbit$1.invokeSuspend(RabbitRoute.kt:44)
at com.example.routes.RabbitRouteKt$randomRabbit$1.invoke(RabbitRoute.kt)
at com.example.routes.RabbitRouteKt$randomRabbit$1.invoke(RabbitRoute.kt)
at io.ktor.server.routing.Route$buildPipeline$1$1.invokeSuspend(Route.kt:116)
at io.ktor.server.routing.Route$buildPipeline$1$1.invoke(Route.kt)
at io.ktor.server.routing.Route$buildPipeline$1$1.invoke(Route.kt)
at io.ktor.util.pipeline.SuspendFunctionGun.loop(SuspendFunctionGun.kt:120)
at io.ktor.util.pipeline.SuspendFunctionGun.proceed(SuspendFunctionGun.kt:78)
at io.ktor.util.pipeline.SuspendFunctionGun.execute$ktor_utils(SuspendFunctionGun.kt:98)
at io.ktor.util.pipeline.Pipeline.execute(Pipeline.kt:77)
at io.ktor.server.routing.Routing$executeResult$$inlined$execute$1.invokeSuspend(Pipeline.kt:478)
at io.ktor.server.routing.Routing$executeResult$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.server.routing.Routing$executeResult$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.util.debug.ContextUtilsKt.initContextInDebugMode(ContextUtils.kt:17)
at io.ktor.server.routing.Routing.executeResult(Routing.kt:190)
at io.ktor.server.routing.Routing.interceptor(Routing.kt:64)
at io.ktor.server.routing.Routing$Plugin$install$1.invokeSuspend(Routing.kt:140)
at io.ktor.server.routing.Routing$Plugin$install$1.invoke(Routing.kt)
at io.ktor.server.routing.Routing$Plugin$install$1.invoke(Routing.kt)
at io.ktor.util.pipeline.SuspendFunctionGun.loop(SuspendFunctionGun.kt:120)
at io.ktor.util.pipeline.SuspendFunctionGun.proceed(SuspendFunctionGun.kt:78)
at io.ktor.server.engine.BaseApplicationEngineKt$installDefaultTransformationChecker$1.invokeSuspend(BaseApplicationEngine.kt:124)
at io.ktor.server.engine.BaseApplicationEngineKt$installDefaultTransformationChecker$1.invoke(BaseApplicationEngine.kt)
at io.ktor.server.engine.BaseApplicationEngineKt$installDefaultTransformationChecker$1.invoke(BaseApplicationEngine.kt)
at io.ktor.util.pipeline.SuspendFunctionGun.loop(SuspendFunctionGun.kt:120)
at io.ktor.util.pipeline.SuspendFunctionGun.proceed(SuspendFunctionGun.kt:78)
at io.ktor.util.pipeline.SuspendFunctionGun.execute$ktor_utils(SuspendFunctionGun.kt:98)
at io.ktor.util.pipeline.Pipeline.execute(Pipeline.kt:77)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1$invokeSuspend$$inlined$execute$1.invokeSuspend(Pipeline.kt:478)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1$invokeSuspend$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1$invokeSuspend$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.util.debug.ContextUtilsKt.initContextInDebugMode(ContextUtils.kt:17)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1.invokeSuspend(DefaultEnginePipeline.kt:123)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1.invoke(DefaultEnginePipeline.kt)
at io.ktor.server.engine.DefaultEnginePipelineKt$defaultEnginePipeline$1.invoke(DefaultEnginePipeline.kt)
at io.ktor.util.pipeline.SuspendFunctionGun.loop(SuspendFunctionGun.kt:120)
at io.ktor.util.pipeline.SuspendFunctionGun.proceed(SuspendFunctionGun.kt:78)
at io.ktor.util.pipeline.SuspendFunctionGun.execute$ktor_utils(SuspendFunctionGun.kt:98)
at io.ktor.util.pipeline.Pipeline.execute(Pipeline.kt:77)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1$invokeSuspend$$inlined$execute$1.invokeSuspend(Pipeline.kt:478)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1$invokeSuspend$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1$invokeSuspend$$inlined$execute$1.invoke(Pipeline.kt)
at io.ktor.util.debug.ContextUtilsKt.initContextInDebugMode(ContextUtils.kt:17)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1.invokeSuspend(NettyApplicationCallHandler.kt:119)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1.invoke(NettyApplicationCallHandler.kt)
at io.ktor.server.netty.NettyApplicationCallHandler$handleRequest$1.invoke(NettyApplicationCallHandler.kt)
at kotlinx.coroutines.intrinsics.UndispatchedKt.startCoroutineUndispatched(Undispatched.kt:44)
at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:112)
at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:126)
at kotlinx.coroutines.BuildersKt__Builders_commonKt.launch(Builders.common.kt:56)
at kotlinx.coroutines.BuildersKt.launch(Unknown Source)
at io.ktor.server.netty.NettyApplicationCallHandler.handleRequest(NettyApplicationCallHandler.kt:37)
at io.ktor.server.netty.NettyApplicationCallHandler.channelRead(NettyApplicationCallHandler.kt:29)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
at io.netty.channel.AbstractChannelHandlerContext.access$600(AbstractChannelHandlerContext.java:61)
at io.netty.channel.AbstractChannelHandlerContext$7.run(AbstractChannelHandlerContext.java:425)
at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.ktor.server.netty.EventLoopGroupProxy$Companion.create$lambda$1$lambda$0(NettyApplicationEngine.kt:296)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:833)

there is just one line of this message that ponit to the my files in this file when of the path that respond about that
package com.example.routes

import com.example.data.model.Rabbit
import io.ktor.http.*
import io.ktor.server.application.*
import io.ktor.server.response.*
import io.ktor.server.routing.*

private const val BASE_URL = “http://localhost:8080”
private val rabbitList = listOf(
Rabbit(“Carl”, “A cute brown rabbit”, “$BASE_URL/rabbits/rabbit1.jpg”),
Rabbit(“Emma”, “Emma likes to eat apples”, “$BASE_URL/rabbits/rabbit2.png”),
Rabbit(“Florian”, “Florian is always hungry”, “$BASE_URL/rabbits/rabbit3.jpg”),
Rabbit(“Federico”, “Federico likes to climb mountains”, “$BASE_URL/rabbits/rabbit4.jpg”),
Rabbit(“Gina”, “Gina is a true beauty”, “$BASE_URL/rabbits/rabbit5.jpg”),
)

fun Route.randomRabbit() {

get("/") {
    val rabbits = rabbitList.toMutableList()
    val newRabbit = rabbits.random()
    rabbits.remove(newRabbit)
    call.respond(
        HttpStatusCode.OK,
        newRabbit
    )
    if (rabbits.isEmpty()) {
        rabbits.addAll(rabbitList)
    }
}

}

2

Since you’re using KTOR, let me ask: did you use the KTOR project generator? I found that it was pretty good at setting up all the stuff I need for my project to work.

It looks like you haven’t registered the Kotlin Serialization plugin with KTOR. Add this code in to wherever your other plugins are being registered:

install(ContentNegotiation) {
    json()
}

Also, you’ll probably need to make sure you have both the io.ktor:ktor-serialization-kotlinx-json-jvm and io.ktor:ktor-server-content-negotiation-jvm libraries in your project.