Ktor Koin KGraphQL

KGraphQLServer.kt

import com.apurebase.kgraphql.GraphQL
import com.apurebase.kgraphql.schema.Publisher
import com.apurebase.kgraphql.schema.dsl.SchemaBuilder
import io.ktor.server.application.*
import org.koin.dsl.module
import org.koin.ktor.ext.inject
import org.koin.ktor.plugin.Koin
import org.koin.logger.slf4jLogger
import kotlin.getValue

fun main(args: Array<String>) {
    io.ktor.server.netty.EngineMain.main(args)
}

// DI Setup
fun interface HelloService {
    fun sayHello(): String
}

fun Application.module() {
    install(Koin) {
        slf4jLogger()
        modules(module {
            single<HelloService> {
                HelloService { "Hello, World from the HelloService!" }
            }
        })
    }
    configureGraphQL()
}

// GraphQL Setup
data class HelloMessage(val message: String)

fun Application.configureGraphQL() {
    install(GraphQL) {
        playground = true
        schema {
            hello(this)
            mutation(this@configureGraphQL)
            type<HelloMessage> {
                description = "A hello message"
            }
        }
    }
}

// Query, Mutation, Subscription builders
fun Application.hello(builder: SchemaBuilder): Publisher {
    val helloService by inject<HelloService>()

    return builder.query("hello") {
        description = "Trigger the HelloService to say hello"
        resolver { ->
            val message = helloService.sayHello()
            HelloMessage(message)
        }
    }
}

// Reversed order of parameters between SchemaBuilder <~> Application
fun SchemaBuilder.mutation(app: Application): Publisher {
    // val dependency by app.inject<Dependency>()
    return mutation("mutateSomething") {
        description = "Mutates something"
        resolver { input: String ->
            println("Do something with $input")
        }
    }
}