Hello, I just started using koin in ktor project ...

# koin

[Paulius Ruminas]

Hello,

I just started using koin in ktor project and I added additional functionality to allow registration of singleton by KClass argument e.g.:

// Register by KClass
private fun Module.single(
    type: KClass<*>,
    createdAtStart: Boolean = false,
    override: Boolean = false
): BeanDefinition<*> {
    val beanDefinition = BeanDefinition<Any>(
        qualifier = null,
        scopeName = null,
        primaryType = type
    ).apply {
        this.definition = {
            val constructor = type.getFirstJavaConstructor()
            val args = getArguments(constructor, this)

            constructor.makeInstance(args)
        }
        this.kind = Kind.Single
    }

    declareDefinition(beanDefinition, Options(createdAtStart, override))

    return beanDefinition
}

// Inject by KClass
private fun <T : Any> Application.inject(type: KClass<T>): Lazy<T> = lazy { getKoin().rootScope.get(type.java) }

// Module declaration
val myModule = module {
    // findKClasses - returns List<KClass<*>>
    findKClasses().forEach { single(it) }
}

We have classes that we need to resolve dynamically by KClass so that is why we need an ability to register them by KClass.

It works now but I wonder how much this code is prone to breaking changes in the future. Or is there an "official way" to achieve this?

[arnaud.giuliani]

in Ktor you can use the koin=core-ext extensions to declare a component without gaving to write a constructor

[arnaud.giuliani]

https://github.com/InsertKoinIO/koin/blob/master/koin-projects/koin-core-ext/src/main/kotlin/org/koin/experimental/builder/ModuleExt.kt#L28

[arnaud.giuliani]

https://gist.github.com/arnaudgiuliani/7ad4601432a54b39dce49f5647880936

[Paulius Ruminas]

All of these functions use reified type parameter. If I use classgraph library to search for classes I don't have that information at compile time so I can't use any of these functions.

[arnaud.giuliani]

ok I see your issue

[Paulius Ruminas]

https://github.com/InsertKoinIO/koin/issues/475

I created an issue with a little bit more information.