Services

Services are the centerpieces of the library. A service is an interface annotated with the @Rpc annotation, and contains a set of methods and fields that can be executed or accessed remotely. Additionally, a service always has a type of RemoteService, which can be specified explicitly, or assumed implicitly by the compiler.

A simple service can be declared as follows:

                @Rpc
                interface MyService : RemoteService {
                    suspend fun hello(name: String): String
                }
            

Here we declare the method hello, that accepts one argument and returns a string. The method is marked with a suspend modifier, which means that we use coroutines to send RPC requests. Note that for now, only suspend methods are supported in service interfaces.

To be able to use a service both in client and server code, the interface should be placed in the common module — kudos to Kotlin Multiplatform.

Now we can implement the service, so server knows how to process incoming requests.

                class MyServiceImpl(override val coroutineContext: CoroutineContext) : MyService {
                    override suspend fun hello(name: String): String {
                        return "Hello, $name! I'm server!"
                    }
                }
            

The server will use that implementation to answer the client requests.

Last modified: 05 November 2024