Kodegen

Kodegen is a library for automatic generation of web API endpoints and API client methods for Ktor applications.

Usage

In your build.gradle, add Kodegen to your dependencies:

dependencies {
    implementation("dk.cachet:kodegen:1.0.0")
}

To generate code, add the dependencies using the kapt configuration:

dependencies {
    kapt("dk.cachet:kodegen:1.0.0")
}

Examples

Basic use

Given the following application service:

@ApplicationService
class ExampleService() {
    suspend fun foo(bar: Baz): Qux
}

Kodegen will, on compilation, generate the following Ktor module:

fun Application.ExampleServiceModule(service: ExampleService, vararg authSchemes: String) {
  routing {
    post("/kodegenApi/exampleService/foo/") {
      val request = call.receive<FooRequest>()
      val bar = request.bar
      val result = service.foo(bar)
      call.respond(result = result)
    }
  }
}

and the following client class:

class ExampleServiceInvoker(val client: HttpClient, val json: Json, val baseUrl: String) {
    suspend fun foo(bar: Baz): Qux {
    val jsonBody = json.stringify(FooRequest.serializer(), FooRequest(bar = bar))
    val response = client.post<String> {
        url("$baseUrl/kodegenApi/dateService/foo")
        body = TextContent(jsonBody, ContentType.Application.Json)
    }
    val result = json.parse(FooResponse.serializer(), response).result
    return result
}

using the following request and response objects:

@Serializable
data class ExampleServiceFooRequest(val bar: Baz)

@Serializable
data class ExampleServiceFooResponse(val result: Qux)

Authentication

The RequiresAuthentication annotation is used to indicate that a user should be authenticated before a method is called. Using it will add an authentication interceptor before routing to the endpoint. The authentication schemes to use for this are passed as parameters to the Ktor module.

Thus, adding RequiresAuthentication to the method foo:

@RequiresAuthentication
fun foo(bar: Baz): Qux
{
    ...
}

results in the route:

authenticate(*authSchemes) {
    post("/kodegenApi/exampleService/foo/") {
        ...
    }
}