Kotlin Clean Architecture Backend

Kotlin backend based on the Clean Architecture principles.

The application is separated into three modules: Domain, Usecases and Adapters

• Domain module contains all entities, it's validation and repository interfaces
• Usecases module performs actions on the domain entities and repositories and does authorization

The domain and usecases modules do not have any external dependencies.

• Adapter layer: each adapter is implemented as a standalone module, lowering dependence on specific frameworks and libraries and making them interchangable. The infrastructure module consumes all adapters (e.g. databases, (graphql) endpoints, authentication logic)

GraphQL endpoints are auto-generated from the Usecases

Technologies:

Ktor, JWT, Exposed, Flyway, OpenAPI/REST & KGraphQL/GraphQL generated endpoints, Gradle.

OpenAPI REST

Docs URL: http://localhost:8080/docs

API definitions: http://localhost:8080/openapi.json

GraphQL

Playground URL: http://localhost:8080/graphql

Login

query Login {
  LoginUser(a0: { email: "erik@erikschouten.com", password: "P@ssw0rd!" })
}

Retrieve current user

query CurrentUser {
  AuthenticatedUser {
    id
    email
    authorities
  }
}

HTTP Headers

{
  "Authorization": "Bearer [TOKEN FROM LOGIN]"
}

Create new user

mutation CreateUser {
  CreateUser(
    a0: {
      email: "calvin@erikschouten.com"
      password: "Penait1!"
      authorities: [USER]
    }
  ) {
    id
    email
    authorities
  }
}

HTTP Headers

{
  "Authorization": "Bearer [TOKEN FROM LOGIN]"
}