Cats

Introduction In a previous article, I demonstrated a simple application using Cats and Cats Effect. We used an approach where errors were not explicitly represented in the API types.This approach works well for small services with simple APIs. Our final service was defined like this: 1 2 3 4 5 6 7 8 9 trait UserService[F[_]] { def createUser(userCreate: UserCreate): F[UserResponse] def login(loginRequest: LoginRequest): F[AuthResponse] def refreshTokens(refreshToken: String): F[AuthResponse] def getUser(id: UUID): F[UserResponse] def updateUserStatus(id: UUID, isActive: Boolean): F[Boolean] def validateUserForAccess(token: String): F[User] def listActiveUsers(offset: Long, count: Long): F[List[UserResponse]] } We used the Raise/Handle approach, and our error model was defined as a sealed trait hierarchy (though one could use enums as well). ...

Introduction In this article, we’ll build a simple application using the Cats ecosystem. The application will expose a REST API for user management, including an OpenAPI documentation endpoint. Some endpoints will require JWT token authentication, also we’ll use the Bcrypt library to generate password hashes. We’ll demonstrate both unit testing and integration testing using testcontainers to run a Postgres database in Docker. The GitHub repository for this project is available here. ...