Use Scala macros to generate your RESTy models
Let's say you have the following User model in your business layer:
case class User(id: Int, name: String, email: String, registeredOn: DateTime)But, now you want to create well-formed models to describe the requests/responses of your HTTP REST APIs:
// Response to GET /users/$id (Retrieve an existing user) case class UserGet(id: Int, name: String, email: String) // Request body of POST /users (Create a new user) case class UserPost(name: String, email: String) //Request body of PATCH /users/$id (Edit name of an existing user) case class UserPatch(name: Option[String])That is a lot of boilerplate! Keeping all these request models in sync with your business model and/or adding/removing fields quickly becomes tedious for more complicated models. With MetaRest, all you need to do is:
import com.github.pathikrit.metarest._ @Resource case class User( @get id : Int, @get @post @patch name : String, @get @post email : String, registeredOn : DateTime )The above annotated code would generate code essentially looking like this:
object User { case class Get(id: Int, name: String, email: String) case class Post(name: String, email: String) case class Patch(name: Option[String]) // Note: all fields in a PATCH are optional }Now, you can have a well defined CRUD interface for your API:
trait UserRepo { def getAll: List[User.Get] def get(id: Int): User.Get def create(request: User.Post): User.Get def replace(id: Int, request: User.Put): User.Get def update(id: Int, request: User.Patch): User.Get def delete(id: Int): User.Get }sbt
In your build.sbt, add the following entries:
resolvers += Resolver.bintrayRepo("pathikrit", "maven") libraryDependencies += "com.github.pathikrit" %% "metarest" % "2.0.0" addCompilerPlugin("org.scalameta" % "paradise" % "3.0.0-M8" cross CrossVersion.full)Although this library currently only supports Scala 2.11+, older versions of this library that used to support Scala 2.10.x are available here.