Levijatanu Levijatanu - 2 months ago 9
Scala Question

EvolutionsComponents in compile-time dependency injection play project

Im trying to understand how to run evolutions using compile-time DI.

import play.api.ApplicationLoader.Context
import play.api.cache.EhCacheComponents
import play.api.mvc.EssentialFilter
import play.api.routing.Router
import play.api._
import play.api.db.evolutions.{ DynamicEvolutions, EvolutionsComponents}
import play.filters.gzip.GzipFilter
import router.Routes

class AppLoader extends ApplicationLoader {
override def load(context: Context): Application = {
LoggerConfigurator(context.environment.classLoader).foreach(_.configure(context.environment))
new AppComponents(context).application
}


}

class AppComponents(context: Context) extends BuiltInComponentsFromContext(context) with EhCacheComponents with EvolutionsComponents {

lazy val applicationController = new controllers.Application(defaultCacheApi)
lazy val usersController = new controllers.Users(defaultCacheApi)
lazy val assets = new controllers.Assets(httpErrorHandler)

applicationEvolutions

// Routes is a generated class
override def router: Router = new Routes(httpErrorHandler, applicationController, usersController, assets)

val gzipFilter = new GzipFilter(shouldGzip =
(request, response) => {
val contentType = response.header.headers.get("Content-Type")
contentType.exists(_.startsWith("text/html")) || request.path.endsWith("jsroutes.js")
})

override lazy val httpFilters: Seq[EssentialFilter] = Seq(gzipFilter)


}


But I keep getting error
Error:(19, 7) class AppComponents needs to be abstract, since method dbApi in trait EvolutionsComponents of type => play.api.db.DBApi is not defined
class AppComponents(context: Context) extends BuiltInComponentsFromContext(context) with EhCacheComponents with EvolutionsComponents

I'am newbie in Scala.

Answer

dbApi comes from the DBComponents trait, so your AppComponents class needs to also extend DBComponents.