Scala Play Framework Slick session doesn't work - scala

Question

I'm trying a simple test application with Slick and the Play2 Framework, but the compiler keeps complaining the implicit session cannot be inferred.
Here is my Build.scala:
import sbt._
import Keys._
import play.Project._
object ApplicationBuild extends Build {
val appName = "dummy"
val appVersion = "1.0"
val appDependencies = Seq(
jdbc,
"mysql" % "mysql-connector-java" % "5.1.26",
"com.typesafe.slick" %% "slick" % "1.0.1"
)
val main = play.Project(appName, appVersion, appDependencies).settings(
// Add your own project settings here
)
}
And this is my Global singleton that holds my database connections:
package models
import play.api.Play.current
import play.api.db.DB
import slick.session.Session
import slick.driver.MySQLDriver.simple._
import scala.slick.session.Database.threadLocalSession
object Global {
lazy val database = Database.forDataSource(DB.getDataSource())
lazy val session = database.createSession()
}
And my controller:
package controllers
import scala.language.implicitConversions
import play.api._
import play.api.mvc._
import models.Global.session
import slick.driver.MySQLDriver.simple._
object Application extends Controller {
def index = Action {
/*slick.driver.MySQLDriver.simple.*/Query(Foo).foreach( _ => () ) // Do nothing for now
Ok(views.html.index("hola"))
}
object Foo extends Table[(Long, String, String)]("Foo") {
def * = column[Long]("id") ~ column[String]("bar1") ~ column[String]("bar2")
}
}
As you can see my Global.session val is imported, but it keeps saying no implicit session was found.

Answer 1

To make queries you need two things: connection to the database and a session, so your problem is how you define and use them.
With Database.threadLocalSession in scope, you can make your queries like this :
Database.forURL("jdbc:h2:mem:play", driver = "org.h2.Driver") withSession {
//create table
Foo.ddl.create
//insert data
Foo.insert((1.toLong,"foo","bar"))
//get data
val data : (Long,String,String) = (for{f<-Foo}yield(f)).first
}
or you can do it like this:
val database = Database.forDataSource(DB.getDataSource())
database.withSession{ implicit session : Session =>
Foo.ddl.create
Foo.insert((1.toLong,"foo","bar"))
val data : (Long,String,String) = (for{f<-Foo}yield(f)).first
}
I have create a test and it works fine, you can play with it:
"Foo should be creatable " in {
running(FakeApplication(additionalConfiguration = inMemoryDatabase())) {
val database = Database.forDataSource(DB.getDataSource())
database.withSession{ implicit session : Session =>
Foo.ddl.create
Foo.insert((1.toLong,"foo","bar"))
val data : (Long,String,String) = (for{f<-Foo}yield(f)).first
data._1 must equalTo(1)
}
}
}
Also you may look at here