SELECT and then return the result or insert the new row and then return the result

[Eugene Dzhurinsky]

Hello!

I'm pretty new to Slick, and I am trying to figure out what would be the best way to combine SELECT and INSERT actions w/o an external execution context, to resemble this:

- SELECT something FROM table1 JOIN table 2 .....

- if there is a record - then return the wrapped case class

- if there is no record - then create a new case class instance and insert it into the database, then return the newly created object

I guess that I can implement that with the map/flatMap and collect, but those require the execution context passed from external, and I don't really want to pollute my DAO metods with the context, I need to return just an instance of Future[X]

Thanks!

[Eugene Dzhurinsky]

So far I've got something like:

      override def findCredentialsOrRegister(oauthCredentials: OAuth): Future[User] = {


        val userFound = (for (
          creds ← oauthTable.filter(x ⇒ x.service === oauthCredentials.service && x.serviceId === oauthCredentials.serviceId);
          user ← userTable.filter(x ⇒ x.username === creds.username)
        ) yield user).result




        val authenticate = userFound.flatMap {
          case Seq(user) ⇒
            DBIO.from(Future.successful(user))
          case Seq() ⇒
            val newUUID = UUID.randomUUID
            val user = User(newUUID.toString, UUID.randomUUID().toString, Instant.now())
            DBIO.seq(
              userTable += user,
              oauthTable += oauthCredentials.copy(username = newUUID.toString)
            ) andThen DBIO.from(Future.successful(user))
        }


        db.run(authenticate)
      }

Doesn't really seem to be a clean & idiomatic solution.