Scala Slick compose column type mappers - postgresql

Question

I'm using slick-pg which adds support(with implicits) for the List and DateTime types in slick.
Unfortunately I cannot use List[DateTime] - slick does not understand composition of those types, but I've checked that both work correctly on their own(for example List[Int] and DateTime).
Is there a way to easily compose those two implicits?

Answer 1

1. Try to add
implicit def dateTimeList =
MappedColumnType.base[List[DateTime], List[Timestamp]](
_.map(dt => new Timestamp(dt.getMillis)),
_.map(ts => new DateTime(ts.getTime))
)
Just in case, the whole code that compiles:
import java.sql.Timestamp
import org.joda.time.DateTime
import slick.jdbc.PostgresProfile.api._
import slick.lifted.ProvenShape
import slick.basic.Capability
import slick.jdbc.JdbcCapabilities
import com.github.tototoshi.slick.PostgresJodaSupport._
import com.github.tminglei.slickpg._
object App {
trait MyPostgresProfile extends ExPostgresProfile
with PgArraySupport
with PgDate2Support
with PgRangeSupport
with PgHStoreSupport
// with PgPlayJsonSupport
with PgSearchSupport
// with PgPostGISSupport
with PgNetSupport
with PgLTreeSupport {
def pgjson = "jsonb" // jsonb support is in postgres 9.4.0 onward; for 9.3.x use "json"
// Add back `capabilities.insertOrUpdate` to enable native `upsert` support; for postgres 9.5+
override protected def computeCapabilities: Set[Capability] =
super.computeCapabilities + /*JdbcProfile.capabilities.insertOrUpdate*/ JdbcCapabilities.insertOrUpdate
override val api = MyAPI
object MyAPI extends API with ArrayImplicits
with DateTimeImplicits
// with JsonImplicits
with NetImplicits
with LTreeImplicits
with RangeImplicits
with HStoreImplicits
with SearchImplicits
with SearchAssistants {
implicit val strListTypeMapper = new SimpleArrayJdbcType[String]("text").to(_.toList)
// implicit val playJsonArrayTypeMapper =
// new AdvancedArrayJdbcType[JsValue](pgjson,
// (s) => utils.SimpleArrayUtils.fromString[JsValue](Json.parse(_))(s).orNull,
// (v) => utils.SimpleArrayUtils.mkString[JsValue](_.toString())(v)
// ).to(_.toList)
}
}
object MyPostgresProfile extends MyPostgresProfile
import MyPostgresProfile.api._
// This can be used instead of slick-joda-mapper library
// implicit def dateTime =
// MappedColumnType.base[DateTime, Timestamp](
// dt => new Timestamp(dt.getMillis),
// ts => new DateTime(ts.getTime)
// )
implicit def dateTimeList =
MappedColumnType.base[List[DateTime], List[Timestamp]](
_.map(dt => new Timestamp(dt.getMillis)),
_.map(ts => new DateTime(ts.getTime))
)
case class Record(id: Int, name: String, friends: List[Int], registered: DateTime, visits: List[DateTime])
class RecordTable(tag: Tag) extends Table[Record](tag, Some("public"), "records") {
def id: Rep[Int] = column[Int]("id", O.PrimaryKey, O.AutoInc)
def name: Rep[String] = column[String]("name")
def friends: Rep[List[Int]] = column[List[Int]]("friends")
def registered: Rep[DateTime] = column[DateTime]("registered")
def visits: Rep[List[DateTime]] = column[List[DateTime]]("visits")
def * : ProvenShape[Record] = (id, name, friends, registered, visits) <> (Record.tupled, Record.unapply)
}
val records: TableQuery[RecordTable] = TableQuery[RecordTable]
}
build.sbt
name := "slickdemo"
version := "0.1"
scalaVersion := "2.12.3"
libraryDependencies += "com.typesafe.slick" %% "slick" % "3.2.1"
libraryDependencies += "org.slf4j" % "slf4j-nop" % "1.7.25"
libraryDependencies += "com.typesafe.slick" %% "slick-hikaricp" % "3.2.1"
libraryDependencies += "org.postgresql" % "postgresql" % "42.1.4"
libraryDependencies += "com.github.tminglei" %% "slick-pg" % "0.15.3"
libraryDependencies += "joda-time" % "joda-time" % "2.9.9"
libraryDependencies += "org.joda" % "joda-convert" % "1.9.2"
libraryDependencies += "com.github.tototoshi" % "slick-joda-mapper_2.12" % "2.3.0"
Based on answer and documentation.
2. Alternatively you can add
implicit val dateTimeArrayTypeMapper =
new AdvancedArrayJdbcType[DateTime]("timestamp",
(s) => utils.SimpleArrayUtils.fromString[DateTime](DateTime.parse)(s).orNull,
(v) => utils.SimpleArrayUtils.mkString[DateTime](_.toString)(v)
).to(_.toList)
after strListTypeMapper and playJsonArrayTypeMapper.