scanamo

Type Members

1. trait DerivedDynamoFormat extends AnyRef

   

2. trait DynamoFormat[T] extends Serializable

   

   Type class for defining serialisation to and from DynamoDB's AttributeValue

   Type class for defining serialisation to and from DynamoDB's AttributeValue

   >>> val listOptionFormat = DynamoFormat[List[Option[Int]]]
   >>> listOptionFormat.read(listOptionFormat.write(List(Some(1), None, Some(3))))
   Right(List(Some(1), None, Some(3)))

   Also supports automatic derivation for case classes

   >>> case class Farm(animals: List[String])
   >>> case class Farmer(name: String, age: Long, farm: Farm)
   >>> val farmerF = DynamoFormat[Farmer]
   >>> farmerF.read(farmerF.write(Farmer("McDonald", 156L, Farm(List("sheep", "cow")))))
   Right(Farmer(McDonald,156,Farm(List(sheep, cow))))

   and for sealed trait + case object hierarchies

   >>> sealed trait Animal
   >>> case object Aardvark extends Animal
   >>> case object Zebra extends Animal
   >>> case class Pet(name: String, animal: Animal)
   >>> val petF = DynamoFormat[Pet]
   >>> petF.read(petF.write(Pet("Amy", Aardvark)))
   Right(Pet(Amy,Aardvark))
   
   >>> petF.read(petF.write(Pet("Zebediah", Zebra)))
   Right(Pet(Zebediah,Zebra))

   Problems reading a value are detailed

   >>> import cats.syntax.either._
   
   >>> case class Developer(name: String, age: String, problems: Int)
   >>> val invalid = DynamoFormat[Farmer].read(DynamoFormat[Developer].write(Developer("Alice", "none of your business", 99)))
   >>> invalid
   Left(InvalidPropertiesError(NonEmptyList(PropertyReadError(age,NoPropertyOfType(N,{S: none of your business,})), PropertyReadError(farm,MissingProperty))))
   
   >>> invalid.leftMap(cats.Show[error.DynamoReadError].show)
   Left('age': not of type: 'N' was '{S: none of your business,}', 'farm': missing)

   Optional properties are defaulted to None

   >>> case class LargelyOptional(a: Option[String], b: Option[String])
   >>> DynamoFormat[LargelyOptional].read(DynamoFormat[Map[String, String]].write(Map("b" -> "X")))
   Right(LargelyOptional(None,Some(X)))

   Custom formats can often be most easily defined using DynamoFormat.coercedXmap, DynamoFormat.xmap or DynamoFormat.iso

3. trait EnumDynamoFormat extends DerivedDynamoFormat

   

   prop> sealed trait Animal
   prop> case object Aardvark extends Animal
   prop> case object Hippopotamus extends Animal
   prop> case object Zebra extends Animal
   
   prop> import org.scalacheck._
   prop> implicit val arbitraryAnimal: Arbitrary[Animal] = Arbitrary(Gen.oneOf(List(Aardvark, Hippopotamus, Zebra)))
   
   prop> (a: Animal) =>
       | DynamoFormat[Animal].read(DynamoFormat[Animal].write(a)) == Right(a)

   >>> DynamoFormat[Animal].write(Zebra).getS
   Zebra

4. abstract class EnumerationDynamoFormat[T] extends DynamoFormat[T]