Magical Shapeless JsonFormats for spray-json
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


Automatically derive spray-json JsonFormats, powered by shapeless (no macros were written during the creation of this library).

For documentation, read the scaladocs and for examples read the test cases.

Please read the documentation and examples thoroughly before raising a ticket.


libraryDependencies += "com.github.fommil" %% "spray-json-shapeless" % "1.0.0"
import spray.json._
import fommil.sjs._

// your ADT here
package adt {
  sealed trait SimpleTrait
  case class Foo(s: String) extends SimpleTrait
  case class Bar() extends SimpleTrait
  case object Baz extends SimpleTrait
  case class Faz(o: Option[String]) extends SimpleTrait
object MyFormats extends DefaultJsonProtocol with FamilyFormats {
  // gives a slight performance boost, but isn't necessary
  implicit val MyAdtFormats = shapeless.cachedImplicit[JsonFormat[SimpleTrait]]
import MyFormats._

Foo("foo").toJson              // """{"s":"foo"}"""
Faz(Some("meh")).toJson        // """{"o":"meh"}"""
Faz(None).toJson               // "{}"
Foo("foo"): SimpleTrait.toJson // """{"type":"Foo","s":"foo"}"""
Bar(): SimpleTrait.toJson      // """{"type":"Bar"}"""
Baz: SimpleTrait.toJson        // """{"type":"Baz"}"""
Fuzz: SimpleTrait.toJson       // """{"type":"Fuzz"}"""


spray-json-shapeless is Free Software under the Apache License v2.

I would prefer a copyleft license because TypeSafe have set the precedent of closing sources and it is extremely concerning that this is happening within our community. The best way to fight back is by writing software with a license that guarantees your software's freedom.

I do not have a problem with anyone charging for software (I don't mind if something is not free as in gratis) but I abhor software which does not provide source code or allow me to change (i.e. fix it when it breaks, which it does almost always): free as in libre.

However, both of the primary upstream projects, spray-json and shapeless, are published under Apache v2, so it is more appropriate to publish this project on the same terms.