json-macro is an attempt at a scalameta macro for play-json that avoids the overhead of play-json's functional syntax. See this blog post for details.
Compatibility is currently tested against play-json 2.6.0-M1. That means it is compatible with play-json 2.5.x as well but that is mostly incidental. Once 2.6.x becomes final I plan to support the latest stable release of play-json moving forward. Any version that has the same Reads/Writes API should automatically be supported by json-macro.
Add the follow to your build.sbt:
resolvers += Resolver.bintrayRepo("gregghz", "gregghz")
addCompilerPlugin("org.scalameta" % "paradise" % "3.0.0-beta4" cross CrossVersion.full)
libraryDependencies += "com.gregghz" %% "json-macro" % "0.1.0"
In contrast with Play's Json.format[A] macro, json-macro has to use an annotation until #160 is resolved:
import com.gregghz.json._
@JsonRecord
case class Thing(a: String)
This will expand into roughly the following code:
case class Thing(a: String)
object Thing {
implicit val reads: Reads[Thing] = Reads[Thing] { json =>
for {
a <- (json \ "a").validate[String]
} yield Thing(a)
}
implicit val writes: Writes[Thing] = Writes[Thing] { obj =>
Json.obj(
"a" -> obj.a
)
}
}
You can also override the keys used in the serialized json:
import com.gregghz.json._
@JsonRecord
case class Thing(a: String ~ hello)
This will expand into the following:
case class Thing(a: String)
object Thing {
implicit val reads: Reads[Thing] = Reads[Thing] { json =>
for {
a <- (json \ "hello").validate[String]
} yield Thing(a)
}
implicit val writes: Writes[Thing] = Writes[Thing] { obj =>
Json.obj(
"hello" -> obj.a
)
}
}