scalapb-circe
Dependency
Include in your build.sbt file
core
libraryDependencies += "io.github.scalapb-json" %% "scalapb-circe" % "0.12.1"for scala-js or scala-native
libraryDependencies += "io.github.scalapb-json" %%% "scalapb-circe" % "0.12.1"macros
libraryDependencies += "io.github.scalapb-json" %% "scalapb-circe-macros" % "0.12.1"Usage
JsonFormat
There are four functions you can use directly to serialize/deserialize your messages:
JsonFormat.toJsonString(msg) // returns String
JsonFormat.toJson(msg) // returns Json
JsonFormat.fromJsonString(str) // return MessageType
JsonFormat.fromJson(json) // return MessageTypeImplicit Circe Codecs
You can also import codecs to support Circe's implicit syntax for objects of type GeneratedMessage and GeneratedEnum.
Assume a proto message:
message Guitar {
int32 number_of_strings = 1;
}import io.circe.syntax._
import io.circe.parser._
import scalapb_circe.codec._
Guitar(42).asJson.noSpaces // returns {"numberOfStrings":42}
decode[Guitar]("""{"numberOfStrings": 42}""") // returns Right(Guitar(42))
Json.obj("numberOfStrings" -> Json.fromInt(42)).as[Guitar] // returns Right(Guitar(42))You can define an implicit scalapb_circe.Printer and/or scalapb_circe.Parser to control printing and parsing settings.
For example, to include default values in Json:
import io.circe.syntax._
import io.circe.parser._
import scalapb_circe.codec._
import scalapb_circe.Printer
implicit val p: Printer = new Printer(includingDefaultValueFields = true)
Guitar(0).asJson.noSpaces // returns {"numberOfStrings": 0}Finally, you can include scalapb GeneratedMessage and GeneratedEnums in regular case classes with semi-auto derivation:
import io.circe.generic.semiauto._
import io.circe.syntax._
import io.circe._
import scalapb_circe.codec._ // IntelliJ might say this is unused.
case class Band(guitars: Seq[Guitar])
object Band {
implicit val dec: Decoder[Band] = deriveDecoder[Band]
implicit val enc: Encoder[Band] = deriveEncoder[Band]
}
Band(Seq(Guitar(42))).asJson.noSpaces // returns {"guitars":[{"numberOfStrings":42}]}