akka-http-scalapb

akka-http protobuf and json marshalling/unmarshalling for ScalaPB messages

Versions

Version	Release date	Akka Http version	ScalaPB version	Scala versions
`0.2.5`	2022-02-06	`10.2.7`	`0.11.5` (`0.12.0` json4s)	`2.13.8`, `2.12.15`
`0.2.4`	2021-03-24	`10.2.4`	`0.11.0` (`0.11.0` json4s)	`2.13.5`, `2.12.13`
`0.2.3`	2020-09-18	`10.2.0`	`0.10.8` (`0.10.1` json4s)	`2.13.3`, `2.12.12`
`0.2.2`	2020-05-10	`10.1.11`	`0.10.3` (`0.10.1` json4s)	`2.13.2`, `2.12.11`
`0.2.1`	2019-07-13	`10.1.8`	`0.9.0` (`0.9.2` json4s)	`2.13.0`, `2.12.8`, `2.11.12`
`0.2.0`	2019-06-22	`10.1.8`	`0.9.0` (`0.9.2` json4s)	`2.13.0`, `2.12.8`, `2.11.12`
`0.1.0`	2019-01-27	`10.1.7`	`0.8.4` (`0.7.2` json4s)	`2.12.8`, `2.11.12`

The complete list can be found in the CHANGELOG file.

Getting akka-http-scalapb

Libraries are published to Maven Central. Add to your build.sbt:

libraryDependencies += "fr.davit" %% "akka-http-scalapb" % <version> // binary & json support

Quick start

For the examples, we are using the following proto domain model

message Item {
  string name = 1;
  int64 id    = 2;
}

message Order {
  reapeated Item items = 1;
}

The implicit marshallers and unmarshallers for your generated proto classes are defined in ScalaPBSupport. You simply need to have them in scope.

import akka.http.scaladsl.server.Directives._
import fr.davit.akka.http.scaladsl.marshallers.scalapb.ScalaPBSupport._

object MyProtoService {

  val route =
    get {
      pathSingleSlash {
        complete(Item("thing", 42))
      }
    } ~ post {
      entity(as[Order]) { order =>
        val itemsCount = order.items.size
        val itemNames = order.items.map(_.name).mkString(", ")
        complete(s"Ordered $itemsCount items: $itemNames")
      }
    }
}

Marshalling/Unmarshalling of the generated classes depends on the Accept/Content-Type header sent by the client:

Content-Type: application/json: json
Content-Type: application/x-protobuf: binary
Content-Type: application/x-protobuffer: binary
Content-Type: application/protobuf: binary
Content-Type: application/vnd.google.protobuf: binary

No Accept header or matching several (eg Accept: application/*) will take the 1st matching type from the above list.

Json only

If you are using scalaPB for json (un)marshalling only, you can use ScalaPBJsonSupport from the sub module

libraryDependencies += "fr.davit" %% "akka-http-scalapb-json4s" % <version> // json support only

Binary only

If you are using scalaPB for binary (un)marshalling only, you can use ScalaPBBinarySupport form the sub module

libraryDependencies += "fr.davit" %% "akka-http-scalapb-binary" % <version> // binary support only

Limitation

Only json (un)marshallers are able to support collections of proto messages as root object.

Entity streaming (http chunked transfer) is at the moment not supported by the library.

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