akka-http avro marshalling/unmarshalling for generated java avro specific records

After the akka licencing change, no further development is expected on akka-http-avro. If you're migrating to pekko-http, see pekko-http-avro.

The complete list can be found in the CHANGELOG file.

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

libraryDependencies += "fr.davit" %% "akka-http-avro" % <version>

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

{
  "namespace": "com.example",
  "type": "record",
  "name": "Item",
  "fields": [
    {
      "name": "name",
      "type": "string"
    },
    {
      "name": "id",
      "type": "long"
    }
  ]
}

and

{
  "namespace": "com.example",
  "type": "record",
  "name": "Order",
  "fields": [
    {
      "name": "items",
      "type": {
        "type" : "array",
        "items": "com.example.Item"
      }
    }
  ]
}

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

• Content-Type: application/json: json
• Content-Type: avro/binary: binary

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

The implicit marshallers and unmarshallers for your generated avro classes are defined in AvroSupport. Specific (un)marshallers can be imported from AvroBinarySupport, AvroJsonSupport. You simply need to have them in scope.

import akka.http.scaladsl.server.Directives._
import fr.davit.akka.http.scaladsl.marshallers.avro.AvroSupport._


object MyAvroService {

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

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