Simple example of a mutation with complex input type argument

SangriaMutationExample.scala

import sangria.schema._
import sangria.execution._
import sangria.macros._
import sangria.macros.derive._
import sangria.marshalling.circe._
import scala.concurrent.ExecutionContext.Implicits.global
import io.circe.generic.auto._

// Some basic data structures

case class Author(name: String, publishedBooks: Int = 0)
case class Book(title: String, authors: Seq[Author])

// Stub repository to store the value

class Repo {
  private var storedBook: Option[Book] = None

  def saveBook(book: Book): Unit = {
    storedBook = Some(book)
  }

  def loadBook(): Option[Book] = storedBook
}

// Input object defined explicitly

implicit val AuthorInputType = InputObjectType[Author]("AuthorInput", List(
  InputField("name", StringType),
  InputField("publishedBooks", IntType, defaultValue = 0)))

// Input object derived with macro

implicit val BookInputType = deriveInputObjectType[Book](
  InputObjectTypeName("BookInput"))

// Output objects

implicit val AuthorType = deriveObjectType[Unit, Author]()
val BookType = deriveObjectType[Unit, Book]()

// Schema definition

val BookArg = Argument("book", BookInputType)

val QueryType = ObjectType("Query", fields[Repo, Unit](
  Field("book", OptionType(BookType), resolve = _.ctx.loadBook())))

val MutationType = ObjectType("Mutation", fields[Repo, Unit](
  Field("saveBook", OptionType(BookType),
    arguments = BookArg :: Nil,
    resolve = c ⇒ {
      val book = c arg BookArg

      c.ctx.saveBook(book)
      book
    })))

val schema = Schema(QueryType, Some(MutationType))

// Test query

val query =
  gql"""
    mutation {
      saveBook(book: {title: "Sapiens", authors: [{name: "Yuval Noah Harari", publishedBooks: 6}]}) {
        title
        authors {
          name
          publishedBooks
        }
      }
    }
  """

val context = new Repo

val result = Executor.execute(schema, query, context)

result.foreach(res ⇒ println(res.spaces2))

// Prints:
//
// {
//   "data" : {
//     "saveBook" : {
//       "title" : "Sapiens",
//       "authors" : [
//         {
//           "name" : "Yuval Noah Harari",
//           "publishedBooks" : 6
//         }
//       ]
//     }
//   }
// }

Thanks for the example. I just needed to add the JsonFormat to get it to work.

import play.api.libs.json._
import scala.concurrent.Future

  implicit val authorType = Json.format[Author]
  implicit val bookFormat = Json.format[Book]