Move circe codecs to the core module

build.sbt

@@ -57,13 +57,14 @@ lazy val core = crossProject(JSPlatform, JVMPlatform)
   .settings(
     testFrameworks := Seq(new TestFramework("zio.test.sbt.ZTestFramework")),
     libraryDependencies ++= Seq(
-      "com.lihaoyi"    %%% "fastparse"    % "2.1.3",
-      "com.propensive" %%% "magnolia"     % "0.12.2",
-      "com.propensive" %%% "mercator"     % "0.2.1",
-      "dev.zio"        %%% "zio"          % "1.0.0-RC17",
-      "dev.zio"        %%% "zio-streams"  % "1.0.0-RC17",
-      "dev.zio"        %%% "zio-test"     % "1.0.0-RC17" % "test",
-      "dev.zio"        %%% "zio-test-sbt" % "1.0.0-RC17" % "test",
+      "com.lihaoyi"    %%% "fastparse"        % "2.1.3",
+      "com.propensive" %%% "magnolia"         % "0.12.2",
+      "com.propensive" %%% "mercator"         % "0.2.1",
+      "dev.zio"        %%% "zio"              % "1.0.0-RC17",
+      "dev.zio"        %%% "zio-streams"      % "1.0.0-RC17",
+      "dev.zio"        %%% "zio-test"         % "1.0.0-RC17" % "test",
+      "dev.zio"        %%% "zio-test-sbt"     % "1.0.0-RC17" % "test",
+      "io.circe"       %%% "circe-derivation" % "0.12.0-M7" % Optional,
       compilerPlugin("com.olegpy" %% "better-monadic-for" % "0.3.1")
     )
   )
@@ -103,7 +104,6 @@ lazy val http4s = project
       "org.http4s"    %% "http4s-circe"        % "0.21.0-M5",
       "org.http4s"    %% "http4s-blaze-server" % "0.21.0-M5",
       "io.circe"      %% "circe-parser"        % "0.12.3",
-      "io.circe"      %% "circe-derivation"    % "0.12.0-M7",
       compilerPlugin(
         ("org.typelevel" %% "kind-projector" % "0.11.0")
           .cross(CrossVersion.full)

core/src/main/scala/caliban/GraphQLRequest.scala

@@ -0,0 +1,25 @@
+package caliban
+
+import caliban.interop.circe._
+
+import scala.language.higherKinds
+
+/**
+ * Represents a GraphQL request, containing a query, an operation name and a map of variables.
+ */
+case class GraphQLRequest(
+  query: String,
+  operationName: Option[String],
+  variables: Option[Map[String, InputValue]]
+)
+
+object GraphQLRequest {
+  implicit def circeDecoder[F[_]: IsCirceDecoder]: F[GraphQLRequest] =
+    GraphQLRequestCirce.graphQLRequestDecoder.asInstanceOf[F[GraphQLRequest]]
+}
+
+private object GraphQLRequestCirce {
+  import io.circe._
+  import io.circe.derivation._
+  val graphQLRequestDecoder: Decoder[GraphQLRequest] = deriveDecoder[GraphQLRequest]
+}

core/src/main/scala/caliban/GraphQLResponse.scala

@@ -1,6 +1,28 @@
 package caliban
 
+import caliban.interop.circe._
+
+import scala.language.higherKinds
+
 /**
  * Represents the result of a GraphQL query, containing a data object and a list of errors.
  */
 case class GraphQLResponse[+E](data: ResponseValue, errors: List[E])
+
+object GraphQLResponse {
+  implicit def circeEncoder[F[_]: IsCirceEncoder, E]: F[GraphQLResponse[E]] =
+    GraphQLResponceCirce.graphQLResponseEncoder.asInstanceOf[F[GraphQLResponse[E]]]
+}
+
+private object GraphQLResponceCirce {
+  import io.circe._
+  import io.circe.syntax._
+  val graphQLResponseEncoder: Encoder[GraphQLResponse[CalibanError]] = Encoder
+    .instance[GraphQLResponse[CalibanError]](
+      response =>
+        Json.obj(
+          "data"   -> response.data.asJson,
+          "errors" -> Json.fromValues(response.errors.map(err => Json.fromString(err.toString)))
+        )
+    )
+}

core/src/main/scala/caliban/Value.scala

@@ -1,8 +1,12 @@
 package caliban
 
-import scala.util.Try
+import caliban.Value._
+import caliban.interop.circe._
 import zio.stream.Stream
 
+import scala.language.higherKinds
+import scala.util.Try
+
 sealed trait InputValue
 sealed trait ResponseValue
 sealed trait Value extends InputValue with ResponseValue
@@ -89,6 +93,9 @@ object InputValue {
   case class ListValue(values: List[InputValue])          extends InputValue
   case class ObjectValue(fields: Map[String, InputValue]) extends InputValue
   case class VariableValue(name: String)                  extends InputValue
+
+  implicit def circeDecoder[F[_]: IsCirceDecoder]: F[InputValue] =
+    ValueCirce.inputValueDecoder.asInstanceOf[F[InputValue]]
 }
 
 object ResponseValue {
@@ -102,4 +109,47 @@ object ResponseValue {
   case class StreamValue(stream: Stream[Throwable, ResponseValue]) extends ResponseValue {
     override def toString: String = "<stream>"
   }
+
+  implicit def circeEncoder[F[_]](implicit ev: IsCirceEncoder[F]): F[ResponseValue] =
+    ValueCirce.responseValueEncoder.asInstanceOf[F[ResponseValue]]
+}
+
+private object ValueCirce {
+  import io.circe._
+  private def jsonToValue(json: Json): InputValue =
+    json.fold(
+      NullValue,
+      BooleanValue,
+      number =>
+        number.toBigInt.map(IntValue.apply) orElse
+          number.toBigDecimal.map(FloatValue.apply) getOrElse
+          FloatValue(number.toDouble),
+      StringValue,
+      array => InputValue.ListValue(array.toList.map(jsonToValue)),
+      obj => InputValue.ObjectValue(obj.toMap.map { case (k, v) => k -> jsonToValue(v) })
+    )
+  val inputValueDecoder: Decoder[InputValue] = Decoder.instance(hcursor => Right(jsonToValue(hcursor.value)))
+  val responseValueEncoder: Encoder[ResponseValue] = Encoder
+    .instance[ResponseValue]({
+      case NullValue => Json.Null
+      case v: IntValue =>
+        v match {
+          case IntValue.IntNumber(value)    => Json.fromInt(value)
+          case IntValue.LongNumber(value)   => Json.fromLong(value)
+          case IntValue.BigIntNumber(value) => Json.fromBigInt(value)
+        }
+      case v: FloatValue =>
+        v match {
+          case FloatValue.FloatNumber(value)      => Json.fromFloatOrNull(value)
+          case FloatValue.DoubleNumber(value)     => Json.fromDoubleOrNull(value)
+          case FloatValue.BigDecimalNumber(value) => Json.fromBigDecimal(value)
+        }
+      case StringValue(value)              => Json.fromString(value)
+      case BooleanValue(value)             => Json.fromBoolean(value)
+      case EnumValue(value)                => Json.fromString(value)
+      case ResponseValue.ListValue(values) => Json.arr(values.map(responseValueEncoder.apply): _*)
+      case ResponseValue.ObjectValue(fields) =>
+        Json.obj(fields.map { case (k, v) => k -> responseValueEncoder.apply(v) }: _*)
+      case s: ResponseValue.StreamValue => Json.fromString(s.toString)
+    })
 }

core/src/main/scala/caliban/interop/circe/circe.scala

@@ -0,0 +1,23 @@
+package caliban.interop.circe
+
+import io.circe._
+
+import scala.language.higherKinds
+
+/**
+ * This class is an implementation of the pattern described in https://blog.7mind.io/no-more-orphans.html
+ * It makes it possible to mark circe dependency as optional and keep Encoders defined in the companion object.
+ */
+private[caliban] trait IsCirceEncoder[F[_]]
+private[caliban] object IsCirceEncoder {
+  implicit val isCirceEncoder: IsCirceEncoder[Encoder] = null
+}
+
+/**
+ * This class is an implementation of the pattern described in https://blog.7mind.io/no-more-orphans.html
+ * It makes it possible to mark circe dependency as optional and keep Decoders defined in the companion object.
+ */
+private[caliban] trait IsCirceDecoder[F[_]]
+private[caliban] object IsCirceDecoder {
+  implicit val isCirceDecoder: IsCirceDecoder[Decoder] = null
+}

core/src/test/scala/caliban/GraphQLRequestSpec.scala

@@ -0,0 +1,21 @@
+package caliban
+
+import io.circe._
+import zio.test.Assertion._
+import zio.test._
+
+object GraphQLRequestSpec
+    extends DefaultRunnableSpec(
+      suite("GraphQLRequestSpec")(
+        test("can be parsed from JSON") {
+          val request = Json
+            .obj("query" -> Json.fromString("{}"), "operationName" -> Json.fromString("op"), "variables" -> Json.obj())
+          assert(
+            request.as[GraphQLRequest],
+            isRight(
+              equalTo(GraphQLRequest(query = "{}", operationName = Some("op"), variables = Some(Map.empty)))
+            )
+          )
+        }
+      )
+    )

core/src/test/scala/caliban/GraphQLResponseSpec.scala

@@ -0,0 +1,20 @@
+package caliban
+
+import caliban.Value._
+import io.circe._
+import io.circe.syntax._
+import zio.test.Assertion._
+import zio.test._
+
+object GraphQLResponseSpec
+    extends DefaultRunnableSpec(
+      suite("GraphQLResponseSpec")(
+        test("can be converted to JSON") {
+          val response = GraphQLResponse(StringValue("data"), Nil)
+          assert(
+            response.asJson,
+            equalTo(Json.obj("data" -> Json.fromString("data"), "errors" -> Json.arr()))
+          )
+        }
+      )
+    )

http4s/src/main/scala/caliban/Http4sAdapter.scala

@@ -7,7 +7,6 @@ import cats.effect.Effect
 import cats.effect.syntax.all._
 import cats.~>
 import fs2.{ Pipe, Stream }
-import io.circe.derivation.deriveDecoder
 import io.circe._
 import io.circe.parser._
 import io.circe.syntax._
@@ -17,68 +16,16 @@ import org.http4s.dsl.Http4sDsl
 import org.http4s.server.websocket.WebSocketBuilder
 import org.http4s.websocket.WebSocketFrame
 import org.http4s.websocket.WebSocketFrame.Text
-import zio.interop.catz._
 import zio._
+import zio.interop.catz._
 
 object Http4sAdapter {
 
-  case class GraphQLRequest(query: String, operationName: Option[String], variables: Option[Json] = None)
-
-  implicit val queryDecoder: Decoder[GraphQLRequest] = deriveDecoder[GraphQLRequest]
-
-  private def responseToJson(responseValue: ResponseValue): Json =
-    responseValue match {
-      case NullValue => Json.Null
-      case v: IntValue =>
-        v match {
-          case IntValue.IntNumber(value)    => Json.fromInt(value)
-          case IntValue.LongNumber(value)   => Json.fromLong(value)
-          case IntValue.BigIntNumber(value) => Json.fromBigInt(value)
-        }
-      case v: FloatValue =>
-        v match {
-          case FloatValue.FloatNumber(value)      => Json.fromFloatOrNull(value)
-          case FloatValue.DoubleNumber(value)     => Json.fromDoubleOrNull(value)
-          case FloatValue.BigDecimalNumber(value) => Json.fromBigDecimal(value)
-        }
-      case StringValue(value)  => Json.fromString(value)
-      case BooleanValue(value) => Json.fromBoolean(value)
-      case EnumValue(value)    => Json.fromString(value)
-      case ListValue(values)   => Json.arr(values.map(responseToJson): _*)
-      case ObjectValue(fields) => Json.obj(fields.map { case (k, v) => k -> responseToJson(v) }: _*)
-      case s: StreamValue      => Json.fromString(s.toString)
-    }
-
-  implicit def responseEncoder[E]: Encoder[GraphQLResponse[E]] =
-    (response: GraphQLResponse[E]) =>
-      Json.obj(
-        "data"   -> responseToJson(response.data),
-        "errors" -> Json.fromValues(response.errors.map(err => Json.fromString(err.toString)))
-      )
-
-  private def jsonToValue(json: Json): InputValue =
-    json.fold(
-      NullValue,
-      BooleanValue,
-      number =>
-        number.toBigInt.map(IntValue.apply) orElse
-          number.toBigDecimal.map(FloatValue.apply) getOrElse
-          FloatValue(number.toDouble),
-      StringValue,
-      array => InputValue.ListValue(array.toList.map(jsonToValue)),
-      obj => InputValue.ObjectValue(obj.toMap.map { case (k, v) => k -> jsonToValue(v) })
-    )
-
-  private def jsonToVariables(json: Json): Map[String, InputValue] = jsonToValue(json) match {
-    case InputValue.ObjectValue(fields) => fields
-    case _                              => Map()
-  }
-
   private def execute[R, Q, M, S, E](
     interpreter: GraphQL[R, Q, M, S, E],
     query: GraphQLRequest
   ): URIO[R, GraphQLResponse[E]] =
-    interpreter.execute(query.query, query.operationName, query.variables.map(jsonToVariables).getOrElse(Map()))
+    interpreter.execute(query.query, query.operationName, query.variables.getOrElse(Map()))
 
   def makeRestService[R, Q, M, S, E](interpreter: GraphQL[R, Q, M, S, E]): HttpRoutes[RIO[R, *]] = {
     object dsl extends Http4sDsl[RIO[R, *]]
@@ -137,7 +84,7 @@ object Http4sAdapter {
                       case Some(query) =>
                         val operationName = payload.downField("operationName").success.flatMap(_.value.asString)
                         (for {
-                          result <- execute(interpreter, GraphQLRequest(query, operationName))
+                          result <- execute(interpreter, GraphQLRequest(query, operationName, None))
                           _ <- result.data match {
                                 case ObjectValue((fieldName, StreamValue(stream)) :: Nil) =>
                                   stream.foreach { item =>