Add service transformation utils (#1644)

CHANGELOG.md

@@ -5,6 +5,10 @@ When adding entries, please treat them as if they could end up in a release any
 
 Thank you!
 
+# 0.18.30
+
+* Add utilities for Service.Builder in [#1644](https://github.com/disneystreaming/smithy4s/pull/1644)
+
 # 0.18.29
 
 * Fix for decoding of required nullable fields and some combinations of refinements with nullable fields (see [#1637](https://github.com/disneystreaming/smithy4s/pull/1637))

modules/bootstrapped/test/src/smithy4s/builder/ServiceBuilderSpec.scala

@@ -20,12 +20,14 @@ import munit._
 import smithy4s.kinds.PolyFunction5
 import smithy4s.example.FooServiceGen
 import smithy.api.Documentation
+import smithy4s.schema.OperationSchema
+import smithy4s.kinds.PolyFunction
 
 class ServiceBuilderSpec extends FunSuite {
 
   val service = smithy4s.example.FooService
 
-  val builder = smithy4s.Service.Builder.fromService(service)
+  val builder = service.toBuilder
 
   test(
     "can replace the following values (Id, Version and Hints) using withId, withVersion, withHints"
@@ -91,4 +93,30 @@ class ServiceBuilderSpec extends FunSuite {
     )
   }
 
+  test("can easily transform endpoint's inputs using schema PolyFunctions") {
+
+    val fk = new PolyFunction[Schema, Schema] {
+      def apply[A](schema: Schema[A]): Schema[A] =
+        schema.withId(schema.shapeId.withNamespace("replaced"))
+    }
+
+    val result = builder
+      .mapEndpointEach(
+        Endpoint.mapSchema(
+          OperationSchema
+            .mapInputK(fk)
+            .andThen(
+              OperationSchema.mapOutputK(fk)
+            )
+        )
+      )
+      .build
+
+    val namespaces =
+      result.endpoints.map(_.input.shapeId.namespace).toSet ++
+        result.endpoints.map(_.output.shapeId.namespace).toSet
+
+    assert(namespaces == Set("replaced"))
+  }
+
 }

modules/core/src/smithy4s/Endpoint.scala

@@ -120,6 +120,13 @@ trait Endpoint[Op[_, _, _, _, _], I, E, O, SI, SO] { self =>
 
 object Endpoint {
 
+  def mapSchema[Op[_, _, _, _, _]](
+      f: PolyFunction5[OperationSchema, OperationSchema]
+  ): PolyFunction5[Endpoint[Op, *, *, *, *, *], Endpoint[Op, *, *, *, *, *]] =
+    new PolyFunction5[Endpoint[Op, *, *, *, *, *], Endpoint[Op, *, *, *, *, *]] {
+      def apply[I, E, O, SI, SO](fa: Endpoint[Op, I, E, O, SI, SO]): Endpoint[Op, I, E, O, SI, SO] = fa.mapSchema(f(_))
+    }
+
   trait Middleware[A] { self =>
     def prepare[Alg[_[_, _, _, _, _]]](service: Service[Alg])(endpoint: service.Endpoint[_, _, _, _, _]): A => A
     final def biject[B](to: A => B)(from: B => A): Middleware[B] = new Middleware[B] {

modules/core/src/smithy4s/Service.scala

@@ -203,6 +203,8 @@ trait Service[Alg[_[_, _, _, _, _]]] extends FunctorK5[Alg] with HasId {
     */
   final def fromBifunctorHandlers[F[_, _]](handlers: EndpointHandler[Operation, Kind2[F]#toKind5]*) : FromHandlers[Kind2[F]#toKind5]
     = fromHandlers[Kind2[F]#toKind5](handlers:_*)
+
+  final def toBuilder: Service.Builder[Alg, Operation] = Service.Builder.fromService(this)
 }
 
 object Service {

modules/core/src/smithy4s/ShapeId.scala

@@ -20,7 +20,11 @@ import smithy.api.IdRef
 
 final case class ShapeId(namespace: String, name: String) extends HasId {
   def show = s"$namespace#$name"
+
+  def withNamespace(namespace: String): ShapeId = copy(namespace = namespace)
+  def withName(name: String): ShapeId = copy(name = name)
   def withMember(member: String): ShapeId.Member = ShapeId.Member(this, member)
+
   override def toString = show
   override def id: ShapeId = this
 }

modules/core/src/smithy4s/schema/OperationSchema.scala

@@ -19,6 +19,8 @@ package smithy4s
 package schema
 
 import smithy4s.internals.InputOutput
+import smithy4s.kinds.PolyFunction5
+import smithy4s.kinds.PolyFunction
 
 final case class OperationSchema[I, E, O, SI, SO] private[smithy4s] (
     id: ShapeId,
@@ -96,3 +98,55 @@ final case class OperationSchema[I, E, O, SI, SO] private[smithy4s] (
     copy(streamedOutput = streamedOutput.map(f))
 
 }
+
+object OperationSchema {
+  def mapInputK(
+      fk: PolyFunction[Schema, Schema]
+  ): PolyFunction5[OperationSchema, OperationSchema] =
+    new PolyFunction5[OperationSchema, OperationSchema] {
+      def apply[I, E, O, SI, SO](
+          op: OperationSchema[I, E, O, SI, SO]
+      ): OperationSchema[I, E, O, SI, SO] =
+        op.mapInput(fk(_))
+    }
+
+  def mapOutputK(
+      fk: PolyFunction[Schema, Schema]
+  ): PolyFunction5[OperationSchema, OperationSchema] =
+    new PolyFunction5[OperationSchema, OperationSchema] {
+      def apply[I, E, O, SI, SO](
+          op: OperationSchema[I, E, O, SI, SO]
+      ): OperationSchema[I, E, O, SI, SO] =
+        op.mapOutput(fk(_))
+    }
+
+  def mapErrorK(
+      fk: PolyFunction[ErrorSchema, ErrorSchema]
+  ): PolyFunction5[OperationSchema, OperationSchema] =
+    new PolyFunction5[OperationSchema, OperationSchema] {
+      def apply[I, E, O, SI, SO](
+          op: OperationSchema[I, E, O, SI, SO]
+      ): OperationSchema[I, E, O, SI, SO] =
+        op.mapError(fk(_))
+    }
+
+  def mapStreamingInputK(
+      fk: PolyFunction[StreamingSchema, StreamingSchema]
+  ): PolyFunction5[OperationSchema, OperationSchema] =
+    new PolyFunction5[OperationSchema, OperationSchema] {
+      def apply[I, E, O, SI, SO](
+          op: OperationSchema[I, E, O, SI, SO]
+      ): OperationSchema[I, E, O, SI, SO] =
+        op.mapStreamedInput(fk(_))
+    }
+
+  def mapStreamingOutputK(
+      fk: PolyFunction[StreamingSchema, StreamingSchema]
+  ): PolyFunction5[OperationSchema, OperationSchema] =
+    new PolyFunction5[OperationSchema, OperationSchema] {
+      def apply[I, E, O, SI, SO](
+          op: OperationSchema[I, E, O, SI, SO]
+      ): OperationSchema[I, E, O, SI, SO] =
+        op.mapStreamedOutput(fk(_))
+    }
+}