codegen: Jsoniter support (#840)

build.sbt

@@ -1971,10 +1971,12 @@ lazy val openapiCodegenCore: ProjectMatrix = (projectMatrix in file("openapi-cod
       scalaOrganization.value % "scala-reflect" % scalaVersion.value,
       scalaOrganization.value % "scala-compiler" % scalaVersion.value % Test,
       "com.beachape" %% "enumeratum" % "1.7.3" % Test,
-      "com.beachape" %% "enumeratum-circe" % "1.7.3" % Test
+      "com.beachape" %% "enumeratum-circe" % "1.7.3" % Test,
+      "com.github.plokhotnyuk.jsoniter-scala" %% "jsoniter-scala-core" % "2.28.2" % Test,
+      "com.github.plokhotnyuk.jsoniter-scala" %% "jsoniter-scala-macros" % "2.28.2" % Provided
     )
   )
-  .dependsOn(core % Test, circeJson % Test)
+  .dependsOn(core % Test, circeJson % Test, jsoniterScala % Test)
 
 lazy val openapiCodegenSbt: ProjectMatrix = (projectMatrix in file("openapi-codegen/sbt-plugin"))
   .enablePlugins(SbtPlugin)

doc/generator/sbt-openapi-codegen.md

@@ -26,8 +26,8 @@ Add your OpenApi file to the project, and override the `openapiSwaggerFile` sett
 openapiSwaggerFile := baseDirectory.value / "swagger.yaml"
 ```
 
-At this point your compile step will try to generate the endpoint definitions 
-to the `sttp.tapir.generated.TapirGeneratedEndpoints` object, where you can access the 
+At this point your compile step will try to generate the endpoint definitions
+to the `sttp.tapir.generated.TapirGeneratedEndpoints` object, where you can access the
 defined case-classes and endpoint definitions.
 
 ## Usage and options
@@ -42,6 +42,7 @@ openapiSwaggerFile              baseDirectory.value / "swagger.yaml" The swagger
 openapiPackage                  sttp.tapir.generated                 The name for the generated package.
 openapiObject                   TapirGeneratedEndpoints              The name for the generated object.
 openapiUseHeadTagForObjectName  false                                If true, put endpoints in separate files based on first declared tag.
+openapiJsonSerdeLib             circe                                The json serde library to use.
 =============================== ==================================== =====================================================================
 ```
 
@@ -58,6 +59,7 @@ val docs = TapirGeneratedEndpoints.generatedEndpoints.toOpenAPI("My Bookshop", "
 ### Output files
 
 To expand on the `openapiUseHeadTagForObjectName` setting a little more, suppose we have the following endpoints:
+
 ```yaml
 paths:
   /foo:
@@ -66,33 +68,53 @@ paths:
         - Baz
         - Foo
     put:
-      tags: []
+      tags: [ ]
   /bar:
     get:
       tags:
         - Baz
         - Bar
 ```
-In this case 'head' tag for `GET /foo` and `GET /bar` would be 'Baz', and `PUT /foo` has no tags (and thus no 'head' tag).
 
-If `openapiUseHeadTagForObjectName = false` (assuming default settings for the other flags) then all endpoint definitions
-will be output to the `TapirGeneratedEndpoints.scala` file, which will contain a single `object TapirGeneratedEndpoints`.
+In this case 'head' tag for `GET /foo` and `GET /bar` would be 'Baz', and `PUT /foo` has no tags (and thus no 'head'
+tag).
+
+If `openapiUseHeadTagForObjectName = false` (assuming default settings for the other flags) then all endpoint
+definitions
+will be output to the `TapirGeneratedEndpoints.scala` file, which will contain a
+single `object TapirGeneratedEndpoints`.
 
 If `openapiUseHeadTagForObjectName = true`, then the  `GET /foo` and `GET /bar` endpoints would be output to a
 `Baz.scala` file, containing a single `object Baz` with those endpoint definitions; the `PUT /foo` endpoint, by dint of
 having no tags, would be output to the `TapirGeneratedEndpoints` file, along with any schema and parameter definitions.
 
-### Limitations
+### Json Support
 
-Currently, the generated code depends on `"io.circe" %% "circe-generic"`. In the future probably we will make the encoder/decoder json lib configurable (PRs welcome).
+```eval_rst
+===================== ================================================================== ===================================================================
+ openapiJsonSerdeLib         required dependencies                                       Conditional requirements
+===================== ================================================================== ===================================================================
+circe                 "io.circe" %% "circe-core"                                         "com.beachape" %% "enumeratum-circe" (scala 2 enum support).
+                      "io.circe" %% "circe-generic"                                      "org.latestbit" %% "circe-tagged-adt-codec" (scala 3 enum support).
+jsoniter              "com.github.plokhotnyuk.jsoniter-scala" %% "jsoniter-scala-core"
+                      "com.github.plokhotnyuk.jsoniter-scala" %% "jsoniter-scala-macros"
+===================== ================================================================== ===================================================================
+```
 
-String-like enums in Scala 2 depend on both `"com.beachape" %% "enumeratum"` and `"com.beachape" %% "enumeratum-circe"`.
-For Scala 3 we derive native enums, and depend on `"org.latestbit" %% "circe-tagged-adt-codec"` for json serdes and `"io.github.bishabosha" %% "enum-extensions"` for query param serdes.
+### Limitations
+
+Currently, string-like enums in Scala 2 depend upon the enumeratum library (`"com.beachape" %% "enumeratum"`).
+For Scala 3 we derive native enums, and depend on `"io.github.bishabosha" %% "enum-extensions"` for generating query
+param serdes.
 Other forms of OpenApi enum are not currently supported.
 
+Models containing binary data cannot be re-used between json and multi-part form endpoints, due to having different
+representation types for the binary data
+
 We currently miss a lot of OpenApi features like:
- - tags
- - ADTs
- - missing model types and meta descriptions (like date, minLength)
- - file handling
+
+- tags
+- ADTs
+- missing model types and meta descriptions (like date, minLength)
+- file handling
 

openapi-codegen/cli/src/main/scala/sttp/tapir/codegen/GenScala.scala

@@ -46,6 +46,9 @@ object GenScala {
   private val headTagForNamesOpt: Opts[Boolean] =
     Opts.flag("headTagForNames", "Whether to group generated endpoints by first declared tag", "t").orFalse
 
+  private val jsonLibOpt: Opts[Option[String]] =
+    Opts.option[String]("jsonLib", "Json library to use for serdes", "j").orNone
+
   private val destDirOpt: Opts[File] =
     Opts
       .option[String]("destdir", "Destination directory", "d")
@@ -59,15 +62,15 @@ object GenScala {
       }
 
   val cmd: Command[IO[ExitCode]] = Command("genscala", "Generate Scala classes", helpFlag = true) {
-    (fileOpt, packageNameOpt, destDirOpt, objectNameOpt, targetScala3Opt, headTagForNamesOpt).mapN {
-      case (file, packageName, destDir, maybeObjectName, targetScala3, headTagForNames) =>
+    (fileOpt, packageNameOpt, destDirOpt, objectNameOpt, targetScala3Opt, headTagForNamesOpt, jsonLibOpt).mapN {
+      case (file, packageName, destDir, maybeObjectName, targetScala3, headTagForNames, jsonLib) =>
         val objectName = maybeObjectName.getOrElse(DefaultObjectName)
 
         def generateCode(doc: OpenapiDocument): IO[Unit] = for {
           contents <- IO.pure(
-            BasicGenerator.generateObjects(doc, packageName, objectName, targetScala3, headTagForNames)
+            BasicGenerator.generateObjects(doc, packageName, objectName, targetScala3, headTagForNames, jsonLib.getOrElse("circe"))
           )
-          destFiles <- contents.toVector.traverse{ case (fileName, content) => writeGeneratedFile(destDir, fileName, content) }
+          destFiles <- contents.toVector.traverse { case (fileName, content) => writeGeneratedFile(destDir, fileName, content) }
           _ <- IO.println(s"Generated endpoints written to: ${destFiles.mkString(", ")}")
         } yield ()
 

openapi-codegen/core/src/main/scala/sttp/tapir/codegen/BasicGenerator.scala

@@ -16,6 +16,11 @@ import sttp.tapir.codegen.openapi.models.OpenapiSchemaType.{
   OpenapiSchemaUUID
 }
 
+object JsonSerdeLib extends Enumeration {
+  val Circe, Jsoniter = Value
+  type JsonSerdeLib = Value
+}
+
 object BasicGenerator {
 
   val classGenerator = new ClassDefinitionGenerator()
@@ -26,9 +31,20 @@ object BasicGenerator {
       packagePath: String,
       objName: String,
       targetScala3: Boolean,
-      useHeadTagForObjectNames: Boolean
+      useHeadTagForObjectNames: Boolean,
+      jsonSerdeLib: String
   ): Map[String, String] = {
-    val EndpointDefs(endpointsByTag, queryParamRefs) = endpointGenerator.endpointDefs(doc, useHeadTagForObjectNames)
+    val normalisedJsonLib = jsonSerdeLib.toLowerCase match {
+      case "circe"    => JsonSerdeLib.Circe
+      case "jsoniter" => JsonSerdeLib.Jsoniter
+      case _ =>
+        System.err.println(
+          s"!!! Unrecognised value $jsonSerdeLib for json serde lib -- should be one of circe, jsoniter. Defaulting to circe !!!"
+        )
+        JsonSerdeLib.Circe
+    }
+
+    val EndpointDefs(endpointsByTag, queryParamRefs, jsonParamRefs) = endpointGenerator.endpointDefs(doc, useHeadTagForObjectNames)
     val taggedObjs = endpointsByTag.collect {
       case (Some(headTag), body) if body.nonEmpty =>
         val taggedObj =
@@ -38,7 +54,7 @@ object BasicGenerator {
            |
            |object $headTag {
            |
-           |${indent(2)(imports)}
+           |${indent(2)(imports(normalisedJsonLib))}
            |
            |${indent(2)(body)}
            |
@@ -50,9 +66,9 @@ object BasicGenerator {
         |
         |object $objName {
         |
-        |${indent(2)(imports)}
+        |${indent(2)(imports(normalisedJsonLib))}
         |
-        |${indent(2)(classGenerator.classDefs(doc, targetScala3, queryParamRefs).getOrElse(""))}
+        |${indent(2)(classGenerator.classDefs(doc, targetScala3, queryParamRefs, normalisedJsonLib, jsonParamRefs).getOrElse(""))}
         |
         |${indent(2)(endpointsByTag.getOrElse(None, ""))}
         |
@@ -61,19 +77,28 @@ object BasicGenerator {
     taggedObjs + (objName -> mainObj)
   }
 
-  private[codegen] def imports: String =
-    """import sttp.tapir._
-      |import sttp.tapir.model._
-      |import sttp.tapir.json.circe._
-      |import sttp.tapir.generic.auto._
-      |import io.circe.generic.auto._
-      |""".stripMargin
+  private[codegen] def imports(jsonSerdeLib: JsonSerdeLib.JsonSerdeLib): String = {
+    val jsonImports = jsonSerdeLib match {
+      case JsonSerdeLib.Circe =>
+        """import sttp.tapir.json.circe._
+          |import io.circe.generic.semiauto._""".stripMargin
+      case JsonSerdeLib.Jsoniter =>
+        """import sttp.tapir.json.jsoniter._
+          |import com.github.plokhotnyuk.jsoniter_scala.macros._
+          |import com.github.plokhotnyuk.jsoniter_scala.core._""".stripMargin
+    }
+    s"""import sttp.tapir._
+       |import sttp.tapir.model._
+       |import sttp.tapir.generic.auto._
+       |$jsonImports
+       |""".stripMargin
+  }
 
   def indent(i: Int)(str: String): String = {
     str.linesIterator.map(" " * i + _).mkString("\n")
   }
 
-  def mapSchemaSimpleTypeToType(osst: OpenapiSchemaSimpleType): (String, Boolean) = {
+  def mapSchemaSimpleTypeToType(osst: OpenapiSchemaSimpleType, multipartForm: Boolean = false): (String, Boolean) = {
     osst match {
       case OpenapiSchemaDouble(nb) =>
         ("Double", nb)
@@ -91,8 +116,10 @@ object BasicGenerator {
         ("String", nb)
       case OpenapiSchemaBoolean(nb) =>
         ("Boolean", nb)
-      case OpenapiSchemaBinary(nb) =>
+      case OpenapiSchemaBinary(nb) if multipartForm =>
         ("sttp.model.Part[java.io.File]", nb)
+      case OpenapiSchemaBinary(nb) =>
+        ("Array[Byte]", nb)
       case OpenapiSchemaAny(nb) =>
         ("io.circe.Json", nb)
       case OpenapiSchemaRef(t) =>