Simplify Encoderdecoder (#2998)

Co-authored-by: pablf <pablofemenia@proton.me>

zio-http/shared/src/main/scala/zio/http/FormField.scala

@@ -77,6 +77,21 @@ sealed trait FormField {
       ZIO.succeed(Chunk.fromArray(value.getBytes(Charsets.Utf8)))
   }
 
+  /**
+   * Gets the value of this form field as a chunk of bytes. If it is a text
+   * field, the value gets encoded as an UTF-8 byte stream.
+   */
+  final def asStream(implicit trace: Trace): ZStream[Any, Nothing, Byte] = this match {
+    case FormField.Text(_, value, _, _)                =>
+      ZStream.fromChunk(Chunk.fromArray(value.getBytes(Charsets.Utf8)))
+    case FormField.Binary(_, value, _, _, _)           =>
+      ZStream.fromChunk(value)
+    case FormField.StreamingBinary(_, _, _, _, stream) =>
+      stream
+    case FormField.Simple(_, value)                    =>
+      ZStream.fromChunk(Chunk.fromArray(value.getBytes(Charsets.Utf8)))
+  }
+
   def name(newName: String): FormField = this match {
     case FormField.Binary(_, data, contentType, transferEncoding, filename)          =>
       FormField.Binary(newName, data, contentType, transferEncoding, filename)

zio-http/shared/src/main/scala/zio/http/codec/internal/BodyCodec.scala

@@ -24,7 +24,7 @@ import zio.schema._
 
 import zio.http.Header.Accept.MediaTypeWithQFactor
 import zio.http.codec.{BinaryCodecWithSchema, HttpCodecError, HttpContentCodec}
-import zio.http.{Body, MediaType}
+import zio.http.{Body, FormField, MediaType}
 
 /**
  * A BodyCodec encapsulates the logic necessary to both encode and decode bodies
@@ -39,11 +39,21 @@ private[http] sealed trait BodyCodec[A] { self =>
    */
   type Element
 
+  /**
+   * Attempts to decode the `A` from a FormField using the given codec.
+   */
+  def decodeFromField(field: FormField)(implicit trace: Trace): IO[Throwable, A]
+
   /**
    * Attempts to decode the `A` from a body using the given codec.
    */
   def decodeFromBody(body: Body)(implicit trace: Trace): IO[Throwable, A]
 
+  /**
+   * Encodes the `A` to a FormField in the given codec.
+   */
+  def encodeToField(value: A, mediaTypes: Chunk[MediaTypeWithQFactor], name: String)(implicit trace: Trace): FormField
+
   /**
    * Encodes the `A` to a body in the given codec.
    */
@@ -74,8 +84,15 @@ private[http] object BodyCodec {
   case object Empty extends BodyCodec[Unit] {
     type Element = Unit
 
+    def decodeFromField(field: FormField)(implicit trace: Trace): IO[Throwable, Unit] = ZIO.unit
+
     def decodeFromBody(body: Body)(implicit trace: Trace): IO[Nothing, Unit] = ZIO.unit
 
+    def encodeToField(value: Unit, mediaTypes: Chunk[MediaTypeWithQFactor], name: String)(implicit
+      trace: Trace,
+    ): FormField =
+      throw HttpCodecError.CustomError("UnsupportedEncodingType", s"Unit can't be encoded to a FormField")
+
     def encodeToBody(value: Unit, mediaTypes: Chunk[MediaTypeWithQFactor])(implicit trace: Trace): Body = Body.empty
 
     def schema: Schema[Unit] = Schema[Unit]
@@ -90,6 +107,19 @@ private[http] object BodyCodec {
     def mediaType(accepted: Chunk[MediaTypeWithQFactor]): Option[MediaType] =
       Some(codec.chooseFirstOrDefault(accepted)._1)
 
+    def decodeFromField(field: FormField)(implicit trace: Trace): IO[Throwable, A] = {
+      val codec0 = codec
+        .lookup(field.contentType)
+        .toRight(HttpCodecError.CustomError("UnsupportedMediaType", s"MediaType: ${field.contentType}"))
+      codec0 match {
+        case Left(error)                                                       => ZIO.fail(error)
+        case Right(BinaryCodecWithSchema(_, schema)) if schema == Schema[Unit] =>
+          ZIO.unit.asInstanceOf[IO[Throwable, A]]
+        case Right(BinaryCodecWithSchema(codec, schema))                       =>
+          field.asChunk.flatMap { chunk => ZIO.fromEither(codec.decode(chunk)) }.flatMap(validateZIO(schema))
+      }
+    }
+
     def decodeFromBody(body: Body)(implicit trace: Trace): IO[Throwable, A] = {
       val codec0 = codecForBody(codec, body)
       codec0 match {
@@ -101,8 +131,27 @@ private[http] object BodyCodec {
       }
     }
 
+    def encodeToField(value: A, mediaTypes: Chunk[MediaTypeWithQFactor], name: String)(implicit
+      trace: Trace,
+    ): FormField = {
+      val (mediaType, BinaryCodecWithSchema(codec0, _)) = codec.chooseFirstOrDefault(mediaTypes)
+      if (mediaType.binary) {
+        FormField.binaryField(
+          name,
+          codec0.encode(value),
+          mediaType,
+        )
+      } else {
+        FormField.textField(
+          name,
+          codec0.encode(value).asString,
+          mediaType,
+        )
+      }
+    }
+
     def encodeToBody(value: A, mediaTypes: Chunk[MediaTypeWithQFactor])(implicit trace: Trace): Body = {
-      val (mediaType, bc @ BinaryCodecWithSchema(_, _)) = codec.chooseFirst(mediaTypes)
+      val (mediaType, bc @ BinaryCodecWithSchema(_, _)) = codec.chooseFirstOrDefault(mediaTypes)
       Body.fromChunk(bc.codec.encode(value)).contentType(mediaType)
     }
 
@@ -115,20 +164,40 @@ private[http] object BodyCodec {
     def mediaType(accepted: Chunk[MediaTypeWithQFactor]): Option[MediaType] =
       Some(codec.chooseFirstOrDefault(accepted)._1)
 
+    def decodeFromField(field: FormField)(implicit trace: Trace): IO[Throwable, ZStream[Any, Nothing, E]] =
+      ZIO.fromEither {
+        codec
+          .lookup(field.contentType)
+          .toRight(HttpCodecError.CustomError("UnsupportedMediaType", s"MediaType: ${field.contentType}"))
+          .map { case BinaryCodecWithSchema(codec, schema) =>
+            (field.asStream >>> codec.streamDecoder >>> validateStream(schema)).orDie
+          }
+      }
+
     def decodeFromBody(body: Body)(implicit
       trace: Trace,
-    ): IO[Throwable, ZStream[Any, Nothing, E]] = {
+    ): IO[Throwable, ZStream[Any, Nothing, E]] =
       ZIO.fromEither {
         codecForBody(codec, body).map { case bc @ BinaryCodecWithSchema(_, schema) =>
           (body.asStream >>> bc.codec.streamDecoder >>> validateStream(schema)).orDie
         }
       }
+
+    def encodeToField(value: ZStream[Any, Nothing, E], mediaTypes: Chunk[MediaTypeWithQFactor], name: String)(implicit
+      trace: Trace,
+    ): FormField = {
+      val (mediaType, BinaryCodecWithSchema(codec0, _)) = codec.chooseFirstOrDefault(mediaTypes)
+      FormField.streamingBinaryField(
+        name,
+        value >>> codec0.streamEncoder,
+        mediaType,
+      )
     }
 
     def encodeToBody(value: ZStream[Any, Nothing, E], mediaTypes: Chunk[MediaTypeWithQFactor])(implicit
       trace: Trace,
     ): Body = {
-      val (mediaType, bc @ BinaryCodecWithSchema(_, _)) = codec.chooseFirst(mediaTypes)
+      val (mediaType, bc @ BinaryCodecWithSchema(_, _)) = codec.chooseFirstOrDefault(mediaTypes)
       Body.fromStreamChunked(value >>> bc.codec.streamEncoder).contentType(mediaType)
     }