From b7f5f3b17974399037cf3a0c34a305279d1d30ec Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 11:52:55 +0200
Subject: [PATCH 1/9] added compression feature for circe-akka-serializer

---
 README.md                                     |  1 +
 .../src/main/resources/reference.conf         | 14 +++++
 .../ash/circe/CirceAkkaSerializer.scala       | 25 ++++++--
 .../virtuslab/ash/circe/CirceTraitCodec.scala | 44 ++++++++-----
 .../org/virtuslab/ash/circe/Compression.scala | 61 +++++++++++++++++++
 .../src/test/resources/application.conf       | 24 ++++++--
 .../resources/more_than_1KiB_object_file.txt  | 30 +++++++++
 .../ash/circe/CirceAkkaSerializerSpec.scala   | 43 ++++++++++++-
 .../ash/circe/CustomSerializer.scala          |  5 +-
 ...a => MigrationAndCompressionTestKit.scala} |  8 +--
 10 files changed, 221 insertions(+), 34 deletions(-)
 create mode 100644 circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
 create mode 100644 circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
 rename circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/{MigrationTestKit.scala => MigrationAndCompressionTestKit.scala} (80%)

diff --git a/README.md b/README.md
index eef6bb02..662c43dc 100644
--- a/README.md
+++ b/README.md
@@ -251,6 +251,7 @@ class ExampleSerializer(actorSystem: ExtendedActorSystem)
   override lazy val packagePrefix = "org.project"
 }
 ```
+`CirceAkkaSerializer` can be configured to use Gzip compression when serializing payloads greater than defined size (default is without compression). See [default reference.conf file](circe-akka-serializer/src/main/resources/reference.conf) with comments for details.  
 
 For more guidelines on how to use the serializer,
 read [Akka documentation about serialization](https://doc.akka.io/docs/akka/current/serialization.html),
diff --git a/circe-akka-serializer/src/main/resources/reference.conf b/circe-akka-serializer/src/main/resources/reference.conf
index 4b0e3552..d256b384 100644
--- a/circe-akka-serializer/src/main/resources/reference.conf
+++ b/circe-akka-serializer/src/main/resources/reference.conf
@@ -1,5 +1,19 @@
 # Default configuration
 
 org.virtuslab.ash {
+
   verbose-debug-logging = off
+
+  # settings for compression of the payload
+  compression {
+    # Compression algorithm.
+    # - off  : no compression
+    # - gzip : using common java gzip
+    algorithm = off
+
+    # If compression is enabled with the `algorithm` setting,
+    # the payload will be compressed if it's size is bigger than this value.
+    compress-larger-than = 0 KiB
+  }
+
 }
diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
index 4f5446d8..7e0e6e97 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
@@ -47,6 +47,16 @@ abstract class CirceAkkaSerializer[Ser <: AnyRef: ClassTag](system: ExtendedActo
   private lazy val log = Logging(system, getClass)
   private lazy val conf = system.settings.config.getConfig("org.virtuslab.ash")
   private lazy val isDebugEnabled = conf.getBoolean("verbose-debug-logging") && log.isDebugEnabled
+  private lazy val compressionAlgorithm: Compression.Algorithm = conf.getString("compression.algorithm") match {
+    case "off" =>
+      Compression.Off
+    case "gzip" =>
+      Compression.GZip(conf.getBytes("compression.compress-larger-than"))
+    case other =>
+      throw new IllegalArgumentException(
+        s"Unknown compression algorithm value: [$other], possible values are: 'off' and 'gzip'")
+  }
+  protected val bufferSize: Int = 1024 * 4
 
   override lazy val classTagEvidence: ClassTag[Ser] = implicitly[ClassTag[Ser]]
   override lazy val errorCallback: String => Unit = x => log.error(x)
@@ -58,9 +68,10 @@ abstract class CirceAkkaSerializer[Ser <: AnyRef: ClassTag](system: ExtendedActo
     val startTime = if (isDebugEnabled) System.nanoTime else 0L
     codecsMap.get(manifest(o)) match {
       case Some((encoder, _)) =>
-        val res = printer.print(encoder.asInstanceOf[Encoder[AnyRef]](o)).getBytes(UTF_8)
-        logDuration("Serialization", o, startTime, res)
-        res
+        val bytes = printer.print(encoder.asInstanceOf[Encoder[AnyRef]](o)).getBytes(UTF_8)
+        val result = Compression.compressIfNeeded(bytes, bufferSize, compressionAlgorithm)
+        logDuration("Serialization", o, startTime, result)
+        result
       case None =>
         throw new RuntimeException(
           s"Serialization of [${o.getClass.getName}] failed. Call Register[A] for this class or its supertype and append result to `def codecs`.")
@@ -71,9 +82,10 @@ abstract class CirceAkkaSerializer[Ser <: AnyRef: ClassTag](system: ExtendedActo
     val startTime = if (isDebugEnabled) System.nanoTime else 0L
     codecsMap.get(manifestMigrationsMap.getOrElse(manifest, manifest)) match {
       case Some((_, decoder)) =>
-        val res = parser.parseByteArray(bytes).flatMap(_.as(decoder)).fold(e => throw e, identity)
-        logDuration("Deserialization", res, startTime, bytes)
-        res
+        val decompressedBytes = Compression.decompressIfNeeded(bytes, bufferSize)
+        val result = parser.parseByteArray(decompressedBytes).flatMap(_.as(decoder)).fold(e => throw e, identity)
+        logDuration("Deserialization", result, startTime, bytes)
+        result
       case None =>
         throw new NotSerializableException(
           s"Manifest [$manifest] did not match any known codec. If you're not currently performing a rolling upgrade, you must add a manifest migration to correct codec.")
@@ -115,4 +127,5 @@ abstract class CirceAkkaSerializer[Ser <: AnyRef: ClassTag](system: ExtendedActo
         bytes.length)
     }
   }
+
 }
diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
index 47af8757..95e8432a 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
@@ -54,15 +54,6 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
 
   val errorCallback: String => Unit
 
-  Seq(
-    (codecs, "codecs"),
-    (manifestMigrations, "manifestMigrations"),
-    (packagePrefix, "packagePrefix"),
-    (classTagEvidence, "classTagEvidence"),
-    (errorCallback, "errorCallback")).foreach { x =>
-    assert(x._1 != null, s"${x._2} must be declared as a def or a lazy val to work correctly")
-  }
-
   private val mirror = ru.runtimeMirror(getClass.getClassLoader)
 
   protected val codecsMap: Map[String, (Encoder[_ <: Ser], Decoder[_ <: Ser])] = codecs
@@ -85,8 +76,7 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
     .toMap
     .withDefaultValue("")
 
-  def manifest(o: AnyRef): String = parentsUpToRegisteredTypeMap(o.getClass.getName)
-
+  // Decoder apply method - decodes from Json into an object of type Ser
   override def apply(c: HCursor): Result[Ser] = {
     c.value.asObject match {
       case Some(obj) =>
@@ -103,6 +93,7 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
     }
   }
 
+  // Encoder apply method - encodes given object of type Ser into Json
   override def apply(a: Ser): Json = {
     val manifestString = manifest(a)
     val encoder = codecsMap.get(manifestString) match {
@@ -114,6 +105,33 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
     Json.obj((manifestString, encoder.asInstanceOf[Encoder[Ser]](a)))
   }
 
+  def manifest(o: AnyRef): String = parentsUpToRegisteredTypeMap(o.getClass.getName)
+
+  /*
+   * All code below serves as a check - it checks,
+   * whether class extending this trait is a valid implementation.
+   * doNeededChecksOnStart() gets invoked on object creation.
+   */
+  doNeededChecksOnStart()
+
+  private def doNeededChecksOnStart(): Unit = {
+    checkImplementationForInvalidMembersDeclarations()
+    checkSerializableTypesForMissingCodec(packagePrefix)
+    checkCodecsForNull()
+    checkCodecsForDuplication()
+  }
+
+  private def checkImplementationForInvalidMembersDeclarations(): Unit = {
+    Seq(
+      (codecs, "codecs"),
+      (manifestMigrations, "manifestMigrations"),
+      (packagePrefix, "packagePrefix"),
+      (classTagEvidence, "classTagEvidence"),
+      (errorCallback, "errorCallback")).foreach { x =>
+      assert(x._1 != null, s"${x._2} must be declared as a def or a lazy val to work correctly")
+    }
+  }
+
   private def checkSerializableTypesForMissingCodec(packagePrefix: String): Unit = {
     val reflections = new Reflections(packagePrefix)
     val foundSerializables = reflections.getSubTypesOf(classTag[Ser].runtimeClass).asScala.filterNot(_.isInterface)
@@ -142,8 +160,4 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
       errorCallback(s"Codec for class ${x._1} has been declared multiple times with types ${x._2.mkString(",")}.")
     }
   }
-
-  checkSerializableTypesForMissingCodec(packagePrefix)
-  checkCodecsForNull()
-  checkCodecsForDuplication()
 }
diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
new file mode 100644
index 00000000..0bfc93a2
--- /dev/null
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
@@ -0,0 +1,61 @@
+package org.virtuslab.ash.circe
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.util.zip.GZIPInputStream
+import java.util.zip.GZIPOutputStream
+
+import scala.annotation.tailrec
+
+object Compression {
+  sealed trait Algorithm
+  case object Off extends Algorithm
+  case class GZip(greaterThan: Long) extends Algorithm
+  // TODO: add support for LZ4 java compression:
+  // https://github.com/VirtusLab/akka-serialization-helper/issues/159
+  // case class LZ4(greaterThan: Long) extends Algorithm
+
+  private[circe] def compressIfNeeded(
+      bytes: Array[Byte],
+      bufferSize: Int,
+      compressionAlgorithm: Algorithm): Array[Byte] =
+    compressionAlgorithm match {
+      case Compression.Off => bytes
+      case Compression.GZip(largerThan) =>
+        if (bytes.length <= largerThan) {
+          bytes
+        } else {
+          val byteArrayOutputStream = new ByteArrayOutputStream(bufferSize)
+          val outputStream = new GZIPOutputStream(byteArrayOutputStream)
+          try outputStream.write(bytes)
+          finally outputStream.close()
+          byteArrayOutputStream.toByteArray
+        }
+    }
+
+  private[circe] def decompressIfNeeded(bytes: Array[Byte], bufferSize: Int): Array[Byte] =
+    if (isCompressedWithGzip(bytes)) {
+      val inputStream = new GZIPInputStream(new ByteArrayInputStream(bytes))
+      val outputStream = new ByteArrayOutputStream()
+      val buffer = new Array[Byte](bufferSize)
+
+      @tailrec def readChunk(): Unit =
+        inputStream.read(buffer) match {
+          case -1 => ()
+          case n =>
+            outputStream.write(buffer, 0, n)
+            readChunk()
+        }
+
+      try readChunk()
+      finally inputStream.close()
+      outputStream.toByteArray
+    } else {
+      bytes
+    }
+
+  private[circe] def isCompressedWithGzip(bytes: Array[Byte]): Boolean =
+    (bytes != null) && (bytes.length >= 2) &&
+    (bytes(0) == GZIPInputStream.GZIP_MAGIC.toByte) &&
+    (bytes(1) == (GZIPInputStream.GZIP_MAGIC >> 8).toByte)
+}
diff --git a/circe-akka-serializer/src/test/resources/application.conf b/circe-akka-serializer/src/test/resources/application.conf
index a7070e43..5a5ecb81 100644
--- a/circe-akka-serializer/src/test/resources/application.conf
+++ b/circe-akka-serializer/src/test/resources/application.conf
@@ -9,9 +9,23 @@ akka.actor {
   allow-java-serialization = off
 }
 
-#Uncomment below to enable logging
-
+# Uncomment chosen settings below to enable debug logging OR change compression settings
 #akka.loglevel = "DEBUG"
-#org.virtuslab.ash {
-#  verbose-debug-logging = on
-#}
+org.virtuslab.ash {
+
+  # enables debug logging
+  #verbose-debug-logging = on
+
+  # settings for compression of the payload
+  compression {
+    # Compression algorithm.
+    # - off  : no compression
+    # - gzip : using common java gzip
+    algorithm = off
+
+    # If compression is enabled with the `algorithm` setting,
+    # the payload will be compressed if it's size is bigger than this value.
+    compress-larger-than = 1 KiB  #  value set for testing purposes - do not change
+  }
+
+}
diff --git a/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
new file mode 100644
index 00000000..7cbac02e
--- /dev/null
+++ b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
@@ -0,0 +1,30 @@
+type::<notype>
+type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
+type::AnyRef
+type::phoenix.core.serialization.PhoenixAkkaSerialization[phoenix.bets.infrastructure.BetsAkkaSerializable]
+type::phoenix.core.serialization.PhoenixCodecs
+type::Unit
+type::Object
+type::(): Object
+type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
+type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
+type::io.circe.Codec[phoenix.punters.PunterEntity.PunterId]
+type::io.circe.Codec.AsObject[phoenix.punters.PunterEntity.PunterId]
+type::(implicit codec: shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]]): io.circe.Codec.AsObject[phoenix.punters.PunterEntity.PunterId]
+type::[A](implicit codec: shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[A]]): io.circe.Codec.AsObject[A]
+type::io.circe.generic.semiauto.type
+type::io.circe.generic.type
+type::io.circe.type
+type::io.type
+type::phoenix.punters.PunterEntity.PunterId
+type::shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]]
+type::io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]
+type::anon$lazy$macro$5
+type::Serializable
+type::anon$lazy$macro$5.super.type
+type::[T0]T0
+type::(implicit gen: shapeless.LabelledGeneric.Aux[phoenix.punters.PunterEntity.PunterId,shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out], codec: shapeless.Lazy[io.circe.generic.codec.ReprAsObjectCodec[shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out]]): io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]
+type::[A, R](implicit gen: shapeless.LabelledGeneric.Aux[A,R], codec: shapeless.Lazy[io.circe.generic.codec.ReprAsObjectCodec[R]]): io.circe.generic.codec.DerivedAsObjectCodec[A]
+type::io.circe.generic.codec.DerivedAsObjectCodec.type
+type::io.circe.generic.codec.type
+type::shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out
\ No newline at end of file
diff --git a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
index 11fe1199..3ea7a7d0 100644
--- a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
+++ b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
@@ -1,13 +1,17 @@
 package org.virtuslab.ash.circe
 
+import scala.io.Source
+
 import akka.actor.testkit.typed.scaladsl.ActorTestKit
 import akka.actor.testkit.typed.scaladsl.SerializationTestKit
 import akka.actor.typed.ActorSystem
 import com.typesafe.config.ConfigFactory
+import com.typesafe.config.ConfigValueFactory
 import org.scalatest.matchers.should
 import org.scalatest.wordspec.AnyWordSpecLike
 
-import org.virtuslab.ash.circe.MigrationTestKit.SerializationData
+import org.virtuslab.ash.circe.Compression.isCompressedWithGzip
+import org.virtuslab.ash.circe.MigrationAndCompressionTestKit.SerializationData
 import org.virtuslab.ash.circe.data.Tree.Node._
 import org.virtuslab.ash.circe.data._
 
@@ -17,7 +21,7 @@ class CirceAkkaSerializerSpec extends AnyWordSpecLike with should.Matchers {
     val testKit: ActorTestKit = ActorTestKit(config)
     val system: ActorSystem[Nothing] = testKit.system
     val serializationTestKit = new SerializationTestKit(system)
-    val migrationTestKit = new MigrationTestKit(system)
+    val migrationTestKit = new MigrationAndCompressionTestKit(system)
 
     "serialize standard data" in {
       import org.virtuslab.ash.circe.data.StdData._
@@ -83,5 +87,40 @@ class CirceAkkaSerializerSpec extends AnyWordSpecLike with should.Matchers {
       serializationTestKit.verifySerialization(GenericClass(StdData.One(1, 1, "aaa"), Tree.Leaf()))
     }
 
+    // setup for testing compression feature - with compression enabled
+    val compressionConfig =
+      config.withValue("org.virtuslab.ash.compression.algorithm", ConfigValueFactory.fromAnyRef("gzip"))
+    val compressionTestKit: ActorTestKit = ActorTestKit(compressionConfig)
+    val compressionActorSystem: ActorSystem[Nothing] = compressionTestKit.system
+    val compressionSerializationTestKit = new MigrationAndCompressionTestKit(compressionActorSystem)
+
+    val heavyWeightString = Source.fromResource("more_than_1KiB_object_file.txt").getLines.toList.mkString("\n")
+    val lightWeightString = "x"
+    val largeSerializableObject = StdData.One(123, 456.0f, heavyWeightString)
+    val smallSerializableObject = StdData.One(123, 456.0f, lightWeightString)
+
+    "compress payload using GZip compression algorithm when gzip compression is enabled and payload's size is bigger than threshold" in {
+      val largeObjectSerialized = compressionSerializationTestKit.serialize(largeSerializableObject)
+      isCompressedWithGzip(largeObjectSerialized._1) shouldBe true
+    }
+
+    "decompress payload properly when it has been compressed previously with GZip compression algorithm" in {
+      val largeObjectSerialized = compressionSerializationTestKit.serialize(largeSerializableObject)
+      val deserializedObject = compressionSerializationTestKit.deserialize(largeObjectSerialized)
+      deserializedObject shouldEqual largeSerializableObject
+    }
+
+    "not compress payload when gzip compression is enabled and payload's size is smaller than threshold" in {
+      val smallObjectSerialized = compressionSerializationTestKit.serialize(smallSerializableObject)
+      isCompressedWithGzip(smallObjectSerialized._1) shouldBe false
+    }
+
+    // below example uses standard `config` from circe-akka-serializer/src/test/resources/application.conf
+    // which is available in the migrationTestKit object - so compression is disabled
+    "not compress payload when compression is configuration is set to 'off'" in {
+      val largeObjectSerialized = migrationTestKit.serialize(largeSerializableObject)
+      isCompressedWithGzip(largeObjectSerialized._1) shouldBe false
+    }
+
   }
 }
diff --git a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CustomSerializer.scala b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CustomSerializer.scala
index b7b2c74e..3df6caa9 100644
--- a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CustomSerializer.scala
+++ b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CustomSerializer.scala
@@ -17,7 +17,7 @@ class CustomSerializer(actorSystem: ExtendedActorSystem)
 
   override def identifier: Int = 42352
 
-  override lazy val codecs =
+  override lazy val codecs: Seq[Registration[_ <: CirceSerializabilityTrait]] =
     Seq(
       Register[Tree],
       Register[StdData],
@@ -26,7 +26,8 @@ class CustomSerializer(actorSystem: ExtendedActorSystem)
       Register(implicitly[ru.TypeTag[ModifiedCodec]], prepareEncoder, prepareDecoder),
       Register[GenericClass[CirceSerializabilityTrait, CirceSerializabilityTrait]])
 
-  override lazy val manifestMigrations = Seq("org.virtuslab.ash.data.OldName" -> classOf[TopTraitMigration])
+  override lazy val manifestMigrations: Seq[(String, Class[TopTraitMigration])] =
+    Seq("org.virtuslab.ash.data.OldName" -> classOf[TopTraitMigration])
 
   override lazy val packagePrefix = "org.virtuslab.ash"
 }
diff --git a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationTestKit.scala b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationAndCompressionTestKit.scala
similarity index 80%
rename from circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationTestKit.scala
rename to circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationAndCompressionTestKit.scala
index 71d90cb5..fc008e17 100644
--- a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationTestKit.scala
+++ b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/MigrationAndCompressionTestKit.scala
@@ -5,10 +5,10 @@ import akka.actor.typed.scaladsl.adapter._
 import akka.serialization.SerializationExtension
 import akka.serialization.Serializers
 
-import org.virtuslab.ash.circe.MigrationTestKit.SerializationData
+import org.virtuslab.ash.circe.MigrationAndCompressionTestKit.SerializationData
 
 /**
- * Utilities to test serialization migration.
+ * Utilities to test serialization migration and compression.
  * To perform round trip:
  * {{{
  * val migrationTestKit = new MigrationTestKit(system)
@@ -18,7 +18,7 @@ import org.virtuslab.ash.circe.MigrationTestKit.SerializationData
  * original == result
  * }}}
  */
-class MigrationTestKit(system: ActorSystem[_]) {
+class MigrationAndCompressionTestKit(system: ActorSystem[_]) {
   private val serialization = SerializationExtension(system.toClassic)
 
   def serialize(objAnyRef: AnyRef): SerializationData = {
@@ -33,6 +33,6 @@ class MigrationTestKit(system: ActorSystem[_]) {
   }
 }
 
-object MigrationTestKit {
+object MigrationAndCompressionTestKit {
   type SerializationData = (Array[Byte], Int, String)
 }

From cb9b6e69ec90cfad87178c61769546f8db5b073f Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 12:17:23 +0200
Subject: [PATCH 2/9] Added newline character for checks

---
 .../src/test/resources/more_than_1KiB_object_file.txt           | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
index 7cbac02e..89e7e53f 100644
--- a/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
+++ b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
@@ -27,4 +27,4 @@ type::(implicit gen: shapeless.LabelledGeneric.Aux[phoenix.punters.PunterEntity.
 type::[A, R](implicit gen: shapeless.LabelledGeneric.Aux[A,R], codec: shapeless.Lazy[io.circe.generic.codec.ReprAsObjectCodec[R]]): io.circe.generic.codec.DerivedAsObjectCodec[A]
 type::io.circe.generic.codec.DerivedAsObjectCodec.type
 type::io.circe.generic.codec.type
-type::shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out
\ No newline at end of file
+type::shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out

From b3b5152c625269e1ab2fae388582de7217bea92b Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 12:21:00 +0200
Subject: [PATCH 3/9] removed trailing space from README

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 662c43dc..b274067f 100644
--- a/README.md
+++ b/README.md
@@ -251,7 +251,7 @@ class ExampleSerializer(actorSystem: ExtendedActorSystem)
   override lazy val packagePrefix = "org.project"
 }
 ```
-`CirceAkkaSerializer` can be configured to use Gzip compression when serializing payloads greater than defined size (default is without compression). See [default reference.conf file](circe-akka-serializer/src/main/resources/reference.conf) with comments for details.  
+`CirceAkkaSerializer` can be configured to use Gzip compression when serializing payloads greater than defined size (default is without compression). See [default reference.conf file](circe-akka-serializer/src/main/resources/reference.conf) with comments for details.
 
 For more guidelines on how to use the serializer,
 read [Akka documentation about serialization](https://doc.akka.io/docs/akka/current/serialization.html),

From be30f02aa652817c37f5997efcf53c4141561c32 Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 12:30:42 +0200
Subject: [PATCH 4/9] few minor PR fixes

---
 .../src/main/scala/org/virtuslab/ash/circe/Compression.scala   | 3 +--
 .../org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala      | 2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
index 0bfc93a2..6239f0e2 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
@@ -11,8 +11,7 @@ object Compression {
   sealed trait Algorithm
   case object Off extends Algorithm
   case class GZip(greaterThan: Long) extends Algorithm
-  // TODO: add support for LZ4 java compression:
-  // https://github.com/VirtusLab/akka-serialization-helper/issues/159
+  // TODO (#159): add support for LZ4 java compression
   // case class LZ4(greaterThan: Long) extends Algorithm
 
   private[circe] def compressIfNeeded(
diff --git a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
index 3ea7a7d0..e08bb93f 100644
--- a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
+++ b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
@@ -94,7 +94,7 @@ class CirceAkkaSerializerSpec extends AnyWordSpecLike with should.Matchers {
     val compressionActorSystem: ActorSystem[Nothing] = compressionTestKit.system
     val compressionSerializationTestKit = new MigrationAndCompressionTestKit(compressionActorSystem)
 
-    val heavyWeightString = Source.fromResource("more_than_1KiB_object_file.txt").getLines.toList.mkString("\n")
+    val heavyWeightString = Source.fromResource("more_than_1KiB_object_file.txt").getLines().toList.mkString("\n")
     val lightWeightString = "x"
     val largeSerializableObject = StdData.One(123, 456.0f, heavyWeightString)
     val smallSerializableObject = StdData.One(123, 456.0f, lightWeightString)

From 5a67a19fe69c998efc7a390166d451a7e1f63316 Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 12:40:22 +0200
Subject: [PATCH 5/9] replace real logs with random strings

---
 .../resources/more_than_1KiB_object_file.txt  | 93 +++++++++++++------
 1 file changed, 63 insertions(+), 30 deletions(-)

diff --git a/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
index 89e7e53f..62b42176 100644
--- a/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
+++ b/circe-akka-serializer/src/test/resources/more_than_1KiB_object_file.txt
@@ -1,30 +1,63 @@
-type::<notype>
-type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
-type::AnyRef
-type::phoenix.core.serialization.PhoenixAkkaSerialization[phoenix.bets.infrastructure.BetsAkkaSerializable]
-type::phoenix.core.serialization.PhoenixCodecs
-type::Unit
-type::Object
-type::(): Object
-type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
-type::phoenix.bets.infrastructure.BetsAkkaSerialization.type
-type::io.circe.Codec[phoenix.punters.PunterEntity.PunterId]
-type::io.circe.Codec.AsObject[phoenix.punters.PunterEntity.PunterId]
-type::(implicit codec: shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]]): io.circe.Codec.AsObject[phoenix.punters.PunterEntity.PunterId]
-type::[A](implicit codec: shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[A]]): io.circe.Codec.AsObject[A]
-type::io.circe.generic.semiauto.type
-type::io.circe.generic.type
-type::io.circe.type
-type::io.type
-type::phoenix.punters.PunterEntity.PunterId
-type::shapeless.Lazy[io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]]
-type::io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]
-type::anon$lazy$macro$5
-type::Serializable
-type::anon$lazy$macro$5.super.type
-type::[T0]T0
-type::(implicit gen: shapeless.LabelledGeneric.Aux[phoenix.punters.PunterEntity.PunterId,shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out], codec: shapeless.Lazy[io.circe.generic.codec.ReprAsObjectCodec[shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out]]): io.circe.generic.codec.DerivedAsObjectCodec[phoenix.punters.PunterEntity.PunterId]
-type::[A, R](implicit gen: shapeless.LabelledGeneric.Aux[A,R], codec: shapeless.Lazy[io.circe.generic.codec.ReprAsObjectCodec[R]]): io.circe.generic.codec.DerivedAsObjectCodec[A]
-type::io.circe.generic.codec.DerivedAsObjectCodec.type
-type::io.circe.generic.codec.type
-type::shapeless.labelled.FieldType[Symbol @@ String("value"),String] :: shapeless.ops.hlist.ZipWithKeys.hnilZipWithKeys.Out
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||
+this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string || this is some random string ||

From 9694e2d3b5c7e7284ad4694f386562878f17cb16 Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 13:47:20 +0200
Subject: [PATCH 6/9] fix structure in circe-akka-serializer reference.conf

---
 .../src/main/resources/reference.conf         | 24 ++++++++---------
 .../ash/circe/CirceAkkaSerializer.scala       |  2 +-
 .../src/test/resources/application.conf       | 26 +++++++++----------
 .../ash/circe/CirceAkkaSerializerSpec.scala   |  2 +-
 4 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/circe-akka-serializer/src/main/resources/reference.conf b/circe-akka-serializer/src/main/resources/reference.conf
index d256b384..ce838d7c 100644
--- a/circe-akka-serializer/src/main/resources/reference.conf
+++ b/circe-akka-serializer/src/main/resources/reference.conf
@@ -1,19 +1,19 @@
 # Default configuration
 
 org.virtuslab.ash {
+  circe {
+    verbose-debug-logging = off
 
-  verbose-debug-logging = off
+    # settings for compression of the payload
+    compression {
+      # Compression algorithm.
+      # - off  : no compression
+      # - gzip : using common java gzip
+      algorithm = off
 
-  # settings for compression of the payload
-  compression {
-    # Compression algorithm.
-    # - off  : no compression
-    # - gzip : using common java gzip
-    algorithm = off
-
-    # If compression is enabled with the `algorithm` setting,
-    # the payload will be compressed if it's size is bigger than this value.
-    compress-larger-than = 0 KiB
+      # If compression is enabled with the `algorithm` setting,
+      # the payload will be compressed if its size is bigger than this value.
+      compress-larger-than = 32 KiB
+    }
   }
-
 }
diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
index 7e0e6e97..437d8a65 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceAkkaSerializer.scala
@@ -45,7 +45,7 @@ abstract class CirceAkkaSerializer[Ser <: AnyRef: ClassTag](system: ExtendedActo
     with AkkaCodecs {
 
   private lazy val log = Logging(system, getClass)
-  private lazy val conf = system.settings.config.getConfig("org.virtuslab.ash")
+  private lazy val conf = system.settings.config.getConfig("org.virtuslab.ash.circe")
   private lazy val isDebugEnabled = conf.getBoolean("verbose-debug-logging") && log.isDebugEnabled
   private lazy val compressionAlgorithm: Compression.Algorithm = conf.getString("compression.algorithm") match {
     case "off" =>
diff --git a/circe-akka-serializer/src/test/resources/application.conf b/circe-akka-serializer/src/test/resources/application.conf
index 5a5ecb81..ea87a6b4 100644
--- a/circe-akka-serializer/src/test/resources/application.conf
+++ b/circe-akka-serializer/src/test/resources/application.conf
@@ -12,20 +12,20 @@ akka.actor {
 # Uncomment chosen settings below to enable debug logging OR change compression settings
 #akka.loglevel = "DEBUG"
 org.virtuslab.ash {
+  circe {
+    # enables debug logging
+    #verbose-debug-logging = on
 
-  # enables debug logging
-  #verbose-debug-logging = on
+    # settings for compression of the payload
+    compression {
+      # Compression algorithm.
+      # - off  : no compression
+      # - gzip : using common java gzip
+      algorithm = off
 
-  # settings for compression of the payload
-  compression {
-    # Compression algorithm.
-    # - off  : no compression
-    # - gzip : using common java gzip
-    algorithm = off
-
-    # If compression is enabled with the `algorithm` setting,
-    # the payload will be compressed if it's size is bigger than this value.
-    compress-larger-than = 1 KiB  #  value set for testing purposes - do not change
+      # If compression is enabled with the `algorithm` setting,
+      # the payload will be compressed if it's size is bigger than this value.
+      compress-larger-than = 1 KiB  #  value set for testing purposes - do not change
+    }
   }
-
 }
diff --git a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
index e08bb93f..3c06da66 100644
--- a/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
+++ b/circe-akka-serializer/src/test/scala/org/virtuslab/ash/circe/CirceAkkaSerializerSpec.scala
@@ -89,7 +89,7 @@ class CirceAkkaSerializerSpec extends AnyWordSpecLike with should.Matchers {
 
     // setup for testing compression feature - with compression enabled
     val compressionConfig =
-      config.withValue("org.virtuslab.ash.compression.algorithm", ConfigValueFactory.fromAnyRef("gzip"))
+      config.withValue("org.virtuslab.ash.circe.compression.algorithm", ConfigValueFactory.fromAnyRef("gzip"))
     val compressionTestKit: ActorTestKit = ActorTestKit(compressionConfig)
     val compressionActorSystem: ActorSystem[Nothing] = compressionTestKit.system
     val compressionSerializationTestKit = new MigrationAndCompressionTestKit(compressionActorSystem)

From f15b0da430fc2e819585e67e9643c3ddaa6cd2f0 Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Fri, 3 Jun 2022 16:56:55 +0200
Subject: [PATCH 7/9] PR fixes and improvements

---
 .../org/virtuslab/ash/circe/CirceTraitCodec.scala    | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
index 95e8432a..4a927c11 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/CirceTraitCodec.scala
@@ -76,7 +76,9 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
     .toMap
     .withDefaultValue("")
 
-  // Decoder apply method - decodes from Json into an object of type Ser
+  /**
+   * Decoder apply method - decodes from Json into an object of type Ser
+   */
   override def apply(c: HCursor): Result[Ser] = {
     c.value.asObject match {
       case Some(obj) =>
@@ -93,7 +95,9 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
     }
   }
 
-  // Encoder apply method - encodes given object of type Ser into Json
+  /**
+   * Encoder apply method - encodes given object of type Ser into Json
+   */
   override def apply(a: Ser): Json = {
     val manifestString = manifest(a)
     val encoder = codecsMap.get(manifestString) match {
@@ -115,13 +119,13 @@ trait CirceTraitCodec[Ser <: AnyRef] extends Codec[Ser] {
   doNeededChecksOnStart()
 
   private def doNeededChecksOnStart(): Unit = {
-    checkImplementationForInvalidMembersDeclarations()
+    checkImplementationForInvalidMemberDeclarations()
     checkSerializableTypesForMissingCodec(packagePrefix)
     checkCodecsForNull()
     checkCodecsForDuplication()
   }
 
-  private def checkImplementationForInvalidMembersDeclarations(): Unit = {
+  private def checkImplementationForInvalidMemberDeclarations(): Unit = {
     Seq(
       (codecs, "codecs"),
       (manifestMigrations, "manifestMigrations"),

From 053c11597d2feebb01929d5dda01b4635a8abb00 Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Sat, 4 Jun 2022 18:39:52 +0200
Subject: [PATCH 8/9] added useful comment on  check

---
 .../org/virtuslab/ash/circe/Compression.scala      | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
index 6239f0e2..8a918bb4 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
@@ -53,6 +53,20 @@ object Compression {
       bytes
     }
 
+  /*
+  Since we are encoding JSON for Ser <: AnyRef types - they will start with '{' char for Json objects or with '[' char for Arrays.
+  Thus, the first element of the `bytes` array is either the 123 Byte number - which is the decimal representation of the { character,
+  or - the 91 Byte number - which is the decimal representation of the [ character.
+
+   So, below quick comment on why isCompressedWithGzip will not return false positives (for not compressed JSON data):
+
+    bytes(0) == GZIPInputStream.GZIP_MAGIC.toByte
+    gets evaluated to:
+    bytes(0) == 35615.toByte
+    which gets evaluated to:
+    bytes(0) == 31 // where 31 is of type Byte
+    And since bytes(0) holds a Byte with value equal to 123 or 91 - this will never be true.
+   */
   private[circe] def isCompressedWithGzip(bytes: Array[Byte]): Boolean =
     (bytes != null) && (bytes.length >= 2) &&
     (bytes(0) == GZIPInputStream.GZIP_MAGIC.toByte) &&

From 718ff204198a42545a31753460f31d350bd09dee Mon Sep 17 00:00:00 2001
From: LukaszKontowski <lkontowski@virtuslab.com>
Date: Sat, 4 Jun 2022 19:04:32 +0200
Subject: [PATCH 9/9] added more comments

---
 .../src/main/resources/reference.conf               |  6 ++++--
 .../scala/org/virtuslab/ash/circe/Compression.scala | 13 +++++++++----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/circe-akka-serializer/src/main/resources/reference.conf b/circe-akka-serializer/src/main/resources/reference.conf
index ce838d7c..c089231e 100644
--- a/circe-akka-serializer/src/main/resources/reference.conf
+++ b/circe-akka-serializer/src/main/resources/reference.conf
@@ -4,9 +4,11 @@ org.virtuslab.ash {
   circe {
     verbose-debug-logging = off
 
-    # settings for compression of the payload
+    # Settings for compression of the payload - here we decide, if compression should be possible
+    # when serializing an object. It does not not affect deserialization process - so even with
+    # `compression.algorithm = off` deserialization of objects compressed with Gzip will be successfull.
     compression {
-      # Compression algorithm.
+      # Compression algorithm:
       # - off  : no compression
       # - gzip : using common java gzip
       algorithm = off
diff --git a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
index 8a918bb4..720ea0b6 100644
--- a/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
+++ b/circe-akka-serializer/src/main/scala/org/virtuslab/ash/circe/Compression.scala
@@ -54,9 +54,14 @@ object Compression {
     }
 
   /*
-  Since we are encoding JSON for Ser <: AnyRef types - they will start with '{' char for Json objects or with '[' char for Arrays.
-  Thus, the first element of the `bytes` array is either the 123 Byte number - which is the decimal representation of the { character,
-  or - the 91 Byte number - which is the decimal representation of the [ character.
+  Since we are encoding JSON for Ser <: AnyRef types - they can start with:
+  a) '{' char for Json objects or
+  b) '[' char for Arrays or
+  c) '"' char for String
+  Thus, the first element of the `bytes` array could be one of three below:
+  a) 123 Byte number - which is the decimal representation of the { character
+  b) 91 Byte number - which is the decimal representation of the [ character
+  c) 34 Byte number - which is the decimal representation of the " character
 
    So, below quick comment on why isCompressedWithGzip will not return false positives (for not compressed JSON data):
 
@@ -65,7 +70,7 @@ object Compression {
     bytes(0) == 35615.toByte
     which gets evaluated to:
     bytes(0) == 31 // where 31 is of type Byte
-    And since bytes(0) holds a Byte with value equal to 123 or 91 - this will never be true.
+    And since bytes(0) holds a Byte with value equal to 123, 91 or 34 - this will never be true.
    */
   private[circe] def isCompressedWithGzip(bytes: Array[Byte]): Boolean =
     (bytes != null) && (bytes.length >= 2) &&