MessagePack Codecs

Introduction

MessagePack is a binary serialization format designed for efficient data exchange between different systems and languages. In this section, we will explore how to derive MessagePack codecs from a ZIO Schema. MessagePack codecs allow us to easily serialize and deserialize data in MessagePack format.

Installation

To use MessagePack codecs, you need to add the following dependency to your build.sbt file:

libraryDependencies += "dev.zio" %% "zio-schema-msg-pack" % "1.5.0"

BinaryCodec

The MessagePackCodec object inside the zio.schema.codec package provides the messagePackCodec operator which allows us to derive MessagePack codecs from a ZIO Schema:

object MessagePackCodec {
  implicit def messagePackCodec[A](implicit schema: Schema[A]): BinaryCodec[A] = ???
}

Example

Let's try an example to see how it works:

import zio._
import zio.schema.codec._
import zio.schema.{DeriveSchema, Schema}

case class Person(name: String, age: Int)

object Person {
  implicit val schema: Schema[Person] =
    DeriveSchema.gen
  implicit val msgPackCodec: BinaryCodec[Person] =
    MessagePackCodec.messagePackCodec(schema)
}

object Main extends ZIOAppDefault {
  def run = for {
    _ <- ZIO.debug("MessagePack Codec Example:")
    person: Person = Person("John", 42)
    encoded: Chunk[Byte] = Person.msgPackCodec.encode(person)
    _ <- ZIO.debug(s"person object encoded to MessagePack's binary format: ${toHex(encoded)}")
    decoded <- ZIO.fromEither(Person.msgPackCodec.decode(encoded))
    _ <- ZIO.debug(s"MessagePack object decoded to Person class: $decoded")
  } yield ()

  def toHex(bytes: Chunk[Byte]): String =
    bytes.map("%02x".format(_)).mkString(" ")
}

The output of the above program is:

MessagePack Codec Example:
person object encoded to MessagePack's binary format: 82 a4 6e 61 6d 65 a4 4a 6f 68 6e a3 61 67 65 2a
MessagePack object decoded to Person class: Person(John,42)