Re: Is it possible to serialize / deserialize case classes without defining a protocol for each of them?

[Sean Walsh]

Not to besmirch the excellent spray-json library but I had to go with json4s(ala) for this very reason, which uses Jackson under the covers.  With this library I can just do write(my object) or read[MyObject].  I haven't done any performance comparisons.

On Friday, April 26, 2013 11:06:59 AM UTC-4, michael...@googlemail.com wrote:

Hi,

I want to serialize case classes to json. I tried the example from the documentation and it works without problems:

object Test {

  case class Color(name: String, red: Int, green: Int, blue: Int)

  object MyJsonProtocol extends DefaultJsonProtocol {

    implicit val colorFormat = jsonFormat4(Color)

  }

  def main(args: Array[String]) {

    import MyJsonProtocol._

    val json = Color("CadetBlue", 95, 158, 160).toJson

    println(json)

    val color = json.convertTo[Color]

    println(color)

  }

}

I have a huge number of different case classes I want to serialize / deserialize. Using this approach I have to define a protocol for each class which is quite cumbersome. Is it possible to serialize / deserialize case classes using spray-json withou defining a protocol for each one of them?

Thanks,

Michael

[Johannes Rudolph]

On Fri, Apr 26, 2013 at 5:06 PM, <michael...@googlemail.com> wrote:
> I have a huge number of different case classes I want to serialize /
> deserialize. Using this approach I have to define a protocol for each class
> which is quite cumbersome. Is it possible to serialize / deserialize case
> classes using spray-json withou defining a protocol for each one of them?

There's an issue to track this:

https://github.com/spray/spray-json/issues/28

I don't think it's currently possible to support this in a type-safe,
configurable manner without falling back to reflection (but maybe that
would be ok). There's a solution on the horizon using macros, not sure
if it can be made to work with Scala 2.10 but maybe later with more
powerful macros.

--
Johannes

-----------------------------------------------
Johannes Rudolph
http://virtual-void.net

[che...@tingatech.com]

Not directly related to Spray , but if you use scala 2.10.1 and json4s

There is some conflict due to scala 2.10.0 and 2.10.1, which causing very strange behavior, you can read it here

https://github.com/json4s/json4s/issues/46

Chester

[david...@gmail.com]

We've been successfully using jackson-module-scala for over a year with a pretty good level of success - we've had to work around a few problems, but most of them have been addressed in the current trunk of the project, and a few more (shameless plug for my own commits) will be released in the next point version.

We've written a simple adapter trait + object called JacksonSupport that when mixed in gives implicit serializer and deserializers for anything that extends Product - I've moved away from using this directly (not a huge fan of being able to accidentally arbitrarily send anything over the wire), but adding a single implicit val to the companion object for each case class you want to use as a transport is easy and works very very well.

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[Diego Alvarez Zuluaga]

Hi dpratt

Do you have any public working example with JacksonSupport trait and spray?

Tks