Unveiling Play 2.1 JSON API Bonus: JSON Inception with Scala 2.10 macros

http://mandubian.com/2012/11/11/JSON-inception/

by mandubian • 14 years ago

61 32 14 years ago

mandubian10• 14 years ago

If you have any question, don't hesitate to ask (or go to website and talk on disqus)...

taligent4• 14 years ago

Nice work. Play 2 needs a LOT of work to get back to the simplicity and elegance of Play 1. This sort of effort really helps that.

mrspeaker• 14 years ago

To be fair, Play 2 is also vastly more powerful than Play 1 - the core concepts powering it are complex, but they lend flexibility that allow features like this to be added on top.

mandubian10• 14 years ago

And Play2 core is composed of very robust components without any runtime enhancement, any magic. Using Scala power, we can build very clean tools, such as this one, without perverting typesafe/fully-compiled basements.

robfig• 14 years ago

What does Play 2 enable that was not possible or straightforward in Play 1?

(For Java, that is)

jjm• 14 years ago

It also shows that the Scala feature set is growing (macros) and that the play group is not afraid of the awesome 210 [1] :-)

[1] http://www.scala-lang.org/node/16606

bdesimone• 14 years ago

Could you please expand on why you felt v2 was a departure from Play v1 in terms of simplicity and elegance? Why do you think that is -- and why was that trade off not the right design decision (or was it?) in your point of view. And finally, why does this effort "help that."

I am genuinely curious about your conclusions, but I'm frustrated by not being able to guess how you got there as I'm not a java web developer.

alanreid• 14 years ago

I love the idea! This makes a lot more sense than writing Formatters and repeating code everywhere. I'll play with this later today. Thanks!

mandubian10• 14 years ago

You're welcome! The idea is to simplify writing basic Reads/Writes for simple Scala structures. In this way, you can focus on writing more complex JSON validation/transformation when you need it... For JSON coast-to-coast design that I introduced in previous article, this is quite useful!

dpratt2• 14 years ago

I've been using Jerkson (a layer on top of the excellent Jackson JSON processing library) to do case class marshalling/unmarshalling. It works quite well - in fact, nearly perfectly, but it still uses runtime type inspection to get things done. A nice, simplistic typesafe compiled parser would be ideal.

I'd love it if the play folks would break this out of the core library - it seems like this would be applicable to the whole Scala ecosystem, and not just Play.

codewright• 14 years ago

Isn't Jerkson abandoned?

mandubian10• 14 years ago

Not really alive at least and not compiled for Scala 2.10

dpratt2• 14 years ago

There are a few github forks that have added a couple useful things. For my use case (converting case classes to/from JSON in scala 2.9.2) it works perfectly.

I've also written a Jackson plugin that knows how to marshal POSO classes - it's just an introspector that uses the scala convention instead of the JavaBeans convention. By and large it works well - perhaps I should put it up on github.

xwowsersx• 14 years ago

This is awesome.

Something ironic about this though:

"As we are perfectionnist..."

mandubian10• 14 years ago

Just an expression for transition, nothing more... why ironic?

iso-8859-1• 14 years ago

because typo

jeremyjh• 14 years ago

Great work. This is a perfect application of Scala macros.

Unveiling Play 2.1 JSON API Bonus: JSON Inception with Scala 2.10 macros

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