The unified validation API aims to provide a comprehensive toolkit to validate data from any format against user defined rules, and transform them to other types.

Basically, assuming you have this:

import play.api.libs.json._
import play.api.data.mapping._

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

val json = Json.parse("""{
  "name": "Julien",
  "age": 28,
  "lovesChocolate": true
}""")

implicit val personRule = {
  import play.api.data.mapping.json.Rules._
  Rule.gen[JsValue, Person]
}

It can do this:

scala> personRule.validate(json)
res0: play.api.data.mapping.VA[Person] = Success(Person(Julien,28,true))

BUT IT'S NOT LIMITED TO JSON

It's also a unification of play's Form Validation API, and its Json validation API.

Being based on the same concepts as play's Json validation API, it should feel very similar to any developer already working with it. The unified validation API is, rather than a totally new design, a simple generalization of those concepts.

The unified validation API is designed around a core defined in package play.api.data.mapping, and "extensions". Each extension provides primitives to validate and serialize data from / to a particular format (Json, form encoded request body, etc.). See the extensions documentation for more information.

To learn more about data validation, please consult Validation and transformation with Rule, for data serialization read Serialization with Write. If you just want to figure all this out by yourself, please see the Cookbook.

Add the following lines in your build.sbt

resolvers += Resolver.sonatypeRepo("releases")

// If you want only the core
libraryDependencies +="io.github.jto" %% "validation-core" % "1.1"

// Json validation for play-json
libraryDependencies +="io.github.jto" %% "validation-json" % "1.1"

// Json validation for json4s
libraryDependencies += "io.github.jto" %% "validation-json4s" % "1.1"

// Form validation
libraryDependencies +="io.github.jto" %% "validation-form" % "1.1"

// XML validation
libraryDependencies +="io.github.jto" %% "validation-xml % "1.1"

The 1.1.X versions are builded with play 2.4, if you are using play 2.3 you need to use the 1.0.2 version.

All the required documentation is directly readable from Github: https://github.com/jto/validation/tree/master/documentation/tut

• Validating and transforming data
• Combining Rules
• Validation Inception
• Validating Json
• Serializing data with Write
• Combining Writes
• Play's Form API migration
• Play's Json API migration
• Extensions: Supporting new types
• Cookbook

• Julien Tournay - http://jto.github.io
• Nick - https://github.com/stanch
• Ian Hummel - https://github.com/themodernlife
• Arthur Gautier - https://github.com/baloo
• Jacques B - https://github.com/Timshel
• Alexandre Tamborrino - https://github.com/atamborrino