JarCastingJsZipper 
See this project's wiki for installation instructions, and project rationale.
Usage
We'll use following JSON object.
import play.api.libs.json._
import play.api.libs.json.monad.syntax._
import play.api.libs.json.extensions._
val js = Json.obj(
"key1" -> Json.obj(
"key11" -> "TO_FIND",
"key12" -> 123L,
"key13" -> JsNull
),
"key2" -> 123,
"key3" -> true,
"key4" -> Json.arr("TO_FIND", 345.6, "test", Json.obj("key411" -> Json.obj("key4111" -> "TO_FIND")))
)
js: play.api.libs.json.JsObject = {"key1":{"key11":"TO_FIND","key12":123,"key13":null},"key2":123,"key3":true,"key4":["TO_FIND",345.6,"test",{"key411":{"key4111":"TO_FIND"}}]}
Basic Manipulations
Setting multiple paths/values
js.set(
(__ \ "key4")(2) -> JsNumber(765.23),
(__ \ "key1" \ "key12") -> JsString("toto")
)
res1: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND","key12":"toto","key13":null},"key2":123,"key3":true,"key4":["TO_FIND",345.6,765.23,{"key411":{"key4111":"TO_FIND"}}]}
Deleting Multiple Paths and Values
js.delete(
(__ \ "key4")(2),
(__ \ "key1" \ "key12"),
(__ \ "key1" \ "key13")
)
res2: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND"},"key2":123,"key3":true,"key4":["TO_FIND",345.6,{"key411":{"key4111":"TO_FIND"}}]}
Finding Paths/Values by Filter
js.findAll( (_,v) => v == JsString("TO_FIND") ).toList
res5: List[(play.api.libs.json.JsPath, play.api.libs.json.JsValue)] = List(
(/key1/key11,"TO_FIND"),
(/key4(0),"TO_FIND"),
(/key4(3)/key411/key4111,"TO_FIND")
)
Updating Values According to a Filter Based on a Value
js.updateAll( (_:JsValue) == JsString("TO_FIND") ){ js =>
val JsString(str) = js
JsString(str + "2")
}
res6: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND2","key12":123,"key13":null},"key2":123,"key3":true,"key4":["TO_FIND2",345.6,"test",{"key411":{"key4111":"TO_FIND2"}}]}
Updating Values According to a Filter Based on Path and Value
js.updateAll{ (path, js) =>
JsPathExtension.hasKey(path) == Some("key4111")
}{ (path, js) =>
val JsString(str) = js
JsString(str + path.path.last)
}
res1: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND","key12":123,"key13":null},"key2":123,"key3":true,"key4":["TO_FIND",345.6,"test",{"key411":{"key4111":"TO_FIND/key4111"}}]}
Creating an Object from Scratch
val build = JsExtensions.buildJsObject(
__ \ "key1" \ "key11" -> JsString("toto"),
__ \ "key1" \ "key12" -> JsNumber(123L),
(__ \ "key2")(0) -> JsBoolean(true),
__ \ "key3" -> Json.arr(1, 2, 3)
)
build: play.api.libs.json.JsValue = {"key1":{"key11":"toto","key12":123},"key3":[1,2,3],"key2":[true]}
Monadic Manipulations
Let's use Future as our Monad.
Imagine you call several services returning Future[JsValue] and you want to build/update a JsObject from it. Until now, if you wanted to do that with Play2/Json, it was quite tricky and required some code.
Updating Multiple Future Values at Given Paths
val maybeJs = js.setM[Future](
(__ \ "key4")(2) -> future{ JsNumber(765.23) },
(__ \ "key1" \ "key12") -> future{ JsString("toto") }
)
maybeJs: scala.concurrent.Future[play.api.libs.json.JsValue] = scala.concurrent.impl.Promise$DefaultPromise@6beb722d
Await.result(maybeJs, Duration("2 seconds"))
res4: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND","key12":"toto","key13":null},"key2":123,"key3":true,"key4":["TO_FIND",345.6,765.23,{"key411":{"key4111":"TO_FIND"}}]}
Updating Multiple Future Values According to a Filter
val maybeJs = js.updateAllM[Future]( (_:JsValue) == JsString("TO_FIND") ){ js =>
Future {
val JsString(str) = js
JsString(str + "2")
}
}
maybeJs: scala.concurrent.Future[play.api.libs.json.JsValue] = scala.concurrent.impl.Promise$DefaultPromise@35a4bb1a
Await.result(maybeJs, Duration("2 seconds"))
res6: play.api.libs.json.JsValue = {"key1":{"key11":"TO_FIND2","key12":123,"key13":null},"key2":123,"key3":true,"key4":["TO_FIND2",345.6,"test",{"key411":{"key4111":"TO_FIND2"}}]}
Creating a Future[JsArray] from Scratch
val maybeArr = JsExtensions.buildJsArrayM[Future](
Future { JsNumber(123.45) },
Future { JsString("toto") }
)
maybeArr: scala.concurrent.Future[play.api.libs.json.JsValue] = scala.concurrent.impl.Promise$DefaultPromise@220d48e4
scala> Await.result(maybeArr, Duration("2 seconds"))
res0: play.api.libs.json.JsValue = [123.45,"toto"]