init

.gitignore

@@ -0,0 +1,6 @@
+/RUNNING_PID
+/logs/
+/project/*-shim.sbt
+/project/project/
+/project/target/
+/target/

build.sbt

@@ -0,0 +1,12 @@
+name := """play-json-naming"""
+
+version := "1.0"
+
+scalaVersion := "2.11.5"
+
+crossScalaVersions := Seq("2.10.4", "2.11.5")
+
+libraryDependencies ++= Seq(
+  "com.typesafe.play" %% "play-json" % "2.3.7" % "provided",
+  "org.scalatest" %% "scalatest" % "2.1.6" % "test"
+)

project/build.properties

@@ -0,0 +1,4 @@
+#Activator-generated Properties
+#Mon Jan 19 19:48:42 JST 2015
+template.uuid=a855816c-0367-44ba-9adb-6a903f6ad599
+sbt.version=0.13.7

src/main/scala/com/github/tototoshi/play/json/JsonNaming.scala

@@ -0,0 +1,25 @@
+package com.github.tototoshi.play.json
+
+import play.api.libs.json._
+
+object JsonNaming {
+
+  private def mapKeys[A, B](m: Seq[(A, B)])(f: A => A): Seq[(A, B)] =
+    m.map { case (k, v) => (f(k), v) }
+
+  def snakecase[T](format: Format[T]): Format[T] = new Format[T] {
+    def reads(json: JsValue): JsResult[T] = {
+      format.reads(json match {
+        case obj: JsObject => JsObject(mapKeys(obj.fields)(StringUtil.camelcase))
+        case x => x
+      })
+    }
+
+    def writes(o: T): JsValue = {
+      format.writes(o) match {
+        case obj: JsObject => JsObject(mapKeys(obj.fields)(StringUtil.snakecase))
+        case x => x
+      }
+    }
+  }
+}

src/main/scala/com/github/tototoshi/play/json/StringUtil.scala

@@ -0,0 +1,19 @@
+package com.github.tototoshi.play.json
+
+import play.api.libs.json._
+
+private[json] object StringUtil {
+
+  def camelcase(s: String): String = (s.split("_").toList match {
+    case head :: tail => head :: tail.map(_.capitalize)
+    case x => x
+  }).mkString
+
+  def snakecase(s: String): String = s.foldLeft(new StringBuilder) {
+    case (s, c) if Character.isUpperCase(c) =>
+      s.append("_").append(Character.toLowerCase(c))
+    case (s, c) =>
+      s.append(c)
+  }.toString
+
+}

src/test/scala/com/github/tototoshi/play/json/JsonNamingSuite.scala

@@ -0,0 +1,25 @@
+package com.github.tototoshi.play.json
+
+import org.scalatest._
+import play.api.libs.json._
+
+case class Name(firstName: String, lastName: String)
+case class User(id: Int, nameData: Name)
+
+class JsonNamingSuite extends FunSuite with ShouldMatchers {
+
+
+  implicit val nameFormat = JsonNaming.snakecase(Json.format[Name])
+  implicit val userFormat = JsonNaming.snakecase(Json.format[User])
+
+  val jsonString = """{"id":1,"name_data":{"first_name":"Toshiyuki","last_name":"Takahashi"}}"""
+
+  test("read") {
+    Json.parse(jsonString).validate[User].get should be(User(1, Name("Toshiyuki", "Takahashi")))
+  }
+
+  test("write") {
+    Json.toJson(User(1, Name("Toshiyuki", "Takahashi"))) should be(Json.parse(jsonString))
+  }
+
+}

src/test/scala/com/github/tototoshi/play/json/StringUtilSuite.scala

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+package com.github.tototoshi.play.json
+
+import org.scalatest._
+import play.api.libs.json._
+
+class StringUtilSuite extends FunSuite with ShouldMatchers {
+
+  test("camelCase -> snake_case") {
+    StringUtil.snakecase("play") should be("play")
+    StringUtil.snakecase("playJson") should be("play_json")
+  }
+
+  test("snake_case -> camelCase") {
+    StringUtil.camelcase("play") should be("play")
+    StringUtil.camelcase("play_json") should be("playJson")
+  }
+
+}