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jkugiyajkugiya
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Supports snakecase.
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‎src/main/scala/spray/json/SnakeCaseJsonSupport.scala‎

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package spray.json
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import scala.reflect.ClassTag
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import scala.collection.mutable
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/**
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* Provides snake cased JsonFormats
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*/
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trait SnakeCaseJsonSupport extends DefaultJsonProtocol {
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override protected def extractFieldNames(classTag: ClassTag[_]): Array[String] = {
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def snakify(name: String) = {
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val chars = name.toCharArray
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val len = name.length
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val sb = new mutable.StringBuilder(len + len / 5)
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def isAlphabetic(char: Char): Boolean = (char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z')
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def go(i: Int, rest: Int, processedUpper: Boolean, processedAlphaNumeric: Boolean): String =
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if (rest == 0) {
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sb.toString()
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} else if (rest > 1 && chars(i).isUpper && chars(i + 1).isLower) {
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if (processedAlphaNumeric) {
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sb.append('_')
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}
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sb.append(chars(i).toLower).append(chars(i + 1))
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go(i + 2, rest - 2, false, true)
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} else if (chars(i).isUpper) {
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if (!processedUpper && processedAlphaNumeric) {
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sb.append('_')
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}
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sb.append(chars(i).toLower)
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go(i + 1, rest - 1, true, chars(i).isDigit || isAlphabetic(chars(i)))
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} else if (!isAlphabetic(chars(i))) {
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sb.append(chars(i))
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go(i + 1, rest - 1, false, chars(i).isDigit)
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} else {
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sb.append(chars(i).toLower)
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go(i + 1, rest - 1, chars(i).isUpper, chars(i).isDigit || isAlphabetic(chars(i)))
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}
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go(0, len, true, false)
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}
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super.extractFieldNames(classTag).map {
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snakify(_)
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}
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}
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}
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object SnakeCaseJsonSupport extends SnakeCaseJsonSupport

‎src/test/scala/spray/json/SnakeCaseJsonSupportSpec.scala‎

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package spray.json
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import java.util.Locale
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import org.specs2.mutable._
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class SnakeCaseJsonSupportSpec extends Specification with SnakeCaseJsonSupport {
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private val PASS1 = """([A-Z]+)([A-Z][a-z])""".r
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private val PASS2 = """([a-z\d])([A-Z])""".r
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private val REPLACEMENT = "$1_$2"
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def snakify(name: String) =
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PASS2.replaceAllIn(PASS1.replaceAllIn(name, REPLACEMENT), REPLACEMENT).toLowerCase(Locale.US)
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"SnakeCaseJsonSUpport" should {
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"convert field names to snake cased fields names." in {
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// Given
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case class SampleFields(
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HelloWorld: Int = 0,
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A1AAbBBBBBbCCcc: Int = 0,
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AbAAbbAAAbbb1AA2bb1AA2AAAAbb1bAA: Int = 0,
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x: Int = 0,
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Y: Int = 0,
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`^There-arE_Non_(Alphabetic))_character!S`: Int = 0,
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`tHere-Are_(AlsO)_noN_(alphaBetic))_CharaCter!s`: Int = 0,
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` There are space character `: Int = 0,
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` これは　マルチバイトAbcのaBc確認です。`: Int = 0,
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aa: Int = 0,
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AA: Int = 0,
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Aa: Int = 0,
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aA: Int = 0,
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AAA: Int = 0,
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AAa: Int = 0,
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AaA: Int = 0,
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aAA: Int = 0,
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aaA: Int = 0,
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aAa: Int = 0,
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Aaa: Int = 0,
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aaa: Int = 0
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)
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case class SampleFields2(
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aaa123bbb: Int = 0,
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aaA123bbb: Int = 0,
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aaa123Bbb: Int = 0,
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aaA123Bbb: Int = 0,
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aaa123: Int = 0,
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aaA123: Int = 0,
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aAA123: Int = 0
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)
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implicit val jsonFormat1: RootJsonFormat[SampleFields] =
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jsonFormat21(SampleFields.apply)
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implicit val jsonFormat2: RootJsonFormat[SampleFields2] =
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jsonFormat7(SampleFields2.apply)
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// When
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val sampleFields1 = SampleFields().toJson.asJsObject
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val sampleFields2 = SampleFields2().toJson.asJsObject
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// Then
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val fields1 = sampleFields1.fields
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fields1.contains(snakify("HelloWorld")) mustEqual true
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fields1.contains(snakify("A1AAbBBBBBbCCcc")) mustEqual true
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fields1.contains(snakify("AbAAbbAAAbbb1AA2bb1AA2AAAAbb1bAA")) mustEqual true
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fields1.contains(snakify("x")) mustEqual true
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fields1.contains(snakify("Y")) mustEqual true
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fields1.contains(snakify("^There-arE_Non_(Alphabetic))_character!S")) mustEqual true
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fields1.contains(snakify("tHere-Are_(AlsO)_noN_(alphaBetic))_CharaCter!s")) mustEqual true
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fields1.contains(snakify(" There are space character ")) mustEqual true
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fields1.contains(snakify(" これは　マルチバイトAbcのaBc確認です。")) mustEqual true
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fields1.contains(snakify("aa")) mustEqual true
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fields1.contains(snakify("aA")) mustEqual true
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fields1.contains(snakify("Aa")) mustEqual true
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fields1.contains(snakify("AA")) mustEqual true
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fields1.contains(snakify("AAA")) mustEqual true
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fields1.contains(snakify("aaA")) mustEqual true
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fields1.contains(snakify("aAa")) mustEqual true
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fields1.contains(snakify("Aaa")) mustEqual true
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fields1.contains(snakify("AAa")) mustEqual true
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fields1.contains(snakify("AaA")) mustEqual true
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fields1.contains(snakify("aAA")) mustEqual true
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fields1.contains(snakify("aaa")) mustEqual true
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val fields2 = sampleFields2.fields
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fields2.contains(snakify("aaa123bbb")) mustEqual true
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fields2.contains(snakify("aaa123Bbb")) mustEqual true
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fields2.contains(snakify("aaA123bbb")) mustEqual true
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fields2.contains(snakify("aaa123")) mustEqual true
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fields2.contains(snakify("aaA123")) mustEqual true
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fields2.contains(snakify("aAA123")) mustEqual true
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}
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"deserialize snake cased json" in {
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// Given
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case class SampleFields(
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a: Int,
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aA: Int,
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helloWorld: Int,
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HelloTheWorld: Int
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)
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implicit val jsonFormat: RootJsonFormat[SampleFields] =
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jsonFormat4(SampleFields.apply)
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val json = JsObject(
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"hello_the_world" -> 4.toJson,
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"a_a" -> 2.toJson,
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"a" -> 1.toJson,
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"hello_world" -> 3.toJson
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)
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// When
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val result = jsonFormat.read(json)
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// Then
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result mustEqual SampleFields(
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a = 1, aA = 2, helloWorld = 3, HelloTheWorld = 4
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)
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}
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}
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}

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