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Simplify and optimize prettyPrint and stringify methods #1280

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32187e9
test: safer assertions by checking the Jackson node class and not onl…
gaeljw Dec 31, 2025
5f452a5
refactor: remove intermediate JsonGenerator and StringWriter for pret…
gaeljw Jan 3, 2026
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121 changes: 48 additions & 73 deletions play-json/jvm/src/main/scala/play/api/libs/json/jackson/JacksonJson.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@ package play.api.libs.json.jackson

import java.io.InputStream
import java.io.OutputStream
import java.io.StringWriter

import scala.annotation.switch
import scala.annotation.tailrec
Expand All @@ -20,7 +19,6 @@ import com.fasterxml.jackson.core.JsonParser
import com.fasterxml.jackson.core.JsonTokenId
import com.fasterxml.jackson.core.Version
import com.fasterxml.jackson.core.json.JsonWriteFeature
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter

import com.fasterxml.jackson.databind.Module.SetupContext
import com.fasterxml.jackson.databind._
Expand Down Expand Up @@ -283,43 +281,56 @@ private[play] object JacksonJson {
}

private[play] case class JacksonJson(defaultMapperJsonConfig: JsonConfig) {
private var currentMapper: ObjectMapper = null
private val defaultMapper: ObjectMapper = JsonMapper
.builder(
new JsonFactoryBuilder()
.streamReadConstraints(defaultMapperJsonConfig.streamReadConstraints)
.streamWriteConstraints(defaultMapperJsonConfig.streamWriteConstraints)
.build()
)
.addModules(
new ParameterNamesModule(),
new Jdk8Module(),
new JavaTimeModule(),
new DefaultScalaModule(),
new PlayJsonMapperModule(defaultMapperJsonConfig),
)
.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
.disable(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS)
.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)
.build()

private[play] def mapper(): ObjectMapper = if (currentMapper == null) {
defaultMapper
} else {
currentMapper
private var currentMapper: ObjectMapper = null
private var currentMapperWithEscapeNonAscii: ObjectMapper = null

private val defaultMapper: ObjectMapper = buildMapper(false)
private val defaultMapperWithEscapeNonAscii: ObjectMapper = buildMapper(true)

private def buildMapper(escapeNonAscii: Boolean): ObjectMapper = {
JsonMapper
.builder(
new JsonFactoryBuilder()
.streamReadConstraints(defaultMapperJsonConfig.streamReadConstraints)
.streamWriteConstraints(defaultMapperJsonConfig.streamWriteConstraints)
.build()
)
.addModules(
new ParameterNamesModule(),
new Jdk8Module(),
new JavaTimeModule(),
new DefaultScalaModule(),
new PlayJsonMapperModule(defaultMapperJsonConfig),
)
.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
.disable(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS)
.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)
.configure(JsonWriteFeature.ESCAPE_NON_ASCII, escapeNonAscii)
.build()
}

private[play] def mapper(escapeNonAscii: Boolean = false): ObjectMapper = {
if (escapeNonAscii) {
if (currentMapperWithEscapeNonAscii == null) {
defaultMapperWithEscapeNonAscii
} else {
currentMapperWithEscapeNonAscii
}
} else {
if (currentMapper == null) {
defaultMapper
} else {
currentMapper
}
}
}

private[play] def setObjectMapper(mapper: ObjectMapper): Unit = {
this.currentMapper = mapper
this.currentMapperWithEscapeNonAscii = mapper.copy().enable(JsonWriteFeature.ESCAPE_NON_ASCII.mappedFeature)
}

private def stringJsonGenerator(out: StringWriter) =
mapper().getFactory.createGenerator(out)

private def stringJsonGenerator(out: OutputStream) =
mapper().getFactory.createGenerator(out)

def parseJsValue(data: Array[Byte]): JsValue =
mapper().readValue(mapper().getFactory.createParser(data), classOf[JsValue])

Expand All @@ -329,53 +340,17 @@ private[play] case class JacksonJson(defaultMapperJsonConfig: JsonConfig) {
def parseJsValue(stream: InputStream): JsValue =
mapper().readValue(mapper().getFactory.createParser(stream), classOf[JsValue])

private def withStringWriter[T](f: StringWriter => T): T = {
val sw = new StringWriter()

try {
f(sw)
} catch {
case err: Throwable => throw err
} finally {
if (sw != null) try {
sw.close()
} catch {
case _: Throwable => ()
}
}
}

def generateFromJsValue(jsValue: JsValue, escapeNonASCII: Boolean): String =
withStringWriter { sw =>
val gen = stringJsonGenerator(sw)

if (escapeNonASCII) {
gen.enable(JsonWriteFeature.ESCAPE_NON_ASCII.mappedFeature)
}
mapper(escapeNonASCII).writeValueAsString(jsValue)

mapper().writeValue(gen, jsValue)
sw.flush()
sw.getBuffer.toString
}

def prettyPrint(jsValue: JsValue): String = withStringWriter { sw =>
val gen = stringJsonGenerator(sw).setPrettyPrinter(
new DefaultPrettyPrinter()
)
def prettyPrint(jsValue: JsValue): String = {
val writer: ObjectWriter = mapper().writerWithDefaultPrettyPrinter()

writer.writeValue(gen, jsValue)
sw.flush()
sw.getBuffer.toString
writer.writeValueAsString(jsValue)
}

def prettyPrintToStream(jsValue: JsValue, stream: OutputStream): Unit = {
val gen = stringJsonGenerator(stream).setPrettyPrinter(
new DefaultPrettyPrinter()
)
val writer: ObjectWriter = mapper().writerWithDefaultPrettyPrinter()

writer.writeValue(gen, jsValue)
writer.writeValue(stream, jsValue)
}

def jsValueToBytes(jsValue: JsValue): Array[Byte] =
Expand Down
36 changes: 26 additions & 10 deletions play-json/jvm/src/test/scala/play/api/libs/json/JsonSpec.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ import java.util.TimeZone

import com.fasterxml.jackson.databind.JsonNode
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.node.{ ArrayNode, NumericNode, ObjectNode }
import play.api.libs.functional.syntax._
import play.api.libs.json.Json._
import play.api.libs.json.jackson.JacksonJson
Expand Down Expand Up @@ -469,36 +470,51 @@ class JsonSpec extends org.specs2.mutable.Specification {
}

"Serialize and deserialize Jackson ObjectNodes" in {
val on = mapper
val on: ObjectNode = mapper
.createObjectNode()
.put("foo", 1)
.put("bar", "two")
val json = Json.obj("foo" -> 1, "bar" -> "two")
val json = Json.obj("foo" -> 1, "bar" -> "two")
val deserialized: JsResult[JsonNode] = fromJson[JsonNode](json)

toJson(on).must_==(json) and (
fromJson[JsonNode](json).map(_.toString).must_==(JsSuccess(on.toString))
deserialized.map(_.isInstanceOf[ObjectNode]).must_==(JsSuccess(true))
) and (
deserialized.map(_.toString).must_==(JsSuccess(on.toString))
)
}

"Serialize and deserialize Jackson ArrayNodes" in {
val an = mapper
val an: ArrayNode = mapper
.createArrayNode()
.add("one")
.add(2)
val json = Json.arr("one", 2)
val json = Json.arr("one", 2)
val deserialized: JsResult[JsonNode] = fromJson[JsonNode](json)

toJson(an).must(equalTo(json)) and (
fromJson[JsonNode](json).map(_.toString).must_==(JsSuccess(an.toString))
deserialized.map(_.isInstanceOf[ArrayNode]).must_==(JsSuccess(true))
) and (
deserialized.map(_.toString).must_==(JsSuccess(an.toString))
)
}

"Deserialize integer JsNumber as Jackson number node" in {
val jsNum = JsNumber(new java.math.BigDecimal("50"))
fromJson[JsonNode](jsNum).map(_.toString).must_==(JsSuccess("50"))
val jsNum = JsNumber(new java.math.BigDecimal("50"))
val deserialized: JsResult[JsonNode] = fromJson[JsonNode](jsNum)

deserialized.map(_.isInstanceOf[NumericNode]).must_==(JsSuccess(true)) and (
deserialized.map(_.toString).must_==(JsSuccess("50"))
)
}

"Deserialize float JsNumber as Jackson number node" in {
val jsNum = JsNumber(new java.math.BigDecimal("12.345"))
fromJson[JsonNode](jsNum).map(_.toString).must_==(JsSuccess("12.345"))
val jsNum = JsNumber(new java.math.BigDecimal("12.345"))
val deserialized: JsResult[JsonNode] = fromJson[JsonNode](jsNum)

deserialized.map(_.isInstanceOf[NumericNode]).must_==(JsSuccess(true)) and (
deserialized.map(_.toString).must_==(JsSuccess("12.345"))
)
}

"Serialize JsNumbers with integers correctly" in {
Expand Down
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