66 lines
2 KiB
Scala
66 lines
2 KiB
Scala
package docs.stream.cookbook
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import scala.concurrent.Await
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import scala.concurrent.duration._
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class RecipeDigest extends RecipeSpec {
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"Recipe for calculating digest" must {
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"work" in {
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//#calculating-digest
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import java.security.MessageDigest
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import akka.NotUsed
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import akka.stream.{ Attributes, Outlet, Inlet, FlowShape }
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import akka.stream.scaladsl.{ Sink, Source }
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import akka.util.ByteString
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import akka.stream.stage._
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val data: Source[ByteString, NotUsed] = Source.single(ByteString("abc"))
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class DigestCalculator(algorithm: String) extends GraphStage[FlowShape[ByteString, ByteString]] {
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val in = Inlet[ByteString]("DigestCalculator.in")
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val out = Outlet[ByteString]("DigestCalculator.out")
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override val shape = FlowShape(in, out)
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override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new GraphStageLogic(shape) {
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private val digest = MessageDigest.getInstance(algorithm)
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setHandler(out, new OutHandler {
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override def onPull(): Unit = pull(in)
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})
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setHandler(in, new InHandler {
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override def onPush(): Unit = {
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val chunk = grab(in)
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digest.update(chunk.toArray)
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pull(in)
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}
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override def onUpstreamFinish(): Unit = {
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emit(out, ByteString(digest.digest()))
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completeStage()
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}
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})
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}
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}
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val digest: Source[ByteString, NotUsed] = data.via(new DigestCalculator("SHA-256"))
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//#calculating-digest
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Await.result(digest.runWith(Sink.head), 3.seconds) should be(
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ByteString(
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0xba, 0x78, 0x16, 0xbf,
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0x8f, 0x01, 0xcf, 0xea,
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0x41, 0x41, 0x40, 0xde,
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0x5d, 0xae, 0x22, 0x23,
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0xb0, 0x03, 0x61, 0xa3,
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0x96, 0x17, 0x7a, 0x9c,
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0xb4, 0x10, 0xff, 0x61,
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0xf2, 0x00, 0x15, 0xad))
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}
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}
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}
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