60497f6561
Also-by: Johan Andrén <johan@markatta.com> Also-by: Roland Kuhn <rk@rkuhn.info> Also-by: Martynas Mickevičius <mmartynas@gmail.com>
101 lines
3.3 KiB
Scala
101 lines
3.3 KiB
Scala
package docs.stream.cookbook
|
|
|
|
import akka.NotUsed
|
|
import akka.stream.scaladsl.{ Flow, Sink, Source }
|
|
import akka.util.ByteString
|
|
|
|
import scala.concurrent.Await
|
|
import scala.concurrent.duration._
|
|
|
|
class RecipeByteStrings extends RecipeSpec {
|
|
|
|
"Recipes for bytestring streams" must {
|
|
|
|
"have a working chunker" in {
|
|
val rawBytes = Source(List(ByteString(1, 2), ByteString(3), ByteString(4, 5, 6), ByteString(7, 8, 9)))
|
|
val ChunkLimit = 2
|
|
|
|
//#bytestring-chunker
|
|
import akka.stream.stage._
|
|
|
|
class Chunker(val chunkSize: Int) extends PushPullStage[ByteString, ByteString] {
|
|
private var buffer = ByteString.empty
|
|
|
|
override def onPush(elem: ByteString, ctx: Context[ByteString]): SyncDirective = {
|
|
buffer ++= elem
|
|
emitChunkOrPull(ctx)
|
|
}
|
|
|
|
override def onPull(ctx: Context[ByteString]): SyncDirective = emitChunkOrPull(ctx)
|
|
|
|
override def onUpstreamFinish(ctx: Context[ByteString]): TerminationDirective =
|
|
if (buffer.nonEmpty) ctx.absorbTermination()
|
|
else ctx.finish()
|
|
|
|
private def emitChunkOrPull(ctx: Context[ByteString]): SyncDirective = {
|
|
if (buffer.isEmpty) {
|
|
if (ctx.isFinishing) ctx.finish()
|
|
else ctx.pull()
|
|
} else {
|
|
val (emit, nextBuffer) = buffer.splitAt(chunkSize)
|
|
buffer = nextBuffer
|
|
ctx.push(emit)
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
val chunksStream = rawBytes.transform(() => new Chunker(ChunkLimit))
|
|
//#bytestring-chunker
|
|
|
|
val chunksFuture = chunksStream.grouped(10).runWith(Sink.head)
|
|
|
|
val chunks = Await.result(chunksFuture, 3.seconds)
|
|
|
|
chunks.forall(_.size <= 2) should be(true)
|
|
chunks.fold(ByteString())(_ ++ _) should be(ByteString(1, 2, 3, 4, 5, 6, 7, 8, 9))
|
|
}
|
|
|
|
"have a working bytes limiter" in {
|
|
val SizeLimit = 9
|
|
|
|
//#bytes-limiter
|
|
import akka.stream.stage._
|
|
class ByteLimiter(val maximumBytes: Long) extends PushStage[ByteString, ByteString] {
|
|
private var count = 0
|
|
|
|
override def onPush(chunk: ByteString, ctx: Context[ByteString]): SyncDirective = {
|
|
count += chunk.size
|
|
if (count > maximumBytes) ctx.fail(new IllegalStateException("Too much bytes"))
|
|
else ctx.push(chunk)
|
|
}
|
|
}
|
|
|
|
val limiter = Flow[ByteString].transform(() => new ByteLimiter(SizeLimit))
|
|
//#bytes-limiter
|
|
|
|
val bytes1 = Source(List(ByteString(1, 2), ByteString(3), ByteString(4, 5, 6), ByteString(7, 8, 9)))
|
|
val bytes2 = Source(List(ByteString(1, 2), ByteString(3), ByteString(4, 5, 6), ByteString(7, 8, 9, 10)))
|
|
|
|
Await.result(bytes1.via(limiter).grouped(10).runWith(Sink.head), 3.seconds)
|
|
.fold(ByteString())(_ ++ _) should be(ByteString(1, 2, 3, 4, 5, 6, 7, 8, 9))
|
|
|
|
an[IllegalStateException] must be thrownBy {
|
|
Await.result(bytes2.via(limiter).grouped(10).runWith(Sink.head), 3.seconds)
|
|
}
|
|
}
|
|
|
|
"demonstrate compacting" in {
|
|
|
|
val data = Source(List(ByteString(1, 2), ByteString(3), ByteString(4, 5, 6), ByteString(7, 8, 9)))
|
|
|
|
//#compacting-bytestrings
|
|
val compacted: Source[ByteString, NotUsed] = data.map(_.compact)
|
|
//#compacting-bytestrings
|
|
|
|
Await.result(compacted.grouped(10).runWith(Sink.head), 3.seconds).forall(_.isCompact) should be(true)
|
|
}
|
|
|
|
}
|
|
|
|
}
|