Akka-http 1.0-RC4 on android 5.0.1 : that rocks !

[alain marcel]

Hi everybody !

Following code is a server realized with akka-http on android that serves files.

For this to work, just call new ServerForDownloadFile() in an android AsyncTask.

class ServerForDownloadTask extends AsyncTask[AnyRef, Void, AnyRef] {

protected def doInBackground(args: AnyRef*): AnyRef = {

try {

new ServerForDownloadFile()

} catch { case e: Exception => println(e) }

}

return null

}

protected def onProgressUpdate(progress: Integer*) {}

protected def onPostExecute(result: Long) {}

}

Take care : this will work only with scala 2.11 (not with scala 2.12) because android is java 6 compatible (not java 8).

ServerForDownloadFile.scala

======================

package app

import java.io.File

import java.io.FileInputStream

import java.nio.channels.FileChannel

import java.nio.ByteBuffer

import java.nio.MappedByteBuffer

import scala.concurrent.Future

import scala.concurrent.duration._

import scala.util.Try

import scala.util.control.NonFatal

import akka.actor.ActorSystem

import akka.http.scaladsl.Http

import akka.http.scaladsl.model.HttpEntity.ChunkStreamPart

import akka.http.scaladsl.model._

import akka.stream.ActorMaterializer

import akka.stream.scaladsl.Sink

import akka.stream.scaladsl.Source

import akka.util.ByteString

import akka.util.Timeout

import android.os.Environment

class ByteBufferIterator(buffer:ByteBuffer, chunkSize:Int) extends Iterator[ByteString] {

require(buffer.isReadOnly)

require(chunkSize > 0)

override def hasNext = buffer.hasRemaining

override def next(): ByteString = {

val size = chunkSize min buffer.remaining()

val temp = buffer.slice()

temp.limit(size)

buffer.position(buffer.position() + size)

ByteString(temp)

}

}

class ServerForDownloadFile {

def map1(path: String) : MappedByteBuffer = {

val inputStream = new FileInputStream(path)

val channel: FileChannel = inputStream.getChannel();

val result = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size);

channel.close()

result

}

implicit val system = ActorSystem()

implicit val materializer = ActorMaterializer()

implicit val askTimeout: Timeout = 500.millis

import HttpMethods._

val requestHandler: HttpRequest => HttpResponse = {

case HttpRequest(GET, uri, headers, _, _) =>

val dir: File = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)

val path: String = dir.getPath.toString + "/myfile.avi"

println("=========== path=" + path)

val result = Try {

val mappedByteBuffer = map1(path)

val iterator = new ByteBufferIterator(mappedByteBuffer, 4096)

var cnt = 0

val chunks = Source(() => iterator).map { x =>

if ( cnt % 10000 == 0 )

println("Chunk of size " + x.size + "  cnt=" + cnt)

cnt += 1

ChunkStreamPart(x)

}

HttpResponse(entity = HttpEntity.Chunked(MediaTypes.`application/octet-stream`, chunks))

} recover {

case NonFatal(cause) =>

HttpResponse(StatusCodes.InternalServerError, entity = cause.getMessage)

}

result.get

case _: HttpRequest => HttpResponse(StatusCodes.NotFound, entity = "Unknown resource!")

}

val address = "localhost"

val serverSource: Source[Http.IncomingConnection, Future[Http.ServerBinding]] = Http(system).bind(interface = address, port = 8080)

val bindingFuture: Future[Http.ServerBinding] = serverSource.to(Sink.foreach { connection =>

// foreach materializes the source

println("Accepted new connection from " + connection.remoteAddress)

// ... and then actually handle the connection

connection.handleWithSyncHandler(requestHandler)

}).run()

while (true )

Thread.sleep(100)

}

[Johannes Rudolph]

Hi Alain,

On Friday, July 3, 2015 at 9:05:50 AM UTC+2, alain marcel wrote:

Following code is a server realized with akka-http on android that serves files.

For this to work, just call new ServerForDownloadFile() in an android AsyncTask.

Thanks for sharing! Any reason you are using a iterator over a memory mapped file instead of a SynchronousFileSource from akka-stream?

Johannes