Scala: InputStream to Array[Byte]

Question

With Scala, what is the best way to read from an InputStream to a bytearray?

I can see that you can convert an InputStream to char array

Source.fromInput         


        

Answer 1

Here's an approach using scalaz-stream:

import scalaz.concurrent.Task
import scalaz.stream._
import scodec.bits.ByteVector

def allBytesR(is: InputStream): Process[Task, ByteVector] =
  io.chunkR(is).evalMap(_(4096)).reduce(_ ++ _).lastOr(ByteVector.empty)

Answer 2

Source.fromInputStream(is).map(_.toByte).toArray

Answer 3

We can do it using google API ByteStreams

import com.google.common.io.ByteStreams

pass the stream to ByteStreams.toByteArray method for conversion

ByteStreams.toByteArray(stream)

Answer 4

def inputStreamToByteArray(is: InputStream): Array[Byte] = {
    val buf = ListBuffer[Byte]()
    var b = is.read()
    while (b != -1) {
        buf.append(b.byteValue)
        b = is.read()
    }
    buf.toArray
}

Answer 5

import scala.tools.nsc.io.Streamable
Streamable.bytes(is)

Don't remember how recent that is: probably measured in days. Going back to 2.8, it's more like

new Streamable.Bytes { def inputStream() = is } toByteArray