Scala: InputStream to Array[Byte]
How about:
Stream.continually(is.read).takeWhile(_ != -1).map(_.toByte).toArray
Update:
Use LazyList instead of Stream
(since 2.13.x deprecated)
LazyList.continually(is.read).takeWhile(_ != -1).map(_.toByte).toArray
Just removed bottleneck in our server code by replacing
Stream.continually(request.getInputStream.read()).takeWhile(_ != -1).map(_.toByte).toArray
with
org.apache.commons.io.IOUtils.toByteArray(request.getInputStream)
Or in pure Scala:
def bytes(in: InputStream, initSize: Int = 8192): Array[Byte] = {
var buf = new Array[Byte](initSize)
val step = initSize
var pos, n = 0
while ({
if (pos + step > buf.length) buf = util.Arrays.copyOf(buf, buf.length << 1)
n = in.read(buf, pos, step)
n != -1
}) pos += n
if (pos != buf.length) buf = util.Arrays.copyOf(buf, pos)
buf
}
Do not forget to close an opened input stream in any case:
val in = request.getInputStream
try bytes(in) finally in.close()
In a similar vein to Eastsun's answer... I started this as a comment, but it ended up getting just a bit to long!
I'd caution against using Stream
, if holding a reference to the head element then streams can easily consume a lot of memory.
Given that you're only going to read in the file once, then Iterator
is a much better choice:
def inputStreamToByteArray(is: InputStream): Array[Byte] =
Iterator continually is.read takeWhile (-1 !=) map (_.toByte) toArray