IO Helpers - Automated Backup and Restoration of Lucene Indices with Amazon S3 - http://eng.kifi.com/automated-backup-and-restoration-of-lucene-indices-with-amazon-s3/

IO.scala

import java.io._
import java.util.zip.{GZIPInputStream, GZIPOutputStream}
import org.apache.commons.compress.archivers.tar.{TarArchiveInputStream, TarArchiveEntry, TarArchiveOutputStream}
import org.apache.commons.io.{IOUtils, FileUtils}

object IO {

  def addToArchive(tarArchive: TarArchiveOutputStream, file: File, base: String = ""): Unit = {
    val entryName = base + file.getName
    val entry = new TarArchiveEntry(file, entryName)
    tarArchive.putArchiveEntry(entry)
    entry.setSize(file.length())
    if (file.isFile) { FileUtils.copyFile(file, tarArchive) }
    tarArchive.closeArchiveEntry()
    if (file.isDirectory) file.listFiles().foreach(addToArchive(tarArchive, _, entryName + "/"))
  }

  def extractArchive(tarArchive: TarArchiveInputStream, destDir: String): Seq[File] = {
    val files = new ListBuffer[File]
    var entryOption = Option(tarArchive.getNextTarEntry)
    while (entryOption.isDefined) {
      entryOption.foreach { entry =>
        val file = new File(destDir, entry.getName)
        files.append(file)
        if (entry.isFile) {
          val out = FileUtils.openOutputStream(file)
          try { IOUtils.copyLarge(tarArchive, out, 0, entry.getSize) }
          catch { case e: Throwable => files.foreach(_.delete()); throw e } // directories created by FileUtils.openOutputStream may not be cleaned up
          finally { out.close() }
        }
        else {
          try { FileUtils.forceMkdir(file) }
          catch { case e: Throwable => files.foreach(_.delete()); throw e } // directories created by FileUtils.forceMkdir may not be cleaned up
        }
      }
      entryOption = Option(tarArchive.getNextTarEntry)
    }
    files.toList
  }

  def compress(file: File, outputStream: OutputStream): Unit = {
    val gZip = new GZIPOutputStream(outputStream)
    val compressedTarArchive = new TarArchiveOutputStream(gZip)
    compressedTarArchive.setBigNumberMode(TarArchiveOutputStream.BIGNUMBER_STAR)
    addToArchive(compressedTarArchive, file)
    compressedTarArchive.finish()
    gZip.finish()
  }

  def compress(file: File, destDir: String = FileUtils.getTempDirectoryPath): File = {
    val tarGz = new File(destDir, file.getName + ".tar.gz")
    val out = FileUtils.openOutputStream(tarGz)
    try { compress(file, out) }
    catch { case e: Throwable => tarGz.delete(); throw e }
    finally { out.close() }
    tarGz
  }

  def uncompress(tarGzStream: InputStream, destDir: String): Unit = {
    val uncompressedTarArchive = new TarArchiveInputStream(new GZIPInputStream(tarGzStream))
    extractArchive(uncompressedTarArchive, destDir)
  }

  def uncompress(tarGz: File, destDir: String): Unit = {
    val inputStream = FileUtils.openInputStream(tarGz)
    try { uncompress(inputStream, destDir) }
    finally { inputStream.close() }
  }
}