sss.openstar.attachments.FileStreamPersister.scala Maven / Gradle / Ivy

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package sss.openstar.attachments

import java.io.{File, FileOutputStream, InputStream}
import java.net.URL
import java.nio.file.{Files, Paths}

import com.google.common.io.ByteStreams

import scala.util.Try

class FileStreamPersister(attachmentsFolder: File) extends StreamPersister {

  require(attachmentsFolder.exists(), s"Folder $attachmentsFolder must exist")
  require(attachmentsFolder.isDirectory, s"Folder $attachmentsFolder must be a directory")
  require(attachmentsFolder.canWrite, s"Folder $attachmentsFolder must be writable")
  require(attachmentsFolder.canRead, s"Folder $attachmentsFolder must be readable")

  private val fileUrlPrefix = "file://"

  override def saveStream(in: InputStream, path: String*): Try[UniqueLocator] = Try {
    val saveTo = createFileToSaveTo(path: _*)
    val size = saveFile(in, saveTo)
    val location = fileToLocation(saveTo)
    UniqueLocator(location, Some(size))
  }

  override def getStream(locator: UniqueLocator): Try[InputStream] = Try {
    new URL(locator.location).openStream()
  }

  private def saveFile(in: InputStream, file: File): Long = {
    val os = new FileOutputStream(file)
    try {
      ByteStreams.copy(in, os)
    } finally {
      os.close()
      //end of the line
      in.close()
    }
  }

  private def fileToLocation(file: File): String = {
    s"$fileUrlPrefix${file.getAbsolutePath}"
  }

  private def createFileToSaveTo(path: String*): File = {
    val targetPath = Paths.get(attachmentsFolder.getAbsolutePath, path: _*)
    Files.createDirectories(targetPath.getParent)
    targetPath.toFile
  }

}