Generate rebel.xml for a webapp with the web-plugin for sbt

jrebel.scala

val generateJRebel = TaskKey[Unit]("generate-jrebel", "Generates a rebel.xml for a webapp")

  def generateJRebelXmlTask =
    (resourceManaged in Compile, crossTarget in Compile, crossTarget in Test, webappResources in Compile, streams) map {
        (tgt, src, tst, extra, s) =>
          val content = (scala.xml.Utility trimProper {
            <application
                xsi:schemaLocation="http://www.zeroturnaround.com/alderaan/rebel-2_0.xsd"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xmlns="http://www.zeroturnaround.com"
                >
              <classpath>
                <dir name={src.getAbsolutePath + "/classes"} />
                <dir name={tst.getAbsolutePath + "/test-classes"}></dir>
              </classpath>
              <web>
                <link>
                  {extra map { e => <dir name={e.getAbsolutePath} />}}
                </link>
              </web>
            </application>
          }).toString()
          val res = tgt / "rebel.xml"
          s.log.info("Generating %s.".format(res, content))
          IO.write(res, content, Codec.UTF8, append = false)
      }

  val jrebelSettings = Seq(
    generateJRebel in Compile <<= generateJRebelXmlTask,
    generateJRebel <<= generateJRebel in Compile,
    compile in Compile <<= (compile in Compile).dependsOn(generateJRebel in Compile)
  )