databinder dispatch not properly handling HTTP 302 and authentication

Question

I am using dispatch 0.11.0, Scala 2.10 and trying to get this code to work

val svc = url("https://my-server/img/cat.jpg").as(username, password)
val respBody = Http(svc OK as.Response(_.getResponseBodyAsStream))
respBody onComplete {
   case Success(stream) => {
     val fos = new java.io.FileOutputStream("myfile.jpg")
     Iterator
       .continually (stream.read)
       .takeWhile (-1 !=)
       .foreach (fos.write)
     fos.close()
   }
   case Failure(exception) => {
     Logger.log.error(exception.toString)
   }
 }

When the server returns 302, dispatch doesn't handle authenticaton properly and Failure was executed. The odd thing is if I point the url to a JSON endpoint which returns a 401, the authentication works just fine. I don't know why the server is setup to return 2 different statuses for unauthorized access but I need to figure out how to deal with this. Any insights will be much appreciated.

Thanks, Bob

Answer 1

Try as_!() instead of as(), it uses preemptive auth.

source:

  def as(user: String, password: String) =
    subject.setRealm(new RealmBuilder()
      .setPrincipal(user)
      .setPassword(password)
      .build())
  def as_!(user: String, password: String) =
    subject.setRealm(new RealmBuilder()
      .setPrincipal(user)
      .setPassword(password)
      .setUsePreemptiveAuth(true)
      .setScheme(AuthScheme.BASIC)
      .build())