How to upload files and get formfields in akka-http - scala

Question

I am trying to upload a file via akka-http, and have gotten it to work with the following snippet
def tempDestination(fileInfo: FileInfo): File =
File.createTempFile(fileInfo.fileName, ".tmp")
val route =
storeUploadedFile("csv", tempDestination) {
case (metadata, file) =>
//Do my operation on the file.
complete("File Uploaded. Status OK")
}
But I'd also want to send a param1/param2 in the posted form.
I tried the following, and it works, but I am having to send the parameters via the URL (http://host:port/csv-upload?userid=arvind)
(post & path("csv-upload")) {
storeUploadedFile("csv", tempDestination) {
case (metadata, file) =>
parameters('userid) { userid =>
//logic for processing the file
complete(OK)
}
}
}
The restriction on the file size is around 200-300 MB. I added the following property to my conf
akka{
http{
parsing{
max-content-length=200m
}
}
}
Is there a way, I can get the parameters via the formFields directive ?
I tried the following
fileUpload("csv") {
case (metadata, byteSource) =>
formFields('userid) { userid =>
onComplete(byteSource.runWith(FileIO.toPath(Paths.get(metadata.fileName)))) {
case Success(value) =>
logger.info(s"${metadata}")
complete(StatusCodes.OK)
case Failure(exception) =>
complete("failure")
But, with the above code, I hit the following exception
java.lang.IllegalStateException: Substream Source cannot be materialized more than once
at akka.stream.impl.fusing.SubSource$$anon$13.setCB(StreamOfStreams.scala:792)
at akka.stream.impl.fusing.SubSource$$anon$13.preStart(StreamOfStreams.scala:802)
at akka.stream.impl.fusing.GraphInterpreter.init(GraphInterpreter.scala:306)
at akka.stream.impl.fusing.GraphInterpreterShell.init(ActorGraphInterpreter.scala:593)
Thanks,
Arvind

Answer 1

I got this working with sth like:
path("upload") {
formFields(Symbol("payload")) { payload =>
println(s"Server received request with additional payload: $payload")
def tempDestination(fileInfo: FileInfo): File = File.createTempFile(fileInfo.fileName, ".tmp.server")
storeUploadedFile("binary", tempDestination) {
case (metadataFromClient: FileInfo, uploadedFile: File) =>
println(s"Server stored uploaded tmp file with name: ${uploadedFile.getName} (Metadata from client: $metadataFromClient)")
complete(Future(FileHandle(uploadedFile.getName, uploadedFile.getAbsolutePath, uploadedFile.length())))
}
}
}
Full example:
https://github.com/pbernet/akka_streams_tutorial/blob/master/src/main/scala/akkahttp/HttpFileEcho.scala