Reading a CSV files using Akka Streams

akka, akka-stream, scala

Solution

Actually, `akka-streams` provides a function to directly read from a file.

FileIO.fromPath(Paths.get("a.csv"))
      .via(Framing.delimiter(ByteString("\n"), 256, true).map(_.utf8String))
      .runForeach(println)

Here, `runForeach` method is to print the lines. If you have a proper `Sink` to process these lines, use it instead of this function. For example, if you want to split the lines by `'` and print the total number of words in it:

val sink: Sink[String] = Sink.foreach(x => println(x.split(",").size))

FileIO.fromPath(Paths.get("a.csv"))
      .via(Framing.delimiter(ByteString("\n"), 256, true).map(_.utf8String))
      .to(sink)
      .run()

Problem

I'm reading a csv file. I am using Akka Streams to do this so that I can create a graph of actions to perform on each line. I've got the following toy example up and running. ``` def main(args: Array[String]): Unit = { implicit val system = ActorSystem("MyAkkaSystem") implicit val materializer = ActorMaterializer() val source = akka.stream.scaladsl.Source.fromIterator(Source.fromFile("a.csv").getLines) val sink = Sink.foreach(println) source.runWith(sink) } ``` The two `Source` types don't sit easy with me. Is this idiomatic or is there is a better way to write this?

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