Scalatra: chunked transfer Encoding HTTP endpoint example

chunked_encoding_client.py

#
#   a simple client for the endpoint.
#
import requests
import time
r = requests.get("http://localhost:8080/chunks", stream=True)
t0 = time.time()
for message in r.iter_lines(chunk_size=1):
    print("At %d s, recieved: %s" % (time.time()-t0, message.decode("utf-8")))

ScalatraChunkedEncoding.scala

import org.json4s.{DefaultFormats, Formats}
import scala.language.postfixOps
import scalate.ScalateSupport
import org.scalatra._
import java.io.PrintWriter

class Chunks extends ScalatraServlet with ScalateSupport {
  /*
    Simple example of chunked transfer encoding in Scalatra (scala web framework)
  */

  get("/") {
    response.setHeader("Content-Type", "text/html")
    response.setHeader("Transfer-Encoding", "chunked")
    response.setStatus(200)

    val out = response.getWriter

    0 to 100 foreach { i=>
      sendMessage(s"Hello! This is message $i.", out)
      Thread.sleep(1000)
    }
  }

  def sendMessage(message:String, output:PrintWriter): Unit = {
    output.println(message)
    output.flush()
    println("SENT: " + message)
  }
}