Starting with the basics, I've implemented an Echo server (which seems to be the "hello, world" of network programming). It's quite simple - wait for a connection, read a single line of text, send the text straight back and close the connection. Here's what I've come up with (I'm certain it could be made more concise, but then in Scala "there's always a more consise way to do it")
import java.net._
import java.io._
import scala.actors._
import scala.actors.Actor._
case class Echo(socket: Socket)
object Service extends Actor {
implicit def inputStreamWrapper(in: InputStream) =
new BufferedReader(new InputStreamReader(in))
implicit def outputStreamWrapper(out: OutputStream) =
new PrintWriter(new OutputStreamWriter(out))
def echo(in: BufferedReader, out: PrintWriter) {
val line = in.readLine()
out.println(line)
out.flush()
}
def act() {
loop {
receive {
case Echo(socket) =>
actor {
echo(socket.getInputStream(), socket.getOutputStream())
socket.close
}
}
}
}
}
object EchoServer {
Service.start
val serverSocket = new ServerSocket(12111)
def start() {
while(true) {
println("about to block")
val clientSocket = serverSocket.accept()
Service ! Echo(clientSocket)
println("back from actor")
}
}
}
EchoServer.start
