A groovy web server

Based on a suggestion made by Jamie McCrindle, I decided it was time to add some missing Groovy methods related to sockets.

So far, I have added a bunch of IO/streams methods enhancing the JDK core classes, but there were no methods dealing with sockets. But now, this time is over.

I have added two methods:

  • Socket.withStreams(Closure) which takes a closure as argument, and has acces to an input stream and an output stream, and
  • ServerSocket.accept(Closure) which takes a closure argument which uses a socket as argument

What's better than a sample code to illustrate that ? Hey, we're going to implement a simplistic Hello World web server. Here it is...

import java.net.*
server = new ServerSocket(9991)
while(true) {
  server.accept { socket ->
    socket.withStreams { input, output ->
      try {
        input.eachLine { line ->
          println line
          if (line.length() == 0) {
            throw new GroovyRuntimeException()
      } catch (GroovyRuntimeException b) { }
      output.withWriter { writer ->
        writer << "HTTP/1.1 200 OK\n"
        writer << "Content-Type: text/html\n\n"
        writer << "Hello World!"


Thank you Jamie for your code ;-)

Update 2013/02/20: I've tweaked the above script to use the proper closure syntax that we settled with in Groovy 1.0


© 2012 Guillaume Laforge | The views and opinions expressed here are mine and don't reflect the ones from my employer.