Lightweight Real-time Ajax, WebSocket, or Similar for Scala

Question

Our requirements for a real-time web framework include:

• lightweight framework
• scala support on server side
• flexible on communication mechanism : may be Ajax, Server Sent Event or WebSocket.
• relatively little changes required to client html.
  
  • E.g. using the WebSockets js library is fine
  • introducing significant compile time/server side page processing is not. E.g. Play routing annotations are not acceptable
• must have working examples for both:
  • web clients
  • server to server communications
  • fully functional build. Preferably sbt, but maven maybe acceptable

I have evaluated the following frameworks: and each one of them has one or more drawbacks that make usage within our application less than desirable.

• Play: somewhat heavy, but more importantly it introduces custom annotations/processing into the html page. We need VANILLA html pages.

• Spray: closer to the mark. But although I found a number of example applications, the actor-based communication is not working in those examples. The SimpleServer example has a built-in "cases" counter (from SimpleClient) that do not work as given: they could certainly be made to work .. eventually..

• atmosphere: lacking examples

  • jetty, netty: lacked fully functional examples buildable within sbt or maven

• socko : The markdown essentially stipulates using eclipse/scala-IDE for running tests/doing development. That is a non-starter for us (IJ shop). It was unclear how to run examples and/or start their servers from sbt / command line.

Answer 1

I ended up writing a fair amount of custom code wrapped around Netty. After it is in better shape I may drop it on GitHub.