A simple server in Frege.

Server.fr

module Server where

import frege.java.IO hiding (OutputStream)


data Executor = native java.util.concurrent.Executor

data InetSocketAddress = native java.net.InetSocketAddress where
	native new :: Int -> STMutable s InetSocketAddress

data HttpServer = native com.sun.net.httpserver.HttpServer where
	native create "com.sun.net.httpserver.HttpServer.create" :: Mutable s InetSocketAddress -> Int -> STMutable s HttpServer throws IOException
	native createContext :: MutableIO HttpServer -> String -> MutableIO HttpHandler -> IO ()
	native setExecutor :: MutableIO HttpServer -> Maybe Executor -> IO ()
	native start :: MutableIO HttpServer -> IO ()

data OutputStream = mutable native java.io.OutputStream where
	native write :: OutputStream -> ArrayOf RealWorld Byte -> IO () throws IOException
	native close :: OutputStream -> IO () throws IOException

data StringAsBytes = native java.lang.String where
  native getBytes :: String -> STMutable s (JArray Byte)

data HttpExchange = native com.sun.net.httpserver.HttpExchange where
	native getResponseBody :: MutableIO HttpExchange -> IO OutputStream
	native sendResponseHeaders :: MutableIO HttpExchange -> Int -> Long -> IO () throws IOException

data HttpHandler = native com.sun.net.httpserver.HttpHandler where
	-- substitute for a constructor
	native new Server.Handler.newInstance :: (MutableIO HttpExchange -> IO ()) -> STMutable s HttpHandler 

response :: String
response = "<h1>It worked!!</h1>"

handle :: MutableIO HttpExchange -> IO ()
handle t = do
	t.sendResponseHeaders 200 (length response).long
	os <- t.getResponseBody
	bytes <- StringAsBytes.getBytes response
	os.write bytes
	os.close

native module where {
	public static class Handler implements com.sun.net.httpserver.HttpHandler {
		final frege.run7.Func.U handlerFunction;

		public Handler(frege.run7.Func.U function){
			this.handlerFunction = function;
		}

		public static Handler newInstance(frege.run7.Func.U function) {
			Handler h = new Handler(function);
			return h;
		}

		@Override
		public void handle(com.sun.net.httpserver.HttpExchange t) throws java.io.IOException {
			try {
				final frege.run7.Func.U res = RunTM.<frege.run7.Func.U>cast(handlerFunction.apply(Thunk.lazy(t)).call());
				frege.prelude.PreludeBase.TST.run(res).call();
			} catch (Exception e) {
				System.out.println("Failed to execute handler");
			}
			
		}
	}
}

main args = do
	inet <- InetSocketAddress.new 8000
	server <- HttpServer.create inet 0
	handler <- HttpHandler.new handle
	server.createContext "/" handler
	server.start
	println "Serving HTTP on 0.0.0.0 port 8000"