Starts a server on the default port of 6667

When connecting to the server it send "Hi" and then closes the
connection. We thought this could be a good starting point.

issue #3
Dave & Amos

mcferkincaht.cabal

@@ -11,7 +11,8 @@ build-type: Simple
 
 executable program1
   build-depends:       base                == 4.5.*
-  main-is: Server.hs
+                     , network             >= 2.3
+  main-is: Main.hs
   ghc-options:
     -Wall -Werror
   hs-source-dirs: src
@@ -28,3 +29,4 @@ test-suite specs
                      , mtl                 == 2.1.*
                      , hspec               >= 1.3
                      , hspec-expectations  >= 0.3
+                     , network             >= 2.3

spec/ServerSpec.hs

@@ -7,5 +7,5 @@ spec = do
  describe "The Server" $ do
    describe "default port" $ do
      it "is 6667" $ do
-       let testObject = server
+       let testObject = mcferkinServer
        (port testObject) `shouldBe` 6667

src/Main.hs

@@ -4,5 +4,5 @@ import Server
 
 main :: IO ()
 main = do
-  let myServer = server
-  print $ show myServer
+  let server = mcferkinServer
+  startServer server

src/Server.hs

@@ -1,6 +1,7 @@
-module Server ( Server, port, server ) where
+module Server ( Server, port, mcferkinServer, startServer ) where
+import Network.Socket
 
-type Port = Int
+type Port = PortNumber
 
 defaultPort :: Port
 defaultPort = 6667
@@ -9,5 +10,27 @@ data Server = Server {
     port :: Port
   } deriving ( Show )
 
-server :: Server
-server = Server{ port=defaultPort }
+mcferkinServer :: Server
+mcferkinServer = Server{ port=defaultPort }
+
+startServer :: Server -> IO ()
+startServer server = do
+    -- create socket
+    sock <- socket AF_INET Stream 0
+    -- make socket immediately reusable - eases debugging.
+    setSocketOption sock ReuseAddr 1
+    bindSocket sock (SockAddrInet (port server) iNADDR_ANY)
+    -- allow a maximum of 2 outstanding connections
+    listen sock 2
+    mainLoop sock
+
+mainLoop :: Socket -> IO ()
+mainLoop sock = do
+    conn <- accept sock
+    runConn conn
+    mainLoop sock
+
+runConn :: (Socket, SockAddr) -> IO ()
+runConn (sock, _) = do
+    _ <- send sock "Hi!\n"
+    sClose sock