gamnit: move up UDP discovery logic from Tinks! to the lib

[nit.git] / lib / gamnit / network / server.nit

diff --git a/lib/gamnit/network/server.nit b/lib/gamnit/network/server.nit
index fcff7a2..926e620 100644 (file)
--- a/lib/gamnit/network/server.nit
+++ b/lib/gamnit/network/server.nit
@@ -45,7 +45,7 @@
 # ~~~
 module server
 
-import common
+intrude import common
 
 # Game server controller
 class Server
@@ -56,15 +56,15 @@ class Server
        # All connected `RemoteClient`
        var clients = new Array[RemoteClient]
 
-       # Socket accepting new connections
+       # TCP socket accepting new connections
+       #
+       # Opened on the first call to `accept_clients`.
        var listening_socket: TCPServer is lazy do
-               print port
                var socket = new TCPServer(port)
                socket.listen 8
                socket.blocking = false
                return socket
        end
-       init do listening_socket
 
        # Accept currently waiting clients and return them as an array
        fun accept_clients: Array[RemoteClient]
@@ -98,6 +98,47 @@ class Server
                        client.socket.flush
                end
        end
+
+       # Respond to pending discovery requests by sending the TCP listening address and port
+       #
+       # Returns the number of valid requests received.
+       #
+       # The response messages includes the TCP listening address and port
+       # for remote clients to connect with TCP using `connect`.
+       # These connections are accepted by the server with `accept_clients`.
+       fun answer_discovery_requests: Int
+       do
+               var count = 0
+               loop
+                       var ptr = new Ref[nullable SocketAddress](null)
+                       var read = discovery_socket.recv_from(1024, ptr)
+
+                       # No sender means there is no discovery request
+                       var sender = ptr.item
+                       if sender == null then break
+
+                       var words = read.split(" ")
+                       if words.length != 2 or words[0] != discovery_request_message or words[1] != handshake_app_name then
+                               print "Server Warning: Rejected discovery request '{read}' from {sender.address}:{sender.port}"
+                               continue
+                       end
+
+                       var msg = "{discovery_response_message} {handshake_app_name} {self.port}"
+                       discovery_socket.send_to(sender.address, sender.port, msg)
+                       count += 1
+               end
+               return count
+       end
+
+       # UDP socket responding to discovery requests
+       #
+       # Usually opened on the first call to `answer_discovery_request`.
+       var discovery_socket: UDPSocket is lazy do
+               var s = new UDPSocket
+               s.blocking = false
+               s.bind(null, discovery_port)
+               return s
+       end
 end
 
 # Reference to a remote client connected to this server