Verify that roomHello is requesting a supported version.

errors.go

@@ -39,3 +39,10 @@ type ArgError struct {
 }
 
 func (e ArgError) Error() string { return fmt.Sprintf("ARG.ERROR: %s", e.message) }
+
+// VersionError describes a mismatch between requested and supported versions.
+type VersionError struct {
+	message string
+}
+
+func (e VersionError) Error() string { return fmt.Sprintf("VERSION.ERROR: %s", e.message) }

roomgoodbye.go

@@ -12,7 +12,7 @@ import (
 
 // Handles the "good-bye" request that is received each time
 // a player leaves our room.
-func handleGoodbye(conn *websocket.Conn, req *GameonRequest, room string) error {
+func handleGoodbye(conn *websocket.Conn, req *GoodbyeMessage, room string) error {
 	locus := "GOODBYE"
 	checkpoint(locus, fmt.Sprintf("room=%s userid=%s username=%s\n",
 		MyRooms[room], req.UserId, req.Username))

roomhello.go

@@ -25,13 +25,26 @@ type HelloResponse struct {
 // Handles the "hello" request that is received each time
 // a player enters our room. The incoming request is a string
 // with the format <room>,<json>, where the JSON string contains
-// the userid and username of the player entering our room. For
-// example: "Room 3100",{"username": "ebullient","userId": "github:808713"}
+// the version, userid and username of the player entering our room.
+// For example:
+//   roomHello,43a4d07399ea23d648568c6d2d000b65,
+//   {"version": 1,"username": "DevUser","userId": "dummy.DevUser"}
 //
 // Return an error if a problem occurs, otherwise return nil.
-func handleHello(conn *websocket.Conn, req *GameonRequest, room string) (e error) {
-	checkpoint("HELLO", fmt.Sprintf("room=%s userid=%s username=%s\n",
-		config.roomName, req.UserId, req.Username))
+func handleHello(conn *websocket.Conn, req *HelloMessage, room string) (e error) {
+	locus := "HELLO"
+	checkpoint(locus, fmt.Sprintf("room=%s version=%d userid=%s username=%s\n",
+		MyRooms[room], req.Version, req.UserId, req.Username))
+
+	if versionSupported(req.Version) {
+		checkpoint(locus, fmt.Sprintf("VERSION=%d is supported.", req.Version))
+	} else {
+		checkpoint(locus, fmt.Sprintf("VERSION=%d is NOT supported.", req.Version))
+		conn.Close()
+		checkpoint(locus, "CONN.CLOSED")
+		e = VersionError{fmt.Sprintf("Version %d is not supported by this room.", req.Version)}
+		return
+	}
 
 	// Announce to the room and the player that the player has entered
 	// the room. Ignore errors for this.
@@ -75,3 +88,12 @@ func handleHello(conn *websocket.Conn, req *GameonRequest, room string) (e error
 	e = sendPlayerResp(conn, req.UserId, j)
 	return
 }
+
+func versionSupported(v int) bool {
+	for _, v := range SupportedVersions {
+		if v == v {
+			return true
+		}
+	}
+	return false
+}

server.go

@@ -18,6 +18,23 @@ const (
 	lookAround  = "look"
 )
 
+// roomHello,43a4d07399ea23d648568c6d2d000b65,
+// {"version": 1,"username": "DevUser","userId": "dummy.DevUser"}
+type HelloMessage struct {
+	Version  int    `json:"version,omitempty"`
+	UserId   string `json:"userId,omitempty"`
+	Username string `json:"username,omitempty"`
+}
+
+// roomGoodbye,43a4d07399ea23d648568c6d2d000b65,
+// {"username": "DevUser","userId": "dummy.DevUser"}
+type GoodbyeMessage struct {
+	UserId   string `json:"userId,omitempty"`
+	Username string `json:"username,omitempty"`
+}
+
+// room,43a4d07399ea23d648568c6d2d000b65,
+// {"username":"DevUser","userId":"dummy.DevUser","content":"/examine book"}
 type GameonRequest struct {
 	UserId   string `json:"userId,omitempty"`
 	Username string `json:"username,omitempty"`
@@ -68,31 +85,42 @@ func roomHandler(w http.ResponseWriter, r *http.Request) {
 			checkpoint(locus, fmt.Sprintf("PARSE.ERROR err=%s", err.Error()))
 			continue
 		}
-		if config.debug {
-			fmt.Printf("PARSED cmd=%s\n", cmd)
-			fmt.Printf("PARSED room=%s\n", room)
-			fmt.Printf("PARSED JSON=%s\n", j)
-		}
 
-		var req GameonRequest
-		err = json.Unmarshal([]byte(j), &req)
-		if err != nil {
-			checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR err=%s", err.Error()))
-			checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR Offending JSON=%s", j))
-			continue
-		}
 		if config.debug {
-			fmt.Printf("roomHandler cmd='%s'\n", cmd)
-			fmt.Printf("roomHandler room='%s'\n", room)
-			fmt.Printf("roomHandler json='%s'\n", j)
+			checkpoint(locus, fmt.Sprintf("PARSE cmd=%s", cmd))
+			checkpoint(locus, fmt.Sprintf("PARSE room=%s", room))
+			checkpoint(locus, fmt.Sprintf("PARSE json=%s", j))
 		}
 
 		switch cmd {
 		case "roomHello":
+			var req HelloMessage
+			err = json.Unmarshal([]byte(j), &req)
+			if err != nil {
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR err=%s", err.Error()))
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR Offending JSON=%s", j))
+				continue
+			}
 			err = handleHello(conn, &req, room)
+
 		case "roomGoodbye":
+			var req GoodbyeMessage
+			err = json.Unmarshal([]byte(j), &req)
+			if err != nil {
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR err=%s", err.Error()))
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR Offending JSON=%s", j))
+				continue
+			}
 			err = handleGoodbye(conn, &req, room)
+
 		case "room":
+			var req GameonRequest
+			err = json.Unmarshal([]byte(j), &req)
+			if err != nil {
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR err=%s", err.Error()))
+				checkpoint(locus, fmt.Sprintf("JSON.UNMARSHALL.ERROR Offending JSON=%s", j))
+				continue
+			}
 			err = handleRoom(conn, &req, room)
 		default:
 			err = handleInvalidMessage(conn, payload)