Made discovery more reliable & added docs/tests

- Added unit tests - Added documentation for discovery classes - Improved error handling Tags: #story[1281]
2026-05-09 14:28:43 +00:00 · 2017-09-22 00:01:13 +12:00
parent 95ad7a4840
commit 5e3ae40d03
15 changed files with 360 additions and 155 deletions
@@ -0,0 +1,117 @@
+package seng302.discoveryServer;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import seng302.gameServer.messages.Message;
+import seng302.gameServer.messages.RoomCodeRequest;
+import seng302.gameServer.messages.ServerRegistrationMessage;
+import seng302.model.stream.packets.PacketType;
+import seng302.discoveryServer.util.ServerListing;
+import seng302.discoveryServer.util.ServerRepoStreamParser;
+import seng302.discoveryServer.util.ServerTable;
+
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Arrays;
+import java.util.Random;
+
+public class DiscoveryServer {
+    public static final String ANSI_GREEN = "\u001B[32m";
+    public static final String ANSI_YELLOW = "\u001B[33m";
+    public static final String ANSI_BLUE = "\u001B[34m";
+    public static final String ANSI_RESET = "\u001B[0m";
+    public static String DISCOVERY_SERVER = "party.sydney.srv.michaelrausch.nz";
+
+    private ServerTable serverTable;
+    public static final Integer PORT_NUMBER = 9969;
+
+    private final Logger logger = LoggerFactory.getLogger(DiscoveryServer.class);
+
+    private void displayHeader(){
+        String selectedColor = Arrays.asList(ANSI_BLUE, ANSI_GREEN, ANSI_YELLOW).get(new Random().nextInt(2));
+        System.out.println(selectedColor);
+        System.out.println("                              .ccccc.             \n" +
+                "                         .cc;'coooxkl;.           \n" +
+                "                     .:c:::c:,,,,,;c;;,.'.        \n" +
+                "                   .clc,',:,..:xxocc;'..c;        \n" +
+                "                  .c:,';:ox:..:c,,,,,,...cd,      \n" +
+                "                .c:'.,oxxxxl::l:.,loll;..;ol.     \n" +
+                "                ;Oc..:xxxxxxxxx:.,llll,....oc     \n" +
+                "             .,;,',:loxxxxxxxxx:.,llll;.,,.'ld,   \n" +
+                "            .lo;..:xxxxxxxxxxxx:.'cllc,.:l:'cO;   \n" +
+                "           .:;...'cxxxxxxxxxxxxoc;,::,..cdl;;l'   \n" +
+                "         .cl;':,'';oxxxxxxdxxxxxx:....,cooc,cO;   \n" +
+                "     .,,,::;,lxoc:,,:lxxxxxxxxxxxo:,,;lxxl;'oNc   \n" +
+                "   .cdxo;':lxxxxxxc'';cccccoxxxxxxxxxxxxo,.;lc.  " + ANSI_YELLOW + "Party-Parrots-At-Sea Discovery Server v0.1 " + selectedColor +"\n" +
+                "  .loc'.'lxxxxxxxxocc;''''';ccoxxxxxxxxx:..oc     \n" +
+                "olc,..',:cccccccccccc:;;;;;;;;:ccccccccc,.'c,     \n" +
+                "Ol;......................................;l'  ");
+        System.out.println(ANSI_RESET);
+    }
+
+    public DiscoveryServer() throws Exception {
+        displayHeader();
+        serverTable = new ServerTable();
+
+        ServerSocket serverSocket;
+
+        try{
+            serverSocket = new ServerSocket(PORT_NUMBER);
+        }
+        catch(java.net.BindException e){
+            logger.error("FATAL - Could not bind socket, are you sure there isn't already an instance running?");
+            System.exit(1);
+            return;
+        }
+
+        logger.info("Started successfully - Now accepting connections");
+
+        while (true){
+            Socket clientSocket = serverSocket.accept();
+
+            parseRequest(clientSocket);
+
+            clientSocket.close();
+        }
+    }
+
+
+    private void parseRequest(Socket clientSocket) throws Exception {
+        ServerRepoStreamParser parser = new ServerRepoStreamParser(clientSocket.getInputStream());
+
+        if (clientSocket.isConnected() && !clientSocket.isClosed()){
+            PacketType parsePacketResult = parser.parse();
+
+            switch (parsePacketResult){
+                case SERVER_REGISTRATION:
+                    ServerListing listing = parser.getServerListing();
+
+                    if (!serverTable.getAllServers().contains(listing)){
+                        listing.setRoomCode(serverTable.getNextRoomCode().toString());
+                    }
+
+                    serverTable.addServer(listing);
+
+                    Message serverRegMessage = new RoomCodeRequest(listing.getRoomCode());
+                    clientSocket.getOutputStream().write(serverRegMessage.getBuffer());
+                    break;
+
+                case ROOM_CODE_REQUEST:
+                    String desiredRoomCode = parser.getRoomCode();
+
+                    ServerListing serverListing = serverTable.getServerByRoomCode(desiredRoomCode);
+                    Message response;
+
+                    if (serverListing != null){
+                        response = new ServerRegistrationMessage(serverListing.getServerName(), serverListing.getMapName(), serverListing.getAddress(), serverListing.getPortNumber(), 0, 0, desiredRoomCode);
+                    }
+                    else{
+                        response = new ServerRegistrationMessage("", "", "", 0, 0, 0, "");
+                    }
+
+                    clientSocket.getOutputStream().write(response.getBuffer());
+                    break;
+            }
+        }
+    }
+}
@@ -0,0 +1,121 @@
+package seng302.discoveryServer;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import seng302.gameServer.messages.Message;
+import seng302.gameServer.messages.RoomCodeRequest;
+import seng302.gameServer.messages.ServerRegistrationMessage;
+import seng302.model.stream.packets.PacketType;
+import seng302.discoveryServer.util.ServerListing;
+import seng302.discoveryServer.util.ServerRepoStreamParser;
+
+import java.net.Socket;
+import java.util.Timer;
+import java.util.TimerTask;
+
+public class DiscoveryServerClient {
+    private final Integer UPDATE_INTERVAL_MS = 5000;
+
+    private static String roomCode = null;
+    private Timer serverListingUpdateTimer;
+    private Logger logger = LoggerFactory.getLogger(DiscoveryServerClient.class);
+
+    public DiscoveryServerClient() {
+
+    }
+
+    /**
+     * Register the server with the discovery server
+     * @param serverListing The listing to register
+     */
+    public void register(ServerListing serverListing){
+        if (serverListingUpdateTimer != null){
+            serverListingUpdateTimer.cancel();
+            serverListingUpdateTimer = null;
+        }
+
+        serverListingUpdateTimer = new Timer();
+
+        serverListingUpdateTimer.schedule(new TimerTask() {
+            @Override
+            public void run() {
+                try {
+                    sendRegistrationUpdate(serverListing);
+                } catch (Exception e) {
+                    logger.debug("Could not update server listing");
+                }
+            }
+        }, 0, UPDATE_INTERVAL_MS);
+    }
+
+    /**
+     * Stop updating the server registration updates
+     */
+    public void unregister(){
+        serverListingUpdateTimer.cancel();
+    }
+
+    /**
+     * Gets the connection information for a server given a room code
+     *
+     * @param roomCode The room code to search for
+     * @return The ServerListing, or null if there was an error
+     * @throws Exception .
+     */
+    public ServerListing getServerForRoomCode(String roomCode) throws Exception {
+        Socket socket = new Socket(DiscoveryServer.DISCOVERY_SERVER, DiscoveryServer.PORT_NUMBER);
+        ServerRepoStreamParser parser = new ServerRepoStreamParser(socket.getInputStream());
+
+        Message request = new RoomCodeRequest(roomCode); //roomCode);
+        socket.getOutputStream().write(request.getBuffer());
+
+        PacketType packetType = parser.parse();
+
+        if (packetType != PacketType.SERVER_REGISTRATION){
+            logger.debug("Wrong packet received in response to a room code request");
+            return null;
+        }
+
+        socket.close();
+
+        return parser.getServerListing();
+    }
+
+    /**
+     * Sends a registration update to the discovery server.
+     *
+     * @param serverListing The server listing to send
+     * @throws Exception IF there was an error sending the update
+     */
+    private void sendRegistrationUpdate(ServerListing serverListing) throws Exception {
+        Socket socket = new Socket(DiscoveryServer.DISCOVERY_SERVER, DiscoveryServer.PORT_NUMBER);
+        ServerRepoStreamParser parser = new ServerRepoStreamParser(socket.getInputStream());
+
+        Message req = new ServerRegistrationMessage(serverListing);
+
+        socket.getOutputStream().write(req.getBuffer());
+
+        PacketType packetType = parser.parse();
+
+        if (packetType != PacketType.ROOM_CODE_REQUEST){
+            socket.close();
+            return;
+        }
+
+        String roomCode = parser.getRoomCode();
+
+        if (roomCode.length() != 0){
+            DiscoveryServerClient.roomCode = roomCode;
+        }
+
+        socket.close();
+    }
+
+    /**
+     * @return The last room code received by the client
+     */
+    public static String getRoomCode(){
+        return roomCode;
+    }
+}
+
@@ -0,0 +1,50 @@
+package seng302.discoveryServer.util;
+
+import java.io.InputStream;
+
+public class ReadableByteInputStream {
+    private InputStream is;
+
+    public ReadableByteInputStream(InputStream is){
+        this.is = is;
+    }
+
+    /**
+     * Get n bytes from the input stream
+     * @param n number of bytes
+     * @return the bytes read
+     * @throws Exception .
+     */
+    public byte[] getBytes(int n) throws Exception {
+        byte[] bytes = new byte[n];
+        for (int i = 0; i < n; i++) {
+            bytes[i] = (byte) readByte();
+        }
+        return bytes;
+    }
+
+    /**
+     * Skip n bytes
+     * @param n number of bytes to skip
+     * @throws Exception
+     */
+    public void skipBytes(long n) throws Exception {
+        for (int i = 0; i < n; i++) {
+            readByte();
+        }
+    }
+
+    /**
+     * Read the next byte from the stream
+     * @return The byte that was read
+     * @throws Exception .
+     */
+    public int readByte() throws Exception {
+        int currentByte = is.read();
+
+        if (currentByte == -1) {
+            throw new Exception();
+        }
+        return currentByte;
+    }
+}
@@ -0,0 +1,113 @@
+package seng302.discoveryServer.util;
+
+public class ServerListing {
+    public final static int SERVER_TTL_DEFAULT = 10;
+
+    private String serverName = "";
+    private String mapName = "";
+    private String address = "";
+    private int portNumber = 0;
+    private int capacity = 0;
+    private int players = 0;
+    private String roomCode = "";
+    private int ttl = SERVER_TTL_DEFAULT;
+
+
+    public ServerListing(String serverName, String mapName, String address, int portNumber, int capacity){
+        this.serverName = serverName;
+        this.mapName = mapName;
+        this.address = address;
+        this.portNumber = portNumber;
+        this.capacity = capacity;
+    }
+
+    public ServerListing setNumberOfPlayers(int players){
+        this.players = players;
+        return this;
+    }
+
+    public ServerListing setRoomCode(String roomCode){
+        this.roomCode = roomCode;
+        return this;
+    }
+
+    public void refreshTtl(){
+        ttl = SERVER_TTL_DEFAULT;
+    }
+
+    public void decrementTtl(){
+        ttl--;
+    }
+
+    public boolean hasTtlExpired(){
+        return ttl < 0;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (!ServerListing.class.isAssignableFrom(obj.getClass())) {
+            return false;
+        }
+
+        final ServerListing other = (ServerListing) obj;
+
+        if (this.getPortNumber() != other.getPortNumber()){
+            return false;
+        }
+
+        if (!this.getMapName().equals(other.getMapName())){
+            return false;
+        }
+
+        if (!this.getServerName().equals(other.getServerName())){
+            return false;
+        }
+
+        if (this.getCapacity() != other.getCapacity()){
+            return false;
+        }
+
+        if (!this.getAddress().equals(other.getAddress())){
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        return this.getServerName().hashCode() +
+                this.getAddress().hashCode() + this.getMapName().hashCode();
+    }
+
+    public String getRoomCode() {
+        return roomCode;
+    }
+
+    public int getPortNumber() {
+        return portNumber;
+    }
+
+    public String getMapName() {
+        return mapName;
+    }
+
+    public String getServerName() {
+        return serverName;
+    }
+
+    public int getCapacity() {
+        return capacity;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setTtl(Integer ttl){
+        this.ttl = ttl;
+    }
+}
@@ -0,0 +1,109 @@
+package seng302.discoveryServer.util;
+
+
+import seng302.gameServer.messages.Message;
+import seng302.model.stream.packets.PacketType;
+
+import java.io.InputStream;
+import java.util.Arrays;
+
+public class ServerRepoStreamParser {
+    private ReadableByteInputStream inputStream;
+
+    private String roomCode;
+    private String mapName;
+    private ServerListing serverListing;
+
+    public ServerRepoStreamParser(InputStream is){
+        inputStream = new ReadableByteInputStream(is);
+    }
+
+    public PacketType parse() throws Exception {
+        int sync1 = inputStream.readByte();
+        int sync2 = inputStream.readByte();
+
+        PacketType packetType = null;
+
+        if (sync1 == 0x47 && sync2 == 0x83) {
+            int type = inputStream.readByte();
+            inputStream.skipBytes(10);
+            long payloadLength = Message.bytesToLong(inputStream.getBytes(2));
+            byte[] payload = inputStream.getBytes((int) payloadLength);
+            inputStream.skipBytes(4);
+
+            packetType = PacketType.assignPacketType(type, payload);
+
+            switch (packetType) {
+                case ROOM_CODE_REQUEST:
+                    roomCode = parseRoomCodeRequest(payload);
+                    break;
+
+                case LOBBY_REQUEST:
+                    mapName = parseLobbyRequest(payload);
+
+                case SERVER_REGISTRATION:
+                    serverListing = parseServerRegistration(payload);
+                    break;
+            }
+
+        }
+
+        return packetType;
+    }
+    private String parseLobbyRequest(byte[] payload) {
+        int mapNameLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 0 ,4));
+
+        return new String(Arrays.copyOfRange(payload, 4, 4+mapNameLength));
+    }
+
+    private String parseRoomCodeRequest(byte[] payload) {
+        int roomCodeLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 0 ,6));
+
+        return new String(Arrays.copyOfRange(payload, 6, 6+roomCodeLength));
+    }
+
+    public static ServerListing parseServerRegistration(byte[] payload) {
+        int nameLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 0, 6));
+        int mapNameLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 6, 12));
+        int addressLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 12, 18));
+        int roomCodeLength = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 18, 24));
+
+        int portNumber = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 24, 28));
+        int players = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 28, 32));
+        int capacity = (int) Message.bytesToLong(Arrays.copyOfRange(payload, 32, 36));
+
+        int currentPos = 36;
+        int nextPos = currentPos + nameLength;
+        String serverName = new String(Arrays.copyOfRange(payload, currentPos, nextPos));
+
+        currentPos = nextPos;
+        nextPos = currentPos + mapNameLength;
+        String mapName = new String(Arrays.copyOfRange(payload, currentPos, nextPos));
+
+        currentPos = nextPos;
+        nextPos = currentPos + addressLength;
+        String address = new String(Arrays.copyOfRange(payload, currentPos, nextPos));
+
+        currentPos = nextPos;
+        nextPos = currentPos + roomCodeLength;
+        String roomCode = new String(Arrays.copyOfRange(payload, currentPos, nextPos));
+
+        ServerListing serverListing = new ServerListing(serverName, mapName, address, portNumber, capacity);
+        serverListing.setNumberOfPlayers(players);
+        serverListing.setRoomCode(roomCode);
+
+        return serverListing;
+    }
+
+    public String getRoomCode() {
+        return roomCode;
+    }
+
+    public String getMapName() {
+        return mapName;
+    }
+
+    public ServerListing getServerListing() {
+        return serverListing;
+    }
+}
@@ -0,0 +1,97 @@
+package seng302.discoveryServer.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.*;
+
+public class ServerTable {
+    private List<ServerListing> servers;
+    private int lastRoomCode = 4020;
+    private Logger logger = LoggerFactory.getLogger(ServerTable.class);
+
+    public ServerTable(){
+        servers = new ArrayList<>();
+
+        new Timer().schedule(new TimerTask() {
+            @Override
+            public void run() {
+                updateServers();
+            }
+        }, 0, 1000);
+    }
+
+    /**
+     * Update the servers TTL values, and then remove expired servers
+     */
+    private void updateServers() {
+        List<ServerListing> serversToRemove = new ArrayList<>();
+
+        for (ServerListing server : servers){
+            server.decrementTtl();
+
+            if (server.hasTtlExpired()){
+                logger.debug("Removed expired server - " + server.getServerName());
+                serversToRemove.add(server);
+            }
+        }
+
+        servers.removeAll(serversToRemove);
+    }
+
+    /**
+     * Add a server to the table
+     * @param server The server to add
+     */
+    public void addServer(ServerListing server){
+        if (servers.contains(server)){
+           updateTtlForServer(server);
+           return;
+        }
+        logger.debug("Added new server - " + server.getServerName());
+        servers.add(server);
+    }
+
+    /**
+     * Update the TTL for a given server to the default TTL value
+     * @param server The server to update
+     */
+    private void updateTtlForServer(ServerListing server) {
+        for (ServerListing serverListing : servers){
+            if (server.equals(serverListing)){
+                serverListing.refreshTtl();
+            }
+        }
+    }
+
+    /**
+     * @return All the servers in the table
+     */
+    public List<ServerListing> getAllServers(){
+        return Collections.unmodifiableList(servers);
+    }
+
+    /**
+     * Get a server from the table given its room code
+     * @param roomCode The room code to search for
+     * @return The ServerListing of the found server, or null
+     *         the server wasn't found
+     */
+    public ServerListing getServerByRoomCode(String roomCode){
+        for (ServerListing serverListing : servers){
+            if (serverListing.getRoomCode().equals(roomCode)){
+                return serverListing;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @return The next available room code
+     */
+    public Integer getNextRoomCode(){
+        lastRoomCode += 1;
+        return lastRoomCode;
+    }
+}