TD-34: Endpoint for getting all players and tests for this endpoint

Reviewed-on: #7
Reviewed-by: SZUT-Kevin <kevin.schmidt9101@gmail.com>
Reviewed-by: SZUT-Rajbir <rajbir2@schule.bremen.de>

.forgejo/workflows/build.yml

@@ -36,6 +36,11 @@ jobs:
         with:
           name: api.yml
           path: api/api.yml
+      - name: Upload Websocket Spec as Artifact
+        uses: "https://git.euph.dev/actions/upload-artifact@v3"
+        with:
+          name: ws.yml
+          path: ws/ws.yml
       - name: "Stop Gradle"
         run: gradle --stop
 
@@ -85,6 +90,11 @@ jobs:
         with:
           name: api.yml
           path: release
+      - name: Download Websocket Spec
+        uses: "https://git.euph.dev/actions/download-artifact@v3"
+        with:
+          name: ws.yml
+          path: release
       - name: Create Release
         uses: "https://git.euph.dev/actions/release@v2"
         with:
@@ -96,6 +106,3 @@ jobs:
           release-notes: |
             # Tower Defence - Server ${{ github.ref_name }}
             Read the [Documentation](https://git.euph.dev/TowerDefence/Dokumentation/wiki/Server/Config) to see how to setup the server.
-
-
-

api/api.yml

@@ -39,6 +39,34 @@ components:
         - username
         - password
     #############################################
+    #  PlayerLoginData                          #
+    #############################################
+    PlayerLoginData:
+      description: Data needed to log a Player in
+      type: object
+      properties:
+        username:
+          type: string
+        password:
+          type: string
+      required:
+        - username
+        - password
+    #############################################
+    #  PlayerLoginSession                       #
+    #############################################
+    PlayerLoginSession:
+      description: Data needed to log a Player in
+      type: object
+      properties:
+        username:
+          type: string
+        token:
+          type: string
+      required:
+        - username
+        - token
+    #############################################
     #  AdminAuthInfo                            #
     #############################################
     ServerHealth:
@@ -99,6 +127,8 @@ components:
   responses:
     201PlayerCreated:
       description: "201 - Player Created"
+    401PlayerNameOrPasswordWrong:
+      description: "401 - Player Name or Password is Wrong"
     401Unauthorized:
       description: "401 - Unauthorized"
     404NotFound:
@@ -150,6 +180,28 @@ paths:
           $ref: "#/components/responses/409UsernameTaken"
         500:
           $ref: "#/components/responses/500InternalError"
+  /player/login:
+    post:
+      operationId: "PlayerLogin"
+      tags:
+        - server
+      description: "Endpoint for logging a Player in"
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/PlayerLoginData"
+      responses:
+        200:
+          description: "A Login Session, which can be used in the Webhook"
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/PlayerLoginSession"
+        401:
+          $ref: "#/components/responses/401PlayerNameOrPasswordWrong"
+        500:
+          $ref: "#/components/responses/500InternalError"
   /server/health:
     get:
       operationId: "ServerGetHealthcheck"

build.gradle.kts

@@ -53,6 +53,11 @@ dependencies {
     implementation("org.springframework.boot:spring-boot-starter-oauth2-resource-server")
     developmentOnly("org.springframework.boot:spring-boot-devtools")
 
+    //JWT
+    implementation("io.jsonwebtoken:jjwt-api:0.12.6")
+    runtimeOnly("io.jsonwebtoken:jjwt-impl:0.12.6")
+    runtimeOnly("io.jsonwebtoken:jjwt-jackson:0.12.6")
+
     // Postgres
     runtimeOnly("org.postgresql:postgresql")
 

src/main/java/de/towerdefence/server/match/Match.java

@@ -0,0 +1,13 @@
+package de.towerdefence.server.match;
+
+import de.towerdefence.server.player.Player;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@AllArgsConstructor
+@Getter
+public class Match {
+    private final String matchId;
+    private final Player playerOne;
+    private final Player playerTwo;
+}

src/main/java/de/towerdefence/server/match/confirmation/AbortCallback.java

@@ -0,0 +1,8 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.player.Player;
+
+@FunctionalInterface
+public interface AbortCallback {
+    void call(Player player, String matchId);
+}

src/main/java/de/towerdefence/server/match/confirmation/ConfirmationCallbacks.java

@@ -0,0 +1,16 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.match.queue.FoundCallback;
+import de.towerdefence.server.match.queue.QueuedCallback;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class ConfirmationCallbacks {
+    private final FoundCallback foundCallback;
+    private final QueuedCallback queuedCallback;
+    private final AbortCallback abortCallback;
+    private final EstablishedCallback establishedCallback;
+    private final RequeueCallback requeueCallback;
+}

src/main/java/de/towerdefence/server/match/confirmation/EstablishedCallback.java

@@ -0,0 +1,10 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.player.Player;
+
+import java.io.IOException;
+
+@FunctionalInterface
+public interface EstablishedCallback {
+    void call(Player player, String matchId, Player opponent) throws IOException;
+}

src/main/java/de/towerdefence/server/match/confirmation/MatchConfirmationService.java

@@ -0,0 +1,111 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.player.Player;
+import org.springframework.stereotype.Service;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+@Service
+public class MatchConfirmationService {
+
+    private final Map<Player, UnconfirmedMatch> unconfirmedMatch = new HashMap<>();
+
+    public UnconfirmedMatch createMatch(Player player1,
+            Player player2,
+            ConfirmationCallbacks player1Callbacks,
+            ConfirmationCallbacks player2callbacks) {
+        UnconfirmedMatch match = new UnconfirmedMatch(
+                player1,
+                player2,
+                player1Callbacks,
+                player2callbacks);
+        unconfirmedMatch.put(player1, match);
+        unconfirmedMatch.put(player2, match);
+        return match;
+    }
+
+    public void accept(Player player, String matchId) {
+        setPlayerAcceptState(player, matchId, PlayerMatchConfirmState.CONFIRMED);
+    }
+
+    public void decline(Player player, String matchId) {
+        setPlayerAcceptState(player, matchId, PlayerMatchConfirmState.ABORTED);
+    }
+
+    private void setPlayerAcceptState(Player player, String matchId, PlayerMatchConfirmState state) {
+        Optional<UnconfirmedMatch> optionalMatch = getPlayerMatch(player, matchId);
+        if (optionalMatch.isEmpty()) {
+            return;
+        }
+        UnconfirmedMatch match = optionalMatch.get();
+
+        Optional<PlayerMatchConfirmState> optionalPlayerState = match.getPlayerState(player);
+        if (optionalPlayerState.isEmpty()) {
+            unconfirmedMatch.remove(player);
+            return;
+        }
+
+        if (optionalPlayerState.get() != PlayerMatchConfirmState.UNKNOWN) {
+            return;
+        }
+
+        Optional<UnconfirmedMatchState> matchState = match.setPlayerConfirmState(player, state);
+        if (matchState.isEmpty()) {
+            unconfirmedMatch.remove(player);
+            return;
+        }
+        handleMatchConfirmation(match, matchState.get());
+    }
+
+    private void handleMatchConfirmation(UnconfirmedMatch match, UnconfirmedMatchState state) {
+        if (state == UnconfirmedMatchState.WAITING) {
+            return;
+        }
+
+        unconfirmedMatch.remove(match.getPlayer1());
+        unconfirmedMatch.remove(match.getPlayer2());
+
+        ConfirmationCallbacks player1Callbacks = match.getPlayer1Callbacks();
+        ConfirmationCallbacks player2Callbacks = match.getPlayer2Callbacks();
+
+        switch (state) {
+            case ABORTED -> {
+                if (match.getPlayer1State() == PlayerMatchConfirmState.CONFIRMED) {
+                    player1Callbacks.getRequeueCallback().call(
+                            match.getPlayer1(),
+                            match.getMatchId(),
+                            player1Callbacks.getFoundCallback(),
+                            player1Callbacks.getQueuedCallback(),
+                            player1Callbacks.getAbortCallback(),
+                            player1Callbacks.getEstablishedCallback());
+                }
+                if (match.getPlayer2State() == PlayerMatchConfirmState.CONFIRMED) {
+                    player2Callbacks.getRequeueCallback().call(
+                            match.getPlayer2(),
+                            match.getMatchId(),
+                            player2Callbacks.getFoundCallback(),
+                            player2Callbacks.getQueuedCallback(),
+                            player2Callbacks.getAbortCallback(),
+                            player2Callbacks.getEstablishedCallback());
+                }
+            }
+            case CONFIRMED -> {
+                // TODO: Create Match and Send Players the info that the Match is created
+            }
+        }
+    }
+
+    private Optional<UnconfirmedMatch> getPlayerMatch(Player player, String matchId) {
+        UnconfirmedMatch match = unconfirmedMatch.get(player);
+        if (match == null) {
+            return Optional.empty();
+        }
+        if (!match.getMatchId().equals(matchId)) {
+            unconfirmedMatch.remove(player);
+            return Optional.empty();
+        }
+        return Optional.of(match);
+    }
+}

src/main/java/de/towerdefence/server/match/confirmation/PlayerMatchConfirmState.java

@@ -0,0 +1,7 @@
+package de.towerdefence.server.match.confirmation;
+
+public enum PlayerMatchConfirmState {
+    UNKNOWN,
+    CONFIRMED,
+    ABORTED
+}

src/main/java/de/towerdefence/server/match/confirmation/RequeueCallback.java

@@ -0,0 +1,18 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.match.queue.FoundCallback;
+import de.towerdefence.server.match.queue.QueuedCallback;
+import de.towerdefence.server.player.Player;
+
+@FunctionalInterface
+public interface RequeueCallback {
+    void call(
+            Player player,
+            String matchId,
+            FoundCallback foundCallback,
+            QueuedCallback queuedCallback,
+            AbortCallback abortCallback,
+            EstablishedCallback establishedCallback
+    );
+}
+

src/main/java/de/towerdefence/server/match/confirmation/UnconfirmedMatch.java

@@ -0,0 +1,85 @@
+package de.towerdefence.server.match.confirmation;
+
+import de.towerdefence.server.player.Player;
+import lombok.Getter;
+
+import java.time.Instant;
+import java.util.Optional;
+import java.util.UUID;
+
+@Getter
+public class UnconfirmedMatch {
+    private final String matchId;
+    private final long created;
+    public static final long TTL = 30 * 1000;
+    private final Player player1;
+    private final Player player2;
+    private final ConfirmationCallbacks player1Callbacks;
+    private final ConfirmationCallbacks player2Callbacks;
+
+    public UnconfirmedMatch(
+            Player player1,
+            Player player2,
+            ConfirmationCallbacks player1Callbacks,
+            ConfirmationCallbacks player2Callbacks) {
+        this.player1 = player1;
+        this.player2 = player2;
+        this.player1Callbacks = player1Callbacks;
+        this.player2Callbacks = player2Callbacks;
+        this.created = Instant.now().toEpochMilli();
+        this.matchId = UUID.randomUUID().toString();
+    }
+
+    private PlayerMatchConfirmState player1State = PlayerMatchConfirmState.UNKNOWN;
+    private PlayerMatchConfirmState player2State = PlayerMatchConfirmState.UNKNOWN;
+
+    public Optional<UnconfirmedMatchState> setPlayerConfirmState(Player player, PlayerMatchConfirmState state) {
+        Optional<MatchPlayer> matchPlayer = getMatchPlayer(player);
+        if(matchPlayer.isEmpty()){
+            return Optional.empty();
+        }
+
+        switch (matchPlayer.get()){
+            case ONE -> player1State = state;
+            case TWO -> player2State = state;
+        }
+
+        if (player1State == PlayerMatchConfirmState.ABORTED || player2State == PlayerMatchConfirmState.ABORTED) {
+            return Optional.of(UnconfirmedMatchState.ABORTED);
+        }
+        if (player1State == PlayerMatchConfirmState.UNKNOWN || player2State == PlayerMatchConfirmState.UNKNOWN) {
+            return Optional.of(UnconfirmedMatchState.WAITING);
+        }
+        return Optional.of(UnconfirmedMatchState.CONFIRMED);
+    }
+
+    public Optional<PlayerMatchConfirmState> getPlayerState(Player player){
+        Optional<MatchPlayer> matchPlayer = getMatchPlayer(player);
+        if(matchPlayer.isEmpty()){
+            return Optional.empty();
+        }
+
+        return switch (matchPlayer.get()){
+            case ONE -> Optional.of(player1State);
+            case TWO -> Optional.of(player2State);
+        };
+    }
+
+    private enum MatchPlayer{
+        ONE,
+        TWO
+    }
+
+    private Optional<MatchPlayer> getMatchPlayer(Player player){
+        boolean isPlayerOne = player.equals(player1);
+        boolean isPlayerTwo = player.equals(player2);
+        if (!isPlayerOne && !isPlayerTwo) {
+            return Optional.empty();
+        }
+
+        if (isPlayerOne){
+            return Optional.of(MatchPlayer.ONE);
+        }
+        return Optional.of(MatchPlayer.TWO);
+    }
+}

src/main/java/de/towerdefence/server/match/confirmation/UnconfirmedMatchState.java

@@ -0,0 +1,7 @@
+package de.towerdefence.server.match.confirmation;
+
+public enum UnconfirmedMatchState {
+    WAITING,
+    ABORTED,
+    CONFIRMED
+}

src/main/java/de/towerdefence/server/match/queue/FoundCallback.java

@@ -0,0 +1,10 @@
+package de.towerdefence.server.match.queue;
+
+import de.towerdefence.server.player.Player;
+
+import java.io.IOException;
+
+@FunctionalInterface
+public interface FoundCallback {
+    void call(Player player, String matchId, long created, long ttl) throws IOException;
+}

src/main/java/de/towerdefence/server/match/queue/MatchQueueService.java

@@ -0,0 +1,143 @@
+package de.towerdefence.server.match.queue;
+
+import de.towerdefence.server.match.confirmation.*;
+import de.towerdefence.server.player.Player;
+import lombok.AllArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@Service
+@AllArgsConstructor
+public class MatchQueueService {
+    private final static int REQUIRED_PLAYER_COUNT = 2;
+
+    @Autowired
+    private final MatchConfirmationService matchConfirmationService;
+
+    private final List<Player> queue = new ArrayList<>();
+    private final Map<Player, ConfirmationCallbacks> confirmationCallbacks = new HashMap<>();
+
+    public void queuePlayer(
+            Player player,
+            FoundCallback foundCallback,
+            QueuedCallback queuedCallback,
+            AbortCallback abortCallback,
+            EstablishedCallback establishedCallback) {
+        queue.add(player);
+        confirmationCallbacks.put(player, new ConfirmationCallbacks(
+                foundCallback,
+                queuedCallback,
+                abortCallback,
+                establishedCallback,
+                this::onRequeue));
+        tryMatching();
+    }
+
+    public void onRequeue(
+            Player player,
+            String matchId,
+            FoundCallback foundCallback,
+            QueuedCallback queuedCallback,
+            AbortCallback abortCallback,
+            EstablishedCallback establishedCallback) {
+        abortCallback.call(player, matchId);
+        try {
+            queuedCallback.call(player);
+        } catch (IOException ignored) {
+            return;
+        }
+        queuePlayer(player, foundCallback, queuedCallback, abortCallback, establishedCallback);
+    }
+
+    public void unQueuePlayer(Player player) {
+        queue.remove(player);
+        confirmationCallbacks.remove(player);
+    }
+
+    private void tryMatching() {
+        if (queue.size() < REQUIRED_PLAYER_COUNT) {
+            return;
+        }
+
+        List<Player> loopQueue = new ArrayList<>(queue);
+        for (int i = 0; i < loopQueue.size() / REQUIRED_PLAYER_COUNT; i++) {
+            Player player1 = loopQueue.get(REQUIRED_PLAYER_COUNT * i);
+            Player player2 = loopQueue.get(REQUIRED_PLAYER_COUNT * i + 1);
+
+            ConfirmationCallbacks player1Callbacks = confirmationCallbacks.get(player1);
+            ConfirmationCallbacks player2Callbacks = confirmationCallbacks.get(player2);
+
+            UnconfirmedMatch match = this.matchConfirmationService.createMatch(
+                    player1,
+                    player2,
+                    player1Callbacks,
+                    player2Callbacks);
+            sentMatchFound(
+                    match,
+                    player1,
+                    player2,
+                    player1Callbacks,
+                    player2Callbacks);
+
+        }
+        if (queue.size() > REQUIRED_PLAYER_COUNT) {
+            tryMatching();
+        }
+    }
+
+    private void sentMatchFound(
+            UnconfirmedMatch match,
+            Player player1,
+            Player player2,
+            ConfirmationCallbacks player1Callbacks,
+            ConfirmationCallbacks player2Callbacks) {
+        boolean player1disconnected = setMatchFoundToPlayer(player1, player1Callbacks.getFoundCallback(), match);
+        boolean player2disconnected = setMatchFoundToPlayer(player2, player2Callbacks.getFoundCallback(), match);
+
+        queue.remove(player1);
+        queue.remove(player2);
+
+        if (!player1disconnected && !player2disconnected) {
+            return;
+        }
+
+        if (player1disconnected && match.getPlayer2State() != PlayerMatchConfirmState.ABORTED) {
+            player2Callbacks.getRequeueCallback().call(
+                    player2,
+                    match.getMatchId(),
+                    player2Callbacks.getFoundCallback(),
+                    player2Callbacks.getQueuedCallback(),
+                    player2Callbacks.getAbortCallback(),
+                    player2Callbacks.getEstablishedCallback());
+        }
+
+        if (player2disconnected && match.getPlayer1State() != PlayerMatchConfirmState.ABORTED) {
+            player1Callbacks.getRequeueCallback().call(
+                    player1,
+                    match.getMatchId(),
+                    player1Callbacks.getFoundCallback(),
+                    player1Callbacks.getQueuedCallback(),
+                    player1Callbacks.getAbortCallback(),
+                    player1Callbacks.getEstablishedCallback());
+        }
+    }
+
+    private boolean setMatchFoundToPlayer(Player player, FoundCallback callback, UnconfirmedMatch match) {
+        try {
+            callback.call(
+                    player,
+                    match.getMatchId(),
+                    match.getCreated(),
+                    UnconfirmedMatch.TTL);
+        } catch (IOException e) {
+            return true;
+        }
+        return false;
+    }
+}

src/main/java/de/towerdefence/server/match/queue/QueuedCallback.java

@@ -0,0 +1,10 @@
+package de.towerdefence.server.match.queue;
+
+import de.towerdefence.server.player.Player;
+
+import java.io.IOException;
+
+@FunctionalInterface
+public interface QueuedCallback {
+    void call(Player player) throws IOException;
+}

src/main/java/de/towerdefence/server/server/JsonMessage.java

@@ -0,0 +1,37 @@
+package de.towerdefence.server.server;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.io.IOException;
+import java.util.Map;
+
+import org.springframework.web.socket.TextMessage;
+import org.springframework.web.socket.WebSocketSession;
+
+
+@Getter
+@AllArgsConstructor
+public abstract class JsonMessage {
+    protected abstract String getMessageId();
+    protected abstract Map<String, JsonNode> getData(JsonNodeFactory factory);
+
+    public void send(WebSocketSession session) throws IOException {
+        session.sendMessage(new TextMessage(getPayload()));
+    }
+
+    public String getPayload() {
+        JsonNodeFactory factory = new JsonNodeFactory(false);
+        ObjectNode msg = factory.objectNode().put("$id", getMessageId());
+        for (Map.Entry<String, JsonNode> entry : getData(factory).entrySet()) {
+            if(entry.getKey().equals("$id")){
+                continue;
+            }
+            msg.set(entry.getKey(), entry.getValue());
+        }
+        return msg.toString();
+    }
+}

src/main/java/de/towerdefence/server/server/JsonWebsocketHandler.java

@@ -0,0 +1,49 @@
+package de.towerdefence.server.server;
+
+import de.towerdefence.server.player.Player;
+import de.towerdefence.server.session.Channel;
+import de.towerdefence.server.session.SessionsService;
+import lombok.AllArgsConstructor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.web.socket.CloseStatus;
+import org.springframework.web.socket.WebSocketSession;
+import org.springframework.web.socket.handler.TextWebSocketHandler;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+
+@AllArgsConstructor
+public abstract class JsonWebsocketHandler extends TextWebSocketHandler {
+    private static final Logger logger = LoggerFactory.getLogger(JsonWebsocketHandler.class);
+    public final Channel channel;
+    protected final SessionsService sessionsService;
+    protected final Map<WebSocketSession, Player> sessionPlayers = new ConcurrentHashMap<>();
+
+    @Override
+    public void afterConnectionEstablished(WebSocketSession session) {
+        String jwt = session.getHandshakeHeaders().getFirst("Authorization");
+        if (jwt == null){
+            closeSession(session, CloseStatus.NOT_ACCEPTABLE);
+            return;
+        }
+        Optional<Player> player = sessionsService.getSession(jwt, channel);
+        if(player.isEmpty()){
+            closeSession(session, CloseStatus.NOT_ACCEPTABLE);
+            return;
+        }
+        sessionPlayers.put(session, player.get());
+    }
+
+    protected void closeSession(WebSocketSession session, CloseStatus reason){
+        if(session.isOpen()){
+            try{
+                session.close(reason);
+            } catch (Exception exception) {
+                logger.info("Unable to Close the Session", exception);
+            }
+        }
+    }
+
+}

src/main/java/de/towerdefence/server/server/ServerApiController.java

@@ -2,11 +2,15 @@ package de.towerdefence.server.server;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import de.towerdefence.server.oas.ServerApi;
+import de.towerdefence.server.oas.models.PlayerLoginData;
+import de.towerdefence.server.oas.models.PlayerLoginSession;
 import de.towerdefence.server.oas.models.PlayerRegistrationData;
 import de.towerdefence.server.oas.models.ServerHealth;
 import de.towerdefence.server.player.Player;
 import de.towerdefence.server.player.PlayerRepository;
 import de.towerdefence.server.player.PlayerService;
+import de.towerdefence.server.session.Channel;
+import de.towerdefence.server.session.SessionsService;
 import jakarta.servlet.http.HttpServletRequest;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
@@ -25,6 +29,8 @@ public class ServerApiController implements ServerApi {
     private PlayerRepository playerRepository;
     @Autowired
     private PlayerService playerService;
+    @Autowired
+    private SessionsService sessionsService;
 
     @Override
     public Optional<ObjectMapper> getObjectMapper() {
@@ -52,6 +58,26 @@ public class ServerApiController implements ServerApi {
         return new ResponseEntity<>(HttpStatus.CREATED);
     }
 
+    @Override
+    public ResponseEntity<PlayerLoginSession> playerLogin(PlayerLoginData body) {
+        Player player = playerRepository.findByUsername(body.getUsername());
+        if(player == null){
+            return new ResponseEntity<>(HttpStatus.UNAUTHORIZED);
+        }
+        try {
+            if(!playerService.checkPassword(player, body.getPassword())) {
+                return new ResponseEntity<>(HttpStatus.UNAUTHORIZED);
+            }
+        } catch (NoSuchAlgorithmException e) {
+            return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
+        }
+        String token = sessionsService.createSession(player, Channel.CONNECTION);
+        PlayerLoginSession session = new PlayerLoginSession();
+        session.setUsername(player.getUsername());
+        session.setToken(token);
+        return new ResponseEntity<>(session, HttpStatus.OK);
+    }
+
     @Override
     public ResponseEntity<ServerHealth> serverGetHealthcheck() {
         ServerHealth health = new ServerHealth();

src/main/java/de/towerdefence/server/server/WebSocketConfig.java

@@ -1,15 +0,0 @@
-package de.towerdefence.server.server;
-
-import org.springframework.context.annotation.Configuration;
-import org.springframework.web.socket.config.annotation.EnableWebSocket;
-import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
-import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
-
-@Configuration
-@EnableWebSocket
-public class WebSocketConfig implements WebSocketConfigurer {
-    @Override
-    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
-        registry.addHandler(new ServerWebsocketHandler(), "/ws/server").setAllowedOrigins("*");
-    }
-}

src/main/java/de/towerdefence/server/server/channels/WebsocketConfig.java

@@ -0,0 +1,46 @@
+package de.towerdefence.server.server.channels;
+
+import de.towerdefence.server.match.confirmation.MatchConfirmationService;
+import de.towerdefence.server.match.queue.MatchQueueService;
+import de.towerdefence.server.server.JsonWebsocketHandler;
+import de.towerdefence.server.server.channels.connection.ConnectionWebsocketHandler;
+import de.towerdefence.server.server.channels.matchmaking.MatchmakingWebsocketHandler;
+import de.towerdefence.server.server.channels.time.TimeWebsocketHandler;
+import de.towerdefence.server.session.SessionsService;
+import lombok.AllArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.socket.config.annotation.EnableWebSocket;
+import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
+import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
+
+@AllArgsConstructor
+@Configuration
+@EnableWebSocket
+public class WebsocketConfig implements WebSocketConfigurer {
+    private static final String CHANNEL_BASE_PATH = "/ws/";
+    @Autowired
+    private final SessionsService sessionsService;
+    @Autowired
+    private  final MatchQueueService matchQueueService;
+    @Autowired
+    private  final MatchConfirmationService matchConfirmationService;
+
+    @Override
+    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
+        registerJsonChannel(registry, new ConnectionWebsocketHandler(this.sessionsService));
+        registerJsonChannel(registry, new MatchmakingWebsocketHandler(
+                this.sessionsService,
+                this.matchQueueService,
+                this.matchConfirmationService
+        ));
+        registerJsonChannel(registry, new TimeWebsocketHandler(this.sessionsService));
+    }
+
+    private void registerJsonChannel(WebSocketHandlerRegistry registry, JsonWebsocketHandler handler){
+        registry.addHandler(
+                handler,
+                CHANNEL_BASE_PATH + handler.channel.getJsonName()
+        ).setAllowedOrigins("*");
+    }
+}

src/main/java/de/towerdefence/server/server/channels/connection/ConnectionWebsocketHandler.java

@@ -0,0 +1,40 @@
+package de.towerdefence.server.server.channels.connection;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import de.towerdefence.server.player.Player;
+import de.towerdefence.server.server.JsonWebsocketHandler;
+import de.towerdefence.server.server.channels.connection.in.RequestConnectionTokenMessage;
+import de.towerdefence.server.server.channels.connection.out.ProvidedConnectionTokenMessage;
+import de.towerdefence.server.session.Channel;
+import de.towerdefence.server.session.SessionsService;
+import org.springframework.web.socket.CloseStatus;
+import org.springframework.web.socket.TextMessage;
+import org.springframework.web.socket.WebSocketSession;
+
+public class ConnectionWebsocketHandler extends JsonWebsocketHandler {
+    private final ObjectMapper objectMapper = new ObjectMapper();
+
+    public ConnectionWebsocketHandler(SessionsService sessionsService) {
+        super(Channel.CONNECTION, sessionsService);
+    }
+
+    @Override
+    protected void handleTextMessage(WebSocketSession session, TextMessage message) {
+        try{
+            String payload = message.getPayload();
+            switch ( objectMapper.readTree(payload).get("$id").asText()) {
+                case RequestConnectionTokenMessage.MESSAGE_ID -> handleRequestConnectionToken(session, payload);
+                default -> this.closeSession(session, CloseStatus.BAD_DATA);
+            }
+        } catch (Exception ignored) {
+            this.closeSession(session, CloseStatus.BAD_DATA);
+        }
+    }
+
+    private void handleRequestConnectionToken(WebSocketSession session, String payload) throws Exception {
+        RequestConnectionTokenMessage msg = objectMapper.readValue(payload, RequestConnectionTokenMessage.class);
+        Player player = this.sessionPlayers.get(session);
+        String jwt = this.sessionsService.createSession(player, msg.getChannel());
+        new ProvidedConnectionTokenMessage(msg.getChannel(), jwt).send(session);
+    }
+}

src/main/java/de/towerdefence/server/server/channels/connection/in/RequestConnectionTokenMessage.java

@@ -0,0 +1,16 @@
+package de.towerdefence.server.server.channels.connection.in;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import de.towerdefence.server.session.Channel;
+import jakarta.validation.constraints.NotNull;
+import lombok.*;
+
+@Data
+@NotNull
+public class RequestConnectionTokenMessage {
+    public static final String MESSAGE_ID = "RequestConnectionToken";
+
+    @JsonProperty("$id")
+    private String messageId;
+    private Channel channel;
+}

src/main/java/de/towerdefence/server/server/channels/connection/out/ProvidedConnectionTokenMessage.java

@@ -0,0 +1,28 @@
+package de.towerdefence.server.server.channels.connection.out;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import de.towerdefence.server.session.Channel;
+import lombok.AllArgsConstructor;
+
+import java.util.Map;
+
+@AllArgsConstructor
+public class ProvidedConnectionTokenMessage extends JsonMessage {
+    private final Channel channel;
+    private final String token;
+
+    @Override
+    protected String getMessageId() {
+        return "ProvidedConnectionToken";
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of(
+                "channel", factory.textNode(channel.getJsonName()),
+                "token", factory.textNode(token)
+        );
+    }
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/MatchmakingWebsocketHandler.java

@@ -0,0 +1,112 @@
+package de.towerdefence.server.server.channels.matchmaking;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import de.towerdefence.server.match.confirmation.MatchConfirmationService;
+import de.towerdefence.server.match.queue.MatchQueueService;
+import de.towerdefence.server.player.Player;
+import de.towerdefence.server.server.JsonWebsocketHandler;
+import de.towerdefence.server.server.channels.matchmaking.bi.MatchSetSearchStateMessage;
+import de.towerdefence.server.server.channels.matchmaking.in.MatchAcceptedMessage;
+import de.towerdefence.server.server.channels.matchmaking.out.MatchAbortedMessage;
+import de.towerdefence.server.server.channels.matchmaking.out.MatchEstablishedMessage;
+import de.towerdefence.server.server.channels.matchmaking.out.MatchFoundMessage;
+import de.towerdefence.server.session.Channel;
+import de.towerdefence.server.session.SessionsService;
+import org.springframework.web.socket.CloseStatus;
+import org.springframework.web.socket.TextMessage;
+import org.springframework.web.socket.WebSocketSession;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class MatchmakingWebsocketHandler extends JsonWebsocketHandler {
+    protected final Map<Player, WebSocketSession> playerSessions = new ConcurrentHashMap<>();
+    private final ObjectMapper objectMapper = new ObjectMapper();
+    private final MatchQueueService matchQueueService;
+    private final MatchConfirmationService matchConfirmationService;
+
+
+    public MatchmakingWebsocketHandler(
+            SessionsService sessionsService,
+            MatchQueueService matchQueueService,
+            MatchConfirmationService matchConfirmationService
+    ) {
+        super(Channel.MATCHMAKING, sessionsService);
+        this.matchQueueService = matchQueueService;
+        this.matchConfirmationService = matchConfirmationService;
+    }
+
+    @Override
+    public void afterConnectionEstablished(WebSocketSession session) {
+        super.afterConnectionEstablished(session);
+        playerSessions.put(sessionPlayers.get(session), session);
+    }
+
+    @Override
+    protected void handleTextMessage(WebSocketSession session, TextMessage message) {
+        try {
+            String payload = message.getPayload();
+            switch (objectMapper.readTree(payload).get("$id").asText()) {
+                case MatchSetSearchStateMessage.MESSAGE_ID -> handleMatchSetSearchStateMessage(session, payload);
+                case MatchAcceptedMessage.MESSAGE_ID -> handleMatchAcceptedMessage(session, payload);
+                default -> this.closeSession(session, CloseStatus.BAD_DATA);
+            }
+        } catch (Exception ignored) {
+            this.closeSession(session, CloseStatus.BAD_DATA);
+        }
+    }
+
+    private void handleMatchSetSearchStateMessage(WebSocketSession session, String payload) throws Exception {
+        MatchSetSearchStateMessage msg = objectMapper.readValue(payload, MatchSetSearchStateMessage.class);
+        Player player = sessionPlayers.get(session);
+        if (!msg.isSearching()) {
+            this.matchQueueService.unQueuePlayer(player);
+            return;
+        }
+        this.matchQueueService.queuePlayer(
+                player,
+                this::onFound,
+                this::onQueued,
+                this::onAbort,
+                this::onEstablished
+        );
+    }
+
+    private void onFound(Player player, String matchId, long created, long ttl) throws IOException {
+        WebSocketSession session = playerSessions.get(player);
+        MatchFoundMessage msg = new MatchFoundMessage(matchId, created, ttl);
+        msg.send(session);
+    }
+
+    private void onQueued(Player player) throws IOException{
+        WebSocketSession session = playerSessions.get(player);
+        MatchSetSearchStateMessage msg = new MatchSetSearchStateMessage(true);
+        msg.send(session);
+    }
+
+    private void onAbort(Player player, String matchId) {
+        WebSocketSession session = playerSessions.get(player);
+        MatchAbortedMessage msg = new MatchAbortedMessage(matchId);
+        try {
+            msg.send(session);
+        } catch (IOException ignored) {
+        }
+    }
+
+    private void onEstablished(Player player, String matchId, Player opponent) throws IOException {
+        WebSocketSession session = playerSessions.get(player);
+        MatchEstablishedMessage msg = new MatchEstablishedMessage(matchId, opponent.getUsername());
+        msg.send(session);
+    }
+
+    private void handleMatchAcceptedMessage(WebSocketSession session, String payload) throws Exception {
+        MatchAcceptedMessage msg = objectMapper.readValue(payload, MatchAcceptedMessage.class);
+        Player player = sessionPlayers.get(session);
+        if (msg.isAccepted()) {
+            this.matchConfirmationService.accept(player, msg.getMatchId());
+        } else {
+            this.matchConfirmationService.decline(player, msg.getMatchId());
+        }
+    }
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/bi/MatchSetSearchStateMessage.java

@@ -0,0 +1,35 @@
+package de.towerdefence.server.server.channels.matchmaking.bi;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import jakarta.validation.constraints.NotNull;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.util.Map;
+
+@Getter
+@NotNull
+@AllArgsConstructor
+public class MatchSetSearchStateMessage extends JsonMessage {
+    public static final String MESSAGE_ID = "MatchSetSearchState";
+
+    @Getter
+    @JsonProperty("$id")
+    private String messageId;
+
+    private boolean searching;
+
+    public MatchSetSearchStateMessage(boolean searching) {
+        this(MESSAGE_ID, searching);
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of(
+                "searching", factory.booleanNode(this.searching)
+        );
+    }
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/in/MatchAcceptedMessage.java

@@ -0,0 +1,15 @@
+package de.towerdefence.server.server.channels.matchmaking.in;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+@Data
+@NotNull
+public class MatchAcceptedMessage {
+    public static final String MESSAGE_ID = "MatchAccepted";
+    @JsonProperty("$id")
+    private String messageId;
+    private String matchId;
+    private boolean accepted;
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/out/MatchAbortedMessage.java

@@ -0,0 +1,25 @@
+package de.towerdefence.server.server.channels.matchmaking.out;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import lombok.AllArgsConstructor;
+
+import java.util.Map;
+
+@AllArgsConstructor
+public class MatchAbortedMessage extends JsonMessage {
+    private String matchId;
+
+    @Override
+    protected String getMessageId() {
+        return "MatchAborted";
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of(
+                "matchId", factory.textNode(this.matchId)
+        );
+    }
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/out/MatchEstablishedMessage.java

@@ -0,0 +1,27 @@
+package de.towerdefence.server.server.channels.matchmaking.out;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import lombok.AllArgsConstructor;
+
+import java.util.Map;
+
+@AllArgsConstructor
+public class MatchEstablishedMessage extends JsonMessage {
+    private String matchId;
+    private String opponentName;
+
+    @Override
+    protected String getMessageId() {
+        return "MatchEstablished";
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of(
+                "matchId", factory.textNode(this.matchId),
+                "opponentName", factory.textNode(this.opponentName)
+        );
+    }
+}

src/main/java/de/towerdefence/server/server/channels/matchmaking/out/MatchFoundMessage.java

@@ -0,0 +1,29 @@
+package de.towerdefence.server.server.channels.matchmaking.out;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import lombok.AllArgsConstructor;
+
+import java.util.Map;
+
+@AllArgsConstructor
+public class MatchFoundMessage extends JsonMessage {
+    private String matchId;
+    private long created;
+    private long ttl;
+
+    @Override
+    protected String getMessageId() {
+        return "MatchFound";
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of(
+                "matchId", factory.textNode(this.matchId),
+                "created", factory.numberNode(this.created),
+                "ttl", factory.numberNode(this.ttl)
+        );
+    }
+}

src/main/java/de/towerdefence/server/server/channels/time/TimeMessage.java

@@ -0,0 +1,23 @@
+package de.towerdefence.server.server.channels.time;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import de.towerdefence.server.server.JsonMessage;
+import lombok.AllArgsConstructor;
+
+import java.util.Map;
+
+@AllArgsConstructor
+public class TimeMessage extends JsonMessage {
+    private final long time;
+
+    @Override
+    protected String getMessageId() {
+        return "CurrentUnixTime";
+    }
+
+    @Override
+    protected Map<String, JsonNode> getData(JsonNodeFactory factory) {
+        return Map.of("time", factory.numberNode(this.time));
+    }
+}

src/main/java/de/towerdefence/server/server/channels/time/TimeWebsocketHandler.java

@@ -1,19 +1,27 @@
-package de.towerdefence.server.server;
+package de.towerdefence.server.server.channels.time;
 
-import org.springframework.web.socket.TextMessage;
+import de.towerdefence.server.server.JsonWebsocketHandler;
+import de.towerdefence.server.session.Channel;
+import de.towerdefence.server.session.SessionsService;
 import org.springframework.web.socket.WebSocketSession;
-import org.springframework.web.socket.handler.TextWebSocketHandler;
 
 import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.*;
 
-public class ServerWebsocketHandler extends TextWebSocketHandler {
-    private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+public class TimeWebsocketHandler extends JsonWebsocketHandler {
+
     private final Map<WebSocketSession, ScheduledFuture<?>> sessionTaskMap = new ConcurrentHashMap<>();
+    private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+
+    public TimeWebsocketHandler(SessionsService sessionsService) {
+        super(Channel.TIME, sessionsService);
+    }
 
     @Override
-    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
+    public void afterConnectionEstablished(WebSocketSession session) {
+        super.afterConnectionEstablished(session);
+
         ScheduledFuture<?> scheduledTask = scheduler.scheduleAtFixedRate(
                 () -> sendCurrentTime(session),
                 0,
@@ -23,25 +31,16 @@ public class ServerWebsocketHandler extends TextWebSocketHandler {
         sessionTaskMap.put(session, scheduledTask);
     }
 
-    @Override
-    public void handleTextMessage(WebSocketSession session, TextMessage message) {
-        try {
-            String responseMessage = "You are Connected to the Tower Defence Server Websocket";
-            session.sendMessage(new TextMessage(responseMessage));
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-    }
-
     private void sendCurrentTime(WebSocketSession session) {
         ScheduledFuture<?> task = sessionTaskMap.get(session);
         try {
-            session.sendMessage(new TextMessage(String.valueOf(System.currentTimeMillis())));
-        } catch (IllegalStateException | IOException e) {
+            if(!session.isOpen()){
+                throw new RuntimeException("Session is not open");
+            }
+            new TimeMessage(System.currentTimeMillis()).send(session);
+        } catch (RuntimeException | IOException e) {
             task.cancel(true);
             sessionTaskMap.remove(session);
-        } catch (Exception e) {
-            e.printStackTrace();
         }
     }
 }

src/main/java/de/towerdefence/server/session/Channel.java

@@ -0,0 +1,25 @@
+package de.towerdefence.server.session;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public enum Channel {
+    CONNECTION("connection"),
+    MATCHMAKING("matchmaking"),
+    TIME("time");
+
+    private final String jsonName;
+
+    @JsonCreator
+    public static Channel fromJsonName(String jsonName) {
+        for (Channel channel : Channel.values()) {
+            if (channel.getJsonName().equalsIgnoreCase(jsonName)) {
+                return channel;
+            }
+        }
+        throw new IllegalArgumentException("Unknown channel: " + jsonName);
+    }
+}

src/main/java/de/towerdefence/server/session/JwtService.java

@@ -0,0 +1,61 @@
+package de.towerdefence.server.session;
+
+import io.jsonwebtoken.Claims;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.security.Keys;
+import io.jsonwebtoken.security.WeakKeyException;
+import jakarta.annotation.PostConstruct;
+import org.springframework.stereotype.Service;
+
+import javax.crypto.SecretKey;
+import java.nio.charset.StandardCharsets;
+import java.util.Date;
+import java.util.Optional;
+
+@Service
+public class JwtService {
+
+    private final SecretKey secretKey;
+
+    public JwtService(JwtServiceConfig config) throws WeakKeyException {
+        this.secretKey = Keys.hmacShaKeyFor(config.getSecret().getBytes(StandardCharsets.UTF_8));
+    }
+
+    public String generateToken(String username, Channel channel, long ttl) {
+        long now = System.currentTimeMillis();
+        Date issueDate = new Date(now);
+        Date expirationDate = new Date(now + ttl * 1000);
+
+        return Jwts.builder()
+                .subject(username)
+                .claim("channel", channel.getJsonName())
+                .issuedAt(issueDate)
+                .expiration(expirationDate)
+                .signWith(secretKey)
+                .compact();
+    }
+
+    public Optional<String> verifyToken(String token, Channel channel) {
+        Claims claims = Jwts.parser()
+                .verifyWith(secretKey)
+                .build()
+                .parseSignedClaims(token)
+                .getPayload();
+
+        if (claims.getExpiration().before(new Date())) {
+            return Optional.empty();
+        }
+
+        Channel tokenChannel;
+        try {
+            tokenChannel = Channel.fromJsonName(claims.get("channel", String.class));
+        } catch (IllegalArgumentException ignored) {
+            return Optional.empty();
+        }
+        if(!channel.equals(tokenChannel)) {
+            return Optional.empty();
+        }
+
+        return Optional.of(claims.getSubject());
+    }
+}

src/main/java/de/towerdefence/server/session/JwtServiceConfig.java

@@ -0,0 +1,14 @@
+package de.towerdefence.server.session;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Getter
+@Setter
+@Configuration
+@ConfigurationProperties(prefix = "jwt")
+public class JwtServiceConfig {
+    private String secret;
+}

src/main/java/de/towerdefence/server/session/SessionsService.java

@@ -0,0 +1,63 @@
+package de.towerdefence.server.session;
+
+import de.towerdefence.server.player.Player;
+import lombok.AllArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.*;
+
+@Service
+@AllArgsConstructor
+public class SessionsService {
+    private static final int TIME_TO_LIVE_SECONDS = 30;
+
+    private final Map<String, Channel> tokenGrants = new ConcurrentHashMap<>();
+    private final Map<String, Player> sessions = new ConcurrentHashMap<>();
+    private final Map<String, ScheduledFuture<?>> tokenGarbageCollectors = new ConcurrentHashMap<>();
+
+    @Autowired
+    private final JwtService jwtService;
+    private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+
+    public String createSession(Player player, Channel channel){
+        String jwt = jwtService.generateToken(player.getUsername(), channel, TIME_TO_LIVE_SECONDS);
+        if(tokenGrants.containsKey(jwt)){
+            throw new IllegalStateException("The exact same JWT allready exists");
+        }
+        tokenGrants.put(jwt, channel);
+        sessions.put(jwt, player);
+        this.tokenGarbageCollectors.put(jwt, scheduler.schedule(() -> {
+            tokenGrants.remove(jwt);
+            sessions.remove(jwt);
+            tokenGarbageCollectors.remove(jwt);
+        }, TIME_TO_LIVE_SECONDS, TimeUnit.SECONDS));
+        return jwt;
+    }
+
+    public Optional<Player> getSession(String jwt, Channel channel){
+        Channel grantedChannel = tokenGrants.get(jwt);
+        if (grantedChannel == null || !grantedChannel.equals(channel)) {
+            return Optional.empty();
+        }
+        Optional<String> username = jwtService.verifyToken(jwt, channel);
+        if (username.isEmpty()) {
+            return Optional.empty();
+        }
+        Player player = sessions.get(jwt);
+        if (!Objects.equals(player.getUsername(), username.get())) {
+            return Optional.empty();
+        }
+        ScheduledFuture<?> garbageCollector = tokenGarbageCollectors.get(jwt);
+        if (garbageCollector != null && !garbageCollector.isCancelled() && !garbageCollector.isDone()) {
+            garbageCollector.cancel(false);
+        }
+        tokenGarbageCollectors.remove(jwt);
+        tokenGrants.remove(jwt);
+        sessions.remove(jwt);
+        return Optional.of(player);
+    }
+}

src/main/resources/application.properties

@@ -9,8 +9,11 @@ spring.datasource.username=${TD_DB_USER:td_user}
 spring.datasource.password=${TD_DB_PASS:td123}
 spring.jpa.hibernate.ddl-auto=create-drop
 
+# Signing JWT
+jwt.secret=i-am-secret-key-that-you-wont-guess
+
 # TODO: Replace with our own IAM (After completion of the project)
-# JWT Auth
+# JWT Auth for Keycloak
 spring.security.oauth2.client.registration.keycloak.client-id=employee-management-service
 spring.security.oauth2.client.registration.keycloak.authorization-grant-type=authorization_code
 spring.security.oauth2.client.registration.keycloak.scope=openid

src/main/resources/spotbugs-exclude.xml

@@ -2,11 +2,16 @@
     xmlns="https://raw.githubusercontent.com/spotbugs/spotbugs/4.8.6/spotbugs/etc/findbugsfilter.xsd">
     <Match>
         <Source name="~.*" />
-        <Bug code="EI,EI2" /> <!-- We don't care about these codes -->
+        <Bug code="EI,EI2,UuF" /> <!-- We don't care about these codes -->
     </Match>
     <Match>
         <!--Ignore
         Auto Generated Code -->
         <Source name="~.*build/.*" />
     </Match>
+    <Match>
+        <!-- We are not Vulnerable to that Attack in our Context-->
+        <Class name="de.towerdefence.server.session.JwtService"/>
+        <Bug code="M,B,CT"/>
+    </Match>
 </FindBugsFilter>

src/test/java/de/towerdefence/server/IntegrationTest.java

@@ -3,7 +3,6 @@ package de.towerdefence.server;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import de.towerdefence.server.player.Player;
 import de.towerdefence.server.player.PlayerRepository;
-import de.towerdefence.server.player.PlayerService;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.springframework.beans.factory.annotation.Autowired;

ws/example/time_channel.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+
+response=$(curl -s -X 'POST' \
+  'http://localhost:8080/api/v1/player/login' \
+  -H 'accept: application/json' \
+  -H 'Content-Type: application/json' \
+  -d '{
+  "username": "Player1",
+  "password": "1234"
+}')
+
+token=$(echo "$response" | jq -r .token)
+payload='{"$id": "RequestConnectionToken", "channel": "time"}'
+response=$(echo "$payload" | websocat ws://localhost:8080/ws/connection -H "Authorization: $token")
+
+time_token=$(echo "$response" | jq -r .token)
+websocat ws://localhost:8080/ws/time -H "Authorization: $time_token"

ws/ws.yml

@@ -0,0 +1,258 @@
+asyncapi: 3.0.0
+info:
+  title: Game Server
+  version: 0.0.1
+  description: |
+    This is the Websocket Specification for the Tower Defence Game. <br>
+    Because of the limitations of Async API, we expect that the actual json,
+    which is send as payload to always contain a field called `$id` with
+    the corresponding `messageId`. <br>
+    The `messageId` should be handled case sensitive.
+defaultContentType: application/json
+servers:
+  localhost:
+    host: localhost:8080
+    protocol: ws
+    pathname: /ws
+    security:
+      - $ref: "#/components/securitySchemes/JwtAuth"
+
+channels:
+  connection:
+    title: Connection
+    description: |
+      The Base Channel used for:
+      - Authentication
+      - Receiving Tokens for other channels
+      - Reconnection
+    messages:
+      RequestConnectionToken:
+        description: |
+          A Message telling the Server, that
+          you want an Connection Token for a
+          Specific Channel
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            channel:
+              $ref: "#/components/schemas/Channel"
+          required:
+            - $id
+            - channel
+      ProvidedConnectionToken:
+        description: |
+          A Message telling the Server, that
+          you want an Connection Token for a
+          Specific Channel
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            channel:
+              $ref: "#/components/schemas/Channel"
+            token:
+              $ref: "#/components/schemas/JWT"
+          required:
+            - $id
+            - channel
+            - token
+
+  matchmaking:
+    title: Matchmaking
+    description:  |
+      A Channel used to search for a match and
+      to receive one
+    messages:
+      MatchSetSearchState:
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            searching:
+              type: boolean
+          required:
+            - $id
+            - searching
+      MatchFound:
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            matchId:
+              type: string
+            created:
+              description: "Unix Timestamp describing when this Match was found"
+              type: integer
+              format: int64
+            ttl:
+              description: "Time in Milliseconds, how long this Match is open for accepting"
+              type: integer
+              format: int64
+          required:
+            - $id
+            - matchId
+            - created
+            - ttl
+      MatchAccepted:
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            matchId:
+              type: string
+            accepted:
+              type: boolean
+          required:
+            - $id
+            - matchId
+            - accepted
+      MatchAborted:
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            matchId:
+              type: string
+          required:
+            - $id
+            - matchId
+      MatchEstablished:
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            matchId:
+              type: string
+            opponentName:
+              type: string
+          required:
+            - $id
+            - matchId
+            - opponentName
+
+  time:
+    title: Time
+    description: |
+      A Simple example channel for receiving
+      the current Unix time
+    messages:
+      CurrentUnixTime:
+        description: The Current time in Unix Time
+        payload:
+          type: object
+          additionalProperties: false
+          properties:
+            $id:
+              type: string
+              format: messageId
+            time:
+              type: integer
+              format: int64
+          required:
+            - $id
+            - time
+
+operations:
+  requestConnectionToken:
+    title: RequestConnectionToken
+    action: send
+    channel:
+      $ref: "#/channels/connection"
+    messages:
+      - $ref: "#/channels/connection/messages/RequestConnectionToken"
+    reply:
+      channel:
+        $ref: "#/channels/connection"
+      messages:
+        - $ref: "#/channels/connection/messages/ProvidedConnectionToken"
+  searchMatch:
+    title: SearchMatch
+    action: send
+    channel:
+      $ref: "#/channels/matchmaking"
+    messages:
+      - $ref: "#/channels/matchmaking/messages/MatchSetSearchState"
+  setPlayerMatchSearching:
+    title: SetPlayerMatchSearching
+    action: receive
+    channel:
+      $ref: "#/channels/matchmaking"
+    messages:
+      - $ref: "#/channels/matchmaking/messages/MatchSetSearchState"
+  foundMatch:
+    title: FoundGame
+    action: receive
+    channel:
+      $ref: "#/channels/matchmaking"
+    messages:
+      - $ref: "#/channels/matchmaking/messages/MatchFound"
+    reply:
+      channel:
+        $ref: "#/channels/matchmaking"
+      messages:
+        - $ref: "#/channels/matchmaking/messages/MatchAccepted"
+  abortedMatch:
+    title: AbortedMatch
+    action: receive
+    channel:
+      $ref: "#/channels/matchmaking"
+    messages:
+      - $ref: "#/channels/matchmaking/messages/MatchAborted"
+  establishedMatch:
+    title: EstablishedMatch
+    action: receive
+    channel:
+      $ref: "#/channels/matchmaking"
+    messages:
+      - $ref: "#/channels/matchmaking/messages/MatchEstablished"
+  updateTime:
+    title: Updates of the current Unix Time
+    action: receive
+    channel:
+      $ref: "#/channels/time"
+    messages:
+      - $ref: "#/channels/time/messages/CurrentUnixTime"
+
+components:
+  securitySchemes:
+    JwtAuth:
+      name: Authorization
+      description: |
+        A JWT Token has to be provided in the Handshake Header. <br>
+        This Field is expected to be called `Authorization`. <br>
+        It is expected to not have a prefix like `bearer`.
+      type: httpApiKey
+      in: header
+  schemas:
+    JWT:
+      type: string
+      format: jwt
+    Channel:
+      type: string
+      enum:
+        - connection
+        - matchmaking
+        - time
+