Add interceptor for invalid subscriptions

7 files changed, 159 insertions, 8 deletions

diff --git a/src/main/java/org/luxons/sevenwonders/config/TopicSubscriptionInterceptor.java b/src/main/java/org/luxons/sevenwonders/config/TopicSubscriptionInterceptor.java
new file mode 100644
index 00000000..f8d92068
--- /dev/null
+++ b/src/main/java/org/luxons/sevenwonders/config/TopicSubscriptionInterceptor.java
@@ -0,0 +1,38 @@
+package org.luxons.sevenwonders.config;
+
+import java.security.Principal;
+
+import org.luxons.sevenwonders.validation.DestinationAccessValidator;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.simp.stomp.StompCommand;
+import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
+import org.springframework.messaging.support.ChannelInterceptorAdapter;
+import org.springframework.stereotype.Component;
+
+@Component
+public class TopicSubscriptionInterceptor extends ChannelInterceptorAdapter {
+
+    private final DestinationAccessValidator destinationAccessValidator;
+
+    @Autowired
+    public TopicSubscriptionInterceptor(DestinationAccessValidator destinationAccessValidator) {
+        this.destinationAccessValidator = destinationAccessValidator;
+    }
+
+    @Override
+    public Message<?> preSend(Message<?> message, MessageChannel channel) {
+        StompHeaderAccessor headerAccessor = StompHeaderAccessor.wrap(message);
+        if (StompCommand.SUBSCRIBE.equals(headerAccessor.getCommand())) {
+            Principal userPrincipal = headerAccessor.getUser();
+            if (!destinationAccessValidator.hasAccess(userPrincipal.getName(), headerAccessor.getDestination())) {
+                throw new ForbiddenSubscriptionException();
+            }
+        }
+        return message;
+    }
+
+    private static class ForbiddenSubscriptionException extends RuntimeException {
+    }
+}
diff --git a/src/main/java/org/luxons/sevenwonders/config/WebSocketConfig.java b/src/main/java/org/luxons/sevenwonders/config/WebSocketConfig.java
index 3b588894..d54d8da4 100644
--- a/src/main/java/org/luxons/sevenwonders/config/WebSocketConfig.java
+++ b/src/main/java/org/luxons/sevenwonders/config/WebSocketConfig.java
@@ -1,7 +1,9 @@
 package org.luxons.sevenwonders.config;
 
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.simp.config.ChannelRegistration;
 import org.springframework.messaging.simp.config.MessageBrokerRegistry;
 import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
 import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
@@ -12,13 +14,20 @@ import org.springframework.web.socket.server.support.DefaultHandshakeHandler;
 @EnableWebSocketMessageBroker
 public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
 
+    private final TopicSubscriptionInterceptor topicSubscriptionInterceptor;
+
+    @Autowired
+    public WebSocketConfig(TopicSubscriptionInterceptor topicSubscriptionInterceptor) {
+        this.topicSubscriptionInterceptor = topicSubscriptionInterceptor;
+    }
+
     @Override
     public void configureMessageBroker(MessageBrokerRegistry config) {
         // prefixes for all subscriptions
         config.enableSimpleBroker("/queue", "/topic");
         config.setUserDestinationPrefix("/user");
 
-        // prefix for all calls from clients
+        // /app for normal calls, /topic for subscription events
         config.setApplicationDestinationPrefixes("/app", "/topic");
     }
 
@@ -35,4 +44,8 @@ public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
         return new AnonymousUsersHandshakeHandler();
     }
 
+    @Override
+    public void configureClientInboundChannel(ChannelRegistration registration) {
+        registration.setInterceptors(topicSubscriptionInterceptor);
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/org/luxons/sevenwonders/game/Decks.java b/src/main/java/org/luxons/sevenwonders/game/Decks.java
index 12fda17f..abc8e817 100644
--- a/src/main/java/org/luxons/sevenwonders/game/Decks.java
+++ b/src/main/java/org/luxons/sevenwonders/game/Decks.java
@@ -9,8 +9,6 @@ import org.luxons.sevenwonders.game.cards.Card;
 
 public class Decks {
 
-    private static final int HAND_SIZE = 7;
-
     private Map<Integer, List<Card>> cardsPerAge = new HashMap<>();
 
     public Decks(Map<Integer, List<Card>> cardsPerAge) {
@@ -23,7 +21,7 @@ public class Decks {
                           .flatMap(List::stream)
                           .filter(c -> c.getName().equals(cardName))
                           .findAny()
-                          .orElseThrow(CardNotFoundException::new);
+                          .orElseThrow(() -> new CardNotFoundException(cardName));
     }
 
     Map<Integer, List<Card>> deal(int age, int nbPlayers) {
@@ -41,20 +39,24 @@ public class Decks {
     }
 
     private void validateNbCards(List<Card> deck, int nbPlayers) {
-        if (nbPlayers * HAND_SIZE != deck.size()) {
+        if (deck.size() % nbPlayers != 0) {
             throw new IllegalArgumentException(
-                    String.format("%d cards is not the expected number for %d players", deck.size(), nbPlayers));
+                    String.format("Cannot deal %d cards evenly between %d players", deck.size(), nbPlayers));
         }
     }
 
     private Map<Integer, List<Card>> deal(List<Card> deck, int nbPlayers) {
         Map<Integer, List<Card>> hands = new HashMap<>(nbPlayers);
         for (int i = 0; i < deck.size(); i++) {
-            hands.putIfAbsent(i % nbPlayers, new ArrayList<>()).add(deck.get(i));
+            hands.putIfAbsent(i % nbPlayers, new ArrayList<>());
+            hands.get(i % nbPlayers).add(deck.get(i));
         }
         return hands;
     }
 
     public class CardNotFoundException extends RuntimeException {
+        CardNotFoundException(String message) {
+            super(message);
+        }
     }
 }
diff --git a/src/main/java/org/luxons/sevenwonders/game/Game.java b/src/main/java/org/luxons/sevenwonders/game/Game.java
index 70a5b615..53b8bc53 100644
--- a/src/main/java/org/luxons/sevenwonders/game/Game.java
+++ b/src/main/java/org/luxons/sevenwonders/game/Game.java
@@ -48,6 +48,10 @@ public class Game {
         return table.getPlayers();
     }
 
+    public boolean containsUser(String userName) {
+        return getPlayers().stream().anyMatch(p -> p.getUserName().equals(userName));
+    }
+
     private void startNewAge() {
         currentAge++;
         hands = decks.deal(currentAge, table.getNbPlayers());
diff --git a/src/main/java/org/luxons/sevenwonders/game/Lobby.java b/src/main/java/org/luxons/sevenwonders/game/Lobby.java
index 241c5530..35f72f0f 100644
--- a/src/main/java/org/luxons/sevenwonders/game/Lobby.java
+++ b/src/main/java/org/luxons/sevenwonders/game/Lobby.java
@@ -86,6 +86,10 @@ public class Lobby {
         return owner.getUserName().equals(userName);
     }
 
+    public boolean containsUser(String userName) {
+        return players.stream().anyMatch(p -> p.getUserName().equals(userName));
+    }
+
     private static class GameAlreadyStartedException extends IllegalStateException {
     }
 
diff --git a/src/main/java/org/luxons/sevenwonders/repositories/LobbyRepository.java b/src/main/java/org/luxons/sevenwonders/repositories/LobbyRepository.java
index bede34af..21348890 100644
--- a/src/main/java/org/luxons/sevenwonders/repositories/LobbyRepository.java
+++ b/src/main/java/org/luxons/sevenwonders/repositories/LobbyRepository.java
@@ -18,6 +18,8 @@ public class LobbyRepository {
 
     private Map<String, Lobby> lobbies = new HashMap<>();
 
+    private Map<Long, Lobby> lobbiesById = new HashMap<>();
+
     private long lastGameId = 0;
 
     @Autowired
@@ -36,6 +38,7 @@ public class LobbyRepository {
         long id = lastGameId++;
         Lobby lobby = new Lobby(id, gameName, owner, gameDefinitionLoader.getGameDefinition());
         lobbies.put(gameName, lobby);
+        lobbiesById.put(id, lobby);
         return lobby;
     }
 
@@ -47,7 +50,15 @@ public class LobbyRepository {
         return lobby;
     }
 
-    private static class LobbyNotFoundException extends RuntimeException {
+    public Lobby find(long lobbyId) {
+        Lobby lobby = lobbiesById.get(lobbyId);
+        if (lobby == null) {
+            throw new LobbyNotFoundException(String.valueOf(lobbyId));
+        }
+        return lobby;
+    }
+
+    public static class LobbyNotFoundException extends RuntimeException {
         LobbyNotFoundException(String name) {
             super("Lobby not found for game '" + name + "'");
         }
diff --git a/src/main/java/org/luxons/sevenwonders/validation/DestinationAccessValidator.java b/src/main/java/org/luxons/sevenwonders/validation/DestinationAccessValidator.java
new file mode 100644
index 00000000..bc7e52ce
--- /dev/null
+++ b/src/main/java/org/luxons/sevenwonders/validation/DestinationAccessValidator.java
@@ -0,0 +1,79 @@
+package org.luxons.sevenwonders.validation;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.luxons.sevenwonders.game.Game;
+import org.luxons.sevenwonders.game.Lobby;
+import org.luxons.sevenwonders.repositories.GameRepository;
+import org.luxons.sevenwonders.repositories.LobbyRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class DestinationAccessValidator {
+
+    private static final Pattern lobbyDestination = Pattern.compile(".*?/lobby/(?<id>\\d+?)(/.*)?");
+
+    private static final Pattern gameDestination = Pattern.compile(".*?/game/(?<id>\\d+?)(/.*)?");
+
+    private final LobbyRepository lobbyRepository;
+
+    private final GameRepository gameRepository;
+
+    @Autowired
+    public DestinationAccessValidator(LobbyRepository lobbyRepository, GameRepository gameRepository) {
+        this.lobbyRepository = lobbyRepository;
+        this.gameRepository = gameRepository;
+    }
+
+    public boolean hasAccess(String userName, String destination) {
+        if (userName == null) {
+            // unnamed user cannot belong to anything
+            return false;
+        }
+        if (hasForbiddenGameReference(userName, destination)) {
+            return false;
+        }
+        if (hasForbiddenLobbyReference(userName, destination)) {
+            return false;
+        }
+        return true;
+    }
+
+    private boolean hasForbiddenGameReference(String userName, String destination) {
+        Matcher gameMatcher = gameDestination.matcher(destination);
+        if (!gameMatcher.matches()) {
+            return false; // no game reference is always OK
+        }
+        int gameId = extractId(gameMatcher);
+        return !isUserInGame(userName, gameId);
+    }
+
+    private boolean hasForbiddenLobbyReference(String userName, String destination) {
+        Matcher lobbyMatcher = lobbyDestination.matcher(destination);
+        if (!lobbyMatcher.matches()) {
+            return false; // no lobby reference is always OK
+        }
+        int lobbyId = extractId(lobbyMatcher);
+        return !isUserInLobby(userName, lobbyId);
+    }
+
+    private boolean isUserInGame(String userName, int gameId) {
+        Game game = gameRepository.find(gameId);
+        return game.containsUser(userName);
+    }
+
+    private boolean isUserInLobby(String userName, int lobbyId) {
+        Lobby lobby = lobbyRepository.find(lobbyId);
+        return lobby.containsUser(userName);
+    }
+
+    private static int extractId(Matcher matcher) {
+        String id = matcher.group("id");
+        if (id == null) {
+            throw new IllegalArgumentException("No id matched in the destination");
+        }
+        return Integer.parseInt(id);
+    }
+}