Throttle client-link requests per player

integrations/common/src/main/java/net/scopenet/core/ClientLink.java

@@ -22,6 +22,9 @@ public final class ClientLink {
     private final Map<UUID, String> lastState = new ConcurrentHashMap<>();
     private final Map<UUID, String> lastClaimsKey = new ConcurrentHashMap<>();
     private final Set<UUID> clients = ConcurrentHashMap.newKeySet();
+    private final Map<UUID, Long> lastRequest = new ConcurrentHashMap<>();
+    /** One request per player at most this often; a modded client can't turn the link into a panel flood. */
+    static final long MIN_REQUEST_GAP_MS = 400;
 
     public ClientLink(Env env, PlayerCache cache, String serverName, BiConsumer<CorePlayer, byte[]> out) {
         this.env = env; this.cache = cache; this.serverName = serverName; this.out = out;
@@ -30,7 +33,7 @@ public final class ClientLink {
     public boolean hasClient(UUID uuid) { return clients.contains(uuid); }
 
     public void disconnected(UUID uuid) {
-        clients.remove(uuid); lastState.remove(uuid); lastClaimsKey.remove(uuid); cache.forget(uuid);
+        clients.remove(uuid); lastState.remove(uuid); lastClaimsKey.remove(uuid); lastRequest.remove(uuid); cache.forget(uuid);
     }
 
     private void send(CorePlayer p, JsonObject message) { out.accept(p, Wire.encode(message.toString())); }
@@ -42,6 +45,9 @@ public final class ClientLink {
         catch (RuntimeException e) { return; }
         String type = PlayerCache.str(msg, "t", "");
         if (!env.features.clientLink()) return;
+        long now = env.clock.getAsLong();
+        Long previous = lastRequest.put(p.uuid(), now);
+        if (previous != null && now - previous < MIN_REQUEST_GAP_MS && !type.equals("hello")) return;
         switch (type) {
             case "hello" -> hello(p);
             case "refresh" -> { if (clients.contains(p.uuid())) { lastState.remove(p.uuid()); cache.refresh(p, info -> pushState(p)); } }