Simple whitelist system

src/main/java/io/github/gaming32/worldhost/config/WorldHostConfig.java

@@ -19,22 +19,15 @@ public class WorldHostConfig {
     private String serverIp = DEFAULT_SERVER_IP;
 
     private OnlineStatusLocation onlineStatusLocation = OnlineStatusLocation.RIGHT;
-
     private boolean enableFriends = true;
-
     private boolean enableReconnectionToasts = false;
-
     private boolean noUPnP = false;
-
     private boolean useShortIp = false;
-
     private boolean showOutdatedWorldHost = true;
-
     private boolean shareButton = true;
-
     private boolean allowFriendRequests = true;
-
     private boolean announceFriendsOnline = true;
+    private boolean whitelistJoins = false;
 
     private final Set<UUID> friends = Collections.synchronizedSet(new LinkedHashSet<>());
 
@@ -203,6 +196,15 @@ public void setAnnounceFriendsOnline(boolean announceFriendsOnline) {
         this.announceFriendsOnline = announceFriendsOnline;
     }
 
+    @ConfigProperty(order = 10)
+    public boolean isWhitelistJoins() {
+        return whitelistJoins;
+    }
+
+    public void setWhitelistJoins(boolean whitelistJoins) {
+        this.whitelistJoins = whitelistJoins;
+    }
+
     public Set<UUID> getFriends() {
         return friends;
     }

src/main/java/io/github/gaming32/worldhost/mixin/MixinPlayerList.java

@@ -0,0 +1,25 @@
+package io.github.gaming32.worldhost.mixin;
+
+import com.mojang.authlib.GameProfile;
+import io.github.gaming32.worldhost.WorldHost;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.players.PlayerList;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(PlayerList.class)
+public class MixinPlayerList {
+    @Shadow @Final private MinecraftServer server;
+
+    @Inject(method = "isWhiteListed", at = @At("HEAD"), cancellable = true)
+    private void whitelistFriends(GameProfile profile, CallbackInfoReturnable<Boolean> cir) {
+        if (!WorldHost.CONFIG.isWhitelistJoins()) return;
+        if (!server.isSingleplayerOwner(profile) && !WorldHost.isFriend(profile.getId())) {
+            cir.setReturnValue(false);
+        }
+    }
+}

src/main/resources/assets/world-host/lang/en_us.json

@@ -20,7 +20,7 @@
   "world-host.config.announceFriendsOnline": "Popup Friends Online",
   "world-host.config.announceFriendsOnline.tooltip": "When a friend goes online, you will get a popup. You can use this option to disable that.",
   "world-host.config.whitelistJoins": "Whitelist Joins",
-  "world-host.config.whitelistJoins.tooltip": "Only allow friends to join your worlds. This will also affect LAN.",
+  "world-host.config.whitelistJoins.tooltip": "Only allow friends to join your worlds. This affects LAN and direct IPs.",
   "world-host.friends": "Friends",
   "world-host.friends.add_silently": "Add Friend Silently",
   "world-host.friends.add_silently.tooltip": "This will add the person as a friend, without notifying them.\nNote that you must both friend each other in order to join each other's games.",

src/main/resources/world-host.mixins.json

@@ -7,6 +7,7 @@
     "MixinCommands",
     "MixinInputConstants",
     "MixinLevelSummary",
+    "MixinPlayerList",
     "MixinPublishCommand",
     "MixinServerConnectionListener_1",
     "ServerConnectionListenerAccessor"