Add online mode hack

README.md

@@ -9,4 +9,3 @@ This will have the better compatibility with other mods.
 * Start server to generate config
 * Setting velocity `player-info-forwarding-mode` to `modern` and `forwarding-secret`
 * Setting `secret` in `config/Fabric-Lite.toml` match velocity config
-* Set server to **offline mode**

src/main/java/one/oktw/FabricProxyLite.java

@@ -13,16 +13,18 @@
 import net.minecraft.text.LiteralText;
 import one.oktw.mixin.ClientConnection_AddressAccessor;
 import one.oktw.mixin.ServerLoginNetworkHandler_ProfileAccessor;
+import org.objectweb.asm.tree.ClassNode;
+import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
+import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
 
-public class FabricProxyLite implements DedicatedServerModInitializer {
+import java.util.List;
+import java.util.Set;
+
+public class FabricProxyLite implements DedicatedServerModInitializer, IMixinConfigPlugin {
     public static ModConfig config;
 
     @Override
     public void onInitializeServer() {
-        // Config
-        AutoConfig.register(ModConfig.class, Toml4jConfigSerializer::new);
-        config = AutoConfig.getConfigHolder(ModConfig.class).getConfig();
-
         // Packet receiver
         ServerLoginNetworking.registerGlobalReceiver(VelocityLib.PLAYER_INFO_CHANNEL, this::handleVelocityPacket);
         ServerLoginConnectionEvents.QUERY_START.register((handler, server, sender, synchronizer) -> sender.sendPacket(VelocityLib.PLAYER_INFO_CHANNEL, PacketByteBufs.empty()));
@@ -44,4 +46,40 @@ private void handleVelocityPacket(MinecraftServer server, ServerLoginNetworkHand
 
         ((ServerLoginNetworkHandler_ProfileAccessor) handler).setProfile(VelocityLib.createProfile(buf));
     }
+
+    // Only load hack mixin if enabled
+    @Override
+    public void onLoad(String mixinPackage) {
+        if (config == null) {
+            AutoConfig.register(ModConfig.class, Toml4jConfigSerializer::new);
+            config = AutoConfig.getConfigHolder(ModConfig.class).getConfig();
+        }
+    }
+
+    @Override
+    public String getRefMapperConfig() {
+        return null;
+    }
+
+    @Override
+    public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
+        return config.getHackOnlineMode() && !config.getSecret().isEmpty();
+    }
+
+    @Override
+    public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {
+    }
+
+    @Override
+    public List<String> getMixins() {
+        return null;
+    }
+
+    @Override
+    public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    }
+
+    @Override
+    public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    }
 }

src/main/java/one/oktw/ModConfig.java

@@ -7,9 +7,20 @@
 @SuppressWarnings({"FieldCanBeLocal", "FieldMayBeFinal"})
 @Config(name = "FabricProxy-Lite")
 public class ModConfig implements ConfigData {
+    private boolean hackOnlineMode = true;
+
     @Comment("Velocity proxy secret")
     private String secret = "";
 
+    public boolean getHackOnlineMode() {
+        String env = System.getenv("FABRIC_PROXY_HACK_ONLINE_MODE");
+        if (env == null) {
+            return hackOnlineMode;
+        } else {
+            return Boolean.parseBoolean(env);
+        }
+    }
+
     public String getSecret() {
         String env = System.getenv("FABRIC_PROXY_SECRET");
         if (env == null) {

src/main/java/one/oktw/mixin/hack/ServerLoginNetworkHandler_SkipKeyPacket.java

@@ -0,0 +1,15 @@
+package one.oktw.mixin.hack;
+
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.network.ServerLoginNetworkHandler;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(ServerLoginNetworkHandler.class)
+public class ServerLoginNetworkHandler_SkipKeyPacket {
+    @Redirect(method = "onHello", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/MinecraftServer;isOnlineMode()Z"))
+    private boolean skipKeyPacket(MinecraftServer minecraftServer) {
+        return false;
+    }
+}

src/main/resources/fabric.mod.json

@@ -22,7 +22,8 @@
     ]
   },
   "mixins": [
-    "core.mixins.json"
+    "core.mixins.json",
+    "hack.mixins.json"
   ],
 
   "depends": {

src/main/resources/hack.mixins.json

@@ -0,0 +1,13 @@
+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "one.oktw.mixin.hack",
+  "plugin": "one.oktw.FabricProxyLite",
+  "compatibilityLevel": "JAVA_8",
+  "mixins": [
+    "ServerLoginNetworkHandler_SkipKeyPacket"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
+}