Automatically add loopback exemption to Windows

bootstrap/standalone/src/main/java/org/geysermc/platform/standalone/GeyserBootstrap.java

@@ -25,16 +25,16 @@
 
 package org.geysermc.platform.standalone;
 
+import java.io.File;
+import java.io.IOException;
+import java.util.UUID;
+
 import org.geysermc.common.PlatformType;
 import org.geysermc.common.bootstrap.IGeyserBootstrap;
 import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.utils.FileUtils;
 import org.geysermc.platform.standalone.console.GeyserLogger;
 
-import java.io.File;
-import java.io.IOException;
-import java.util.UUID;
-
 public class GeyserBootstrap implements IGeyserBootstrap {
     
     private GeyserConfiguration geyserConfig;
@@ -50,6 +50,8 @@ public class GeyserBootstrap implements IGeyserBootstrap {
     public void onEnable() {
         geyserLogger = new GeyserLogger();
         
+        Util.checkLoopback(geyserLogger);
+        
         try {
             File configFile = FileUtils.fileOrCopiedFromResource("config.yml", (x) -> x.replaceAll("generateduuid", UUID.randomUUID().toString()));
             geyserConfig = FileUtils.loadConfig(configFile, GeyserConfiguration.class);

bootstrap/standalone/src/main/java/org/geysermc/platform/standalone/Util.java

@@ -0,0 +1,44 @@
+package org.geysermc.platform.standalone;
+
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.OpenOption;
+import java.nio.file.Paths;
+
+import org.geysermc.platform.standalone.console.GeyserLogger;
+
+public class Util {
+    private static final String checkExemption = "powershell -Command \"CheckNetIsolation LoopbackExempt -s\""; // Java's Exec feature runs as CMD, NetIsolation is only accessible from PowerShell.
+    private static final String loopbackCommand = "powershell -Command \"CheckNetIsolation LoopbackExempt -a -n='Microsoft.MinecraftUWP_8wekyb3d8bbwe'\"";
+    private static final String startScript = "powershell -Command \"Start-Process 'cmd' -ArgumentList /c,%temp%/loopback_minecraft.bat -Verb runAs\"";
+
+    public static void checkLoopback(GeyserLogger geyserLogger) {
+        if (System.getProperty("os.name").equalsIgnoreCase("Windows 10")) {
+            try {
+                Process process = Runtime.getRuntime().exec(checkExemption);
+                InputStream is = process.getInputStream();
+                StringBuilder sb = new StringBuilder();
+
+                while (process.isAlive()) {
+                    if (is.available() != 0) {
+                        sb.append((char) is.read());
+                    }
+                }
+
+                String result = sb.toString();
+
+                if (!result.contains("minecraftuwp")) {
+                    Files.write(Paths.get(System.getenv("temp") + "/loopback_minecraft.bat"), loopbackCommand.getBytes(), new OpenOption[0]);
+                    process = Runtime.getRuntime().exec(startScript);
+
+                    geyserLogger.warning("Added loopback exemption to Windows!");
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+
+                geyserLogger.error("Couldn't auto add loopback exemption to Windows!");
+            }
+        }
+    }
+
+}