Added Server Downloader

patches/net/minecraftforge/fml/relauncher/ServerLaunchWrapper.java.patch

@@ -0,0 +1,36 @@
+--- ../src-base/minecraft/net/minecraftforge/fml/relauncher/ServerLaunchWrapper.java
++++ ../src-work/minecraft/net/minecraftforge/fml/relauncher/ServerLaunchWrapper.java
+@@ -20,10 +20,8 @@
+ package net.minecraftforge.fml.relauncher;
+
+ import java.lang.reflect.Method;
++import kettlefoundation.kettle.downloads.DownloadServerFiles;
+
+-import org.apache.logging.log4j.LogManager;
+-import org.apache.logging.log4j.core.LoggerContext;
+-
+ public class ServerLaunchWrapper {
+
+     /**
+@@ -31,7 +29,10 @@
+      */
+     public static void main(String[] args)
+     {
+-        new ServerLaunchWrapper().run(args);
++      System.out.println("Starting Kettle");
++      DownloadServerFiles.downloadMinecraftServer();
++      DownloadServerFiles.downloadServerLibraries();
++      new ServerLaunchWrapper().run(args);
+     }
+
+     private ServerLaunchWrapper()
+@@ -56,8 +57,7 @@
+         {
+             System.err.printf("We appear to be missing one or more essential library files.\n" +
+             		"You will need to add them to your server before FML and Forge will run successfully.");
+-            e.printStackTrace(System.err);
+-            System.exit(1);
++
+         }
+
+         try

src/main/java/kettlefoundation/kettle/downloads/DownloadServerFiles.java

@@ -0,0 +1,93 @@
+package kettlefoundation.kettle.downloads;
+
+import java.io.*;
+import java.net.URL;
+import java.nio.channels.Channels;
+import java.nio.channels.ReadableByteChannel;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+/**
+ * DownloadServerFiles
+ *
+ * @author Hexeption [email protected]
+ * @since 02/05/2019 - 06:06 PM
+ */
+public class DownloadServerFiles {
+
+  /**
+   * Downloads required Minecraft server jar from the Minecraft cdn.
+   */
+  public static void downloadMinecraftServer() {
+    String fileName = "minecraft_server.1.12.2.jar";
+    String downloadLink = "https://launcher.mojang.com/v1/objects/886945bfb2b978778c3a0288fd7fab09d315b25f/server.jar";
+
+    File minecraftServerJar = new File(fileName);
+    if (!minecraftServerJar.exists() && !minecraftServerJar.isDirectory()) {
+      System.out.println("Downloading Minecraft Server Jar ...");
+      try {
+        URL website = new URL(downloadLink);
+        ReadableByteChannel rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(fileName);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+    }
+  }
+
+  /**
+   * Downloads the required libraries zip from the git repo and extracts the libraries zip into the correct place.
+   */
+  public static void downloadServerLibraries() {
+    String fileName = "libraries.zip";
+    String downloadLink = "https://raw.githubusercontent.com/KettleFoundation/Kettle/master/release/libraries.zip";
+
+    File minecraftlibraries = new File(fileName);
+    if (!minecraftlibraries.exists() && !minecraftlibraries.isDirectory()) {
+      System.out.println("Downloading Server Libraries ...");
+      try {
+        URL website = new URL(downloadLink);
+        ReadableByteChannel rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(fileName);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        System.out.println("Extracting Zip");
+        unzip(minecraftlibraries, ".");
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+    }
+  }
+
+  /**
+   * Extract files and folders in a zip file.
+   *
+   * @param source Zip file to extract data from.
+   * @param out Folder location to put the extracted data into.
+   * @throws IOException if there's an error extracting
+   */
+  private static void unzip(File source, String out) throws IOException {
+    try (ZipInputStream zis = new ZipInputStream(new FileInputStream(source))) {
+      ZipEntry entry = zis.getNextEntry();
+      while (entry != null) {
+        File file = new File(out, entry.getName());
+        if (entry.isDirectory()) {
+          file.mkdirs();
+        } else {
+          File parent = file.getParentFile();
+          if (!parent.exists()) {
+            parent.mkdirs();
+          }
+          try (BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file))) {
+            byte[] buffer = new byte[Math.toIntExact(entry.getSize())];
+            int location;
+            while ((location = zis.read(buffer)) != -1) {
+              bos.write(buffer, 0, location);
+            }
+          }
+        }
+        entry = zis.getNextEntry();
+      }
+    }
+  }
+}