Compare files on client/server

src/main/java/ru/bclib/api/dataexchange/DataExchangeAPI.java

@@ -7,9 +7,14 @@ import net.fabricmc.fabric.api.client.networking.v1.ClientLoginConnectionEvents;
 import net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents;
 import net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents;
 import net.minecraft.network.FriendlyByteBuf;
+import ru.bclib.BCLib;
 import ru.bclib.api.dataexchange.handler.DataExchange;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -20,7 +25,10 @@ import java.util.function.Predicate;
 public class DataExchangeAPI extends DataExchange {
 	private final static List<String> MODS = Lists.newArrayList();
 
-	protected DataExchangeAPI() {
+	/**
+	 * You should never need to create a custom instance of this Object.
+	 */
+	public DataExchangeAPI() {
 		super((api) -> new ConnectorClientside(api), (api) -> new ConnectorServerside(api));
 	}
 
@@ -47,8 +55,8 @@ public class DataExchangeAPI extends DataExchange {
 	 * @param desc The Descriptor you want to add.
 	 */
 	public static void registerDescriptor(DataHandlerDescriptor desc){
-		DataExchangeAPI api = DataExchange.getInstance();
+		DataExchange api = DataExchange.getInstance();
-		api.descriptors.add(desc);
+		api.getDescriptors().add(desc);
 	}
 
 	/**
@@ -72,10 +80,58 @@ public class DataExchangeAPI extends DataExchange {
 	/**
 	 * Registers a File for automatic client syncing.
 	 *
-	 * @param needTransfer If the predicate returns true, the file needs to get copied to the server.
+	 * @param modID The ID of the calling Mod
 	 * @param fileName The name of the File
 	 */
-	public static void addAutoSyncFile(Predicate<Object> needTransfer, File fileName){
+	public static void addAutoSyncFile(String modID, File fileName){
-		DataExchangeAPI.getInstance().addAutoSyncFileData(needTransfer, fileName);
+		getInstance().addAutoSyncFileData(modID, fileName, false, FileHash.NEED_TRANSFER);
+	}
+
+	/**
+	 * Registers a File for automatic client syncing.
+	 *
+	 * @param modID The ID of the calling Mod
+	 * @param uniqueID A unique Identifier for the File. (see {@link ru.bclib.api.dataexchange.FileHash#uniqueID} for
+	 *                 Details
+	 * @param fileName The name of the File
+	 */
+	public static void addAutoSyncFile(String modID, String uniqueID, File fileName){
+		getInstance().addAutoSyncFileData(modID, uniqueID, fileName, false, FileHash.NEED_TRANSFER);
+	}
+
+	/**
+	 * Registers a File for automatic client syncing.
+	 *
+	 * @param modID The ID of the calling Mod
+	 * @param fileName The name of the File
+	 * @param requestContent When {@code true} the content of the file is requested for comparison. This will copy the
+	 *                       entire file from the client to the server.
+	 *                       <p>
+	 *                       You should only use this option, if you need to compare parts of the file in order to decide
+	 *                       If the File needs to be copied. Normally using the {@link ru.bclib.api.dataexchange.FileHash}
+	 *                       for comparison is sufficient.
+	 * @param needTransfer If the predicate returns true, the file needs to get copied to the server.
+	 */
+	public static void addAutoSyncFile(String modID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer){
+		getInstance().addAutoSyncFileData(modID, fileName, requestContent, needTransfer);
+	}
+
+	/**
+	 * Registers a File for automatic client syncing.
+	 *
+	 * @param modID The ID of the calling Mod
+	 * @param uniqueID A unique Identifier for the File. (see {@link ru.bclib.api.dataexchange.FileHash#uniqueID} for
+	 *                 Details
+	 * @param fileName The name of the File
+	 * @param requestContent When {@code true} the content of the file is requested for comparison. This will copy the
+	 *                       entire file from the client to the server.
+	 *                       <p>
+	 *                       You should only use this option, if you need to compare parts of the file in order to decide
+	 *                       If the File needs to be copied. Normally using the {@link ru.bclib.api.dataexchange.FileHash}
+	 *                       for comparison is sufficient.
+	 * @param needTransfer If the predicate returns true, the file needs to get copied to the server.
+	 */
+	public static void addAutoSyncFile(String modID, String uniqueID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer){
+		getInstance().addAutoSyncFileData(modID, uniqueID, fileName, requestContent, needTransfer);
 	}
 }

src/main/java/ru/bclib/api/dataexchange/DataHandler.java

@@ -48,16 +48,16 @@ public abstract class DataHandler {
 		deserializeFromIncomingData(buf, responseSender, false);
 		server.execute(() -> runOnGameThread(null, server, false));
 	}
-	
+
+	protected void serializeData(FriendlyByteBuf buf) {
+	}
+
 	protected void deserializeFromIncomingData(FriendlyByteBuf buf, PacketSender responseSender, boolean isClient){
 	}
 	
 	protected void runOnGameThread(Minecraft client, MinecraftServer server, boolean isClient){
 	}
-	
+
-	protected void serializeData(FriendlyByteBuf buf) {
-	}
-	
 	final protected boolean reply(DataHandler message, MinecraftServer server){
 		if (lastMessageSender==null) return false;
 		message.sendToClient(server, lastMessageSender);

src/main/java/ru/bclib/api/dataexchange/FileHash.java

@@ -3,6 +3,7 @@ package ru.bclib.api.dataexchange;
 import net.minecraft.network.FriendlyByteBuf;
 import org.jetbrains.annotations.NotNull;
 import ru.bclib.BCLib;
+import ru.bclib.api.dataexchange.handler.DataExchange;
 
 import java.io.File;
 import java.io.IOException;
@@ -12,6 +13,7 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
 import java.util.Objects;
+import java.util.function.Predicate;
 
 /**
  * Calculates a hash based on the contents of a File.
@@ -38,11 +40,47 @@ public class FileHash {
      */
     public final int value;
 
-    FileHash(byte[] md5, int size, int value) {
+    /**
+     * A Unique ID for the referenced File.
+     * <p>
+     * Files with the same {@link #modID} need to have a unique IDs. Normally the filename from {@link #FileHash(String, File, byte[], int, int)}
+     * is used to generated that ID, but you can directly specify one using {@link #FileHash(String, String, byte[], int, int)}.
+     */
+    @NotNull
+    public final String uniqueID;
+
+    /**
+     * The ID of the Mod that is registering the File
+     */
+    @NotNull
+    public final String modID;
+
+    FileHash(String modID, File file, byte[] md5, int size, int value) {
+        this(modID, file.getName(), md5, size, value);
+    }
+
+    FileHash(String modID, String uniqueID, byte[] md5, int size, int value) {
+        Objects.nonNull(modID);
+        Objects.nonNull(uniqueID);
         Objects.nonNull(md5);
+
         this.md5 = md5;
         this.size = size;
         this.value = value;
+        this.modID = modID;
+        this.uniqueID = uniqueID;
+    }
+
+    private static int ERR_DOES_NOT_EXIST = -10;
+    private static int ERR_IO_ERROR = -20;
+    static FileHash createForEmpty(String modID, String uniqueID, int errCode){
+        return new FileHash(modID, uniqueID, new byte[0], 0, errCode);
+    }
+
+    final static DataExchange.NeedTransferPredicate NEED_TRANSFER = (clientHash, serverHash, content)-> !clientHash.equals(serverHash);
+
+    public boolean noFile() {
+        return md5.length == 0;
     }
 
     @Override
@@ -58,13 +96,13 @@ public class FileHash {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        FileHash that = (FileHash) o;
+        FileHash fileHash = (FileHash) o;
-        return size == that.size && value == that.value && Arrays.equals(md5, that.md5);
+        return size == fileHash.size && value == fileHash.value && Arrays.equals(md5, fileHash.md5) && uniqueID.equals(fileHash.uniqueID) && modID.equals(fileHash.modID);
     }
 
     @Override
     public int hashCode() {
-        int result = Objects.hash(size, value);
+        int result = Objects.hash(size, value, uniqueID, modID);
         result = 31 * result + Arrays.hashCode(md5);
         return result;
     }
@@ -76,14 +114,17 @@ public class FileHash {
     public String getMd5String(){
         return toHexString(md5);
     }
+
     /**
      * Serializes the Object to a buffer
      * @param buf The buffer to write to
      */
-    public void writeString(FriendlyByteBuf buf) {
+    public void serialize(FriendlyByteBuf buf) {
         buf.writeInt(size);
         buf.writeInt(value);
         buf.writeByteArray(md5);
+        DataHandler.writeString(buf, modID);
+        DataHandler.writeString(buf, uniqueID);
     }
 
     /**
@@ -91,12 +132,14 @@ public class FileHash {
      * @param buf Thea buffer to read from
      * @return The received String
      */
-    public static FileHash readString(FriendlyByteBuf buf){
+    public static FileHash deserialize(FriendlyByteBuf buf){
         final int size = buf.readInt();
         final int value = buf.readInt();
         final byte[] md5 = buf.readByteArray();
+        final String modID = DataHandler.readString(buf);
+        final String uniqueID = DataHandler.readString(buf);
 
-        return new FileHash(md5, size, value);
+        return new FileHash(modID, uniqueID, md5, size, value);
     }
 
     /**
@@ -116,12 +159,28 @@ public class FileHash {
 
     /**
      * Create a new {@link FileHash}.
+     * <p>
+     * Will call {@link #create(String, File, String)} using the name of the File as {@code uniqueID}.
+     * @param modID ID of the calling Mod
      * @param file The input file
+     *
      * @return A new Instance. You can compare instances using {@link #equals(Object)} to determine if two files are
-     * identical.
+     * identical. Will return {@code null} when an error occurs or the File does not exist
      */
-    public static FileHash createFromBinary(File file){
+    public static FileHash create(String modID, File file){
-        if (!file.exists()) return null;
+        return create(modID, file, file.getName());
+    }
+
+    /**
+     * Create a new {@link FileHash}.
+     * @param modID ID of the calling Mod
+     * @param file The input file
+     * @param uniqueID The unique ID that is used for this File (see {@link FileHash#uniqueID} for Details.
+     * @return A new Instance. You can compare instances using {@link #equals(Object)} to determine if two files are
+     * identical. Will return {@code null} when an error occurs or the File does not exist
+     */
+    public static FileHash create(String modID, File file, String uniqueID){
+        if (!file.exists()) return createForEmpty(modID, uniqueID, ERR_DOES_NOT_EXIST);
         final Path path = file.toPath();
 
         int size = 0;
@@ -140,12 +199,14 @@ public class FileHash {
             md.update(data);
             md5 = md.digest();
 
-            return new FileHash(md5, size, value);
+            return new FileHash(modID, uniqueID, md5, size, value);
         } catch (IOException e) {
             BCLib.LOGGER.error("Failed to read file: " + file);
             return null;
         } catch (NoSuchAlgorithmException e) {
             BCLib.LOGGER.error("Unable to build hash for file: " + file);
         }
+
+        return createForEmpty(modID, uniqueID,  ERR_IO_ERROR);
     }
 }

src/main/java/ru/bclib/api/dataexchange/handler/DataExchange.java

@@ -5,29 +5,117 @@ import net.fabricmc.api.Environment;
 import net.fabricmc.fabric.api.client.networking.v1.ClientLoginConnectionEvents;
 import net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents;
 import net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents;
+import net.minecraft.network.FriendlyByteBuf;
 import ru.bclib.api.dataexchange.ConnectorClientside;
 import ru.bclib.api.dataexchange.ConnectorServerside;
 import ru.bclib.api.dataexchange.DataExchangeAPI;
 import ru.bclib.api.dataexchange.DataHandler;
 import ru.bclib.api.dataexchange.DataHandlerDescriptor;
+import ru.bclib.api.dataexchange.FileHash;
+import ru.bclib.util.Pair;
+import ru.bclib.util.Triple;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Predicate;
-import java.util.function.Supplier;
 
 abstract public class DataExchange {
-    private static class AutoFileSyncEntry {
+    @FunctionalInterface
-        public final Predicate<Object> needTransfer;
+    public interface NeedTransferPredicate  {
-        public final File fileName;
+        public boolean test(FileHash clientHash, FileHash serverHash, byte[] content);
+    }
 
-        private AutoFileSyncEntry(Predicate<Object> needTransfer, File fileName) {
+    final static class AutoSyncTriple extends Triple<FileHash, byte[], DataExchange.AutoFileSyncEntry>{
+        public AutoSyncTriple(FileHash first, byte[] second, AutoFileSyncEntry third) {
+            super(first, second, third);
+        }
+    }
+    static class AutoFileSyncEntry {
+        public final NeedTransferPredicate needTransfer;
+        public final File fileName;
+        public final String modID;
+        public final String uniqueID;
+        public final boolean requestContent;
+        private FileHash hash;
+
+        AutoFileSyncEntry(String modID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer) {
+            this(modID, fileName.getName(), fileName, requestContent, needTransfer);
+        }
+
+        AutoFileSyncEntry(String modID, String uniqueID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer) {
             this.needTransfer = needTransfer;
             this.fileName = fileName;
+            this.modID = modID;
+            this.uniqueID = uniqueID;
+            this.requestContent = requestContent;
+        }
+
+        public FileHash getFileHash(){
+            if (hash == null) {
+                hash = FileHash.create(modID, fileName, uniqueID);
+            }
+            return hash;
+        }
+
+        public byte[] getContent(){
+            if (!fileName.exists()) return new byte[0];
+            final Path path = fileName.toPath();
+
+            try {
+                return Files.readAllBytes(path);
+            } catch (IOException e) {
+
+            }
+            return new byte[0];
+        }
+
+
+        public void serialize(FriendlyByteBuf buf){
+            getFileHash().serialize(buf);
+            buf.writeBoolean(requestContent);
+
+            if (requestContent) {
+                byte[] content = getContent();
+                buf.writeInt(content.length);
+                buf.writeByteArray(content);
+            }
+        }
+
+        public static AutoSyncTriple deserializeAndMatch(FriendlyByteBuf buf){
+            Pair<FileHash, byte[]> e = deserialize(buf);
+            AutoFileSyncEntry match = findMatching(e.first);
+            return new AutoSyncTriple(e.first, e.second, match);
+        }
+
+        public static Pair<FileHash, byte[]> deserialize(FriendlyByteBuf buf){
+            FileHash hash = FileHash.deserialize(buf);
+            boolean withContent = buf.readBoolean();
+            byte[] data = null;
+            if (withContent) {
+                int size = buf.readInt();
+                data = buf.readByteArray(size);
+            }
+
+            return new Pair(hash, data);
+        }
+
+        public static AutoFileSyncEntry findMatching(FileHash hash){
+            return DataExchange
+                    .getInstance()
+                    .autoSyncFiles
+                    .stream()
+                    .filter(asf -> asf.modID.equals(hash.modID) && asf.uniqueID.equals(hash.uniqueID))
+                    .findFirst()
+                    .orElse(null);
         }
     }
 
@@ -85,8 +173,8 @@ abstract public class DataExchange {
      * This is automatically called by BCLib. You can register {@link DataHandler}-Objects before this Method is called
      */
     @Environment(EnvType.CLIENT)
-    public void prepareClientside(){
+    public static void prepareClientside(){
-        DataExchangeAPI api = DataExchangeAPI.getInstance();
+        DataExchange api = DataExchange.getInstance();
         api.initClientside();
 
     }
@@ -97,7 +185,7 @@ abstract public class DataExchange {
      * This is automatically called by BCLib. You can register {@link DataHandler}-Objects before this Method is called
      */
     public static void prepareServerside(){
-        DataExchange api = DataExchangeAPI.getInstance();
+        DataExchange api = DataExchange.getInstance();
         api.initServerSide();
     }
 
@@ -124,10 +212,36 @@ abstract public class DataExchange {
     /**
      * Registers a File for automatic client syncing.
      *
+     * @param modID The ID of the calling Mod
      * @param needTransfer If the predicate returns true, the file needs to get copied to the server.
      * @param fileName The name of the File
+     * @param requestContent When {@code true} the content of the file is requested for comparison. This will copy the
+     *                       entire file from the client to the server.
+     *                       <p>
+     *                       You should only use this option, if you need to compare parts of the file in order to decide
+     *                       If the File needs to be copied. Normally using the {@link ru.bclib.api.dataexchange.FileHash}
+     *                       for comparison is sufficient.
      */
-    protected void addAutoSyncFileData(Predicate<Object> needTransfer, File fileName){
+    protected void addAutoSyncFileData(String modID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer){
-       autoSyncFiles.add(new AutoFileSyncEntry(needTransfer, fileName));
+        autoSyncFiles.add(new AutoFileSyncEntry(modID, fileName, requestContent, needTransfer));
+    }
+
+    /**
+     * Registers a File for automatic client syncing.
+     *
+     * @param modID The ID of the calling Mod
+     * @param uniqueID A unique Identifier for the File. (see {@link ru.bclib.api.dataexchange.FileHash#uniqueID} for
+     *                 Details
+     * @param needTransfer If the predicate returns true, the file needs to get copied to the server.
+     * @param fileName The name of the File
+     * @param requestContent When {@code true} the content of the file is requested for comparison. This will copy the
+     *                       entire file from the client to the server.
+     *                       <p>
+     *                       You should only use this option, if you need to compare parts of the file in order to decide
+     *                       If the File needs to be copied. Normally using the {@link ru.bclib.api.dataexchange.FileHash}
+     *                       for comparison is sufficient.
+     */
+    protected void addAutoSyncFileData(String modID, String uniqueID, File fileName, boolean requestContent, NeedTransferPredicate needTransfer){
+       autoSyncFiles.add(new AutoFileSyncEntry(modID, uniqueID, fileName, requestContent, needTransfer));
     }
 }

src/main/java/ru/bclib/api/dataexchange/handler/HelloClient.java

@@ -7,7 +7,6 @@ import net.fabricmc.loader.api.FabricLoader;
 import net.fabricmc.loader.api.ModContainer;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screens.Screen;
-import net.minecraft.client.gui.screens.worldselection.EditWorldScreen;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.server.MinecraftServer;
@@ -15,10 +14,12 @@ import ru.bclib.BCLib;
 import ru.bclib.api.dataexchange.DataExchangeAPI;
 import ru.bclib.api.dataexchange.DataHandler;
 import ru.bclib.api.dataexchange.DataHandlerDescriptor;
+import ru.bclib.api.dataexchange.FileHash;
 import ru.bclib.api.datafixer.DataFixerAPI;
-import ru.bclib.gui.screens.ConfirmFixScreen;
 import ru.bclib.gui.screens.WarnBCLibVersionMismatch;
+import ru.bclib.util.Triple;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -26,6 +27,11 @@ import java.util.Map.Entry;
 import java.util.Optional;
 import java.util.function.Consumer;
 
+/**
+ * Sent from the Server to the Client.
+ * <p>
+ * For Details refer to {@link HelloServer}
+ */
 public class HelloClient extends DataHandler {
 	public static DataHandlerDescriptor DESCRIPTOR = new DataHandlerDescriptor(new ResourceLocation(BCLib.MOD_ID, "hello_client"), HelloClient::new, false, false);
 	
@@ -45,20 +51,56 @@ public class HelloClient extends DataHandler {
 	static String getBCLibVersion(){
 		return getModVersion(BCLib.MOD_ID);
 	}
+
+	@Override
+	protected void serializeData(FriendlyByteBuf buf) {
+		final List<String> mods = DataExchangeAPI.registeredMods();
+
+		//write BCLibVersion (=protocol version)
+		buf.writeInt(DataFixerAPI.getModVersion(getBCLibVersion()));
+
+		//write Plugin Versions
+		buf.writeInt(mods.size());
+		for (String modID : mods) {
+			writeString(buf, modID);
+			buf.writeInt(DataFixerAPI.getModVersion(getModVersion(modID)));
+		}
+
+		//send config Data
+		final List<DataExchange.AutoFileSyncEntry> autoSyncFiles = DataExchange.getInstance().autoSyncFiles;
+		buf.writeInt(autoSyncFiles.size());
+		for (DataExchange.AutoFileSyncEntry entry : autoSyncFiles) {
+			System.out.println("Serializing " + entry.getFileHash());
+			entry.serialize(buf);
+		}
+	}
 	
 	String bclibVersion ="0.0.0";
 	Map<String, String> modVersion = new HashMap<>();
+	List<DataExchange.AutoSyncTriple> autoSyncedFiles = null;
 	@Override
 	protected void deserializeFromIncomingData(FriendlyByteBuf buf, PacketSender responseSender, boolean fromClient) {
+		//read BCLibVersion (=protocol version)
 		bclibVersion = DataFixerAPI.getModVersion(buf.readInt());
+
+		//read Plugin Versions
 		modVersion = new HashMap<>();
-		
 		int count = buf.readInt();
-		for (int i=0; i< count; i++){
+		for (int i=0; i< count; i++) {
 			String id = readString(buf);
 			String version = DataFixerAPI.getModVersion(buf.readInt());
 			modVersion.put(id, version);
 		}
+
+		//read config Data
+		count = buf.readInt();
+		autoSyncedFiles = new ArrayList<>(count);
+		for (int i=0; i< count; i++) {
+			System.out.println("Deserializing ");
+			DataExchange.AutoSyncTriple t = DataExchange.AutoFileSyncEntry.deserializeAndMatch(buf);
+			autoSyncedFiles.add(t);
+			System.out.println(t.first);
+		}
 	}
 	
 	@Override
@@ -75,17 +117,13 @@ public class HelloClient extends DataHandler {
 			String ver = getModVersion(e.getKey());
 			BCLib.LOGGER.info("    - " + e.getKey() + " (client="+ver+", server="+ver+")");
 		}
-	}
+
-	
+		for (DataExchange.AutoSyncTriple e : autoSyncedFiles) {
-	@Override
+			if (e.third == null) {
-	protected void serializeData(FriendlyByteBuf buf) {
+				BCLib.LOGGER.info("    - File " + e.first.modID + "." + e.first.uniqueID + ": Does not exist on client.");
-		final List<String> mods = DataExchangeAPI.registeredMods();
+			} else if (e.third.needTransfer.test(e.third.getFileHash(), e.first, e.second)) {
-		buf.writeInt(DataFixerAPI.getModVersion(getBCLibVersion()));
+				BCLib.LOGGER.info("    - File " + e.first.modID + "." + e.first.uniqueID + ": Needs Transfer");
-		
+			}
-		buf.writeInt(mods.size());
-		for (String modID : mods) {
-			writeString(buf, modID);
-			buf.writeInt(DataFixerAPI.getModVersion(getModVersion(modID)));
 		}
 	}
 	

src/main/java/ru/bclib/api/dataexchange/handler/HelloServer.java

@@ -10,6 +10,34 @@ import ru.bclib.api.dataexchange.DataHandler;
 import ru.bclib.api.dataexchange.DataHandlerDescriptor;
 import ru.bclib.api.datafixer.DataFixerAPI;
 
+/**
+ * This message is sent once a player enters the world. It initiates a sequence of Messages that will sync files between both
+ * client and server.
+ * <p>
+ * <tab<le>
+ *     <tr>
+ *         <th>Server</th>
+ *         <th></th>
+ *         <th>Client</th>
+ *         <th></th>
+ *     </tr>
+ *     <tr>
+ *         <td colspan="4">Player enters World</td>
+ *     </tr>
+ *     <tr>
+ *         <td></td>
+ *         <td>&lt;--</td>
+ *         <td>{@link HelloServer}</td>
+ *         <td>Sends the current BLib-Version installed on the Client</td>
+ *     </tr>
+ *	   <tr>
+ *         <td>{@link HelloClient}</td>
+ *         <td>--&gt;</td>
+ *         <td></td>
+ *         <td>Sends the current BClIb-Version and the Version of all Plugins on the Server</td>
+ *     </tr>
+ * </table>
+ */
 public class HelloServer extends DataHandler {
 	public static DataHandlerDescriptor DESCRIPTOR = new DataHandlerDescriptor(new ResourceLocation(BCLib.MOD_ID, "hello_server"), HelloServer::new, false, true);
 	
@@ -17,6 +45,11 @@ public class HelloServer extends DataHandler {
 	public HelloServer() {
 		super(DESCRIPTOR.IDENTIFIER, false);
 	}
+
+	@Override
+	protected void serializeData(FriendlyByteBuf buf) {
+		buf.writeInt(DataFixerAPI.getModVersion(HelloClient.getBCLibVersion()));
+	}
 	
 	@Override
 	protected void deserializeFromIncomingData(FriendlyByteBuf buf, PacketSender responseSender, boolean fromClient) {
@@ -29,9 +62,4 @@ public class HelloServer extends DataHandler {
 		BCLib.LOGGER.info("Received Hello from Client. (server="+localBclibVersion+", client="+bclibVersion+")");
 		reply(new HelloClient(), server);
 	}
-	
-	@Override
-	protected void serializeData(FriendlyByteBuf buf) {
-		buf.writeInt(DataFixerAPI.getModVersion(HelloClient.getBCLibVersion()));
-	}
 }

src/main/java/ru/bclib/config/Config.java

@@ -26,7 +26,7 @@ public abstract class Config {
 		this.registerEntries();
 		this.autoSync = autoSync;
 
-		DataExchangeAPI.addAutoSyncFile((content)->{return false;}, keeper.getConfigFile());
+		DataExchangeAPI.addAutoSyncFile(BCLib.MOD_ID, "CONFIG_"+modID+"_"+group, keeper.getConfigFile());
 	}
 	
 	public void saveChanges() {

src/main/java/ru/bclib/util/Pair.java

@@ -0,0 +1,11 @@
+package ru.bclib.util;
+
+public class Pair <A, B>{
+    public final A first;
+    public final B second;
+
+    public Pair(A first, B second) {
+        this.first = first;
+        this.second = second;
+    }
+}

src/main/java/ru/bclib/util/Triple.java

@@ -0,0 +1,10 @@
+package ru.bclib.util;
+
+public class Triple <A, B, C> extends Pair<A, B>{
+    public final C third;
+
+    public Triple(A first, B second, C third) {
+        super(first, second);
+        this.third = third;
+    }
+}