List all mod versions from server and client

src/main/java/ru/bclib/api/WorldDataAPI.java

@@ -8,6 +8,7 @@ import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.NbtIo;
 import net.minecraft.world.level.storage.LevelStorageSource.LevelStorageAccess;
 import ru.bclib.BCLib;
+import ru.bclib.api.dataexchange.DataExchangeAPI;
 import ru.bclib.api.datafixer.DataFixerAPI;
 
 import java.io.File;
@@ -62,11 +63,14 @@ public class WorldDataAPI {
 	
 	/**
 	 * Register mod cache, world cache is located in world data folder.
+	 * <p>
+	 * Will also register the Mod for the {@link DataExchangeAPI} using {@link DataExchangeAPI#registerMod(String)}
 	 *
 	 * @param modID - {@link String} modID.
 	 */
 	public static void registerModCache(String modID) {
 		MODS.add(modID);
+		DataExchangeAPI.registerMod(modID);
 	}
 	
 	/**

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

@@ -1,5 +1,6 @@
 package ru.bclib.api.dataexchange;
 
+import com.google.common.collect.Lists;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents;
@@ -7,9 +8,11 @@ import net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents;
 import net.minecraft.network.FriendlyByteBuf;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 public class DataExchangeAPI {
+	private final static List<String> MODS = Lists.newArrayList();
 	private static DataExchangeAPI instance;
 	private ConnectorServerside server;
 	private ConnectorClientside client;
@@ -46,6 +49,23 @@ public class DataExchangeAPI {
 		ServerPlayConnectionEvents.DISCONNECT.register(server::onPlayDisconnect);
 	}
 	
+	/**
+	 * Register a mod to participate in the DataExchange.
+	 *
+	 * @param modID - {@link String} modID.
+	 */
+	public static void registerMod(String modID) {
+		MODS.add(modID);
+	}
+	
+	/**
+	 * Returns the IDs of all registered Mods.
+	 * @return List of modIDs
+	 */
+	public static List<String> registeredMods(){
+		return MODS;
+	}
+	
 	/**
 	 * Add a new Descriptor for a DataHandler.
 	 * @param desc The Descriptor you want to add.

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

@@ -1,5 +1,7 @@
 package ru.bclib.api.dataexchange;
 
+import io.netty.buffer.ByteBufUtil;
+import io.netty.util.CharsetUtil;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking;
@@ -16,6 +18,8 @@ import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.server.network.ServerGamePacketListenerImpl;
 import org.jetbrains.annotations.NotNull;
 
+import java.nio.charset.StandardCharsets;
+
 public abstract class DataHandler {
 	private final boolean originatesOnServer;
 	@NotNull
@@ -104,4 +108,23 @@ public abstract class DataHandler {
 	public String toString() {
 		return "DataHandler{" + "originatesOnServer=" + originatesOnServer + ", identifier=" + identifier + '}';
 	}
+	
+	/**
+	 * Write a String to a buffer (Convenience Method)
+	 * @param buf The buffer to write to
+	 * @param s The String you want to write
+	 */
+	public static void writeString(FriendlyByteBuf buf, String s){
+		buf.writeByteArray(s.getBytes(StandardCharsets.UTF_8));
+	}
+	
+	/**
+	 * Read a string from a buffer (Convenience Method)
+	 * @param buf Thea buffer to read from
+	 * @return The received String
+	 */
+	public static String readString(FriendlyByteBuf buf){
+		byte[] data = buf.readByteArray();
+		return new String(data, StandardCharsets.UTF_8);
+	}
 }

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

@@ -1,5 +1,7 @@
 package ru.bclib.api.dataexchange.handler;
 
+import io.netty.buffer.ByteBufUtil;
+import io.netty.util.CharsetUtil;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.fabricmc.fabric.api.networking.v1.PacketSender;
@@ -8,11 +10,18 @@ import net.fabricmc.loader.api.ModContainer;
 import net.minecraft.client.Minecraft;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.MinecraftServer;
 import ru.bclib.BCLib;
+import ru.bclib.api.WorldDataAPI;
+import ru.bclib.api.dataexchange.DataExchangeAPI;
 import ru.bclib.api.dataexchange.DataHandler;
 import ru.bclib.api.dataexchange.DataHandlerDescriptor;
 import ru.bclib.api.datafixer.DataFixerAPI;
 
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Optional;
 
 public class HelloServer extends DataHandler {
@@ -35,22 +44,41 @@ public class HelloServer extends DataHandler {
 		return getModVersion(BCLib.MOD_ID);
 	}
 	
+	String bclibVersion ="0.0.0";
+	Map<String, String> modVersion = new HashMap<>();
 	@Override
 	protected void deserializeFromIncomingData(FriendlyByteBuf buf, PacketSender responseSender, boolean fromClient) {
-		String bclibVersion = DataFixerAPI.getModVersion(buf.readInt());
+		bclibVersion = DataFixerAPI.getModVersion(buf.readInt());
-		String localBclibVersion = getBCLibVersion();
+		modVersion = new HashMap<>();
 		
-		BCLib.LOGGER.info("Hello Server received from BCLib. (server="+localBclibVersion+", client="+bclibVersion+")");
+		int count = buf.readInt();
+		for (int i=0; i< count; i++){
+			String id = readString(buf);
+			String version = DataFixerAPI.getModVersion(buf.readInt());
+			modVersion.put(id, version);
+		}
 	}
 	
 	@Override
-	@Environment(EnvType.CLIENT)
+	protected void runOnServer(MinecraftServer server) {
-	protected void runOnClient(Minecraft client) {
+		String localBclibVersion = getBCLibVersion();
-	
+		BCLib.LOGGER.info("Hello Server received from BCLib. (server="+localBclibVersion+", client="+bclibVersion+")");
+		
+		for (Entry<String, String> e : modVersion.entrySet()){
+			String ver = getModVersion(e.getKey());
+			BCLib.LOGGER.info("    - " + e.getKey() + " (server="+ver+", client="+ver+")");
+		}
 	}
 	
 	@Override
 	protected void serializeData(FriendlyByteBuf buf) {
+		final List<String> mods = DataExchangeAPI.registeredMods();
 		buf.writeInt(DataFixerAPI.getModVersion(getBCLibVersion()));
+		
+		buf.writeInt(mods.size());
+		for (String modID : mods) {
+			writeString(buf, modID);
+			buf.writeInt(DataFixerAPI.getModVersion(getModVersion(modID)));
+		}
 	}
 }