Status response

pom.xml

@@ -77,6 +77,11 @@
             <artifactId>guava</artifactId>
             <version>24.1-jre</version>
         </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.8.2</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/mc/core/ByteArrayOutputNetStream.java

@@ -0,0 +1,40 @@
+/*
+ * DmitriyMX <dimon550@gmail.com>
+ * 2018-04-08
+ */
+package mc.core;
+
+import java.io.ByteArrayOutputStream;
+
+public class ByteArrayOutputNetStream extends NetStream {
+    private ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+    @Override
+    public byte readByte() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(byte[] buffer) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readUnsignedShort() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeByte(int value) {
+        baos.write(value);
+    }
+
+    @Override
+    public void writeBytes(byte[] buffer) {
+        baos.write(buffer, 0, buffer.length);
+    }
+
+    public byte[] toByteArray() {
+        return baos.toByteArray();
+    }
+}

src/main/java/mc/core/Config.java

@@ -7,7 +7,7 @@ package mc.core;
 public interface Config {
     int getMaxPlayers();
     String getDescriptionServer();
-    String getFaviconBase64();
+    byte[] getFaviconBase64();
     String getHost();
     int getPort();
 }

src/main/java/mc/core/Main.java

@@ -10,11 +10,13 @@ import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 @Slf4j
 public class Main {
-    public static void main(String[] args) {
-        ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
-        Config config = context.getBean("config", Config.class);
+    public static ApplicationContext appContext; //FIXME
 
-        Server server = context.getBean("server", Server.class);
+    public static void main(String[] args) {
+        appContext = new ClassPathXmlApplicationContext("spring.xml");
+        Config config = appContext.getBean("config", Config.class);
+
+        Server server = appContext.getBean("server", Server.class);
         try {
             server.start(config.getHost(), config.getPort());
         } catch (StartServerException e) {

src/main/java/mc/core/NetStream.java

@@ -42,6 +42,18 @@ public abstract class NetStream {
         return result;
     }
 
+    public void writeVarInt(int value) {
+        do {
+            byte temp = (byte)(value & 0b01111111);
+            value >>>= 7;
+            if (value != 0) {
+                temp |= 0b10000000;
+            }
+
+            writeByte(temp);
+        } while (value != 0);
+    }
+
     public String readString() {
         int length = readVarInt();
 
@@ -51,7 +63,15 @@ public abstract class NetStream {
         return new String(buffer, StandardCharsets.UTF_8);
     }
 
+    public void writeString(String value) {
+        writeVarInt(value.length());
+        writeBytes(value.getBytes());
+    }
+
     public abstract byte readByte();
     public abstract void readBytes(byte[] buffer);
     public abstract int readUnsignedShort();
+
+    public abstract void writeByte(int value);
+    public abstract void writeBytes(byte[] buffer);
 }

src/main/java/mc/core/SCPacket.java

@@ -0,0 +1,9 @@
+/*
+ * DmitriyMX <dimon550@gmail.com>
+ * 2018-04-08
+ */
+package mc.core;
+
+public interface SCPacket {
+    byte[] toByteArray();
+}

src/main/java/mc/core/embedded/ConfigFromSpring.java

@@ -19,7 +19,7 @@ import java.util.Base64;
 public class ConfigFromSpring implements Config {
     @Setter
     private String descriptionServer;
-    private String faviconBase64;
+    private byte[] faviconBase64;
     @Setter
     private int maxPlayers;
     @Setter
@@ -30,10 +30,8 @@ public class ConfigFromSpring implements Config {
     public void setFaviconBase64(File faviconImageFile) {
         log.debug("faviconImageFile: {}", faviconImageFile.getAbsolutePath());
         try {
-            faviconBase64 = new String(
-                Base64.getEncoder().encode(
+            faviconBase64 = Base64.getEncoder().encode(
                 FileUtils.readFileToByteArray(faviconImageFile)
-                )
             );
         } catch (IOException e) {
             log.warn("Can't load favicon", e);

src/main/java/mc/core/netty/NettyServer.java

@@ -24,7 +24,8 @@ public class NettyServer implements Server{
                 socketChannel.pipeline().addLast(
                         new LoggingHandler(),
                         new PacketDecoder(),
-                        new PacketHandler()
+                        new PacketHandler(),
+                        new PacketEncoder()
                 );
             }
         };

src/main/java/mc/core/netty/PacketEncoder.java

@@ -0,0 +1,32 @@
+/*
+ * DmitriyMX <dimon550@gmail.com>
+ * 2018-04-08
+ */
+package mc.core.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+import lombok.extern.slf4j.Slf4j;
+import mc.core.NetStream;
+import mc.core.SCPacket;
+
+@Slf4j
+public class PacketEncoder extends MessageToByteEncoder<SCPacket> {
+    @Override
+    protected void encode(ChannelHandlerContext ctx, SCPacket pkt, ByteBuf out) throws Exception {
+        State state = ctx.channel().attr(State.ATTR_STATE).get();
+        Integer id = state.getServerSidePaclet(pkt.getClass());
+        if (id == null) {
+            log.error("Packet not found: {}:{}", state.name(), pkt.getClass().getSimpleName());
+            return;
+        }
+
+        byte[] bytes = pkt.toByteArray();
+        NetStream netStream = new WrapperNetStream(out);
+
+        netStream.writeVarInt(bytes.length + NetStream.sizeVarInt(id));
+        netStream.writeVarInt(id);
+        netStream.writeBytes(bytes);
+    }
+}

src/main/java/mc/core/netty/PacketHandler.java

@@ -4,11 +4,16 @@
  */
 package mc.core.netty;
 
+import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import mc.core.CSPacket;
+import mc.core.Config;
+import mc.core.Main;
 import mc.core.netty.packets.StatusRequest;
+import mc.core.netty.packets.StatusResponse;
 
 import java.lang.reflect.Method;
 import java.util.Arrays;
@@ -23,17 +28,27 @@ public class PacketHandler extends SimpleChannelInboundHandler<CSPacket> {
         Optional<Method> optionalMethod = Arrays.stream(this.getClass().getDeclaredMethods())
                 .filter(method -> method.getName().equals("on" + packet.getClass().getSimpleName())
                     && method.getParameterCount() == 2
-                    && method.getParameterTypes()[0].isAssignableFrom(ctx.getClass())
+                    && method.getParameterTypes()[0].isAssignableFrom(Channel.class)
                     && method.getParameterTypes()[1].isAssignableFrom(packet.getClass()))
                 .findFirst();
 
         if (optionalMethod.isPresent()) {
             Method method = optionalMethod.get();
-            method.invoke(this, ctx, packet);
+            method.invoke(this, ctx.channel(), packet);
         }
     }
 
-    public void onStatusRequest(ChannelHandlerContext ctx, StatusRequest packet) {
-        log.info("Catch!");
+    public void onStatusRequest(Channel channel, StatusRequest packet) {
+        if (!packet.getNextState().equals(State.UNKNOWN)) {
+            channel.attr(State.ATTR_STATE).set(packet.getNextState());
+        }
+
+        Config config = Main.appContext.getBean("config", Config.class); //FIXME
+        StatusResponse pkt = new StatusResponse();
+        pkt.setDescription(config.getDescriptionServer());
+        pkt.setMaxOnline(config.getMaxPlayers());
+        pkt.setFaviconBase64(config.getFaviconBase64());
+
+        channel.writeAndFlush(pkt);
     }
 }

src/main/java/mc/core/netty/State.java

@@ -8,7 +8,9 @@ import com.google.common.collect.ImmutableMap;
 import io.netty.util.AttributeKey;
 import lombok.RequiredArgsConstructor;
 import mc.core.CSPacket;
+import mc.core.SCPacket;
 import mc.core.netty.packets.StatusRequest;
+import mc.core.netty.packets.StatusResponse;
 
 import java.util.Arrays;
 import java.util.Map;
@@ -16,10 +18,14 @@ import java.util.Optional;
 
 @RequiredArgsConstructor
 public enum State {
-    UNKNOWN(0, ImmutableMap.of()),
-    STATUS(1, ImmutableMap.of(
+    UNKNOWN(0, ImmutableMap.of(), ImmutableMap.of()),
+    STATUS(1,
+        ImmutableMap.of(
             0, StatusRequest.class
-    ));
+        ), ImmutableMap.of(
+            StatusResponse.class, 0
+        )
+    );
 
     public static final AttributeKey<State> ATTR_STATE = AttributeKey.newInstance("ATTR_STATE");
 
@@ -33,8 +39,13 @@ public enum State {
 
     private final int id;
     private final Map<Integer, Class<? extends CSPacket>> clientSidePackets;
+    private final Map<Class<? extends SCPacket>, Integer> serverSidePackets;
 
     public Class<? extends CSPacket> getClientSidePacket(final int packetId) {
         return clientSidePackets.get(packetId);
     }
+
+    public Integer getServerSidePaclet(final Class<? extends SCPacket> clazz) {
+        return serverSidePackets.get(clazz);
+    }
 }

src/main/java/mc/core/netty/WrapperNetStream.java

@@ -26,4 +26,14 @@ public class WrapperNetStream extends NetStream {
     public int readUnsignedShort() {
         return byteBuf.readUnsignedShort();
     }
+
+    @Override
+    public void writeByte(int value) {
+        byteBuf.writeByte(value);
+    }
+
+    @Override
+    public void writeBytes(byte[] buffer) {
+        byteBuf.writeBytes(buffer);
+    }
 }

src/main/java/mc/core/netty/packets/StatusResponse.java

@@ -0,0 +1,56 @@
+/*
+ * DmitriyMX <dimon550@gmail.com>
+ * 2018-04-08
+ */
+package mc.core.netty.packets;
+
+import com.google.gson.JsonObject;
+import lombok.Setter;
+import lombok.ToString;
+import mc.core.ByteArrayOutputNetStream;
+import mc.core.SCPacket;
+
+@ToString
+public class StatusResponse implements SCPacket {
+    private static final String name = "1.12.2";
+    private static final int protocol = 340;
+
+    @Setter
+    private int maxOnline;
+    @Setter
+    private int online;
+    @Setter
+    private String description;
+    @Setter
+    private byte[] faviconBase64;
+
+    @Override
+    public byte[] toByteArray() {
+        ByteArrayOutputNetStream netStream = new ByteArrayOutputNetStream();
+
+        JsonObject versionObj = new JsonObject();
+        versionObj.addProperty("name", name);
+        versionObj.addProperty("protocol", protocol);
+
+        JsonObject playersObj = new JsonObject();
+        playersObj.addProperty("max", maxOnline);
+        playersObj.addProperty("online", online);
+
+        JsonObject descriptionObj = new JsonObject();
+        descriptionObj.addProperty("text", description);
+
+        JsonObject rootObj = new JsonObject();
+        rootObj.add("version", versionObj);
+        rootObj.add("players", playersObj);
+        rootObj.add("description", descriptionObj);
+
+        if (faviconBase64 != null && faviconBase64.length > 0) {
+            rootObj.addProperty("favicon",
+                    "data:image/png;base64," + new String(faviconBase64)
+            );
+        }
+
+        netStream.writeString(rootObj.toString());
+        return netStream.toByteArray();
+    }
+}