MinecraftUtilities/Backend
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Add very basic Java MC server impl

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Rainnny7 2024-04-09 01:47:28 -04:00
parent dd2ce094d2
commit e606a36145
9 changed files with 333 additions and 0 deletions
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89
src/main/java/cc/fascinated/common/packet/MinecraftJavaPacket.java Normal file
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/*
* MIT License
*
* Copyright (c) 2024 Braydon (Rainnny).
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package cc.fascinated.common.packet;
import lombok.NonNull;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
/**
* Represents a packet in the
* Minecraft Java protocol.
*
* @author Braydon
* @see <a href="https://wiki.vg/Protocol">Protocol Docs</a>
*/
public abstract class MinecraftJavaPacket {
/**
* Process this packet.
*
* @param inputStream the input stream to read from
* @param outputStream the output stream to write to
* @throws IOException if an I/O error occurs
*/
public abstract void process(@NonNull DataInputStream inputStream, @NonNull DataOutputStream outputStream) throws IOException;
/**
* Write a variable integer to the output stream.
*
* @param outputStream the output stream to write to
* @param paramInt the integer to write
* @throws IOException if an I/O error occurs
*/
protected final void writeVarInt(DataOutputStream outputStream, int paramInt) throws IOException {
while (true) {
if ((paramInt & 0xFFFFFF80) == 0) {
outputStream.writeByte(paramInt);
return;
}
outputStream.writeByte(paramInt & 0x7F | 0x80);
paramInt >>>= 7;
}
}
/**
* Read a variable integer from the input stream.
*
* @param inputStream the input stream to read from
* @return the integer that was read
* @throws IOException if an I/O error occurs
*/
protected final int readVarInt(@NonNull DataInputStream inputStream) throws IOException {
int i = 0;
int j = 0;
while (true) {
int k = inputStream.readByte();
i |= (k & 0x7F) << j++ * 7;
if (j > 5) {
throw new RuntimeException("VarInt too big");
}
if ((k & 0x80) != 128) {
break;
}
}
return i;
}
}

64
src/main/java/cc/fascinated/common/packet/impl/java/JavaPacketHandshakingInSetProtocol.java Normal file
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package cc.fascinated.common.packet.impl.java;
import cc.fascinated.common.packet.MinecraftJavaPacket;
import lombok.AllArgsConstructor;
import lombok.NonNull;
import lombok.ToString;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
/**
* This packet is sent by the client to the server to set
* the hostname, port, and protocol version of the client.
*
* @author Braydon
* @see <a href="https://wiki.vg/Protocol#Handshake">Protocol Docs</a>
*/
@AllArgsConstructor @ToString
public final class JavaPacketHandshakingInSetProtocol extends MinecraftJavaPacket {
private static final byte ID = 0x00; // The ID of the packet
private static final int STATUS_HANDSHAKE = 1; // The status handshake ID
/**
* The hostname of the server.
*/
@NonNull private final String hostname;
/**
* The port of the server.
*/
private final int port;
/**
* The protocol version of the server.
*/
private final int protocolVersion;
/**
* Process this packet.
*
* @param inputStream the input stream to read from
* @param outputStream the output stream to write to
* @throws IOException if an I/O error occurs
*/
@Override
public void process(@NonNull DataInputStream inputStream, @NonNull DataOutputStream outputStream) throws IOException {
try (ByteArrayOutputStream handshakeBytes = new ByteArrayOutputStream();
DataOutputStream handshake = new DataOutputStream(handshakeBytes)
) {
handshake.writeByte(ID); // Write the ID of the packet
writeVarInt(handshake, protocolVersion); // Write the protocol version
writeVarInt(handshake, hostname.length()); // Write the length of the hostname
handshake.writeBytes(hostname); // Write the hostname
handshake.writeShort(port); // Write the port
writeVarInt(handshake, STATUS_HANDSHAKE); // Write the status handshake ID
// Write the handshake bytes to the output stream
writeVarInt(outputStream, handshakeBytes.size());
outputStream.write(handshakeBytes.toByteArray());
}
}
}

62
src/main/java/cc/fascinated/common/packet/impl/java/JavaPacketStatusInStart.java Normal file
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package cc.fascinated.common.packet.impl.java;
import cc.fascinated.common.packet.MinecraftJavaPacket;
import lombok.Getter;
import lombok.NonNull;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
/**
* This packet is sent by the client to the server to request the
* status of the server. The server will respond with a json object
* containing the server's status.
*
* @author Braydon
* @see <a href="https://wiki.vg/Protocol#Status_Request">Protocol Docs</a>
*/
@Getter
public final class JavaPacketStatusInStart extends MinecraftJavaPacket {
private static final byte ID = 0x00; // The ID of the packet
/**
* The response json from the server, null if none.
*/
private String response;
/**
* Process this packet.
*
* @param inputStream the input stream to read from
* @param outputStream the output stream to write to
* @throws IOException if an I/O error occurs
*/
@Override
public void process(@NonNull DataInputStream inputStream, @NonNull DataOutputStream outputStream) throws IOException {
// Send the status request
outputStream.writeByte(0x01); // Size of packet
outputStream.writeByte(ID);
// Read the status response
readVarInt(inputStream); // Size of the response
int id = readVarInt(inputStream);
if (id == -1) { // The stream was prematurely ended
throw new IOException("Server prematurely ended stream.");
} else if (id != ID) { // Invalid packet ID
throw new IOException("Server returned invalid packet ID.");
}
int length = readVarInt(inputStream); // Length of the response
if (length == -1) { // The stream was prematurely ended
throw new IOException("Server prematurely ended stream.");
} else if (length == 0) {
throw new IOException("Server returned unexpected value.");
}
// Get the json response
byte[] data = new byte[length];
inputStream.readFully(data);
response = new String(data);
}
}

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src/main/java/cc/fascinated/controller/ServerController.java Normal file
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package cc.fascinated.controller;
import cc.fascinated.model.server.MinecraftServer;
import cc.fascinated.service.pinger.impl.JavaMinecraftServerPinger;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
@RestController
@RequestMapping(value = "/server/")
public class ServerController {
@ResponseBody
@GetMapping(value = "/{hostname}", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<MinecraftServer> getServer(@PathVariable String hostname) {
return ResponseEntity.ok(JavaMinecraftServerPinger.INSTANCE.ping(hostname, 25565));
}
}

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src/main/java/cc/fascinated/model/mojang/JavaServerStatusToken.java Normal file
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package cc.fascinated.model.mojang;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.ToString;
/**
* @author Braydon
*/
@AllArgsConstructor @Getter @ToString
public final class JavaServerStatusToken {
private final String description;
}

10
src/main/java/cc/fascinated/model/server/JavaMinecraftServer.java Normal file
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package cc.fascinated.model.server;
/**
* @author Braydon
*/
public final class JavaMinecraftServer extends MinecraftServer {
public JavaMinecraftServer(String hostname, int port, String motd) {
super(hostname, port, motd);
}
}

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src/main/java/cc/fascinated/model/server/MinecraftServer.java Normal file
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package cc.fascinated.model.server;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.ToString;
/**
* @author Braydon
*/
@AllArgsConstructor @Getter @ToString
public class MinecraftServer {
private final String hostname;
private final int port;
private final String motd;
}

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src/main/java/cc/fascinated/service/pinger/MinecraftServerPinger.java Normal file
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package cc.fascinated.service.pinger;
/**
* @author Braydon
* @param <T> the type of server to ping
*/
public interface MinecraftServerPinger<T> {
T ping(String hostname, int port);
}

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src/main/java/cc/fascinated/service/pinger/impl/JavaMinecraftServerPinger.java Normal file
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package cc.fascinated.service.pinger.impl;
import cc.fascinated.Main;
import cc.fascinated.common.packet.impl.java.JavaPacketHandshakingInSetProtocol;
import cc.fascinated.common.packet.impl.java.JavaPacketStatusInStart;
import cc.fascinated.model.mojang.JavaServerStatusToken;
import cc.fascinated.model.server.JavaMinecraftServer;
import cc.fascinated.service.pinger.MinecraftServerPinger;
import lombok.extern.log4j.Log4j2;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
/**
* @author Braydon
*/
@Log4j2(topic = "Java Pinger")
public final class JavaMinecraftServerPinger implements MinecraftServerPinger<JavaMinecraftServer> {
public static final JavaMinecraftServerPinger INSTANCE = new JavaMinecraftServerPinger();
private static final int TIMEOUT = 3000; // The timeout for the socket
@Override
public JavaMinecraftServer ping(String hostname, int port) {
log.info("Pinging {}:{}...", hostname, port);
// Open a socket connection to the server
try (Socket socket = new Socket()) {
socket.setTcpNoDelay(true);
socket.connect(new InetSocketAddress(hostname, port), TIMEOUT);
// Open data streams to begin packet transaction
try (DataInputStream inputStream = new DataInputStream(socket.getInputStream());
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream())) {
// Begin handshaking with the server
new JavaPacketHandshakingInSetProtocol(hostname, port, 47).process(inputStream, outputStream);
// Send the status request to the server, and await back the response
JavaPacketStatusInStart packetStatusInStart = new JavaPacketStatusInStart();
packetStatusInStart.process(inputStream, outputStream);
System.out.println("packetStatusInStart.getResponse() = " + packetStatusInStart.getResponse());
JavaServerStatusToken token = Main.GSON.fromJson(packetStatusInStart.getResponse(), JavaServerStatusToken.class);
return new JavaMinecraftServer(hostname, port, token.getDescription());
}
} catch (IOException ex) {
ex.printStackTrace();
}
return null;
}
}