add server pinger

src/main/java/cc.fascinated/common/DNSUtils.java

@@ -0,0 +1,59 @@
+package cc.fascinated.common;
+
+import lombok.NonNull;
+import lombok.SneakyThrows;
+import lombok.experimental.UtilityClass;
+import org.xbill.DNS.Record;
+import org.xbill.DNS.*;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+/**
+ * @author Braydon
+ */
+@UtilityClass
+public final class DNSUtils {
+    private static final String SRV_QUERY_PREFIX = "_minecraft._tcp.%s";
+
+    /**
+     * Resolve the hostname to an {@link InetSocketAddress}.
+     *
+     * @param hostname the hostname to resolve
+     * @return the resolved {@link InetSocketAddress}
+     */
+    @SneakyThrows
+    public static InetSocketAddress resolveSRV(@NonNull String hostname) {
+        Record[] records = new Lookup(SRV_QUERY_PREFIX.formatted(hostname), Type.SRV).run(); // Resolve SRV records
+        if (records == null) { // No records exist
+            return null;
+        }
+        String host = null;
+        int port = -1;
+        for (Record record : records) {
+            SRVRecord srv = (SRVRecord) record;
+            host = srv.getTarget().toString().replaceFirst("\\.$", "");
+            port = srv.getPort();
+        }
+        return host == null ? null :  new InetSocketAddress(host, port);
+    }
+
+    /**
+     * Resolve the hostname to an {@link InetAddress}.
+     *
+     * @param hostname the hostname to resolve
+     * @return the resolved {@link InetAddress}
+     */
+    @SneakyThrows
+    public static InetAddress resolveA(@NonNull String hostname) {
+        Record[] records = new Lookup(hostname, Type.A).run(); // Resolve A records
+        if (records == null) { // No records exist
+            return null;
+        }
+        InetAddress address = null;
+        for (Record record : records) {
+            address = ((ARecord) record).getAddress();
+        }
+        return address;
+    }
+}

src/main/java/cc.fascinated/common/IPUtils.java

@@ -0,0 +1,42 @@
+package cc.fascinated.common;
+
+import jakarta.servlet.http.HttpServletRequest;
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class IPUtils {
+    /**
+     * The headers that contain the IP.
+     */
+    private static final String[] IP_HEADERS = new String[] {
+            "CF-Connecting-IP",
+            "X-Forwarded-For"
+    };
+
+    /**
+     * Get the real IP from the given request.
+     *
+     * @param request the request
+     * @return the real IP
+     */
+    public static String getRealIp(HttpServletRequest request) {
+        String ip = request.getRemoteAddr();
+        for (String headerName : IP_HEADERS) {
+            String header = request.getHeader(headerName);
+            if (header == null) {
+                continue;
+            }
+            if (!header.contains(",")) { // Handle single IP
+                ip = header;
+                break;
+            }
+            // Handle multiple IPs
+            String[] ips = header.split(",");
+            for (String ipHeader : ips) {
+                ip = ipHeader;
+                break;
+            }
+        }
+        return ip;
+    }
+}

src/main/java/cc.fascinated/common/PlayerUtils.java

@@ -0,0 +1,90 @@
+package cc.fascinated.common;
+
+import cc.fascinated.Main;
+import cc.fascinated.exception.impl.BadRequestException;
+import cc.fascinated.model.player.Skin;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import lombok.SneakyThrows;
+import lombok.experimental.UtilityClass;
+import lombok.extern.log4j.Log4j2;
+
+import javax.imageio.ImageIO;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.net.URI;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.UUID;
+
+@UtilityClass @Log4j2
+public class PlayerUtils {
+
+    /**
+     * Gets the UUID from the string.
+     *
+     * @param id the id string
+     * @return the UUID
+     */
+    public static UUID getUuidFromString(String id) {
+        UUID uuid;
+        boolean isFullUuid = id.length() == 36;
+        if (id.length() == 32 || isFullUuid) {
+            try {
+                uuid = isFullUuid ? UUID.fromString(id) : UUIDUtils.addDashes(id);
+            } catch (IllegalArgumentException exception) {
+                throw new BadRequestException("Invalid UUID provided: %s".formatted(id));
+            }
+            return uuid;
+        }
+        return null;
+    }
+
+    /**
+     * Gets the skin data from the URL.
+     *
+     * @return the skin data
+     */
+    @SneakyThrows
+    @JsonIgnore
+    public static byte[] getSkinImage(String url) {
+        HttpResponse<byte[]> response = Main.HTTP_CLIENT.send(HttpRequest.newBuilder(URI.create(url)).build(),
+                HttpResponse.BodyHandlers.ofByteArray());
+        return response.body();
+    }
+
+    /**
+     * Gets the part data from the skin.
+     *
+     * @return the part data
+     */
+    public static byte[] getSkinPartBytes(Skin skin, Skin.Parts part, int size) {
+        if (size == -1) {
+            size = part.getDefaultSize();
+        }
+
+        try {
+            BufferedImage image = ImageIO.read(new ByteArrayInputStream(skin.getSkinImage()));
+            if (image == null) {
+                image = ImageIO.read(new ByteArrayInputStream(Skin.DEFAULT_SKIN.getSkinImage())); // Fallback to the default skin
+            }
+            // Get the part of the image (e.g. the head)
+            BufferedImage partImage = image.getSubimage(part.getX(), part.getY(), part.getWidth(), part.getHeight());
+
+            // Scale the image
+            BufferedImage scaledImage = new BufferedImage(size, size, partImage.getType());
+            Graphics2D graphics2D = scaledImage.createGraphics();
+            graphics2D.drawImage(partImage, 0, 0, size, size, null);
+            graphics2D.dispose();
+            partImage = scaledImage;
+
+            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+            ImageIO.write(partImage, "png", byteArrayOutputStream);
+            return byteArrayOutputStream.toByteArray();
+        } catch (Exception ex) {
+            log.error("Failed to get {} part bytes for {}", part.name(), skin.getUrl(), ex);
+            return null;
+        }
+    }
+}

src/main/java/cc.fascinated/common/Tuple.java

@@ -0,0 +1,18 @@
+package cc.fascinated.common;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter @AllArgsConstructor
+public class Tuple<L, R> {
+
+    /**
+     * The left value of the tuple.
+     */
+    private final L left;
+
+    /**
+     * The right value of the tuple.
+     */
+    private final R right;
+}

src/main/java/cc.fascinated/common/UUIDUtils.java

@@ -0,0 +1,25 @@
+package cc.fascinated.common;
+
+import io.micrometer.common.lang.NonNull;
+import lombok.experimental.UtilityClass;
+
+import java.util.UUID;
+
+@UtilityClass
+public class UUIDUtils {
+
+    /**
+     * Add dashes to a UUID.
+     *
+     * @param trimmed the UUID without dashes
+     * @return the UUID with dashes
+     */
+    @NonNull
+    public static UUID addDashes(@NonNull String trimmed) {
+        StringBuilder builder = new StringBuilder(trimmed);
+        for (int i = 0, pos = 20; i < 4; i++, pos -= 4) {
+            builder.insert(pos, "-");
+        }
+        return UUID.fromString(builder.toString());
+    }
+}

src/main/java/cc.fascinated/common/WebRequest.java

@@ -0,0 +1,41 @@
+package cc.fascinated.common;
+
+import lombok.experimental.UtilityClass;
+import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.web.client.RestClient;
+
+@UtilityClass
+public class WebRequest {
+
+    /**
+     * The web client.
+     */
+    private static final RestClient CLIENT = RestClient.builder()
+            .requestFactory(new HttpComponentsClientHttpRequestFactory())
+            .build();
+
+    /**
+     * Gets a response from the given URL.
+     *
+     * @param url the url
+     * @return the response
+     * @param <T> the type of the response
+     */
+    public static <T> T getAsEntity(String url, Class<T> clazz) {
+        try {
+            ResponseEntity<T> profile = CLIENT.get()
+                    .uri(url)
+                    .retrieve()
+                    .toEntity(clazz);
+
+            if (profile.getStatusCode().isError()) {
+                return null;
+            }
+            return profile.getBody();
+        } catch (HttpClientErrorException ex) {
+            return null;
+        }
+    }
+}

src/main/java/cc.fascinated/common/packet/MinecraftJavaPacket.java

@@ -0,0 +1,66 @@
+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;
+    }
+}

src/main/java/cc.fascinated/common/packet/impl/java/JavaPacketHandshakingInSetProtocol.java

@@ -0,0 +1,64 @@
+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());
+        }
+    }
+}

src/main/java/cc.fascinated/common/packet/impl/java/JavaPacketStatusInStart.java

@@ -0,0 +1,62 @@
+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);
+    }
+}