Added PlayerProfile support

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}

src/main/java/io/papermc/lib/PaperLib.java

@@ -5,6 +5,9 @@
 import io.papermc.lib.environments.PaperEnvironment;
 import io.papermc.lib.environments.SpigotEnvironment;
 import io.papermc.lib.features.blockstatesnapshot.BlockStateSnapshotResult;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -163,6 +166,34 @@ public static BlockStateSnapshotResult getBlockState(@Nonnull Block block, boole
  return ENVIRONMENT.getBlockState(block, useSnapshot);
  }
 
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerName The real name of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull String playerName) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerName);
+ }
+
+ /**
+ * Gets information about a potentially offline player, such as their current name or UUID.
+ * Note: Calling this method may contact Mojang's API and will block the current thread with the web request if it does.
+ * Additionally, it's possible that the name or UUID returned is null and/or an IOException is thrown.
+ *
+ * @param playerUUID The UUID of the player to get
+ * @return A PlayerInfo object containing information about a player
+ * @throws IOException Thrown when an IOException is encountered while querying the Mojang API.
+ */
+ @Nonnull
+ public static PlayerInfo getPlayerInfo(@Nonnull UUID playerUUID) throws IOException {
+ return ENVIRONMENT.getPlayerInfo(playerUUID);
+ }
+
  /**
  * Detects if the current MC version is at least the following version.
  *

src/main/java/io/papermc/lib/environments/Environment.java

@@ -11,6 +11,11 @@
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGenerated;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedApiExists;
 import io.papermc.lib.features.chunkisgenerated.ChunkIsGeneratedUnknown;
+import io.papermc.lib.features.playerprofile.BukkitPlayerInfo;
+import io.papermc.lib.features.playerprofile.PaperPlayerInfo;
+import io.papermc.lib.features.playerprofile.PlayerInfo;
+import java.io.IOException;
+import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
@@ -34,6 +39,7 @@ public abstract class Environment {
  protected AsyncTeleport asyncTeleportHandler = new AsyncTeleportSync();
  protected ChunkIsGenerated isGeneratedHandler = new ChunkIsGeneratedUnknown();
  protected BlockStateSnapshot blockStateSnapshotHandler;
+ protected boolean hasPlayerProfile = true;
 
  public Environment() {
  Pattern versionPattern = Pattern.compile("\\(MC: (\\d)\\.(\\d+)\\.?(\\d+?)?\\)");
@@ -67,6 +73,12 @@ public Environment() {
  } else {
  blockStateSnapshotHandler = new BlockStateSnapshotNoOption();
  }
+
+ try {
+ Class.forName("com.destroystokyo.paper.profile.PlayerProfile");
+ } catch (ClassNotFoundException ignored) {
+ hasPlayerProfile = false;
+ }
  }
 
  public abstract String getName();
@@ -87,6 +99,14 @@ public BlockStateSnapshotResult getBlockState(Block block, boolean useSnapshot)
  return blockStateSnapshotHandler.getBlockState(block, useSnapshot);
  }
 
+ public PlayerInfo getPlayerInfo(String playerName) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerName) : new BukkitPlayerInfo(playerName);
+ }
+
+ public PlayerInfo getPlayerInfo(UUID playerUUID) throws IOException {
+ return (hasPlayerProfile) ? new PaperPlayerInfo(playerUUID) : new BukkitPlayerInfo(playerUUID);
+ }
+
  public boolean isVersion(int minor) {
  return isVersion(minor, 0);
  }

src/main/java/io/papermc/lib/features/playerprofile/BukkitPlayerInfo.java

@@ -0,0 +1,187 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class BukkitPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ private static ConcurrentMap<UUID, String> uuidCache = new ConcurrentHashMap<>();
+ private static ConcurrentMap<String, UUID> nameCache = new ConcurrentHashMap<>();
+
+ private static final Object uuidCacheLock = new Object();
+ private static final Object nameCacheLock = new Object();
+
+ private static final JSONParser uuidParser = new JSONParser(); // Thread-safe access via synchronized lock
+ private static final JSONParser nameParser = new JSONParser(); // Thread-safe access via synchronized lock
+
+ public BukkitPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ synchronized (uuidCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ name = Optional.ofNullable(uuidCache.getOrDefault(uuid, null));
+ if (!name.isPresent()) {
+ name = Optional.ofNullable(nameExpensive(uuid));
+ name.ifPresent(v -> uuidCache.put(uuid, v));
+ }
+ }
+ }
+
+ this.name = name.orElse(null);
+ }
+
+ public BukkitPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ synchronized (nameCacheLock) { // Synchronize for thread-safe JSONParser access + defeating potential race conditions causing multiple lookups
+ uuid = Optional.ofNullable(nameCache.getOrDefault(name, null));
+ if (!uuid.isPresent()) {
+ uuid = Optional.ofNullable(uuidExpensive(name));
+ uuid.ifPresent(v -> nameCache.put(name, v));
+ }
+ }
+ }
+
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ nameCache.put(player.getName(), uuid);
+ return player.getName();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/user/profiles/" + uuid.toString().replace("-", "") + "/names"));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONArray json = (JSONArray) nameParser.parse(builder.toString());
+ JSONObject last = (JSONObject) json.get(json.size() - 1);
+ String name = (String) last.get("name");
+
+ nameCache.put(name, uuid);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ uuidCache.put(player.getUniqueId(), name);
+ return player.getUniqueId();
+ }
+
+ // Network lookup
+ HttpURLConnection conn = getConnection(new URL("https://api.mojang.com/users/profiles/minecraft/" + name));
+
+ int code = conn.getResponseCode();
+ try (
+ InputStream in = (code == 200) ? conn.getInputStream() : conn.getErrorStream(); // Ensure we always get some text
+ InputStreamReader reader = new InputStreamReader(in);
+ BufferedReader buffer = new BufferedReader(reader)
+ ) {
+ StringBuilder builder = new StringBuilder();
+ String line;
+ while ((line = buffer.readLine()) != null) {
+ builder.append(line);
+ }
+
+ if (code == 200) {
+ JSONObject json = (JSONObject) uuidParser.parse(builder.toString());
+ UUID uuid = UUID.fromString(((String) json.get("id")).replaceFirst("(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)", "$1-$2-$3-$4-$5")); // Normalize UUID for fromString (expects dashes, Mojang returns non-dashed result)
+ name = (String) json.get("name");
+
+ uuidCache.put(uuid, name);
+ } else if (code == 204) {
+ // No data exists
+ return null;
+ }
+ } catch (ParseException ex) {
+ throw new IOException(ex.getMessage(), ex);
+ }
+
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static HttpURLConnection getConnection(URL url) throws IOException {
+ HttpURLConnection conn = getBaseConnection(url);
+ conn.setInstanceFollowRedirects(true);
+
+ int status;
+ boolean redirect;
+
+ do {
+ status = conn.getResponseCode();
+ redirect = status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER; // Follow redirects
+
+ if (redirect) {
+ // Set cookies on redirect and follow redirect URL
+ String newUrl = conn.getHeaderField("Location");
+ String cookies = conn.getHeaderField("Set-Cookie");
+
+ conn = getBaseConnection(new URL(newUrl));
+ conn.setRequestProperty("Cookie", cookies);
+ conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
+ }
+ } while (redirect);
+
+ return conn;
+ }
+
+ private static HttpURLConnection getBaseConnection(URL url) throws IOException {
+ HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+ // Set standard headers
+ conn.setRequestProperty("Accept", "application/json");
+ conn.setRequestProperty("Connection", "close");
+ conn.setRequestProperty("User-Agent", "PaperMC/PaperLib");
+ conn.setRequestMethod("GET");
+
+ return conn;
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PaperPlayerInfo.java

@@ -0,0 +1,75 @@
+package io.papermc.lib.features.playerprofile;
+
+import com.destroystokyo.paper.profile.PlayerProfile;
+import java.io.IOException;
+import java.util.Optional;
+import java.util.UUID;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class PaperPlayerInfo implements PlayerInfo {
+ private UUID uuid;
+ private String name;
+
+ public PaperPlayerInfo(UUID uuid) throws IOException {
+ this.uuid = uuid;
+
+ Optional<String> name = Optional.ofNullable(nameExpensive(uuid));
+ this.name = name.orElse(null);
+ }
+
+ public PaperPlayerInfo(String name) throws IOException {
+ this.name = name;
+
+ Optional<UUID> uuid = Optional.ofNullable(uuidExpensive(name));
+ this.uuid = uuid.orElse(null);
+ }
+
+ public UUID getUUID() { return uuid; }
+
+ public String getName() { return name; }
+
+ private static String nameExpensive(UUID uuid) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(uuid);
+ if (player != null) {
+ return player.getName();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(uuid);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getName();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+
+ private static UUID uuidExpensive(String name) throws IOException {
+ // Currently-online lookup
+ Player player = Bukkit.getPlayer(name);
+ if (player != null) {
+ return player.getUniqueId();
+ }
+
+ // Cached profile lookup
+ PlayerProfile profile = Bukkit.createProfile(name);
+ if ((profile.isComplete() || profile.completeFromCache()) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Network lookup
+ if (profile.complete(false) && profile.getName() != null && profile.getId() != null) {
+ return profile.getId();
+ }
+
+ // Sorry, nada
+ throw new IOException("Could not load player data from Mojang (rate-limited?)");
+ }
+}

src/main/java/io/papermc/lib/features/playerprofile/PlayerInfo.java

@@ -0,0 +1,20 @@
+package io.papermc.lib.features.playerprofile;
+
+import java.util.UUID;
+import javax.annotation.Nullable;
+
+public interface PlayerInfo {
+ /**
+ * The name of the player.
+ *
+ * @return The name of the payer.
+ */
+ @Nullable String getName();
+
+ /**
+ * The UUID of the player.
+ *
+ * @return The UUID of the player.
+ */
+ @Nullable UUID getUUID();
+}