Implement API for dealing with player UUIDs. Adds BUKKIT-5071

src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java

@@ -4,6 +4,7 @@ import java.io.File;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 
 import net.minecraft.server.BanEntry;
 import net.minecraft.server.EntityPlayer;
@@ -41,6 +42,20 @@ public class CraftOfflinePlayer implements OfflinePlayer, ConfigurationSerializa
         return name;
     }
 
+    // TODO: In 1.7.6+ OfflinePlayer lookup should be by UUID and store it like it does the name now
+    public UUID getUniqueId() {
+        NBTTagCompound data = getData();
+        if (data == null) {
+            return null;
+        }
+
+        if (data.hasKeyOfType("UUIDMost", 4) && data.hasKeyOfType("UUIDLeast", 4)) {
+            return new UUID(data.getLong("UUIDMost"), data.getLong("UUIDLeast"));
+        }
+
+        return null;
+    }
+
     public Server getServer() {
         return server;
     }

src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -14,7 +14,6 @@ import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.Set;
 import java.util.UUID;
 import java.util.logging.Level;
@@ -22,7 +21,6 @@ import java.util.logging.Logger;
 
 import javax.imageio.ImageIO;
 
-import net.minecraft.server.BanEntry;
 import net.minecraft.server.ChunkCoordinates;
 import net.minecraft.server.CommandAchievement;
 import net.minecraft.server.CommandBan;
@@ -141,6 +139,7 @@ import org.bukkit.craftbukkit.updater.BukkitDLUpdaterService;
 import org.bukkit.craftbukkit.util.CraftIconCache;
 import org.bukkit.craftbukkit.util.CraftMagicNumbers;
 import org.bukkit.craftbukkit.util.DatFileFilter;
+import org.bukkit.craftbukkit.util.MojangNameLookup;
 import org.bukkit.craftbukkit.util.Versioning;
 import org.bukkit.entity.Player;
 import org.bukkit.event.inventory.InventoryType;
@@ -514,6 +513,17 @@ public final class CraftServer implements Server {
         return null;
     }
 
+    // TODO: In 1.7.6+ this should use the server's UUID->EntityPlayer map
+    public Player getPlayer(UUID id) {
+        for (Player player : getOnlinePlayers()) {
+            if (player.getUniqueId().equals(id)) {
+                return player;
+            }
+        }
+
+        return null;
+    }
+
     public int broadcastMessage(String message) {
         return broadcast(message, BROADCAST_CHANNEL_USERS);
     }
@@ -1282,6 +1292,17 @@ public final class CraftServer implements Server {
         return result;
     }
 
+    // TODO: In 1.7.6+ this should just lookup the UUID-based player data filename
+    public OfflinePlayer getOfflinePlayer(UUID id) {
+        String name = MojangNameLookup.lookupName(id);
+        if (name == null) {
+            // This is completely wrong
+            name = "InvalidUUID";
+        }
+
+        return getOfflinePlayer(name);
+    }
+
     @SuppressWarnings("unchecked")
     public Set<String> getIPBans() {
         return new HashSet<String>(playerList.getIPBans().getEntries().keySet());

src/main/java/org/bukkit/craftbukkit/util/MojangNameLookup.java

@@ -0,0 +1,63 @@
+package org.bukkit.craftbukkit.util;
+
+import net.minecraft.util.com.google.gson.Gson;
+import net.minecraft.util.com.google.common.base.Charsets;
+import net.minecraft.util.org.apache.commons.io.IOUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.UUID;
+
+public class MojangNameLookup {
+    private static final Logger logger = LogManager.getFormatterLogger(MojangNameLookup.class);
+
+    public static String lookupName(UUID id) {
+        if (id == null) {
+            return null;
+        }
+
+        InputStream inputStream = null;
+        try {
+            URL url = new URL("https://sessionserver.mojang.com/session/minecraft/profile/" + id.toString().replace("-", ""));
+            URLConnection connection = url.openConnection();
+            connection.setConnectTimeout(15000);
+            connection.setReadTimeout(15000);
+            connection.setUseCaches(false);
+            inputStream = connection.getInputStream();
+            String result = IOUtils.toString(inputStream, Charsets.UTF_8);
+            Gson gson = new Gson();
+            Response response = gson.fromJson(result, Response.class);
+            if (response == null || response.name == null) {
+                logger.warn("Failed to lookup name from UUID");
+                return null;
+            }
+
+            if (response.cause != null && response.cause.length() > 0) {
+                logger.warn("Failed to lookup name from UUID: %s", response.errorMessage);
+                return null;
+            }
+
+            return response.name;
+        } catch (MalformedURLException ex) {
+            logger.warn("Malformed URL in UUID lookup");
+            return null;
+        } catch (IOException ex) {
+            IOUtils.closeQuietly(inputStream);
+        } finally {
+            IOUtils.closeQuietly(inputStream);
+        }
+
+        return null;
+    }
+
+    private class Response {
+        String errorMessage;
+        String cause;
+        String name;
+    }
+}