Add `getUUID()` and `getUsername()` to MojangUtils (#2024)

* Add MojangUtils#getUUID() and MojangUtils#getUsername()

* Remove invalid UUID test as Java's UUID will not allow an invalid UUID

* Add `@Blocking` and some JavaDoc comments

* Override `MojangUtils#fromUuid(String)` with `MojangUtils#fromUuid(UUID)` and add a test

* Switch to IOException over custom ones

src/main/java/net/minestom/server/utils/mojang/MojangUtils.java

@@ -11,6 +11,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.IOException;
+import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -24,36 +25,107 @@ public final class MojangUtils {
             .softValues()
             .build();
 
+    /**
+     * Gets a player's UUID from their username
+     * @param username The players username
+     * @return The {@link UUID}
+     * @throws IOException with text detailing the exception
+     */
+    @Blocking
+    public static @NotNull UUID getUUID(String username) throws IOException {
+        // Thanks stackoverflow: https://stackoverflow.com/a/19399768/13247146
+        return UUID.fromString(
+                retrieve(String.format(FROM_USERNAME_URL, username)).get("id")
+                        .getAsString()
+                        .replaceFirst(
+                                "(\\p{XDigit}{8})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}{4})(\\p{XDigit}+)",
+                                "$1-$2-$3-$4-$5"
+                        )
+        );
+    }
+
+    /**
+     * Gets a player's username from their UUID
+     * @param playerUUID The {@link UUID} of the player
+     * @return The player's username
+     * @throws IOException with text detailing the exception
+     */
+    @Blocking
+    public static @NotNull String getUsername(UUID playerUUID) throws IOException {
+        return retrieve(String.format(FROM_UUID_URL, playerUUID)).get("name").getAsString();
+    }
+
+    /**
+     * Gets a {@link JsonObject} with the response from the mojang API
+     * @param uuid The UUID as a {@link UUID}
+     * @return The {@link JsonObject} or {@code null} if the mojang API is down or the UUID is invalid
+     */
+    @Blocking
+    public static @Nullable JsonObject fromUuid(@NotNull UUID uuid) {
+        return fromUuid(uuid.toString());
+    }
+
+    /**
+     * Gets a {@link JsonObject} with the response from the mojang API
+     * @param uuid The UUID as a {@link String}
+     * @return The {@link JsonObject} or {@code null} if the mojang API is down or the UUID is invalid
+     */
     @Blocking
     public static @Nullable JsonObject fromUuid(@NotNull String uuid) {
-        return retrieve(String.format(FROM_UUID_URL, uuid));
+        try {
+            return retrieve(String.format(FROM_UUID_URL, uuid));
+        } catch (IOException e) {
+            return null;
+        }
     }
 
+    /**
+     * Gets a {@link JsonObject} with the response from the mojang API
+     * @param username The username as a {@link String}
+     * @return The {@link JsonObject} or {@code null} if the mojang API is down or the username is invalid
+     */
     @Blocking
     public static @Nullable JsonObject fromUsername(@NotNull String username) {
-        return retrieve(String.format(FROM_USERNAME_URL, username));
+        try {
+            return retrieve(String.format(FROM_USERNAME_URL, username));
+        } catch (IOException e) {
+            return null;
+        }
     }
 
-    private static @Nullable JsonObject retrieve(@NotNull String url) {
-        return URL_CACHE.get(url, s -> {
-            try {
-                // Retrieve from the rate-limited Mojang API
-                final String response = URLUtils.getText(url);
-                // If our response is "", that means the url did not get a proper object from the url
-                // So the username or UUID was invalid, and therefore we return null
-                if (response.isEmpty()) {
-                    return null;
-                }
+    /**
+     * Gets the JsonObject from a URL, expects a mojang player URL so the errors might not make sense if it is not
+     * @param url The url to retrieve
+     * @return The {@link JsonObject} of the result
+     * @throws IOException with the text detailing the exception
+     */
+    private static @NotNull JsonObject retrieve(@NotNull String url) throws IOException {
+        @Nullable final var cacheResult = URL_CACHE.getIfPresent(url);
 
-                JsonObject jsonObject = JsonParser.parseString(response).getAsJsonObject();
-                if (jsonObject.has("errorMessage")) {
-                    return null;
-                }
-                return jsonObject;
-            } catch (IOException e) {
-                MinecraftServer.getExceptionManager().handleException(e);
-                throw new RuntimeException(e);
-            }
-        });
+        if (cacheResult != null) {
+            return cacheResult;
+        }
+
+        final String response;
+        try {
+            // Retrieve from the rate-limited Mojang API
+            response = URLUtils.getText(url);
+        } catch (IOException e) {
+            MinecraftServer.getExceptionManager().handleException(e);
+            throw new RuntimeException(e);
+        }
+
+        // If our response is "", that means the url did not get a proper object from the url
+        // So the username or UUID was invalid, and therefore we return null
+        if (response.isEmpty()) {
+            throw new IOException("The Mojang API is down");
+        }
+
+        JsonObject jsonObject = JsonParser.parseString(response).getAsJsonObject();
+        if (jsonObject.has("errorMessage")) {
+            throw new IOException(jsonObject.get("errorMessage").getAsString());
+        }
+        URL_CACHE.put(url, jsonObject);
+        return jsonObject;
     }
 }

src/test/java/net/minestom/server/utils/TestMojangUtils.java

@@ -3,9 +3,13 @@ package net.minestom.server.utils;
 import net.minestom.server.utils.mojang.MojangUtils;
 import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
+import java.util.UUID;
+
 import static org.junit.jupiter.api.Assertions.*;
 
 public class TestMojangUtils {
+    private final UUID JEB_UUID = UUID.fromString("853c80ef-3c37-49fd-aa49-938b674adae6");
     @Test
     public void testValidNameWorks() {
         var result = MojangUtils.fromUsername("jeb_");
@@ -21,7 +25,7 @@ public class TestMojangUtils {
 
     @Test
     public void testValidUuidWorks() {
-        var result = MojangUtils.fromUuid("853c80ef3c3749fdaa49938b674adae6");
+        var result = MojangUtils.fromUuid(JEB_UUID.toString());
         assertNotNull(result);
         assertEquals("jeb_", result.get("name").getAsString());
         assertEquals("853c80ef3c3749fdaa49938b674adae6", result.get("id").getAsString());
@@ -38,4 +42,27 @@ public class TestMojangUtils {
         var result = MojangUtils.fromUuid("00000000-0000-0000-0000-000000000000");
         assertNull(result);
     }
+
+    @Test
+    public void testValidUUIDWorks() {
+        var result = MojangUtils.fromUuid(JEB_UUID);
+        assertNotNull(result);
+        assertEquals("jeb_", result.get("name").getAsString());
+        assertEquals("853c80ef3c3749fdaa49938b674adae6", result.get("id").getAsString());
+    }
+
+    @Test
+    public void testGetValidNameWorks() throws IOException {
+        assertEquals(JEB_UUID, MojangUtils.getUUID("jeb_"));
+    }
+
+    @Test
+    public void testGetValidUUIDWorks() throws IOException {
+        assertEquals("jeb_", MojangUtils.getUsername(JEB_UUID));
+    }
+
+    @Test
+    public void testGetInvalidNameThrows() {
+        assertThrows(IOException.class, () -> MojangUtils.getUUID("a")); // Too short
+    }
 }