Use UUIDv5 for offline players

mapsync-server/package.json

@@ -19,6 +19,7 @@
         "better-sqlite3": "12.8.0",
         "kysely": "0.28.14",
         "source-map-support": "0.5.21",
+        "uuid": "^14.0.0",
         "ws": "8.20.0",
         "zod": "3.25.76",
         "zod-validation-error": "1.5.0"

mapsync-server/src/auth.ts

@@ -1,3 +1,5 @@
+import { isValidUuid } from "./deps/uuid.ts";
+
 export abstract class AuthState {
     protected constructor(public readonly logName: string | null) {}
 }
@@ -20,6 +22,9 @@ export class Welcomed extends AuthState {
         public readonly uuid: string,
         public readonly authed: boolean,
     ) {
+        if (!isValidUuid(uuid)) {
+            throw new Error(`Invalid UUID: ${uuid}`);
+        }
         super(name + (authed ? "" : "?"));
     }
 }

mapsync-server/src/deps/uuid.ts

@@ -0,0 +1,24 @@
+import node_crypto from "crypto";
+import { stringify as parseUuidBytes } from "uuid";
+import { v5 as _uuidv5 } from "uuid";
+export { validate as isValidUuid } from "uuid";
+
+export const uuidv5 = _uuidv5;
+
+// https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/UUID.html#nameUUIDFromBytes(byte[])
+export function nameUuidFromBytes(bytes: Buffer): string {
+    const hash = node_crypto.createHash("md5").update(bytes).digest();
+    hash[6] &= 0x0f; // Clears the version
+    hash[6] |= 0x30; // Sets version to 3
+    hash[8] &= 0x3f; // Clears the variant
+    hash[8] |= 0x80; // Sets variant to IETF
+    return parseUuidBytes(hash);
+}
+
+export const UUID_NAMESPACE = nameUuidFromBytes(
+    Buffer.from("mapsync:server", "utf8"),
+);
+
+export function createOfflineUuid(name: string) {
+    return uuidv5(`Offline:${name}`, UUID_NAMESPACE);
+}

mapsync-server/src/deps/zod.ts

@@ -0,0 +1,18 @@
+export * from "zod";
+export { fromZodError } from "zod-validation-error";
+
+import * as z from "zod";
+import { createOfflineUuid } from "./uuid.ts";
+
+export function offlineUuid() {
+    return z.preprocess((val) => {
+        if (typeof val !== "string") {
+            return val;
+        }
+        const match = /^AUTH-DISABLED-(.+)/.exec(val) ?? null;
+        if (match === null) {
+            return val;
+        }
+        return createOfflineUuid(match[1]);
+    }, z.string().uuid());
+}

mapsync-server/src/main.ts

@@ -24,6 +24,7 @@ import {
     Welcomed,
 } from "./auth.ts";
 import { SUPPORTED_VERSIONS } from "./constants.ts";
+import { createOfflineUuid } from "./deps/uuid.ts";
 
 let config: metadata.Config = null!;
 let main: ProtocolHandler = null!;
@@ -150,7 +151,7 @@ export class ProtocolHandler {
             }
             client.auth = new Welcomed(
                 packet.claimedUsername,
-                `AUTH-DISABLED-${packet.claimedUsername}`,
+                createOfflineUuid(packet.claimedUsername),
                 false,
             );
         }

mapsync-server/src/metadata.ts

@@ -3,8 +3,7 @@ import node_path from "node:path";
 import { Mutex } from "async-mutex";
 import * as errors from "./deps/errors.ts";
 import * as json from "./deps/json.ts";
-import * as z from "zod";
-import { fromZodError } from "zod-validation-error";
+import * as z from "./deps/zod.ts";
 
 export const DATA_FOLDER = process.env["MAPSYNC_DATA_DIR"] ?? "./mapsync";
 try {
@@ -49,7 +48,7 @@ function parseConfigFile<T>(
         return parser(json.parse(fileContents));
     } catch (e) {
         if (e instanceof z.ZodError) {
-            throw "Could not parse " + file + ": " + fromZodError(e);
+            throw "Could not parse " + file + ": " + z.fromZodError(e);
         }
         throw e;
     }
@@ -96,9 +95,7 @@ export function getConfig(): Config {
 
 const WHITELIST_FILE = "whitelist.json";
 const WHITELIST_MUTEX = new Mutex();
-const WHITELIST_SCHEMA = z.array(
-    z.union([z.string().uuid(), z.string().regex(/^AUTH-DISABLED-.+/)]),
-);
+const WHITELIST_SCHEMA = z.array(z.offlineUuid());
 export const whitelist = new Set<string>();
 
 export async function loadWhitelist() {
@@ -130,9 +127,7 @@ export async function saveWhitelist() {
 
 const UUID_CACHE_FILE = "uuid_cache.json";
 const UUID_CACHE_MUTEX = new Mutex();
-const UUID_CACHE_SCHEMA = z.record(
-    z.union([z.string().uuid(), z.string().regex(/^AUTH-DISABLED-.+/)]),
-);
+const UUID_CACHE_SCHEMA = z.record(z.offlineUuid());
 //                         IGN     UUID
 const uuid_cache = new Map<string, string>();