From 8030284a40de17257d5cfadb7d6d1755f84560ce Mon Sep 17 00:00:00 2001
From: Scott Nonnenberg <scott@signal.org>
Date: Tue, 6 Jan 2026 07:00:18 +1000
Subject: [PATCH] resolveUsernameByLink: Move to libsignal typed API

---
 ts/services/username.preload.ts | 31 ++++++++++++----------------
 ts/textsecure/WebAPI.preload.ts | 36 ++++++++++++++-------------------
 2 files changed, 28 insertions(+), 39 deletions(-)

diff --git a/ts/services/username.preload.ts b/ts/services/username.preload.ts
index 1f97419347..8fc7aa030b 100644
--- a/ts/services/username.preload.ts
+++ b/ts/services/username.preload.ts
@@ -30,6 +30,7 @@ import {
   deleteUsername as doDeleteUsername,
   resolveUsernameLink,
 } from '../textsecure/WebAPI.preload.js';
+import type { ResolveUsernameByLinkOptionsType } from '../textsecure/WebAPI.preload.js';
 import { HTTPError } from '../types/HTTPError.std.js';
 import { findRetryAfterTimeFromError } from '../jobs/helpers/findRetryAfterTimeFromError.std.js';
 import * as Bytes from '../Bytes.std.js';
@@ -364,28 +365,22 @@ export async function resolveUsernameByLinkBase64(
   const entropy = content.subarray(0, USERNAME_LINK_ENTROPY_SIZE);
   const serverId = content.subarray(USERNAME_LINK_ENTROPY_SIZE);
 
-  return resolveUsernameByLink({ entropy, serverId });
+  const uuid = bytesToUuid(serverId);
+  strictAssert(uuid, 'Failed to re-encode server id as uuid');
+
+  return resolveUsernameByLink({ entropy, uuid });
 }
 
-export type ResolveUsernameByLinkOptionsType = Readonly<{
-  entropy: Uint8Array;
-  serverId: Uint8Array;
-}>;
-
-export async function resolveUsernameByLink({
-  entropy,
-  serverId: serverIdBytes,
-}: ResolveUsernameByLinkOptionsType): Promise<string | undefined> {
-  const serverId = bytesToUuid(serverIdBytes);
-  strictAssert(serverId, 'Failed to re-encode server id as uuid');
-
+export async function resolveUsernameByLink(
+  options: ResolveUsernameByLinkOptionsType
+): Promise<string | undefined> {
   try {
-    const { usernameLinkEncryptedValue } = await resolveUsernameLink(serverId);
+    const result = await resolveUsernameLink(options);
+    if (!result) {
+      return undefined;
+    }
 
-    return usernames.decryptUsernameLink({
-      entropy,
-      encryptedUsername: usernameLinkEncryptedValue,
-    });
+    return result.username;
   } catch (error) {
     if (error instanceof HTTPError && error.code === 404) {
       return undefined;
diff --git a/ts/textsecure/WebAPI.preload.ts b/ts/textsecure/WebAPI.preload.ts
index 93befbf7aa..7cf6fce973 100644
--- a/ts/textsecure/WebAPI.preload.ts
+++ b/ts/textsecure/WebAPI.preload.ts
@@ -1061,14 +1061,14 @@ export type ReplaceUsernameLinkResultType = z.infer<
   typeof replaceUsernameLinkResultZod
 >;
 
-const resolveUsernameLinkResultZod = z.object({
-  usernameLinkEncryptedValue: z
-    .string()
-    .transform(x => Bytes.fromBase64(fromWebSafeBase64(x))),
-});
-export type ResolveUsernameLinkResultType = z.infer<
-  typeof resolveUsernameLinkResultZod
->;
+export type ResolveUsernameByLinkOptionsType = Readonly<{
+  entropy: Uint8Array;
+  uuid: string;
+}>;
+export type ResolveUsernameLinkResultType = {
+  username: string;
+  hash: Uint8Array;
+} | null;
 
 export type CreateAccountOptionsType = Readonly<{
   sessionId: string;
@@ -2659,19 +2659,13 @@ export async function deleteUsernameLink(): Promise<void> {
   });
 }
 
-export async function resolveUsernameLink(
-  serverId: string
-): Promise<ResolveUsernameLinkResultType> {
-  return _ajax({
-    host: 'chatService',
-    httpType: 'GET',
-    call: 'usernameLink',
-    urlParameters: `/${encodeURIComponent(serverId)}`,
-    responseType: 'json',
-    unauthenticated: true,
-    accessKey: undefined,
-    groupSendToken: undefined,
-    zodSchema: resolveUsernameLinkResultZod,
+export async function resolveUsernameLink({
+  entropy,
+  uuid,
+}: ResolveUsernameByLinkOptionsType): Promise<ResolveUsernameLinkResultType> {
+  return _retry(async () => {
+    const chat = await socketManager.getUnauthenticatedLibsignalApi();
+    return chat.lookUpUsernameLink({ uuid, entropy });
   });
 }