sdk implementation

sdk/dev/session.ts

@@ -10,25 +10,29 @@ import {
   createClient,
   type MatrixClient,
   MemoryStore,
+  type Room,
   SyncState,
 } from "matrix-js-sdk";
+import { KnownMembership } from "matrix-js-sdk/lib/types";
 
-/** Logs in with a password and returns a client that has finished its first sync. */
+export type Login =
+  | { username: string; password: string }
+  | { accessToken: string; userId: string; deviceId: string };
+
+/**
+ * Returns a client that has finished its first sync, logging in with a
+ * password unless the caller already holds a token.
+ */
 export async function createSession(
   homeserver: string,
-  username: string,
-  password: string,
+  login: Login,
 ): Promise<MatrixClient> {
-  const login = await createClient({ baseUrl: homeserver }).login(
-    "m.login.password",
-    { identifier: { type: "m.id.user", user: username }, password },
-  );
+  const credentials =
+    "accessToken" in login ? login : await logIn(homeserver, login);
 
   const client = createClient({
     baseUrl: homeserver,
-    accessToken: login.access_token,
-    userId: login.user_id,
-    deviceId: login.device_id,
+    ...credentials,
     store: new MemoryStore(),
     useAuthorizationHeader: true,
     fallbackICEServerAllowed: true,
@@ -47,3 +51,49 @@ export async function createSession(
 
   return client;
 }
+
+/**
+ * Joins a room and returns it as the sync loop maintains it. The room object
+ * `joinRoom` itself returns for a room joined just now is a detached copy
+ * that never receives the state the sync delivers, and a session built on
+ * it would never see a member.
+ */
+export async function joinRoom(
+  client: MatrixClient,
+  roomIdOrAlias: string,
+): Promise<Room> {
+  const { roomId } = await client.joinRoom(roomIdOrAlias);
+  const joinedRoom = (): Room | undefined => {
+    const room = client.getRoom(roomId);
+    return room?.hasMembershipState(client.getUserId()!, KnownMembership.Join)
+      ? room
+      : undefined;
+  };
+  return (
+    joinedRoom() ??
+    new Promise<Room>((resolve) => {
+      const onSync = (): void => {
+        const room = joinedRoom();
+        if (room === undefined) return;
+        client.off(ClientEvent.Sync, onSync);
+        resolve(room);
+      };
+      client.on(ClientEvent.Sync, onSync);
+    })
+  );
+}
+
+async function logIn(
+  homeserver: string,
+  { username, password }: { username: string; password: string },
+): Promise<{ accessToken: string; userId: string; deviceId: string }> {
+  const login = await createClient({ baseUrl: homeserver }).login(
+    "m.login.password",
+    { identifier: { type: "m.id.user", user: username }, password },
+  );
+  return {
+    accessToken: login.access_token,
+    userId: login.user_id,
+    deviceId: login.device_id,
+  };
+}