renames and restructure

- session -> matrixrtc (folder) - move MatrixRtcClient to top level of sdk - RtcTransport -> Transport - backend -> media-backend
2026-10-16 23:45:50 +00:00 · 2026-10-08 13:53:57 +02:00
parent d0a2ff12f1
commit 5b13e1da81
51 changed files with 96 additions and 85 deletions
@@ -0,0 +1,321 @@
+/*
+Copyright 2023, 2024 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  type IOpenIDToken,
+  type MatrixClient,
+  parseErrorResponse,
+} from "matrix-js-sdk";
+import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
+import { type Logger } from "matrix-js-sdk/lib/logger";
+
+import {
+  FailToGetOpenIdToken,
+  NoMatrix2AuthorizationService,
+} from "../../errors";
+import { doNetworkOperationWithRetry } from "../../utils/network";
+
+/**
+ * Configuration and access tokens provided by the SFU on successful authentication.
+ */
+export interface SFUConfig {
+  url: string;
+  jwt: string;
+  livekitAlias: string;
+  // NOTE: Currently unused.
+  livekitIdentity: string;
+}
+
+/**
+ * Decoded details from the JWT.
+ */
+interface SFUJWTPayload {
+  /**
+   * Expiration time for the JWT.
+   * Note: This value is in seconds since Unix epoch.
+   */
+  exp: number;
+  /**
+   * Name of the instance which authored the JWT
+   */
+  iss: string;
+  /**
+   * Time at which the JWT can start to be used.
+   * Note: This value is in seconds since Unix epoch.
+   */
+  nbf: number;
+  /**
+   * Subject. The Livekit alias in this context.
+   */
+  sub: string;
+  /**
+   * The set of permissions for the user.
+   */
+  video: {
+    canPublish: boolean;
+    canSubscribe: boolean;
+    room: string;
+    roomJoin: boolean;
+  };
+}
+
+// The bits we need from MatrixClient
+export type OpenIDClientParts = Pick<MatrixClient, "getOpenIdToken">;
+
+/**
+ * Which token service endpoint to use: the MSC4195 one, or the legacy one
+ * with the old identity format. Undefined tries the MSC4195 one and falls
+ * back to the legacy one, for transports we only subscribe on.
+ */
+export type TokenEndpoint = "msc4195" | "legacy";
+
+/**
+ * Gets a bearer token from the homeserver and then use it to authenticate
+ * to the matrix RTC backend in order to get acces to the SFU.
+ * It has built-in retry for calls to the homeserver with a backoff policy.
+ * @param client The Matrix client
+ * @param membership Our own membership identity parts used to send to jwt service.
+ * @param serviceUrl The URL of the livekit SFU service
+ * @param roomId The room id used in the jwt request. This is NOT the livekit_alias. The jwt service will provide the alias. It maps matrix room ids <-> Livekit aliases.
+ * @param opts Additional options to modify which endpoint with which data will be used to acquire the jwt token.
+ * @param opts.tokenEndpoint Which version of the JWT endpoint to use, which affects whether the
+ * RTC backend identity is based on string concatenation (legacy) or a hash (MSC4195).
+ * This function by default uses whatever is possible with the current jwt service installed next to the SFU.
+ * For remote connections this does not matter, since we will not publish there we can rely on the newest option.
+ * @param opts.delayEndpointBaseUrl The URL of the matrix homeserver.
+ * @param opts.delayId The delay id used for the jwt service to manage.
+ * @param logger optional logger.
+ * @returns Object containing the token information
+ * @throws FailToGetOpenIdToken
+ */
+export async function getSFUConfigWithOpenID(
+  client: OpenIDClientParts,
+  membership: CallMembershipIdentityParts,
+  serviceUrl: string,
+  roomId: string,
+  opts?: {
+    tokenEndpoint?: TokenEndpoint;
+    delayEndpointBaseUrl?: string;
+    delayId?: string;
+    /** How long the SFU waits before sending the delegated leave. Needed with `delayId`. */
+    delayTimeoutMs?: number;
+  },
+  logger?: Logger,
+): Promise<SFUConfig> {
+  let openIdToken: IOpenIDToken;
+  try {
+    openIdToken = await doNetworkOperationWithRetry(async () =>
+      client.getOpenIdToken(),
+    );
+  } catch (error) {
+    throw new FailToGetOpenIdToken(
+      error instanceof Error ? error : new Error("Unknown error"),
+    );
+  }
+  logger?.debug("Got openID token", openIdToken);
+  let sfuConfig: { url: string; jwt: string } | undefined;
+
+  const tryBothJwtEndpoints = opts?.tokenEndpoint === undefined; // This is for SFUs where we do not publish.
+
+  const forceMatrix2Jwt = opts?.tokenEndpoint === "msc4195";
+
+  // We want to start using the new endpoint (with optional delay delegation)
+  // if we can use both or if we are forced to use the new one.
+  if (tryBothJwtEndpoints || forceMatrix2Jwt) {
+    try {
+      logger?.info(
+        `Trying to get JWT via default endpoint for focus ${serviceUrl}...`,
+      );
+      const sfuConfig = await getLiveKitJWT(
+        membership,
+        serviceUrl,
+        roomId,
+        openIdToken,
+        opts?.delayEndpointBaseUrl,
+        opts?.delayId,
+        opts?.delayTimeoutMs,
+      );
+
+      return extractFullConfigFromToken(sfuConfig);
+    } catch (e) {
+      logger?.debug(`Failed fetching jwt with matrix 2.0 endpoint:`, e);
+      // Make this throw a hard error in case we force the matrix2.0 endpoint.
+      if (forceMatrix2Jwt) {
+        throw new NoMatrix2AuthorizationService(e as Error);
+      }
+    }
+  }
+
+  // DEPRECATED
+  // here we either have a sfuConfig or we already exited because of `if (forceMatrix2) throw ...`
+  // The only case we can get into this condition is, if `forceMatrix2` is `false`
+  try {
+    logger?.info(
+      `Trying to get JWT with legacy endpoint for focus ${serviceUrl}...`,
+    );
+    sfuConfig = await getLiveKitJWTLegacy(
+      membership.deviceId,
+      serviceUrl,
+      roomId,
+      openIdToken,
+      opts?.delayEndpointBaseUrl,
+      opts?.delayId,
+      opts?.delayTimeoutMs,
+    );
+    logger?.info(`Got JWT from call's active focus URL.`);
+    return extractFullConfigFromToken(sfuConfig);
+  } catch (ex) {
+    throw new FailToGetOpenIdToken(
+      ex instanceof Error ? ex : new Error(`Unknown error ${ex}`),
+    );
+  }
+}
+
+function extractFullConfigFromToken(sfuConfig: {
+  url: string;
+  jwt: string;
+}): SFUConfig {
+  const [, payloadStr] = sfuConfig.jwt.split(".");
+  const payload = JSON.parse(global.atob(payloadStr)) as SFUJWTPayload;
+  return {
+    jwt: sfuConfig.jwt,
+    url: sfuConfig.url,
+    livekitAlias: payload.video.room,
+    // NOTE: Currently unused.
+    // Probably also not helpful since we now compute the backendIdentity on joining the call so we can use it for the encryption manager.
+    // The only reason for us to know it locally is to connect the right users with the lk world. (and to set our own keys)
+    livekitIdentity: payload.sub,
+  };
+}
+
+async function getLiveKitJWTLegacy(
+  deviceId: string,
+  livekitServiceURL: string,
+  matrixRoomId: string,
+  openIDToken: IOpenIDToken,
+  delayEndpointBaseUrl?: string,
+  delayId?: string,
+  delayTimeoutMs?: number,
+): Promise<{ url: string; jwt: string }> {
+  interface IDelayParams {
+    delay_id?: string;
+    delay_timeout?: number;
+    delay_cs_api_url?: string;
+  }
+  let bodyDalayParts: IDelayParams = {};
+  // Also check for empty string
+  if (delayId && delayEndpointBaseUrl) {
+    bodyDalayParts = {
+      delay_id: delayId,
+      delay_timeout: delayTimeoutMs,
+      delay_cs_api_url: delayEndpointBaseUrl,
+    };
+  }
+
+  const makeRequest = async (delayParts: IDelayParams): Promise<Response> => {
+    return await fetch(livekitServiceURL + "/sfu/get", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        // The legacy JWT endpoint uses only the matrix room id to calculate the livekit room alias.
+        // However, the livekit room alias is provided as part of the JWT payload.
+        room: matrixRoomId,
+        openid_token: openIDToken,
+        device_id: deviceId,
+        ...delayParts,
+      }),
+    });
+  };
+
+  const res = await doNetworkOperationWithRetry(async () => {
+    let response = await makeRequest(bodyDalayParts);
+
+    // Old service compatibility check
+    const oldServiceDoesNotSupportDelayParts =
+      response.status === 400 && Object.keys(bodyDalayParts).length > 0;
+    // If http status 400 with M_BAD_JSON and we sent delay parts, retry without them
+    if (oldServiceDoesNotSupportDelayParts) {
+      try {
+        const errorBody = await response.json();
+        if (errorBody.errcode === "M_BAD_JSON") {
+          response = await makeRequest({});
+        }
+      } catch {
+        // If we can't parse the error, treat as real error
+      }
+    }
+
+    return response;
+  });
+
+  if (!res.ok) {
+    throw parseErrorResponse(res, await res.text());
+  }
+  return await res.json();
+}
+
+class NotSupportedError extends Error {
+  public constructor(message: string) {
+    super(message);
+    this.name = "NotSupported";
+  }
+}
+
+export async function getLiveKitJWT(
+  membership: CallMembershipIdentityParts,
+  livekitServiceURL: string,
+  matrixRoomId: string,
+  openIDToken: IOpenIDToken,
+  delayEndpointBaseUrl?: string,
+  delayId?: string,
+  delayTimeoutMs?: number,
+): Promise<{ url: string; jwt: string }> {
+  const { userId, deviceId, memberId } = membership;
+
+  const body = {
+    room_id: matrixRoomId,
+    slot_id: "m.call#ROOM",
+    openid_token: openIDToken,
+    member: {
+      id: memberId,
+      claimed_user_id: userId,
+      claimed_device_id: deviceId,
+    },
+  };
+
+  let bodyDalayParts = {};
+  // Also check for empty string
+  if (delayId && delayEndpointBaseUrl) {
+    bodyDalayParts = {
+      delay_id: delayId,
+      delay_timeout: delayTimeoutMs,
+      delay_cs_api_url: delayEndpointBaseUrl,
+    };
+  }
+
+  const res = await doNetworkOperationWithRetry(async () => {
+    return await fetch(livekitServiceURL + "/get_token", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({ ...body, ...bodyDalayParts }),
+    });
+  });
+
+  if (!res.ok) {
+    const msg = "SFU Config fetch failed with status code " + res.status;
+    if (res.status === 404) {
+      throw new NotSupportedError(msg);
+    } else {
+      throw parseErrorResponse(res, await res.text());
+    }
+  }
+  return await res.json();
+}