feat(player): add retained runtime data channels

Author: vanceingalls

packages/core/src/runtime/bridge.test.ts

@@ -19,6 +19,8 @@ function createMockDeps() {
     onSetRootDuration: vi.fn(),
     onEnablePickMode: vi.fn(),
     onDisablePickMode: vi.fn(),
+    onSetRuntimeData: vi.fn(),
+    onClearRuntimeData: vi.fn(),
     getCanonicalFps: vi.fn(() => 30),
   };
 }
@@ -44,6 +46,16 @@ describe("installRuntimeControlBridge", () => {
     expect(deps.onPause).toHaveBeenCalledOnce();
   });
 
+  it("dispatches set and clear runtime data without global invocation", () => {
+    const deps = createMockDeps();
+    const handler = installRuntimeControlBridge(deps);
+    const payload = { version: 3, segments: [] };
+    handler(makeControlMessage("set-runtime-data", { channel: "captions", payload }));
+    handler(makeControlMessage("clear-runtime-data", { channel: "captions" }));
+    expect(deps.onSetRuntimeData).toHaveBeenCalledWith("captions", payload);
+    expect(deps.onClearRuntimeData).toHaveBeenCalledWith("captions");
+  });
+
   it("dispatches stop-media command", () => {
     const deps = createMockDeps();
     const handler = installRuntimeControlBridge(deps);

packages/core/src/runtime/bridge.ts

@@ -28,6 +28,8 @@ type BridgeDeps = {
   ) => void;
   onEnablePickMode: () => void;
   onDisablePickMode: () => void;
+  onSetRuntimeData?: (channel: string, payload: unknown) => void;
+  onClearRuntimeData?: (channel: string) => void;
   getCanonicalFps: () => number;
 };
 
@@ -75,6 +77,12 @@ const CONTROL_HANDLERS: Record<string, ControlHandler> = {
   "enable-pick-mode": (_d, deps) => deps.onEnablePickMode(),
   "disable-pick-mode": (_d, deps) => deps.onDisablePickMode(),
   "flash-elements": (data) => handleFlashElements(data),
+  "set-runtime-data": (data, deps) => {
+    if (typeof data.channel === "string") deps.onSetRuntimeData?.(data.channel, data.payload);
+  },
+  "clear-runtime-data": (data, deps) => {
+    if (typeof data.channel === "string") deps.onClearRuntimeData?.(data.channel);
+  },
 };
 
 function resolveSeekTimeSeconds(data: BridgeControlData, deps: BridgeDeps): number {

packages/core/src/runtime/entry.ts

@@ -3,13 +3,17 @@ import { installAuthoredOpacityCapture } from "./colorGrading";
 import { fitTextFontSize } from "../text/fitTextFontSize";
 import { pretext } from "../text/pretext";
 import { getVariables } from "./getVariables";
+import { clearRuntimeData, registerRuntimeDataHandler, setRuntimeData } from "./runtimeData";
 
 type HyperframeWindow = Window & {
   __hyperframeRuntimeBootstrapped?: boolean;
   __hyperframes?: {
     fitTextFontSize: typeof fitTextFontSize;
     getVariables: typeof getVariables;
     pretext: typeof pretext;
+    registerRuntimeDataHandler: typeof registerRuntimeDataHandler;
+    setRuntimeData: typeof setRuntimeData;
+    clearRuntimeData: typeof clearRuntimeData;
   };
 };
 
@@ -29,6 +33,9 @@ installAuthoredOpacityCapture();
   fitTextFontSize,
   getVariables,
   pretext,
+  registerRuntimeDataHandler,
+  setRuntimeData,
+  clearRuntimeData,
 };
 
 function bootstrapHyperframeRuntime(): void {

packages/core/src/runtime/init.ts

@@ -62,6 +62,7 @@ import { shouldAttemptPeriodicTimelineBind } from "./timelineRebindPolicy";
 import { installStudioCustomEase } from "./customEase";
 import { parseNumeric } from "./startExpression";
 import { parseStrictFiniteTimingNumber } from "./playbackRate";
+import { clearRuntimeData, setRuntimeData, setRuntimeDataErrorReporter } from "./runtimeData";
 
 const AUTHORED_DURATION_ATTR = "data-hf-authored-duration";
 const AUTHORED_END_ATTR = "data-hf-authored-end";
@@ -127,6 +128,14 @@ export function initSandboxRuntimeModular(): void {
   // Own the analytics bridge before any best-effort runtime installation so
   // early failures are observable instead of disappearing before player setup.
   initRuntimeAnalytics(postRuntimeMessage as (payload: unknown) => void);
+  setRuntimeDataErrorReporter((channel, error) => {
+    postRuntimeMessage({
+      source: "hf-preview",
+      type: "runtime-data-error",
+      channel,
+      message: error instanceof Error ? error.message : String(error),
+    });
+  });
   // SDK moveElement edits must render even when no usable GSAP timeline ever
   // binds (CSS/WAAPI-animated or fully static compositions) — apply at init.
   // This runs at DOMContentLoaded, after inline composition scripts have
@@ -3318,6 +3327,8 @@ export function initSandboxRuntimeModular(): void {
     },
     onEnablePickMode: () => picker.enablePickMode(),
     onDisablePickMode: () => picker.disablePickMode(),
+    onSetRuntimeData: setRuntimeData,
+    onClearRuntimeData: clearRuntimeData,
     getCanonicalFps: () => state.canonicalFps,
   });
 

packages/core/src/runtime/protocol.ts

@@ -5,6 +5,7 @@ export const RUNTIME_PROTOCOL_CAPABILITIES = [
   "rational-fps",
   "seek-keep-playing",
   "composition-manifest-v1",
+  "runtime-data",
 ] as const;
 
 export type RuntimeProtocolFps = {

packages/core/src/runtime/runtimeData.test.ts

@@ -0,0 +1,53 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import {
+  clearRuntimeData,
+  registerRuntimeDataHandler,
+  resetRuntimeDataForTests,
+  setRuntimeData,
+  setRuntimeDataErrorReporter,
+} from "./runtimeData";
+
+describe("runtime data registry", () => {
+  beforeEach(resetRuntimeDataForTests);
+
+  it("delivers retained data when the handler registers later", () => {
+    const handler = vi.fn();
+    setRuntimeData("captions", { words: ["before"] });
+    registerRuntimeDataHandler("captions", handler);
+    expect(handler).toHaveBeenCalledWith({ words: ["before"] });
+  });
+
+  it("replaces handlers and keeps channels isolated", () => {
+    const oldHandler = vi.fn();
+    const newHandler = vi.fn();
+    const other = vi.fn();
+    registerRuntimeDataHandler("captions", oldHandler);
+    registerRuntimeDataHandler("captions", newHandler);
+    registerRuntimeDataHandler("telemetry", other);
+    setRuntimeData("captions", { words: ["latest"] });
+    expect(oldHandler).not.toHaveBeenCalled();
+    expect(newHandler).toHaveBeenCalledOnce();
+    expect(other).not.toHaveBeenCalled();
+  });
+
+  it("notifies the current handler with undefined when cleared", () => {
+    const handler = vi.fn();
+    registerRuntimeDataHandler("captions", handler);
+    setRuntimeData("captions", { words: [] });
+    clearRuntimeData("captions");
+    expect(handler).toHaveBeenLastCalledWith(undefined);
+    const replacement = vi.fn();
+    registerRuntimeDataHandler("captions", replacement);
+    expect(replacement).not.toHaveBeenCalled();
+  });
+
+  it("reports handler exceptions without breaking later delivery", () => {
+    const reporter = vi.fn();
+    setRuntimeDataErrorReporter(reporter);
+    registerRuntimeDataHandler("captions", () => {
+      throw new Error("attach failed");
+    });
+    expect(() => setRuntimeData("captions", {})).not.toThrow();
+    expect(reporter).toHaveBeenCalledWith("captions", expect.any(Error));
+  });
+});

packages/core/src/runtime/runtimeData.ts

@@ -0,0 +1,55 @@
+export type RuntimeDataHandler = (payload: unknown) => void;
+export type RuntimeDataErrorReporter = (channel: string, error: unknown) => void;
+
+const retained = new Map<string, unknown>();
+const handlers = new Map<string, RuntimeDataHandler>();
+let reportError: RuntimeDataErrorReporter = () => undefined;
+
+function validChannel(channel: string): boolean {
+  return /^[a-z][a-z0-9-]{0,63}$/.test(channel);
+}
+
+function deliver(channel: string, payload: unknown): void {
+  const handler = handlers.get(channel);
+  if (!handler) return;
+  try {
+    handler(payload);
+  } catch (error) {
+    reportError(channel, error);
+  }
+}
+
+export function setRuntimeDataErrorReporter(reporter: RuntimeDataErrorReporter): void {
+  reportError = reporter;
+}
+
+export function setRuntimeData(channel: string, payload: unknown): void {
+  if (!validChannel(channel)) return;
+  retained.set(channel, payload);
+  deliver(channel, payload);
+}
+
+export function clearRuntimeData(channel: string): void {
+  if (!validChannel(channel)) return;
+  retained.delete(channel);
+  deliver(channel, undefined);
+}
+
+export function registerRuntimeDataHandler(
+  channel: string,
+  handler: RuntimeDataHandler,
+): () => void {
+  if (!validChannel(channel))
+    throw new Error(`Invalid HyperFrames runtime-data channel: ${channel}`);
+  handlers.set(channel, handler);
+  if (retained.has(channel)) deliver(channel, retained.get(channel));
+  return () => {
+    if (handlers.get(channel) === handler) handlers.delete(channel);
+  };
+}
+
+export function resetRuntimeDataForTests(): void {
+  retained.clear();
+  handlers.clear();
+  reportError = () => undefined;
+}

packages/core/src/runtime/types.ts

@@ -22,7 +22,9 @@ export type RuntimeBridgeControlAction =
   | "set-web-audio-media-disabled"
   | "set-root-duration"
   | "stop-media"
-  | "flash-elements";
+  | "flash-elements"
+  | "set-runtime-data"
+  | "clear-runtime-data";
 
 export type RuntimeBridgeControlMessage = {
   source: "hf-parent";
@@ -39,6 +41,8 @@ export type RuntimeBridgeControlMessage = {
   grading?: RuntimeJson;
   compare?: RuntimeJson;
   seekMode?: "drag" | "commit";
+  channel?: string;
+  payload?: unknown;
 };
 
 export type RuntimeStateMessage = {
@@ -168,6 +172,13 @@ export type RuntimeReadyMessage = {
   type: "ready";
 };
 
+export type RuntimeDataErrorMessage = {
+  source: "hf-preview";
+  type: "runtime-data-error";
+  channel: string;
+  message: string;
+};
+
 /**
  * Analytics events emitted by the runtime.
  *
@@ -218,6 +229,7 @@ export type RuntimeOutboundMessage =
   | RuntimeStageSizeMessage
   | RuntimeMediaAutoplayBlockedMessage
   | RuntimeReadyMessage
+  | RuntimeDataErrorMessage
   | RuntimeAnalyticsMessage
   | RuntimePerformanceMessage
   | RuntimeGroupLevelsMessage;

packages/core/src/runtime/window.d.ts

@@ -30,6 +30,15 @@ declare global {
   interface Window {
     __timelines: Record<string, RuntimeTimelineLike>;
     __player?: PlayerAPI;
+    __hyperframes?: {
+      registerRuntimeDataHandler?: (
+        channel: string,
+        handler: (payload: unknown) => void,
+      ) => () => void;
+      setRuntimeData?: (channel: string, payload: unknown) => void;
+      clearRuntimeData?: (channel: string) => void;
+      [key: string]: unknown;
+    };
     __clipManifest?: RuntimeTimelineMessage;
     __clipTree?: ClipTree;
     __hf?: {