Make mobile terminals load faster (#1147)

* Speed up terminal restores on mobile

* Preserve terminal output bytes in the app

packages/server/src/client/daemon-client.ts

@@ -67,6 +67,7 @@ import type {
   ListTerminalsResponse,
   CreateTerminalResponse,
   SubscribeTerminalResponse,
+  SubscribeTerminalRequest,
   CloseItemsResponse,
   KillTerminalResponse,
   CaptureTerminalResponse,
@@ -3770,13 +3771,19 @@ export class DaemonClient {
 
   async subscribeTerminal(
     terminalId: string,
-    requestId?: string,
+    optionsOrRequestId?:
+      | { restore?: SubscribeTerminalRequest["restore"]; requestId?: string }
+      | string,
   ): Promise<SubscribeTerminalPayload> {
+    const restore = typeof optionsOrRequestId === "object" ? optionsOrRequestId.restore : undefined;
+    const requestId =
+      typeof optionsOrRequestId === "object" ? optionsOrRequestId.requestId : optionsOrRequestId;
     const resolvedRequestId = this.createRequestId(requestId);
     const message = SessionInboundMessageSchema.parse({
       type: "subscribe_terminal_request",
       terminalId,
       requestId: resolvedRequestId,
+      ...(restore ? { restore } : {}),
     });
     const payload = await this.sendCorrelatedRequest({
       requestId: resolvedRequestId,
@@ -4363,6 +4370,8 @@ export class DaemonClient {
       frameKind = "output";
     } else if (frame.opcode === TerminalStreamOpcode.Snapshot) {
       frameKind = "snapshot";
+    } else if (frame.opcode === TerminalStreamOpcode.Restore) {
+      frameKind = "output";
     }
     this.runtimeMetrics?.recordBinaryFrame(
       frameKind,

packages/server/src/client/terminal-stream-router.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, test } from "vitest";
+
+import { TerminalStreamOpcode } from "../shared/binary-frames/index.js";
+import { TerminalStreamRouter, type TerminalStreamEvent } from "./terminal-stream-router.js";
+
+describe("terminal-stream-router", () => {
+  test("routes restore frames as restore events", () => {
+    const router = new TerminalStreamRouter();
+    const events: TerminalStreamEvent[] = [];
+    const payload = new TextEncoder().encode("restored screen");
+
+    router.setSlot("term-1", 7);
+    router.onEvent((event) => events.push(event));
+    router.handleFrame({
+      opcode: TerminalStreamOpcode.Restore,
+      slot: 7,
+      payload,
+    });
+
+    expect(events).toEqual([
+      {
+        terminalId: "term-1",
+        type: "restore",
+        data: payload,
+      },
+    ]);
+  });
+});

packages/server/src/client/terminal-stream-router.ts

@@ -9,7 +9,8 @@ import type { TerminalInput, TerminalState } from "../shared/messages.js";
 
 export type TerminalStreamEvent =
   | { terminalId: string; type: "output"; data: Uint8Array }
-  | { terminalId: string; type: "snapshot"; state: TerminalState };
+  | { terminalId: string; type: "snapshot"; state: TerminalState }
+  | { terminalId: string; type: "restore"; data: Uint8Array };
 
 export class TerminalStreamRouter {
   private readonly terminalSlots = new Map<string, number>();
@@ -97,6 +98,15 @@ export class TerminalStreamRouter {
       return;
     }
 
+    if (frame.opcode === TerminalStreamOpcode.Restore) {
+      this.emit({
+        terminalId,
+        type: "restore",
+        data: frame.payload,
+      });
+      return;
+    }
+
     if (frame.opcode === TerminalStreamOpcode.Snapshot) {
       const state = decodeTerminalSnapshotPayload(frame.payload);
       if (!state) {