fix(terminal): show startup output when a session dies before ready

ui/koko/composables/terminal/protocol.ts

@@ -14,6 +14,56 @@ export enum TerminalWebSocketProtocol {
   Koko = "JMS-KOKO"
 }
 
+const MAX_STARTUP_OUTPUT_BYTES = 8 * 1024;
+
+export function createKokoStartupOutputCapture(maxBytes = MAX_STARTUP_OUTPUT_BYTES) {
+  let chunks: Uint8Array[] = [];
+  let size = 0;
+  let ready = false;
+
+  const append = (data: Uint8Array) => {
+    if (ready || !data.byteLength) return;
+
+    const chunk = data.byteLength > maxBytes ? data.slice(-maxBytes) : Uint8Array.from(data);
+    chunks.push(chunk);
+    size += chunk.byteLength;
+    while (size > maxBytes) {
+      const excess = size - maxBytes;
+      const first = chunks.shift();
+      if (!first) return;
+      if (first.byteLength <= excess) {
+        size -= first.byteLength;
+      } else {
+        chunks.unshift(first.slice(excess));
+        size -= excess;
+      }
+    }
+  };
+
+  const markReady = () => {
+    ready = true;
+    chunks = [];
+    size = 0;
+  };
+
+  const take = () => {
+    if (ready || !size) return "";
+    const output = new Uint8Array(size);
+    let offset = 0;
+    for (const chunk of chunks) {
+      output.set(chunk, offset);
+      offset += chunk.byteLength;
+    }
+    return new TextDecoder().decode(output);
+  };
+
+  return { append, markReady, take };
+}
+
+export function resolveKokoTerminalCloseMessage(startupOutput: string, fallback: string) {
+  return startupOutput.trim() ? startupOutput : fallback;
+}
+
 export interface TerminalIncomingMessage {
   id: string;
   type: string;

ui/koko/composables/terminal/useTerminalMessageHandler.ts

@@ -1,14 +1,13 @@
 import type { HostBridge } from "@jumpserver/connectors-core";
-import type { useKokoHostAdapter } from "#koko/host";
 import type { Terminal } from "@xterm/xterm";
 import type { ComputedRef, Ref } from "vue";
+import type { useKokoHostAdapter } from "#koko/host";
 import type { useKokoConnectionStore } from "#koko/stores/connection";
 import type { useKokoTerminalSettingsStore } from "#koko/stores/terminalSettings";
 import type { ClipboardPermission, ClipboardPolicy } from "#koko/types/clipboard";
 import type { OnlineUser, SettingConfig, ShareUserOptions, TerminalSessionInfo } from "#koko/types/session";
 import type { TerminalCommandEnvelope } from "./envelope";
 import type { TerminalIncomingMessage } from "./protocol";
-import { markKokoTerminalAiSessionInfoReady } from "./useTerminalAiSessions";
 import { HOST_MESSAGE_TYPE, MESSAGE_TYPE, ZMODEM_ACTION_TYPE } from "@jumpserver/connectors-core";
 import { applyXtermTheme, terminalTheme } from "../../utils/terminalTheme";
 import { formatMessage, updateIcon } from "../../utils/terminalUtils";
@@ -25,6 +24,7 @@ import {
   parseTerminalPayload
 } from "./envelope";
 import { parseTerminalIncomingMessage } from "./protocol";
+import { markKokoTerminalAiSessionInfoReady } from "./useTerminalAiSessions";
 
 export type TerminalMessageHandlers = Partial<Record<string, (message: TerminalIncomingMessage) => void>>;
 
@@ -132,6 +132,7 @@ export function createKokoTerminalMessageHandlers(options: {
   setClipboardAccess: (permission?: ClipboardPermission | null, policy?: ClipboardPolicy | null) => void;
   showInfoOnce: (content: string) => void;
   onConnected: (terminalId: string, socket: WebSocket, terminal: Terminal) => void;
+  onTerminalReady?: () => void;
   onZmodemEnd: () => void;
   onZmodemAbort: () => void;
   onServerClose?: (reason: string) => void;
@@ -321,6 +322,7 @@ export function createKokoTerminalMessageHandlers(options: {
       );
     },
     [MESSAGE_TYPE.TERMINAL_READY]: () => {
+      options.onTerminalReady?.();
       const tabId = paneId();
       if (tabId) markKokoTerminalAiSessionInfoReady(tabId);
     },

ui/koko/composables/terminal/useTerminalSocket.ts

@@ -52,7 +52,7 @@ import { useKokoTerminalSettingsStore } from "#koko/stores/terminalSettings";
 import { getDefaultTerminalConfig } from "#koko/utils/guard";
 import { applyXtermTheme, appTerminalTheme, syncXtermBackground, terminalTheme } from "#koko/utils/terminalTheme";
 import { formatMessage, preprocessInput } from "#koko/utils/terminalUtils";
-import { describeTerminalClose } from "./protocol";
+import { createKokoStartupOutputCapture, describeTerminalClose, resolveKokoTerminalCloseMessage } from "./protocol";
 
 const isSocketOpen = (socket: WebSocket) => socket.readyState === WebSocket.OPEN;
 
@@ -131,6 +131,7 @@ export const useKokoTerminalSocket = () => {
   let fitAddon: FitAddon | null = null;
   let sessionReady = false;
   let serverCloseReason: string | undefined;
+  const startupOutput = createKokoStartupOutputCapture();
   let disposeSocketEvents: (() => void) | undefined;
   let hasPendingContainerFit = false;
 
@@ -289,6 +290,7 @@ export const useKokoTerminalSocket = () => {
     onServerClose: (reason) => {
       serverCloseReason = reason;
     },
+    onTerminalReady: startupOutput.markReady,
     onZmodemEnd: zmodem.finishDraining,
     onZmodemAbort: () => {
       zmodem.abortActiveSession();
@@ -331,6 +333,7 @@ export const useKokoTerminalSocket = () => {
   const messageHandler = useKokoTerminalMessageHandler(terminalMessageHandlers, {
     onTerminalOutput: (messageTerminalId, data) => {
       if (messageTerminalId === Number(terminalId.value)) {
+        startupOutput.append(data);
         binaryHandler.handleBinaryMessage(data);
       }
     }
@@ -378,10 +381,13 @@ export const useKokoTerminalSocket = () => {
         lastSendTime: lastSendTime.value.toISOString(),
         lastReceiveTime: lastReceiveTime.value.toISOString()
       });
-      const message = t(detail.messageKey, {
-        code: event.code,
-        reason: detail.reasonKey ? t(detail.reasonKey) : ""
-      });
+      const message = resolveKokoTerminalCloseMessage(
+        startupOutput.take(),
+        t(detail.messageKey, {
+          code: event.code,
+          reason: detail.reasonKey ? t(detail.reasonKey) : ""
+        })
+      );
       if (paneId) hostAdapter.markSessionDisconnected(paneId, message);
       if (!terminalRef.value) return;
       terminalRef.value.write("\r\n");

ui/koko/tests/terminal/paneConnectionIsolation.test.ts

@@ -3,8 +3,8 @@ import { MESSAGE_TYPE } from "@jumpserver/connectors-core";
 import { createPinia, setActivePinia } from "pinia";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import { computed, ref, shallowRef } from "vue";
-import { createKokoTerminalMessageHandlers } from "#koko/composables/terminal/useTerminalMessageHandler";
 import { parseEnvelope, parseJSONPayload } from "#koko/composables/terminal/envelope";
+import { createKokoTerminalMessageHandlers } from "#koko/composables/terminal/useTerminalMessageHandler";
 import { useKokoConnectionStore } from "#koko/stores/connection";
 import {
   clearWorkspaceSessionDetails,
@@ -21,6 +21,7 @@ const { getSessionDetails } = useWorkspaceSessionDetails();
 
 function createPaneHandlers(paneId: string) {
   const onServerClose = vi.fn();
+  const onTerminalReady = vi.fn();
   const socket = { send: vi.fn(), close: vi.fn(), readyState: WebSocket.OPEN } as unknown as WebSocket;
   const terminal = { cols: 80, rows: 24, write: vi.fn(), focus: vi.fn() } as unknown as Terminal;
   const handlers = createKokoTerminalMessageHandlers({
@@ -52,6 +53,7 @@ function createPaneHandlers(paneId: string) {
     setClipboardAccess: vi.fn(),
     showInfoOnce: vi.fn(),
     onConnected: vi.fn(),
+    onTerminalReady,
     onZmodemEnd: vi.fn(),
     onZmodemAbort: vi.fn(),
     onServerClose
@@ -60,6 +62,7 @@ function createPaneHandlers(paneId: string) {
   return {
     handlers,
     onServerClose,
+    onTerminalReady,
     socket,
     terminal,
     created: (terminalId: number) => {
@@ -105,6 +108,14 @@ describe("koko pane connection isolation", () => {
     );
   });
 
+  it("notifies the terminal startup capture when Koko reports the session ready", () => {
+    const pane = createPaneHandlers(PANE_A);
+
+    pane.handlers[MESSAGE_TYPE.TERMINAL_READY]!();
+
+    expect(pane.onTerminalReady).toHaveBeenCalledOnce();
+  });
+
   it("keeps each terminal's session, asset and share state on its own pane", () => {
     const store = useKokoConnectionStore();
     const paneA = createPaneHandlers(PANE_A);

ui/koko/tests/terminal/terminalConnection.test.ts

@@ -1,7 +1,11 @@
 import { afterEach, expect, it, vi } from "vitest";
 import { effectScope, ref } from "vue";
 import { parseEnvelope, parseJSONPayload } from "#koko/composables/terminal/envelope";
-import { describeTerminalClose } from "#koko/composables/terminal/protocol";
+import {
+  createKokoStartupOutputCapture,
+  describeTerminalClose,
+  resolveKokoTerminalCloseMessage
+} from "#koko/composables/terminal/protocol";
 import { useKokoTerminalHeartbeat } from "#koko/composables/terminal/useTerminalHeartbeat";
 import { useKokoTerminalTransport } from "#koko/composables/terminal/useTerminalTransport";
 
@@ -26,6 +30,34 @@ it("distinguishes Koko session end, Koko timeout, offline and unexplained closes
   expect(describeTerminalClose(abnormal, "", true).source).toBe("koko");
 });
 
+it("uses raw startup output for an early close and clears it once ready", () => {
+  const capture = createKokoStartupOutputCapture();
+  const encoded = new TextEncoder().encode("sqlserver: 连接被拒绝");
+
+  capture.append(encoded.slice(0, 13));
+  capture.append(encoded.slice(13));
+  expect(resolveKokoTerminalCloseMessage(capture.take(), "Koko 已结束会话：资产连接已结束")).toBe(
+    "sqlserver: 连接被拒绝"
+  );
+
+  capture.markReady();
+  capture.append(new TextEncoder().encode("must not replace the close reason"));
+  expect(resolveKokoTerminalCloseMessage(capture.take(), "Koko 已结束会话：资产连接已结束")).toBe(
+    "Koko 已结束会话：资产连接已结束"
+  );
+});
+
+it("keeps only the last 8 KiB of startup output", () => {
+  const limit = 8 * 1024;
+  const capture = createKokoStartupOutputCapture(limit);
+  const encoder = new TextEncoder();
+
+  capture.append(encoder.encode("x".repeat(limit)));
+  capture.append(encoder.encode("tail"));
+
+  expect(capture.take()).toBe(`${"x".repeat(limit - 4)}tail`);
+});
+
 it("sends heartbeats only on open sockets, updates send time and stops after close", () => {
   vi.useFakeTimers();
   const socket = { readyState: WebSocket.CONNECTING as number, send: vi.fn() };