ding113 · ding113 · Aug 2, 2026 · Aug 2, 2026 · coderabbitai · Aug 2, 2026
diff --git a/messages/en/settings/config.json b/messages/en/settings/config.json
@@ -171,7 +171,7 @@
       "enforce": "Enabled"
     },
     "replayEnabled": "Request Replay",
-    "replayEnabledDesc": "Caches upstream responses and reuses upstream connections: identical concurrent or reconnecting requests attach to the in-flight stream instead of re-hitting the provider. Follows the ENABLE_REQUEST_REPLAY environment variable until saved here. Default off.",
+    "replayEnabledDesc": "Caches upstream responses and reuses upstream connections: identical concurrent or reconnecting requests attach to the in-flight stream instead of re-hitting the provider. Follows the ENABLE_REQUEST_REPLAY environment variable until saved here. Default on.",
     "cacheEffectivenessEnabled": "Prefix Cache Simulation",
     "cacheEffectivenessEnabledDesc": "Simulates longest-prefix cache hit rates (theoretical vs actual) for observability only; never affects routing. Follows the ENABLE_CACHE_EFFECTIVENESS environment variable until saved here. Default on."
   },

diff --git a/messages/ja/settings/config.json b/messages/ja/settings/config.json
@@ -171,7 +171,7 @@
       "enforce": "有効"
     },
     "replayEnabled": "リクエスト Replay",
-    "replayEnabledDesc": "上流レスポンスをキャッシュし上流接続を再利用します。同一リクエストの並行実行や再接続は進行中のストリームに追随し、プロバイダーへ再送しません。保存するまでは環境変数 ENABLE_REQUEST_REPLAY に従います。デフォルトはオフ。",
+    "replayEnabledDesc": "上流レスポンスをキャッシュし上流接続を再利用します。同一リクエストの並行実行や再接続は進行中のストリームに追随し、プロバイダーへ再送しません。保存するまでは環境変数 ENABLE_REQUEST_REPLAY に従います。デフォルトはオン。",
     "cacheEffectivenessEnabled": "プレフィックスキャッシュシミュレーション",
     "cacheEffectivenessEnabledDesc": "最長プレフィックス一致のキャッシュヒット率(理論値 vs 実測値)を観測目的でシミュレートします。ルーティングには影響しません。保存するまでは環境変数 ENABLE_CACHE_EFFECTIVENESS に従います。デフォルトはオン。"
   },

diff --git a/messages/ru/settings/config.json b/messages/ru/settings/config.json
@@ -171,7 +171,7 @@
       "enforce": "Включено"
     },
     "replayEnabled": "Replay запросов",
-    "replayEnabledDesc": "Кэширует ответы провайдера и переиспользует соединения: одинаковые параллельные или переподключающиеся запросы присоединяются к текущему потоку вместо повторного обращения к провайдеру. До сохранения следует переменной окружения ENABLE_REQUEST_REPLAY. По умолчанию выключено.",
+    "replayEnabledDesc": "Кэширует ответы провайдера и переиспользует соединения: одинаковые параллельные или переподключающиеся запросы присоединяются к текущему потоку вместо повторного обращения к провайдеру. До сохранения следует переменной окружения ENABLE_REQUEST_REPLAY. По умолчанию включено.",
     "cacheEffectivenessEnabled": "Симуляция префиксного кэша",
     "cacheEffectivenessEnabledDesc": "Симулирует хит-рейт кэша по наибольшему префиксу (теория и факт) только для наблюдаемости; не влияет на маршрутизацию. До сохранения следует переменной окружения ENABLE_CACHE_EFFECTIVENESS. По умолчанию включено."
   },

diff --git a/messages/zh-CN/settings/config.json b/messages/zh-CN/settings/config.json
@@ -95,7 +95,7 @@
       "enforce": "启用"
     },
     "replayEnabled": "请求 Replay",
-    "replayEnabledDesc": "缓存上游响应并复用上游连接:并发或断线重连的相同请求直接跟尾在途流,不再重复请求供应商。保存前跟随环境变量 ENABLE_REQUEST_REPLAY,默认关闭。",
+    "replayEnabledDesc": "缓存上游响应并复用上游连接:并发或断线重连的相同请求直接跟尾在途流,不再重复请求供应商。保存前跟随环境变量 ENABLE_REQUEST_REPLAY,默认开启。",
     "cacheEffectivenessEnabled": "前缀缓存模拟",
     "cacheEffectivenessEnabledDesc": "模拟最长前缀匹配的缓存命中率(理论 vs 实际),仅用于观测,不影响路由。保存前跟随环境变量 ENABLE_CACHE_EFFECTIVENESS,默认开启。",
     "affinityIgnoreClientSessionId": "忽略客户端 Session ID",

diff --git a/messages/zh-TW/settings/config.json b/messages/zh-TW/settings/config.json
@@ -171,7 +171,7 @@
       "enforce": "啟用"
     },
     "replayEnabled": "請求 Replay",
-    "replayEnabledDesc": "快取上游回應並重用上游連線:並發或斷線重連的相同請求直接跟尾在途串流,不再重複請求供應商。儲存前跟隨環境變數 ENABLE_REQUEST_REPLAY,預設關閉。",
+    "replayEnabledDesc": "快取上游回應並重用上游連線:並發或斷線重連的相同請求直接跟尾在途串流,不再重複請求供應商。儲存前跟隨環境變數 ENABLE_REQUEST_REPLAY,預設開啟。",
     "cacheEffectivenessEnabled": "前綴快取模擬",
     "cacheEffectivenessEnabledDesc": "模擬最長前綴匹配的快取命中率(理論 vs 實際),僅用於觀測,不影響路由。儲存前跟隨環境變數 ENABLE_CACHE_EFFECTIVENESS,預設開啟。"
   },

diff --git a/src/app/[locale]/settings/config/_components/system-settings-form.tsx b/src/app/[locale]/settings/config/_components/system-settings-form.tsx
@@ -64,6 +64,8 @@ import type {
 interface SystemSettingsFormProps {
   /** Read-only runtime value; SESSION_TTL is not a persisted system setting. */
   sessionTtlSeconds?: number;
+  /** Read-only env fallback used while replayEnabled remains null. */
+  replayDefaultEnabled?: boolean;
   initialSettings: Pick<
     SystemSettings,
     | "siteTitle"
@@ -131,6 +133,7 @@ type DiscoveryNumberValue = number | "";
 export function SystemSettingsForm({
   initialSettings,
   sessionTtlSeconds = 300,
+  replayDefaultEnabled = true,
 }: SystemSettingsFormProps) {
   const router = useRouter();
   const t = useTranslations("settings.config.form");
@@ -214,7 +217,7 @@ export function SystemSettingsForm({
   const [affinityIgnoreClientSessionId, setAffinityIgnoreClientSessionId] = useState(
     initialSettings.affinityIgnoreClientSessionId
   );
-  // null = 跟随环境变量（Replay 默认关 / 缓存模拟默认开）：未触碰开关时按 null 原样保存，
+  // null = 跟随环境变量：未触碰开关时按 null 原样保存，
   // 避免无关字段的保存把覆写写死为布尔值；仅用户切换后才落显式值
   const [replayEnabled, setReplayEnabled] = useState<boolean | null>(initialSettings.replayEnabled);
   const [cacheEffectivenessEnabled, setCacheEffectivenessEnabled] = useState<boolean | null>(
@@ -1187,7 +1190,7 @@ export function SystemSettingsForm({
           <Switch
             id="replay-enabled"
             aria-label={t("replayEnabled")}
-            checked={replayEnabled ?? false}
+            checked={replayEnabled ?? replayDefaultEnabled}
             onCheckedChange={(checked) => setReplayEnabled(checked)}
             disabled={isPending}
           />

diff --git a/src/app/[locale]/settings/config/page.tsx b/src/app/[locale]/settings/config/page.tsx
@@ -35,7 +35,8 @@ export default async function SettingsConfigPage({
 async function SettingsConfigContent({ locale }: { locale: string }) {
   const t = await getTranslations({ locale, namespace: "settings" });
   const settings = await getSystemSettings();
-  const sessionTtlSeconds = Math.max(1, Math.floor(getEnvConfig().SESSION_TTL));
+  const env = getEnvConfig();
+  const sessionTtlSeconds = Math.max(1, Math.floor(env.SESSION_TTL));
 
   return (
     <>
@@ -47,6 +48,7 @@ async function SettingsConfigContent({ locale }: { locale: string }) {
       >
         <SystemSettingsForm
           sessionTtlSeconds={sessionTtlSeconds}
+          replayDefaultEnabled={env.ENABLE_REQUEST_REPLAY}
           initialSettings={{
             siteTitle: settings.siteTitle,
             allowGlobalUsageView: settings.allowGlobalUsageView,

diff --git a/src/lib/config/env.schema.ts b/src/lib/config/env.schema.ts
@@ -196,7 +196,7 @@ export const EnvSchema = z.object({
     .max(64 * 1024 * 1024)
     .default(10 * 1024 * 1024),
   // 请求分离 + Replay：客户端断开后上游继续引流缓存，相同请求体重发续传
-  ENABLE_REQUEST_REPLAY: z.string().default("false").transform(booleanTransform),
+  ENABLE_REQUEST_REPLAY: z.string().default("true").transform(booleanTransform),
   // owner 客户端仍在线时的并发相同请求去重（attached-live）；关闭后仅 detached/completed 可命中
   REPLAY_LIVE_DEDUP_ENABLED: z.string().default("true").transform(booleanTransform),
   // 客户端断开后上游继续引流的最长时长（毫秒；替代默认 60s drain 上限）

diff --git a/src/types/system-config.ts b/src/types/system-config.ts
@@ -159,7 +159,7 @@ export interface SystemSettings {
   affinityIgnoreClientSessionId: boolean;
 
   // F2 Replay（响应缓存与上游连接复用）开关覆写
-  // null = 跟随环境变量 ENABLE_REQUEST_REPLAY（默认 false）
+  // null = 跟随环境变量 ENABLE_REQUEST_REPLAY（默认 true）
   replayEnabled: boolean | null;
 
   // F3b 最长前缀匹配缓存模拟（理论 vs 实际缓存命中率，仅观测不影响路由）开关覆写

diff --git a/tests/unit/lib/env-request-replay.test.ts b/tests/unit/lib/env-request-replay.test.ts
@@ -0,0 +1,15 @@
+import { describe, expect, test } from "vitest";
+import { EnvSchema } from "@/lib/config/env.schema";
+
+describe("EnvSchema - ENABLE_REQUEST_REPLAY", () => {
+  test("defaults to enabled when unset", () => {
+    expect(EnvSchema.parse({}).ENABLE_REQUEST_REPLAY).toBe(true);
+  });
+
+  test.each([
+    ["true", true],
+    ["false", false],
+  ] as const)("preserves an explicit %s value", (value, expected) => {
+    expect(EnvSchema.parse({ ENABLE_REQUEST_REPLAY: value }).ENABLE_REQUEST_REPLAY).toBe(expected);
+  });
+});
diff --git a/tests/unit/settings/system-settings-form-replay-cache-toggles.test.tsx b/tests/unit/settings/system-settings-form-replay-cache-toggles.test.tsx
@@ -155,7 +155,11 @@ describe("SystemSettingsForm replay/cache-effectiveness null 三态", () => {
   });
 
   test("未触碰开关时保存保持 null（跟随环境变量），不写死布尔覆写", async () => {
-    const { unmount } = render(<SystemSettingsForm initialSettings={baseSettings} />);
+    const { unmount } = render(
+      <SystemSettingsForm initialSettings={baseSettings} replayDefaultEnabled={true} />
+    );
+
+    expect(document.getElementById("replay-enabled")?.getAttribute("aria-checked")).toBe("true");
 
     await submitForm();
 
@@ -170,7 +174,9 @@ describe("SystemSettingsForm replay/cache-effectiveness null 三态", () => {
   });
 
   test("用户切换开关后保存为显式覆写，未动的另一开关仍为 null", async () => {
-    const { unmount } = render(<SystemSettingsForm initialSettings={baseSettings} />);
+    const { unmount } = render(
+      <SystemSettingsForm initialSettings={baseSettings} replayDefaultEnabled={true} />
+    );
 
     const switchEl = document.getElementById("replay-enabled");
     if (!switchEl) throw new Error("未找到 replay-enabled 开关");
@@ -183,11 +189,21 @@ describe("SystemSettingsForm replay/cache-effectiveness null 三态", () => {
 
     expect(systemConfigActionMocks.saveSystemSettings).toHaveBeenCalledWith(
       expect.objectContaining({
-        replayEnabled: true,
+        replayEnabled: false,
         cacheEffectivenessEnabled: null,
       })
     );
 
     unmount();
   });
+
+  test("环境变量显式关闭时，null 覆写显示为关闭", () => {
+    const { unmount } = render(
+      <SystemSettingsForm initialSettings={baseSettings} replayDefaultEnabled={false} />
+    );
+
+    expect(document.getElementById("replay-enabled")?.getAttribute("aria-checked")).toBe("false");
+
+    unmount();
+  });
 });