feat: 런타임 메뉴 응답을 한 시간 캐시

공개 navigation REST 응답에 content ETag와 1시간 fresh cache를 적용한다. 만료 뒤 조건부 요청은 내용이 같으면 304를 반환하고 운영 JSON이 바뀌면 새 본문과 ETag를 제공한다.

app/gateway-api/src/navigation/runtimeNavigationConfig.ts

@@ -1,9 +1,14 @@
 import fs from 'node:fs/promises';
+import { createHash } from 'node:crypto';
 
 import type { RuntimeNavigationConfig } from '@sammo-ts/common/navigation/menuConfig';
 import { z } from 'zod';
 
-const zId = z.string().min(1).max(80).regex(/^[a-z0-9][a-z0-9-]*$/u);
+const zId = z
+    .string()
+    .min(1)
+    .max(80)
+    .regex(/^[a-z0-9][a-z0-9-]*$/u);
 const zLabel = z.string().min(1).max(80);
 const zInternalPath = z
     .string()
@@ -98,6 +103,10 @@ export class RuntimeNavigationConfigStore {
     ) {}
 
     async get(): Promise<RuntimeNavigationConfig> {
+        return (await this.getWithEtag()).config;
+    }
+
+    async getWithEtag(): Promise<{ config: RuntimeNavigationConfig; etag: string }> {
         const configPath = await this.resolveConfigPath();
         let raw: unknown;
         try {
@@ -109,7 +118,10 @@ export class RuntimeNavigationConfigStore {
         if (!parsed.success) {
             throw new Error(`메뉴 설정 파일이 올바르지 않습니다: ${configPath}: ${parsed.error.message}`);
         }
-        return parsed.data;
+        return {
+            config: parsed.data,
+            etag: `"${createHash('sha256').update(JSON.stringify(parsed.data)).digest('hex')}"`,
+        };
     }
 
     private async resolveConfigPath(): Promise<string> {

app/gateway-api/src/navigation/runtimeNavigationRoute.ts

@@ -0,0 +1,28 @@
+import type { FastifyInstance } from 'fastify';
+
+import type { RuntimeNavigationConfigStore } from './runtimeNavigationConfig.js';
+
+export const runtimeNavigationCacheControl = 'public, max-age=3600, must-revalidate';
+
+export const matchesIfNoneMatch = (header: string | undefined, etag: string): boolean => {
+    if (!header) return false;
+    return header.split(',').some((candidate) => {
+        const value = candidate.trim();
+        return value === '*' || value.replace(/^W\//u, '') === etag;
+    });
+};
+
+export const registerRuntimeNavigationRoute = (
+    app: FastifyInstance,
+    navigationConfig: RuntimeNavigationConfigStore
+): void => {
+    app.get('/navigation', async (request, reply) => {
+        const current = await navigationConfig.getWithEtag();
+        void reply.header('Cache-Control', runtimeNavigationCacheControl);
+        void reply.header('ETag', current.etag);
+        if (matchesIfNoneMatch(request.headers['if-none-match'], current.etag)) {
+            return reply.code(304).send();
+        }
+        return current.config;
+    });
+};

app/gateway-api/src/server.ts

@@ -32,6 +32,7 @@ import { installGatewayShutdownController } from './lifecycle/shutdownController
 import { RemoteUserIconStore } from './account/remoteUserIconStore.js';
 import { gatewayFastifyRouterOptions } from './fastifyOptions.js';
 import { RuntimeNavigationConfigStore } from './navigation/runtimeNavigationConfig.js';
+import { registerRuntimeNavigationRoute } from './navigation/runtimeNavigationRoute.js';
 
 export const createGatewayApiServer = async () => {
     const config = resolveGatewayApiConfigFromEnv();
@@ -109,10 +110,7 @@ export const createGatewayApiServer = async () => {
         profiles,
         secret: config.gameTokenSecret,
     });
-    app.get('/navigation', async (_request, reply) => {
-        void reply.header('Cache-Control', 'no-store');
-        return navigationConfig.get();
-    });
+    registerRuntimeNavigationRoute(app, navigationConfig);
 
     await app.register(fastifyTRPCPlugin, {
         prefix: config.trpcPath,