Add Brotli pre-compression cache for /octokit/release

src/server/octokit/octokit.controller.ts

@@ -1,7 +1,12 @@
-import { Controller, HttpCode, HttpStatus, Get, Header } from '@nestjs/common';
+import { Controller, HttpStatus, Get, Req, Res } from '@nestjs/common';
 import { InjectableBase } from '../injectable-base.js';
 import { ApiOperation, ApiTags } from '@nestjs/swagger';
 import { OctokitService } from './octokit.service.js';
+import type { FastifyRequest, FastifyReply } from 'fastify';
+import { brotliCompress } from 'node:zlib';
+import { promisify } from 'node:util';
+
+const brotliCompressAsync = promisify(brotliCompress);
 
 @ApiTags('Octokit')
 @Controller('octokit')
@@ -10,23 +15,49 @@ export class OctokitController extends InjectableBase {
         super();
     }
 
-    private releaseCache: unknown = null;
-    @Get('release')
-    @ApiOperation({ summary: '获取最新版本', description: '代理 GitHub API' })
-    @HttpCode(HttpStatus.OK)
-    @Header('Cache-Control', 'public, max-age=10, s-maxage=10')
-    async release(): Promise<unknown> {
-        if (this.releaseCache) {
-            return this.releaseCache;
-        }
+    private releaseFetchPromise: Promise<{ json: string; br: Buffer }> | null = null;
+    private releaseCacheTimer: ReturnType<typeof setTimeout> | null = null;
+
+    private async fetchRelease(): Promise<{ json: string; br: Buffer }> {
         const response = await this.octokit.forApp.repos.getLatestRelease({
             owner: this.octokit.owner,
             repo: this.octokit.repo,
         });
-        this.releaseCache = response.data;
-        setTimeout(() => {
-            this.releaseCache = null;
-        }, 10_000);
-        return this.releaseCache;
+        const json = JSON.stringify(response.data);
+        const br = await brotliCompressAsync(Buffer.from(json));
+        return { json, br };
+    }
+
+    @Get('release')
+    @ApiOperation({ summary: '获取最新版本', description: '代理 GitHub API' })
+    async release(@Req() req: FastifyRequest, @Res() res: FastifyReply): Promise<void> {
+        if (!this.releaseFetchPromise) {
+            const promise = this.fetchRelease();
+            this.releaseFetchPromise = promise;
+            void promise.then(() => {
+                if (this.releaseFetchPromise !== promise) return;
+                if (this.releaseCacheTimer) clearTimeout(this.releaseCacheTimer);
+                this.releaseCacheTimer = setTimeout(() => {
+                    if (this.releaseFetchPromise === promise) this.releaseFetchPromise = null;
+                    this.releaseCacheTimer = null;
+                }, 10_000);
+            });
+            void promise.catch(() => {
+                if (this.releaseFetchPromise === promise) this.releaseFetchPromise = null;
+            });
+        }
+
+        const { json, br } = await this.releaseFetchPromise;
+        const acceptEncoding = req.headers['accept-encoding'] ?? '';
+        const reply = res
+            .status(HttpStatus.OK)
+            .header('Cache-Control', 'public, max-age=10, s-maxage=10')
+            .header('Content-Type', 'application/json; charset=utf-8')
+            .header('Vary', 'Accept-Encoding');
+        if (acceptEncoding.includes('br')) {
+            void reply.header('Content-Encoding', 'br').send(br);
+        } else {
+            void reply.send(json);
+        }
     }
 }