Merge branch 'rework-cache' into 'main'

Rework cache

See merge request soapbox-pub/ditto!156

src/app.ts

@@ -134,7 +134,7 @@ app.get('/users/:username', actorController);
 
 app.get('/nodeinfo/:version', nodeInfoSchemaController);
 
-app.get('/api/v1/instance', cache({ cacheName: 'web', expires: Time.minutes(5) }), instanceController);
+app.get('/api/v1/instance', cache({ expires: Time.minutes(5) }), instanceController);
 
 app.get('/api/v1/apps/verify_credentials', appCredentialsController);
 app.post('/api/v1/apps', createAppController);
@@ -185,10 +185,10 @@ app.get('/api/v1/preferences', preferencesController);
 app.get('/api/v1/search', searchController);
 app.get('/api/v2/search', searchController);
 
-app.get('/api/pleroma/frontend_configurations', frontendConfigController);
+app.get('/api/pleroma/frontend_configurations', cache({ expires: Time.minutes(5) }), frontendConfigController);
 
-app.get('/api/v1/trends/tags', cache({ cacheName: 'web', expires: Time.minutes(15) }), trendingTagsController);
-app.get('/api/v1/trends', cache({ cacheName: 'web', expires: Time.minutes(15) }), trendingTagsController);
+app.get('/api/v1/trends/tags', cache({ expires: Time.minutes(15) }), trendingTagsController);
+app.get('/api/v1/trends', cache({ expires: Time.minutes(15) }), trendingTagsController);
 
 app.get('/api/v1/notifications', requirePubkey, notificationsController);
 app.get('/api/v1/favourites', requirePubkey, favouritesController);

src/middleware/cache.ts

@@ -1,26 +1,45 @@
 import { Debug, type MiddlewareHandler } from '@/deps.ts';
-import ExpiringCache from '@/utils/expiring-cache.ts';
 
 const debug = Debug('ditto:middleware:cache');
 
-export const cache = (options: {
-  cacheName: string;
-  expires?: number;
-}): MiddlewareHandler => {
+interface CacheOpts {
+  expires: number;
+}
+
+/** In-memory cache middleware. */
+export const cache = (opts: CacheOpts): MiddlewareHandler => {
+  let response: Response | undefined;
+  let expires = Date.now() + opts.expires;
+
   return async (c, next) => {
-    const key = c.req.url.replace('http://', 'https://');
-    const cache = new ExpiringCache(await caches.open(options.cacheName));
-    const response = await cache.match(key);
-    if (!response) {
-      debug('Building cache for page', c.req.url);
+    const now = Date.now();
+    const expired = now > expires;
+
+    async function updateCache() {
       await next();
-      const response = c.res.clone();
-      if (response.status < 500) {
-        await cache.putExpiring(key, response, options.expires ?? 0);
+      const res = c.res.clone();
+      if (res.status < 500) {
+        const old = response;
+        response = res;
+        old?.text(); // Prevent memory leaks.
       }
-    } else {
+      return res;
+    }
+
+    if (response && !expired) {
       debug('Serving page from cache', c.req.url);
-      return response;
+      return response.clone();
+    } else {
+      expires = Date.now() + opts.expires;
+      if (response && expired) {
+        debug('Serving stale cache, rebuilding', c.req.url);
+        const stale = response.clone();
+        updateCache();
+        await new Promise((resolve) => setTimeout(resolve, 0));
+        return stale;
+      }
+      debug('Building cache for page', c.req.url);
+      return await updateCache();
     }
   };
 };

src/utils/expiring-cache.test.ts

@@ -1,18 +0,0 @@
-import { assert } from '@/deps-test.ts';
-
-import ExpiringCache from './expiring-cache.ts';
-
-Deno.test('ExpiringCache', async () => {
-  const cache = new ExpiringCache(await caches.open('test'));
-
-  await cache.putExpiring('http://mostr.local/1', new Response('hello world'), 300);
-  await cache.putExpiring('http://mostr.local/2', new Response('hello world'), -1);
-
-  // const resp1 = await cache.match('http://mostr.local/1');
-  const resp2 = await cache.match('http://mostr.local/2');
-
-  // assert(resp1!.headers.get('Expires'));
-  assert(!resp2);
-
-  // await resp1!.text();
-});

src/utils/expiring-cache.ts

@@ -1,68 +0,0 @@
-class ExpiringCache implements Cache {
-  #cache: Cache;
-
-  constructor(cache: Cache) {
-    this.#cache = cache;
-  }
-
-  add(request: RequestInfo | URL): Promise<void> {
-    return this.#cache.add(request);
-  }
-
-  addAll(requests: RequestInfo[]): Promise<void> {
-    return this.#cache.addAll(requests);
-  }
-
-  keys(request?: RequestInfo | URL | undefined, options?: CacheQueryOptions | undefined): Promise<readonly Request[]> {
-    return this.#cache.keys(request, options);
-  }
-
-  matchAll(
-    request?: RequestInfo | URL | undefined,
-    options?: CacheQueryOptions | undefined,
-  ): Promise<readonly Response[]> {
-    return this.#cache.matchAll(request, options);
-  }
-
-  put(request: RequestInfo | URL, response: Response): Promise<void> {
-    return this.#cache.put(request, response);
-  }
-
-  putExpiring(request: RequestInfo | URL, response: Response, expiresIn: number): Promise<void> {
-    const expires = Date.now() + expiresIn;
-
-    const clone = new Response(response.body, {
-      status: response.status,
-      headers: {
-        expires: new Date(expires).toUTCString(),
-        ...Object.fromEntries(response.headers.entries()),
-      },
-    });
-
-    return this.#cache.put(request, clone);
-  }
-
-  async match(request: RequestInfo | URL, options?: CacheQueryOptions | undefined): Promise<Response | undefined> {
-    const response = await this.#cache.match(request, options);
-    const expires = response?.headers.get('Expires');
-
-    if (response && expires) {
-      if (new Date(expires).getTime() > Date.now()) {
-        return response;
-      } else {
-        await Promise.all([
-          this.delete(request),
-          response.text(), // Prevent memory leaks
-        ]);
-      }
-    } else if (response) {
-      return response;
-    }
-  }
-
-  delete(request: RequestInfo | URL, options?: CacheQueryOptions | undefined): Promise<boolean> {
-    return this.#cache.delete(request, options);
-  }
-}
-
-export default ExpiringCache;