From 5fa1fe2c3ecd592a24c77af37872602dd3872d2e Mon Sep 17 00:00:00 2001
From: kakkokari-gtyih <67428053+kakkokari-gtyih@users.noreply.github.com>
Date: Wed, 25 Dec 2024 19:07:49 +0900
Subject: [PATCH] =?UTF-8?q?enhance(url-preview):=20Summaly=E3=81=AE?=
 =?UTF-8?q?=E7=B5=90=E6=9E=9C=E3=82=92=E5=86=85=E9=83=A8=E3=81=A7=E3=82=AD?=
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 =?UTF-8?q?=E3=81=86=E3=81=AB?=
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---
 .../src/server/web/UrlPreviewService.ts       | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/packages/backend/src/server/web/UrlPreviewService.ts b/packages/backend/src/server/web/UrlPreviewService.ts
index 9b5f0acd2c..da6c85cc56 100644
--- a/packages/backend/src/server/web/UrlPreviewService.ts
+++ b/packages/backend/src/server/web/UrlPreviewService.ts
@@ -4,6 +4,7 @@
  */
 
 import { Inject, Injectable } from '@nestjs/common';
+import * as Redis from 'ioredis';
 import { summaly } from '@misskey-dev/summaly';
 import { SummalyResult } from '@misskey-dev/summaly/built/summary.js';
 import { DI } from '@/di-symbols.js';
@@ -15,6 +16,7 @@ import { LoggerService } from '@/core/LoggerService.js';
 import { bindThis } from '@/decorators.js';
 import { ApiError } from '@/server/api/error.js';
 import { MiMeta } from '@/models/Meta.js';
+import { createHash } from 'crypto';
 import type { FastifyRequest, FastifyReply } from 'fastify';
 
 @Injectable()
@@ -25,6 +27,9 @@ export class UrlPreviewService {
 		@Inject(DI.config)
 		private config: Config,
 
+		@Inject(DI.redis)
+		private redisClient: Redis.Redis,
+
 		@Inject(DI.meta)
 		private meta: MiMeta,
 
@@ -74,6 +79,19 @@ export class UrlPreviewService {
 			};
 		}
 
+		const redisCacheKey = createHash('sha256').update(url.trim()).digest('hex');
+
+		const cachedSummary = await this.redisClient.get(`url-preview:${lang}:${redisCacheKey}`);
+
+		if (cachedSummary) {
+			this.logger.succ(`Got preview of ${url}@${lang} from cache`);
+
+			// Cache 7days
+			reply.header('Cache-Control', 'max-age=604800, immutable');
+
+			return JSON.parse(cachedSummary);
+		}
+
 		this.logger.info(this.meta.urlPreviewSummaryProxyUrl
 			? `(Proxy) Getting preview of ${url}@${lang} ...`
 			: `Getting preview of ${url}@${lang} ...`);
@@ -99,6 +117,9 @@ export class UrlPreviewService {
 			// Cache 7days
 			reply.header('Cache-Control', 'max-age=604800, immutable');
 
+			// Cache internally for 1day
+			this.redisClient.setex(`url-preview:${lang}:${redisCacheKey}`, 86400, JSON.stringify(summary));
+
 			return summary;
 		} catch (err) {
 			this.logger.warn(`Failed to get preview of ${url}: ${err}`);