1 files changed, 80 insertions, 0 deletions
diff --git a/packages/backend/src/core/FunoutTimelineService.ts b/packages/backend/src/core/FunoutTimelineService.ts
new file mode 100644
index 0000000000..512b2d9833
--- /dev/null
+++ b/packages/backend/src/core/FunoutTimelineService.ts
@@ -0,0 +1,80 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import * as Redis from 'ioredis';
+import { DI } from '@/di-symbols.js';
+import { bindThis } from '@/decorators.js';
+import { IdService } from '@/core/IdService.js';
+
+@Injectable()
+export class FunoutTimelineService {
+	constructor(
+		@Inject(DI.redisForTimelines)
+		private redisForTimelines: Redis.Redis,
+
+		private idService: IdService,
+	) {
+	}
+
+	@bindThis
+	public push(tl: string, id: string, maxlen: number, pipeline: Redis.ChainableCommander) {
+		// リモートから遅れて届いた(もしくは後から追加された)投稿日時が古い投稿が追加されるとページネーション時に問題を引き起こすため、
+		// 3分以内に投稿されたものでない場合、Redisにある最古のIDより新しい場合のみ追加する
+		if (this.idService.parse(id).date.getTime() > Date.now() - 1000 * 60 * 3) {
+			pipeline.lpush('list:' + tl, id);
+			if (Math.random() < 0.1) { // 10%の確率でトリム
+				pipeline.ltrim('list:' + tl, 0, maxlen - 1);
+			}
+		} else {
+			// 末尾のIDを取得
+			this.redisForTimelines.lindex('list:' + tl, -1).then(lastId => {
+				if (lastId == null || (this.idService.parse(id).date.getTime() > this.idService.parse(lastId).date.getTime())) {
+					this.redisForTimelines.lpush('list:' + tl, id);
+				} else {
+					Promise.resolve();
+				}
+			});
+		}
+	}
+
+	@bindThis
+	public get(name: string, untilId?: string | null, sinceId?: string | null) {
+		if (untilId && sinceId) {
+			return this.redisForTimelines.lrange('list:' + name, 0, -1)
+				.then(ids => ids.filter(id => id < untilId && id > sinceId).sort((a, b) => a > b ? -1 : 1));
+		} else if (untilId) {
+			return this.redisForTimelines.lrange('list:' + name, 0, -1)
+				.then(ids => ids.filter(id => id < untilId).sort((a, b) => a > b ? -1 : 1));
+		} else if (sinceId) {
+			return this.redisForTimelines.lrange('list:' + name, 0, -1)
+				.then(ids => ids.filter(id => id > sinceId).sort((a, b) => a < b ? -1 : 1));
+		} else {
+			return this.redisForTimelines.lrange('list:' + name, 0, -1)
+				.then(ids => ids.sort((a, b) => a > b ? -1 : 1));
+		}
+	}
+
+	@bindThis
+	public getMulti(name: string[], untilId?: string | null, sinceId?: string | null): Promise<string[][]> {
+		const pipeline = this.redisForTimelines.pipeline();
+		for (const n of name) {
+			pipeline.lrange('list:' + n, 0, -1);
+		}
+		return pipeline.exec().then(res => {
+			if (res == null) return [];
+			const tls = res.map(r => r[1] as string[]);
+			return tls.map(ids =>
+				(untilId && sinceId)
+					? ids.filter(id => id < untilId && id > sinceId).sort((a, b) => a > b ? -1 : 1)
+					: untilId
+						? ids.filter(id => id < untilId).sort((a, b) => a > b ? -1 : 1)
+						: sinceId
+							? ids.filter(id => id > sinceId).sort((a, b) => a < b ? -1 : 1)
+							: ids.sort((a, b) => a > b ? -1 : 1),
+			);
+		});
+	}
+}