cache sponsorblock segments in redis (#1482)

common/constants.ts

@@ -1,3 +1,5 @@
+import type { Category } from "sponsorblock-api";
+
 export const ANNOUNCEMENT_CHANNEL = "announcement";
 export const ROOM_NAME_REGEX = /^[a-z0-9_-]+$/i;
 export const USERNAME_LENGTH_MAX = 48;
@@ -14,7 +16,7 @@ export const ALL_VIDEO_SERVICES = [
 	"peertube",
 	"pluto",
 ] as const;
-export const ALL_SKIP_CATEGORIES = [
+export const ALL_SKIP_CATEGORIES: Category[] = [
 	"sponsor",
 	"intro",
 	"outro",

server/ott-config.ts

@@ -444,10 +444,17 @@ export const conf = convict({
 		},
 	},
 	video: {
-		enable_sponsorblock: {
-			doc: "Whether to enable fetching skipable segments from sponsorblock.",
-			format: Boolean,
-			default: true,
+		sponsorblock: {
+			enabled: {
+				doc: "Whether to enable fetching skipable segments from sponsorblock.",
+				format: Boolean,
+				default: true,
+			},
+			cache_ttl: {
+				doc: "The duration in seconds to cache sponsorblock segments for.",
+				format: "nat",
+				default: 60 * 60 * 24 * 7, // 1 week
+			},
 		},
 	},
 });

server/room.ts

@@ -60,7 +60,7 @@ import {
 import storage from "./storage";
 import tokens, { SessionInfo } from "./auth/tokens";
 import { OttException } from "ott-common/exceptions";
-import { getSponsorBlock } from "./sponsorblock";
+import { fetchSegments, getSponsorBlock } from "./sponsorblock";
 import { ResponseError as SponsorblockResponseError, Segment, Category } from "sponsorblock-api";
 import { VideoQueue } from "./videoqueue";
 import { Counter } from "prom-client";
@@ -225,7 +225,7 @@ export class Room implements RoomState {
 	_owner: User | null = null;
 	grants: Grants = new Grants();
 	userRoles: Map<Role, Set<number>>;
-	_autoSkipSegmentCategories: Array<Category> = Array.from(ALL_SKIP_CATEGORIES);
+	_autoSkipSegmentCategories = Array.from(ALL_SKIP_CATEGORIES);
 	restoreQueueBehavior: BehaviorOption = BehaviorOption.Prompt;
 	_enableVoteSkip: boolean = false;
 
@@ -541,7 +541,7 @@ export class Room implements RoomState {
 		}
 
 		if (
-			conf.get("video.enable_sponsorblock") &&
+			conf.get("video.sponsorblock.enabled") &&
 			this.autoSkipSegmentCategories.length > 0 &&
 			this.currentSource
 		) {
@@ -766,7 +766,7 @@ export class Room implements RoomState {
 			);
 		}
 
-		if (conf.get("video.enable_sponsorblock") && this.autoSkipSegmentCategories.length > 0) {
+		if (conf.get("video.sponsorblock.enabled") && this.autoSkipSegmentCategories.length > 0) {
 			if (this.wantSponsorBlock) {
 				this.wantSponsorBlock = false; // Disable this before the request to avoid spamming the sponsorblock if the request takes too long.
 				try {
@@ -946,15 +946,7 @@ export class Room implements RoomState {
 		this.log.info(
 			`fetching sponsorblock segments for ${this.currentSource.service}:${this.currentSource.id}`
 		);
-		const sponsorBlock = await getSponsorBlock();
-		this.videoSegments = await sponsorBlock.getSegments(this.currentSource.id, [
-			"sponsor",
-			"intro",
-			"outro",
-			"interaction",
-			"selfpromo",
-			"preview",
-		]);
+		this.videoSegments = await fetchSegments(this.currentSource.id);
 	}
 
 	/** Updates playbackPosition according to the computed value, and resets _playbackStart */

server/sponsorblock.ts

@@ -1,20 +1,64 @@
-import { SponsorBlock } from "sponsorblock-api";
+import { SponsorBlock, type Segment } from "sponsorblock-api";
 import { redisClient } from "./redisclient";
 import { v4 as uuidv4 } from "uuid";
+import { ALL_SKIP_CATEGORIES } from "ott-common";
+import { conf } from "./ott-config";
+import { getLogger } from "./logger";
+
+const log = getLogger("sponsorblock");
 
 const SPONSORBLOCK_USERID_KEY = `sponsorblock-userid`;
+const SEGMENT_CACHE_PREFIX = "segments";
+
+let _cachedUserId: string | null = null;
 
 export async function getSponsorBlockUserId(): Promise<string> {
+	if (_cachedUserId) {
+		return _cachedUserId;
+	}
 	let userid = await redisClient.get(SPONSORBLOCK_USERID_KEY);
 	if (!userid) {
 		userid = uuidv4();
 		await redisClient.set(SPONSORBLOCK_USERID_KEY, userid);
 	}
+	_cachedUserId = userid;
 	return userid;
 }
 
+/** Used for tests. */
+export function clearUserId() {
+	_cachedUserId = null;
+}
+
 export async function getSponsorBlock(): Promise<SponsorBlock> {
 	const userid = await getSponsorBlockUserId();
 	const sponsorblock = new SponsorBlock(userid);
 	return sponsorblock;
 }
+
+export async function fetchSegments(videoId: string): Promise<Segment[]> {
+	if (conf.get("video.sponsorblock.cache_ttl") > 0) {
+		const cachedSegments = await redisClient.get(`${SEGMENT_CACHE_PREFIX}:${videoId}`);
+		if (cachedSegments) {
+			try {
+				return JSON.parse(cachedSegments);
+			} catch (e) {
+				log.warn(
+					`Failed to parse cached segments for video ${videoId}, fetching fresh segments`
+				);
+			}
+		}
+	}
+	const sponsorblock = await getSponsorBlock();
+	const segments = await sponsorblock.getSegments(videoId, ALL_SKIP_CATEGORIES);
+	await cacheSegments(videoId, segments);
+	return segments;
+}
+
+async function cacheSegments(videoId: string, segments: Segment[]) {
+	await redisClient.setEx(
+		`${SEGMENT_CACHE_PREFIX}:${videoId}`,
+		conf.get("video.sponsorblock.cache_ttl"),
+		JSON.stringify(segments)
+	);
+}

server/tests/unit/sponsorblock.spec.ts

@@ -0,0 +1,62 @@
+import { describe, it, expect, vi, beforeAll, beforeEach, afterEach } from "vitest";
+import { redisClient, buildClients } from "../../redisclient";
+import * as sponsorblock from "../../sponsorblock";
+import { SponsorBlock } from "sponsorblock-api";
+
+vi.mock("sponsorblock-api", () => {
+	return {
+		SponsorBlock: class {
+			getSegments = vi.fn().mockResolvedValue([{ start: 0, end: 1, category: "sponsor" }]);
+		},
+	};
+});
+
+describe("SponsorBlock", () => {
+	beforeAll(async () => {
+		await buildClients();
+	});
+
+	it("should generate and return the same user id and only ping redis once", async () => {
+		sponsorblock.clearUserId();
+		let getSpy = vi.spyOn(redisClient, "get").mockResolvedValue(null);
+		let setSpy = vi.spyOn(redisClient, "set");
+		const { getSponsorBlockUserId } = sponsorblock;
+		const userId = await getSponsorBlockUserId();
+		expect(userId).toBeDefined();
+		const userId2 = await getSponsorBlockUserId();
+		expect(userId2).toEqual(userId);
+
+		expect(redisClient.get).toHaveBeenCalledTimes(1);
+		expect(redisClient.set).toHaveBeenCalledTimes(1);
+		getSpy.mockRestore();
+		setSpy.mockRestore();
+	});
+
+	it("should always return the same user id and only ping redis once", async () => {
+		sponsorblock.clearUserId();
+		let getSpy = vi.spyOn(redisClient, "get").mockResolvedValue("testuserid");
+		let setSpy = vi.spyOn(redisClient, "set");
+		const { getSponsorBlockUserId } = sponsorblock;
+		const userId = await getSponsorBlockUserId();
+		expect(userId).toBe("testuserid");
+		const userId2 = await getSponsorBlockUserId();
+		expect(userId2).toBe("testuserid");
+
+		expect(redisClient.get).toHaveBeenCalledTimes(1);
+		expect(redisClient.set).not.toHaveBeenCalled();
+		getSpy.mockRestore();
+		setSpy.mockRestore();
+	});
+
+	it("should fetch new segments if parsing cached entry fails", async () => {
+		let getSpy = vi.spyOn(redisClient, "get").mockResolvedValue("[invalid json");
+		let setSpy = vi.spyOn(redisClient, "setEx");
+		const { fetchSegments } = sponsorblock;
+		const segments = await fetchSegments("testvideo");
+		expect(segments).toEqual([{ start: 0, end: 1, category: "sponsor" }]);
+		expect(redisClient.get).toHaveBeenCalledTimes(1);
+		expect(redisClient.setEx).toHaveBeenCalledTimes(1);
+		getSpy.mockRestore();
+		setSpy.mockRestore();
+	});
+});