| 1 | /** |
| 2 | * thumbnailCache - 视频封面缓存 Store |
| 3 | * 使用 IndexedDB 持久化存储视频封面 URL，避免重复请求 |
| 4 | */ |
| 5 | |
| 6 | import { getVideoThumbnail } from '@/api/materials/material.api' |
| 7 | import { createPersistStore } from '@/utils/storage/createPersistStore' |
| 8 | |
| 9 | export interface IThumbnailCacheState { |
| 10 | cache: Record<string, string> |
| 11 | } |
| 12 | |
| 13 | const initialState: IThumbnailCacheState = { |
| 14 | cache: {}, |
| 15 | } |
| 16 | |
| 17 | // 并发控制（闭包变量，不进入 store state） |
| 18 | const MAX_CONCURRENT = 3 |
| 19 | let activeCount = 0 |
| 20 | const pending = new Map<string, Promise<string>>() |
| 21 | const queue: Array<() => void> = [] |
| 22 | |
| 23 | function runNext() { |
| 24 | while (activeCount < MAX_CONCURRENT && queue.length > 0) { |
| 25 | const next = queue.shift()! |
| 26 | activeCount++ |
| 27 | next() |
| 28 | } |
| 29 | } |
| 30 | |
| 31 | export const useThumbnailCache = createPersistStore( |
| 32 | { ...initialState }, |
| 33 | (set, get) => ({ |
| 34 | fetchThumbnail(videoUrl: string): Promise<string> { |
| 35 | // 1. 缓存命中 |
| 36 | const cached = get().cache[videoUrl] |
| 37 | if (cached) |
| 38 | return Promise.resolve(cached) |
| 39 | |
| 40 | // 2. 去重：已在请求中 |
| 41 | if (pending.has(videoUrl)) |
| 42 | return pending.get(videoUrl)! |
| 43 | |
| 44 | // 3. 创建请求 Promise |
| 45 | const promise = new Promise<string>((resolve) => { |
| 46 | const execute = async () => { |
| 47 | try { |
| 48 | const res = await getVideoThumbnail(videoUrl) |
| 49 | const thumbnailUrl = res?.data?.thumbnailUrl || '' |
| 50 | if (thumbnailUrl) { |
| 51 | set(state => ({ |
| 52 | cache: { ...state.cache, [videoUrl]: thumbnailUrl }, |
| 53 | })) |
| 54 | } |
| 55 | resolve(thumbnailUrl) |
| 56 | } |
| 57 | catch { |
| 58 | resolve('') |
| 59 | } |
| 60 | finally { |
| 61 | activeCount-- |
| 62 | pending.delete(videoUrl) |
| 63 | runNext() |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | queue.push(execute) |
| 68 | runNext() |
| 69 | }) |
| 70 | |
| 71 | pending.set(videoUrl, promise) |
| 72 | return promise |
| 73 | }, |
| 74 | }), |
| 75 | { name: 'thumbnail-cache', version: 2 }, |
| 76 | 'indexedDB', |
| 77 | ) |
| 78 |