@xiboplayer/cache

Offline caching and download management with parallel chunk downloads.

Overview

Manages media downloads and offline storage for Xibo players:

• Parallel chunk downloads — large files (100MB+) split into configurable chunks, downloaded concurrently
• Header+trailer first — MP4 moov atom fetched first for instant playback start before full download
• MD5 verification — integrity checking with CRC32-based skip optimization
• Download queue — flat queue with barriers for layout-ordered downloading
• CacheProxy — browser-side proxy that communicates with a Service Worker backend
• Widget data via enriched RequiredFiles — RSS/dataset widget data is fetched through server-side enriched RequiredFiles paths (CMS adds download URLs), not via client-side pre-fetching
• Dynamic BASE path — widget HTML <base> tag uses a dynamic path within the Service Worker scope for correct relative URL resolution

Installation

npm install @xiboplayer/cache

Usage

import { CacheProxy } from '@xiboplayer/cache';

const cache = new CacheProxy();
await cache.init();

// Request downloads (delegated to Service Worker)
await cache.requestDownload({ layoutOrder, files });

// Check if a file is cached
const isCached = await cache.has(fileId);

Exports

| Export | Description | |--------|-------------| | CacheProxy | Browser-side proxy communicating with SW backend | | DownloadManager | Core download queue with barrier-based ordering |

Dependencies

• @xiboplayer/utils — logger, events
• spark-md5 — MD5 hashing for file verification

xiboplayer.org · Part of the XiboPlayer SDK