File System Access 句柄持久化与重用实践

概述FSA 句柄可结构化克隆并持久化。本文给出句柄存取与权限校验流程。存取与权限const supportsFSA = typeof window.showOpenFilePicker === 'function';

function openDB(name) { return new Promise((resolve, reject) => { const r = indexedDB.open(name, 1); r.onupgradeneeded = () => { const db = r.result; if (!db.objectStoreNames.contains('handles')) db.createObjectStore('handles'); }; r.onsuccess = () => resolve(r.result); r.onerror = () => reject(r.error); }); }

async function saveHandle(key, handle) {

const db = await openDB('fs-handles');

const tx = db.transaction('handles', 'readwrite');

tx.objectStore('handles').put(handle, key);

await new Promise((resolve, reject) => { tx.oncomplete = resolve; tx.onerror = () => reject(tx.error); });

db.close();

}

async function loadHandle(key) {

const db = await openDB('fs-handles');

const tx = db.transaction('handles', 'readonly');

const req = tx.objectStore('handles').get(key);

const h = await new Promise((resolve, reject) => { req.onsuccess = () => resolve(req.result); req.onerror = () => reject(req.error); });

db.close();

return h;

}

async function ensurePermission(handle, mode = 'readwrite') {

if (typeof handle.requestPermission === 'function') { const s = await handle.requestPermission({ mode }); return s === 'granted'; }

return true;

}