IndexedDB 记录校验摘要与一致性验证实践

概述为每条记录计算并保存摘要，可在读取时验证一致性，发现损坏或意外覆盖。写入与验证function openDB(name) { return new Promise((resolve, reject) => { const r = indexedDB.open(name, 1); r.onupgradeneeded = () => { const db = r.result; if (!db.objectStoreNames.contains('items')) db.createObjectStore('items', { keyPath:'id' }); }; r.onsuccess = () => resolve(r.result); r.onerror = () => reject(r.error); }); } async function sha256Text(text) { const buf = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(text)); return Array.from(new Uint8Array(buf)).map(x=>x.toString(16).padStart(2,'0')).join(''); } async function putRecord(rec) { const db = await openDB('chk'); const tx = db.transaction('items','readwrite'); const hash = await sha256Text(JSON.stringify(rec)); tx.objectStore('items').put({ ...rec, _hash: hash }); await new Promise((res, rej) => { tx.oncomplete = res; tx.onerror = () => rej(tx.error); }); db.close(); } async function getRecord(id) { const db = await openDB('chk'); const tx = db.transaction('items','readonly'); const req = tx.objectStore('items').get(id); const rec = await new Promise((res, rej) => { req.onsuccess = () => res(req.result); req.onerror = () => rej(req.error); }); db.close(); if (!rec) return null; const vhash = await sha256Text(JSON.stringify({ ...rec, _hash: undefined })); if (vhash !== rec._hash) throw new Error('checksum mismatch'); return rec; }