feat & docs: implement zero-knowledge background sync protocol & conflict resolution

This commit is contained in:
2026-05-27 21:50:11 +02:00
parent 55cbe71520
commit 87d719ad9b
6 changed files with 491 additions and 8 deletions
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import { db } from './db.js'
import { getActiveMasterKey } from './auth.js'
const API_BASE = 'http://localhost:5000/api/sync'
const syncingLogbooks = new Set<string>()
// Helper to check if a timestamp is newer
function isNewer(timeA: string | Date, timeB: string | Date): boolean {
return new Date(timeA).getTime() > new Date(timeB).getTime()
}
// Push local sync queue items to the server
async function pushChanges(logbookId: string): Promise<boolean> {
const userId = localStorage.getItem('active_userid')
if (!userId) return false
// Fetch all pending queue items for this logbook
const pending = await db.syncQueue.where({ logbookId }).toArray()
if (pending.length === 0) return true
try {
const response = await fetch(`${API_BASE}/push`, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'X-User-Id': userId
},
body: JSON.stringify({ items: pending })
})
if (!response.ok) {
console.warn('Sync push request was rejected by server')
return false
}
const { results } = await response.json()
// Process results
for (const res of results) {
if (res.status === 'success' || res.status === 'conflict') {
// Find matching queue item
const queueItem = pending.find((item) => item.payloadId === res.payloadId)
if (queueItem && queueItem.id !== undefined) {
// Delete from sync queue
await db.syncQueue.delete(queueItem.id)
}
} else {
console.error(`Sync failed for item ${res.payloadId}:`, res.error)
}
}
return true
} catch (error) {
console.error('Error during sync push:', error)
return false
}
}
// Pull updates from the server and apply last-write-wins
async function pullChanges(logbookId: string): Promise<boolean> {
const userId = localStorage.getItem('active_userid')
if (!userId) return false
try {
const response = await fetch(`${API_BASE}/pull?logbookId=${logbookId}`, {
method: 'GET',
headers: {
'X-User-Id': userId
}
})
if (!response.ok) {
console.warn('Sync pull request was rejected by server')
return false
}
const { yacht, deviation, crews, entries } = await response.json()
// 1. Sync Yacht Payload
if (yacht) {
const local = await db.yachts.get(logbookId)
if (!local || isNewer(yacht.updatedAt, local.updatedAt)) {
await db.yachts.put({
logbookId,
encryptedData: yacht.encryptedData,
iv: yacht.iv,
tag: yacht.tag,
updatedAt: yacht.updatedAt
})
}
}
// 2. Sync Deviation Payload
if (deviation) {
const local = await db.deviations.get(logbookId)
if (!local || isNewer(deviation.updatedAt, local.updatedAt)) {
await db.deviations.put({
logbookId,
encryptedData: deviation.encryptedData,
iv: deviation.iv,
tag: deviation.tag,
updatedAt: deviation.updatedAt
})
}
}
// 3. Sync Crew List Payloads
const serverCrewMap = new Map<string, any>()
if (crews && Array.isArray(crews)) {
for (const c of crews) {
serverCrewMap.set(c.payloadId, c)
const local = await db.crews.get(c.payloadId)
if (!local || isNewer(c.updatedAt, local.updatedAt)) {
await db.crews.put({
payloadId: c.payloadId,
logbookId,
encryptedData: c.encryptedData,
iv: c.iv,
tag: c.tag,
updatedAt: c.updatedAt
})
}
}
}
// Deletions for Crew: If present locally but not on server, and not pending creation locally
const localCrews = await db.crews.where({ logbookId }).toArray()
for (const lc of localCrews) {
if (!serverCrewMap.has(lc.payloadId)) {
// Verify it's not a newly created item offline that hasn't synced yet
const pendingCreate = await db.syncQueue
.where({ payloadId: lc.payloadId, action: 'create' })
.first()
if (!pendingCreate) {
await db.crews.delete(lc.payloadId)
}
}
}
// 4. Sync Journal Entry Payloads
const serverEntryMap = new Map<string, any>()
if (entries && Array.isArray(entries)) {
for (const e of entries) {
serverEntryMap.set(e.payloadId, e)
const local = await db.entries.get(e.payloadId)
if (!local || isNewer(e.updatedAt, local.updatedAt)) {
await db.entries.put({
payloadId: e.payloadId,
logbookId,
encryptedData: e.encryptedData,
iv: e.iv,
tag: e.tag,
updatedAt: e.updatedAt
})
}
}
}
// Deletions for Entries
const localEntries = await db.entries.where({ logbookId }).toArray()
for (const le of localEntries) {
if (!serverEntryMap.has(le.payloadId)) {
const pendingCreate = await db.syncQueue
.where({ payloadId: le.payloadId, action: 'create' })
.first()
if (!pendingCreate) {
await db.entries.delete(le.payloadId)
}
}
}
return true
} catch (error) {
console.error('Error during sync pull:', error)
return false
}
}
// Main function to synchronize a specific logbook
export async function syncLogbook(logbookId: string): Promise<boolean> {
if (!navigator.onLine) return false
const masterKey = getActiveMasterKey()
if (!masterKey) return false
if (syncingLogbooks.has(logbookId)) return false
syncingLogbooks.add(logbookId)
try {
const pushed = await pushChanges(logbookId)
const pulled = await pullChanges(logbookId)
return pushed && pulled;
} finally {
syncingLogbooks.delete(logbookId)
}
}
// Synchronize all user logbooks that are cached locally
export async function syncAllLogbooks(): Promise<void> {
if (!navigator.onLine) return
const masterKey = getActiveMasterKey()
if (!masterKey) return
try {
// 1. Fetch latest logbook lists first (synchronizes db.logbooks index)
const logbooks = await db.logbooks.toArray()
// 2. Synchronize payloads for each logbook
for (const lb of logbooks) {
await syncLogbook(lb.id)
}
} catch (error) {
console.error('Error synchronizing all logbooks:', error)
}
}
// Setup background sync intervals
let syncIntervalId: any = null
export function startBackgroundSync(intervalMs = 30000) {
if (syncIntervalId) clearInterval(syncIntervalId)
// Trigger immediate sync
syncAllLogbooks()
// Set interval
syncIntervalId = setInterval(() => {
syncAllLogbooks()
}, intervalMs)
}
export function stopBackgroundSync() {
if (syncIntervalId) {
clearInterval(syncIntervalId)
syncIntervalId = null
}
}