feat: persist offline users and push subscriptions to disk

Rooms and push subscriptions now survive server restarts via JSON files
on a Docker volume. Stale participant cleanup skips users who have
active push subscriptions — they remain in the room and can still be
pinged for location and notifications when offline.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sync-server/Dockerfile

@@ -15,8 +15,8 @@ RUN npm ci --only=production
 # Copy server code and fix ownership
 COPY --chown=nodejs:nodejs server.js verify-token.js ./
 
-# Set ownership for the whole app directory
-RUN chown -R nodejs:nodejs /app
+# Create data directory for persistence and set ownership
+RUN mkdir -p /app/data && chown -R nodejs:nodejs /app
 
 USER nodejs
 

sync-server/docker-compose.yml

@@ -11,6 +11,8 @@ services:
       - VAPID_SUBJECT=mailto:push@rmaps.online
       # Automatic location request interval (ms) - 0 to disable
       - LOCATION_REQUEST_INTERVAL=60000
+    volumes:
+      - rmaps-sync-data:/app/data
     labels:
       - "traefik.enable=true"
       # HTTP router (redirects to HTTPS via Cloudflare)
@@ -26,6 +28,9 @@ services:
       retries: 3
       start_period: 10s
 
+volumes:
+  rmaps-sync-data:
+
 networks:
   traefik-public:
     external: true

sync-server/server.js

@@ -2,10 +2,12 @@ import { WebSocketServer } from 'ws';
 import { createServer } from 'http';
 import { parse } from 'url';
 import { randomUUID } from 'crypto';
+import { readFileSync, writeFileSync, mkdirSync, existsSync } from 'fs';
 import webpush from 'web-push';
 import { verifyToken, extractTokenFromURL } from './verify-token.js';
 
 const PORT = process.env.PORT || 3001;
+const DATA_DIR = process.env.DATA_DIR || './data';
 const STALE_THRESHOLD_MS = 15 * 60 * 1000; // 15 minutes (match client-side cleanup)
 const LOCATION_REQUEST_INTERVAL_MS = parseInt(process.env.LOCATION_REQUEST_INTERVAL || '60000', 10); // 60 seconds default
 
@@ -23,16 +25,97 @@ if (VAPID_PUBLIC_KEY && VAPID_PRIVATE_KEY) {
   console.log('Push notifications disabled (VAPID keys not configured)');
 }
 
+// ==================== PERSISTENCE ====================
+
+// Ensure data directory exists
+if (!existsSync(DATA_DIR)) {
+  mkdirSync(DATA_DIR, { recursive: true });
+  console.log(`Created data directory: ${DATA_DIR}`);
+}
+
+// Load persisted state from disk
+function loadFromDisk(filename) {
+  const path = `${DATA_DIR}/${filename}`;
+  try {
+    if (existsSync(path)) {
+      const data = JSON.parse(readFileSync(path, 'utf-8'));
+      console.log(`Loaded ${filename}: ${Object.keys(data).length} entries`);
+      return data;
+    }
+  } catch (err) {
+    console.error(`Failed to load ${filename}:`, err.message);
+  }
+  return null;
+}
+
+// Save state to disk (debounced)
+let saveTimers = {};
+function saveToDisk(filename, data) {
+  if (saveTimers[filename]) clearTimeout(saveTimers[filename]);
+  saveTimers[filename] = setTimeout(() => {
+    try {
+      writeFileSync(`${DATA_DIR}/${filename}`, JSON.stringify(data, null, 2));
+    } catch (err) {
+      console.error(`Failed to save ${filename}:`, err.message);
+    }
+  }, 2000); // 2-second debounce
+}
+
 // Room state storage: Map<roomSlug, RoomState>
 const rooms = new Map();
 
 // Client tracking: Map<WebSocket, { roomSlug, participantId, claims, readOnly }>
 const clients = new Map();
 
-// Push subscriptions: Map<roomSlug, Map<endpoint, { subscription, participantId }>>
+// Push subscriptions: Map<roomSlug, Map<endpoint, { subscription, participantId, participantName }>>
 // Using Map keyed by endpoint to deduplicate subscriptions from the same device
 const pushSubscriptions = new Map();
 
+// Restore rooms from disk
+const savedRooms = loadFromDisk('rooms.json');
+if (savedRooms) {
+  for (const [slug, room] of Object.entries(savedRooms)) {
+    // Mark all restored participants as offline (they'll re-join if they connect)
+    for (const p of Object.values(room.participants || {})) {
+      p.status = 'offline';
+    }
+    rooms.set(slug, room);
+  }
+  console.log(`Restored ${rooms.size} room(s) with offline participants`);
+}
+
+// Restore push subscriptions from disk
+const savedSubs = loadFromDisk('push-subscriptions.json');
+if (savedSubs) {
+  for (const [slug, entries] of Object.entries(savedSubs)) {
+    const subsMap = new Map();
+    for (const [endpoint, data] of Object.entries(entries)) {
+      subsMap.set(endpoint, data);
+    }
+    pushSubscriptions.set(slug, subsMap);
+  }
+  console.log(`Restored push subscriptions for ${pushSubscriptions.size} room(s)`);
+}
+
+// Persist helpers
+function persistRooms() {
+  const obj = {};
+  for (const [slug, room] of rooms.entries()) {
+    obj[slug] = room;
+  }
+  saveToDisk('rooms.json', obj);
+}
+
+function persistPushSubscriptions() {
+  const obj = {};
+  for (const [slug, subsMap] of pushSubscriptions.entries()) {
+    if (subsMap.size > 0) {
+      obj[slug] = Object.fromEntries(subsMap.entries());
+    }
+  }
+  saveToDisk('push-subscriptions.json', obj);
+}
+
 function getRoomState(slug) {
   if (!rooms.has(slug)) {
     rooms.set(slug, {
@@ -91,7 +174,19 @@ function cleanupStaleParticipants(room) {
   const now = Date.now();
   const staleIds = [];
 
+  // Build set of participant IDs that have active push subscriptions
+  const pushParticipantIds = new Set();
+  const subsMap = pushSubscriptions.get(room.slug);
+  if (subsMap) {
+    for (const { participantId } of subsMap.values()) {
+      if (participantId) pushParticipantIds.add(participantId);
+    }
+  }
+
   for (const [id, participant] of Object.entries(room.participants)) {
+    // Never clean up participants with push subscriptions — they're still reachable
+    if (pushParticipantIds.has(id)) continue;
+
     const lastSeenMs = typeof participant.lastSeen === 'string'
       ? new Date(participant.lastSeen).getTime()
       : participant.lastSeen;
@@ -102,9 +197,10 @@ function cleanupStaleParticipants(room) {
 
   for (const id of staleIds) {
     delete room.participants[id];
-    console.log(`Cleaned up stale participant: ${id}`);
+    console.log(`Cleaned up stale participant: ${id} (no push subscription)`);
   }
 
+  if (staleIds.length > 0) persistRooms();
   return staleIds;
 }
 
@@ -150,9 +246,12 @@ async function sendPushToRoom(roomSlug, notification, { excludeEndpoint = null,
   }
 
   // Clean up failed subscriptions
-  for (const endpoint of failedEndpoints) {
-    subsMap.delete(endpoint);
-    console.log(`[${roomSlug}] Removed invalid subscription`);
+  if (failedEndpoints.length > 0) {
+    for (const endpoint of failedEndpoints) {
+      subsMap.delete(endpoint);
+      console.log(`[${roomSlug}] Removed invalid subscription`);
+    }
+    persistPushSubscriptions();
   }
 }
 
@@ -219,6 +318,7 @@ function handleMessage(ws, data) {
         type: 'full_state',
         state: room
       }));
+      persistRooms();
       break;
     }
 
@@ -227,6 +327,7 @@ function handleMessage(ws, data) {
       delete room.participants[message.participantId];
       console.log(`[${clientInfo.roomSlug}] Participant left: ${message.participantId}`);
       broadcast(clientInfo.roomSlug, message, ws);
+      persistRooms();
 
       // Send push notification
       if (leavingParticipant) {
@@ -252,6 +353,7 @@ function handleMessage(ws, data) {
         // Broadcast to all OTHER participants
         const count = broadcast(clientInfo.roomSlug, message, ws);
         console.log(`[${clientInfo.roomSlug}] Location update from ${message.participantId} -> ${count} clients`);
+        persistRooms();
       }
       break;
     }
@@ -328,6 +430,7 @@ function handleClose(ws) {
         status: 'offline'
       });
       console.log(`[${clientInfo.roomSlug}] User went offline: ${clientInfo.participantId} (location preserved)`);
+      persistRooms();
     }
     clients.delete(ws);
   }
@@ -336,18 +439,25 @@ function handleClose(ws) {
 // Periodic cleanup of empty rooms
 setInterval(() => {
   const now = Date.now();
+  let changed = false;
   for (const [slug, room] of rooms.entries()) {
-    // Clean stale participants
+    // Clean stale participants (skips those with push subscriptions)
     cleanupStaleParticipants(room);
 
-    // Remove empty rooms older than 24 hours
-    if (Object.keys(room.participants).length === 0 &&
+    // Remove empty rooms older than 24 hours (only if no push subscriptions either)
+    const hasPushSubs = pushSubscriptions.has(slug) && pushSubscriptions.get(slug).size > 0;
+    if (Object.keys(room.participants).length === 0 && !hasPushSubs &&
         now - room.lastActivity > 24 * 60 * 60 * 1000) {
       rooms.delete(slug);
       pushSubscriptions.delete(slug);
       console.log(`Cleaned up empty room: ${slug}`);
+      changed = true;
     }
   }
+  if (changed) {
+    persistRooms();
+    persistPushSubscriptions();
+  }
 }, 5 * 60 * 1000); // Every 5 minutes
 
 // Automatic location request - periodically ask all clients for location updates via silent push
@@ -378,9 +488,12 @@ async function requestLocationFromAllRooms() {
     }
 
     // Clean up failed subscriptions
-    for (const endpoint of failedEndpoints) {
-      subsMap.delete(endpoint);
-      console.log(`[${roomSlug}] Removed stale push subscription`);
+    if (failedEndpoints.length > 0) {
+      for (const endpoint of failedEndpoints) {
+        subsMap.delete(endpoint);
+        console.log(`[${roomSlug}] Removed stale push subscription`);
+      }
+      persistPushSubscriptions();
     }
   }
 }
@@ -472,6 +585,7 @@ const server = createServer(async (req, res) => {
           participantId: participantId || null,
         });
         console.log(`[${roomSlug}] Push subscription added/updated for participant: ${participantId || 'unknown'}`);
+        persistPushSubscriptions();
       }
 
       res.writeHead(200, { 'Content-Type': 'application/json' });
@@ -491,6 +605,7 @@ const server = createServer(async (req, res) => {
         if (subsMap.has(endpoint)) {
           subsMap.delete(endpoint);
           console.log(`[${roomSlug}] Push subscription removed`);
+          persistPushSubscriptions();
         }
       }
 
@@ -685,8 +800,11 @@ const server = createServer(async (req, res) => {
         }
 
         // Clean up failed subscriptions
-        for (const endpoint of failedEndpoints) {
-          subsMap.delete(endpoint);
+        if (failedEndpoints.length > 0) {
+          for (const endpoint of failedEndpoints) {
+            subsMap.delete(endpoint);
+          }
+          persistPushSubscriptions();
         }
       }