yet another attempt at fixing reporting sync changes to client

app.js

@@ -10,8 +10,6 @@ const FileStore = require('session-file-store')(session);
 const os = require('os');
 const sessionSecret = require('./services/session_secret');
 
-require('./services/ping_job');
-
 const app = express();
 
 // view engine setup

public/javascripts/messaging.js

@@ -2,7 +2,6 @@
 
 const messaging = (function() {
     const changesToPushCountEl = $("#changes-to-push-count");
-    let ws = null;
 
     function logError(message) {
         console.log(now(), message); // needs to be separate from .trace()
@@ -21,12 +20,15 @@ const messaging = (function() {
 
         if (message.type === 'sync') {
             lastPingTs = new Date().getTime();
-            const syncData = message.data.filter(sync => sync.source_id !== glob.sourceId);
 
-            if (syncData.length > 0) {
+            if (message.data.length > 0) {
-                console.log(now(), "Sync data: ", message);
+                console.log(now(), "Sync data: ", message.data);
+
+                lastSyncId = message.data[message.data.length - 1].id;
             }
 
+            const syncData = message.data.filter(sync => sync.source_id !== glob.sourceId);
+
             if (syncData.some(sync => sync.entity_name === 'notes_tree')) {
                 console.log(now(), "Reloading tree because of background changes");
 
@@ -59,17 +61,20 @@ const messaging = (function() {
         const protocol = document.location.protocol === 'https:' ? 'wss' : 'ws';
 
         // use wss for secure messaging
-        ws = new WebSocket(protocol + "://" + location.host);
+        const ws = new WebSocket(protocol + "://" + location.host);
         ws.onopen = event => console.log(now(), "Connected to server with WebSocket");
         ws.onmessage = messageHandler;
         ws.onclose = function(){
             // Try to reconnect in 5 seconds
             setTimeout(() => connectWebSocket(), 5000);
         };
+
+        return ws;
     }
 
-    connectWebSocket();
+    const ws = connectWebSocket();
 
+    let lastSyncId = glob.maxSyncIdAtLoad;
     let lastPingTs = new Date().getTime();
     let connectionBrokenNotification = null;
 
@@ -92,7 +97,12 @@ const messaging = (function() {
 
             showMessage("Re-connected to server");
         }
-    }, 3000);
+
+        ws.send(JSON.stringify({
+            type: 'ping',
+            lastSyncId: lastSyncId
+        }));
+    }, 1000);
 
     return {
         logError

routes/index.js

@@ -4,10 +4,12 @@ const express = require('express');
 const router = express.Router();
 const auth = require('../services/auth');
 const source_id = require('../services/source_id');
+const sql = require('../services/sql');
 
 router.get('', auth.checkAuth, async (req, res, next) => {
     res.render('index', {
-        sourceId: await source_id.generateSourceId()
+        sourceId: await source_id.generateSourceId(),
+        maxSyncIdAtLoad: await sql.getSingleValue("SELECT MAX(id) FROM sync")
     });
 });
 

services/consistency_checks.js

@@ -47,7 +47,7 @@ async function runChecks() {
     await runSyncRowChecks("recent_notes", "note_tree_id", errorList);
 
     if (errorList.length > 0) {
-        messaging.sendMessage({type: 'consistency-checks-failed'});
+        messaging.sendMessageToAllClients({type: 'consistency-checks-failed'});
     }
     else {
         log.info("All consistency checks passed.");

services/messaging.js

@@ -1,6 +1,9 @@
 const WebSocket = require('ws');
 const utils = require('./utils');
 const log = require('./log');
+const sql = require('./sql');
+const options = require('./options');
+const sync_setup = require('./sync_setup');
 
 let webSocketServer;
 
@@ -29,6 +32,9 @@ function init(httpServer, sessionParser) {
             if (message.type === 'log-error') {
                 log.error('JS Error: ' + message.error);
             }
+            else if (message.type === 'ping') {
+                sendPing(ws, message.lastSyncId);
+            }
             else {
                 log.error('Unrecognized message: ');
                 log.error(message);
@@ -37,7 +43,15 @@ function init(httpServer, sessionParser) {
     });
 }
 
-async function sendMessage(message) {
+async function sendMessage(client, message) {
+    const jsonStr = JSON.stringify(message);
+
+    if (client.readyState === WebSocket.OPEN) {
+        client.send(jsonStr);
+    }
+}
+
+async function sendMessageToAllClients(message) {
     const jsonStr = JSON.stringify(message);
 
     webSocketServer.clients.forEach(function each(client) {
@@ -47,7 +61,21 @@ async function sendMessage(message) {
     });
 }
 
+async function sendPing(client, lastSentSyncId) {
+    const syncData = await sql.getResults("SELECT * FROM sync WHERE id > ?", [lastSentSyncId]);
+
+    const lastSyncedPush = await options.getOption('last_synced_push');
+
+    const changesToPushCount = await sql.getSingleValue("SELECT COUNT(*) FROM sync WHERE id > ?", [lastSyncedPush]);
+
+    await sendMessage(client, {
+        type: 'sync',
+        data: syncData,
+        changesToPushCount: sync_setup.isSyncSetup ? changesToPushCount : 0
+    });
+}
+
 module.exports = {
     init,
-    sendMessage
+    sendMessageToAllClients
 };

services/ping_job.js

@@ -1,30 +0,0 @@
-const sql = require('./sql');
-const messaging = require('./messaging');
-const options = require('./options');
-const sync_setup = require('./sync_setup');
-
-let lastSentSyncId;
-
-async function sendPing() {
-    const syncData = await sql.getResults("SELECT * FROM sync WHERE id > ?", [lastSentSyncId]);
-
-    const lastSyncedPush = await options.getOption('last_synced_push');
-
-    const changesToPushCount = await sql.getSingleValue("SELECT COUNT(*) FROM sync WHERE id > ?", [lastSyncedPush]);
-
-    messaging.sendMessage({
-        type: 'sync',
-        data: syncData,
-        changesToPushCount: sync_setup.isSyncSetup ? changesToPushCount : 0
-    });
-
-    if (syncData.length > 0) {
-        lastSentSyncId = syncData[syncData.length - 1].id;
-    }
-}
-
-sql.dbReady.then(async () => {
-    lastSentSyncId = await sql.getSingleValue("SELECT MAX(id) FROM sync");
-
-    setInterval(sendPing, 1000);
-});

services/sync.js

@@ -267,7 +267,7 @@ async function checkContentHash(syncContext) {
 
             if (key !== 'recent_notes') {
                 // let's not get alarmed about recent notes which get updated often and can cause failures in race conditions
-                await messaging.sendMessage({type: 'sync-hash-check-failed'});
+                await messaging.sendMessageToAllClients({type: 'sync-hash-check-failed'});
             }
         }
     }

views/index.ejs

@@ -301,7 +301,8 @@
       const baseApiUrl = 'api/';
       const glob = {
           activeDialog: null,
-          sourceId: '<%= sourceId %>'
+          sourceId: '<%= sourceId %>',
+          maxSyncIdAtLoad: <%= maxSyncIdAtLoad %>
       };
     </script>