Generate instanceId and include in hash for cache busting

packages/node_modules/@node-red/editor-api/lib/editor/index.js

@@ -51,7 +51,7 @@ module.exports = {
 
             var ui = require("./ui");
 
-            ui.init(runtimeAPI);
+            ui.init(settings, runtimeAPI);
 
             const editorApp = apiUtil.createExpressApp(settings)
 

packages/node_modules/@node-red/editor-api/lib/editor/ui.js

@@ -25,15 +25,16 @@ var apiUtils = require("../util");
 var theme = require("./theme");
 
 var runtimeAPI;
+let settings;
 var editorClientDir = path.dirname(require.resolve("@node-red/editor-client"));
 var defaultNodeIcon = path.join(editorClientDir,"public","red","images","icons","arrow-in.svg");
 var editorTemplatePath = path.join(editorClientDir,"templates","index.mst");
 var editorTemplate;
-const version = require(path.join(editorClientDir,"package.json")).version
+let cacheBuster
-const cacheBuster = crypto.createHash('md5').update(version).digest("hex").substring(0,12)
 
 module.exports = {
-    init: function(_runtimeAPI) {
+    init: function(_settings, _runtimeAPI) {
+        settings = _settings;
         runtimeAPI = _runtimeAPI;
         editorTemplate = fs.readFileSync(editorTemplatePath,"utf8");
         Mustache.parse(editorTemplate);
@@ -94,6 +95,12 @@ module.exports = {
     },
 
     editor: async function(req,res) {
+        if (!cacheBuster) {
+            // settings.instanceId is set asynchronously to the editor-api
+            // being initiaised. So we defer calculating the cacheBuster hash
+            // until the first load of the editor
+            cacheBuster = crypto.createHash('md5').update(`${settings.version || 'version'}-${settings.instanceId || 'instanceId'}`).digest("hex").substring(0,12)    
+        }
 
         let sessionMessages;
         if (req.session && req.session.messages) {

packages/node_modules/@node-red/runtime/lib/index.js

@@ -27,6 +27,7 @@ var express = require("express");
 var path = require('path');
 var fs = require("fs");
 var os = require("os");
+const crypto = require("crypto")
 
 const {log,i18n,events,exec,util,hooks} = require("@node-red/util");
 
@@ -51,7 +52,7 @@ var adminApi = {
 var nodeApp;
 var adminApp;
 var server;
-
+let userSettings;
 
 /**
  * Initialise the runtime module.
@@ -61,8 +62,9 @@ var server;
  *                              better abstracted.
  * @memberof @node-red/runtime
  */
-function init(userSettings,httpServer,_adminApi) {
+function init(_userSettings,httpServer,_adminApi) {
     server = httpServer;
+    userSettings = _userSettings
 
     if (server && server.on) {
         // Add a listener to the upgrade event so that we can properly timeout connection
@@ -134,7 +136,10 @@ function start() {
         .then(function() { return settings.load(storage)})
         .then(function() { return library.init(runtime)})
         .then(function() {
-
+            if (settings.get('instanceId') === undefined) {
+                settings.set('instanceId', crypto.randomBytes(8).toString('hex'))
+            }
+            userSettings.instanceId = settings.get('instanceId') || ''
             if (log.metric()) {
                 runtimeMetricInterval = setInterval(function() {
                     reportMetrics();

test/unit/@node-red/editor-api/lib/editor/ui_spec.js

@@ -29,7 +29,7 @@ describe("api/editor/ui", function() {
     var app;
 
     before(function() {
-        ui.init({
+        ui.init({}, {
             nodes: {
                 getIcon: function(opts) {
                     return new Promise(function(resolve,reject) {