Allow App Launch When Offline or Unable to Connect to Node-RED

ui/src/App.vue

@@ -1,6 +1,27 @@
 <template>
     <v-app>
-        <div v-if="loading" class="nrdb-splash-loading">
+        <div v-if="error" class="nrdb-placeholder-container">
+            <div class="nrdb-placeholder">
+                <img src="./assets/logo.png">
+                <h1>Node-RED Dashboard 2.0</h1>
+                <img src="./assets/disconnected.png">
+                <!-- eslint-disable-next-line vue/no-v-html -->
+                <p :class="'status-warning'" v-html="error.message" />
+                <br>
+                <h4>What you can try:</h4>
+                <div v-if="error.type === 'server unreachable'" style="border: none" class="nrdb-placeholder">
+                    <v-btn rounded @click="reloadApp">
+                        Reload App
+                    </v-btn>
+                </div>
+                <div v-else-if="error.type === 'no internet'" style="border: none" class="nrdb-placeholder">
+                    <v-btn rounded @click="reloadApp">
+                        Reload App
+                    </v-btn>
+                </div>
+            </div>
+        </div>
+        <div v-else-if="loading" class="nrdb-splash-loading">
             <DashboardLoading />
             Loading...
         </div>
@@ -43,7 +64,8 @@ export default {
     },
     computed: {
         ...mapState('ui', ['dashboards', 'pages', 'widgets']),
-        ...mapState('setup', ['setup']),
+        ...mapState('setup', ['setup', 'error']),
+
         status: function () {
             if (this.dashboards) {
                 const dashboards = Object.keys(this.dashboards)
@@ -223,6 +245,15 @@ export default {
             this.$store.commit('ui/groups', payload.groups)
             this.$store.commit('ui/widgets', payload.widgets)
             this.$store.commit('ui/themes', payload.themes)
+
+            for (const key in payload.themes) {
+                // check if "Default Theme" theme exists
+                if (payload.themes[key].name === 'Default Theme') {
+                    // store the default theme in local storage for use when disconnected from Node-RED
+                    localStorage.setItem('ndrb-theme-default', JSON.stringify(payload.themes[key]))
+                    break
+                }
+            }
         })
     },
     methods: {
@@ -233,6 +264,9 @@ export default {
             this.$router.push({
                 name
             })
+        },
+        reloadApp () {
+            location.reload()
         }
     }
 }

ui/src/main.mjs

@@ -26,18 +26,30 @@ import './stylesheets/common.css'
 import store from './store/index.mjs'
 import { useDataTracker } from './widgets/data-tracker.mjs' // eslint-disable-line import/order
 
-// set a base theme on which we will add our custom NR-defined theme
+// Retrieve the "Default" theme from cache
+function retrieveDefaultThemeFromCache () {
+    const cachedTheme = localStorage.getItem('ndrb-theme-default')
+    if (cachedTheme) {
+        return JSON.parse(cachedTheme)
+    }
+    return null
+}
+
+const defaultTheme = retrieveDefaultThemeFromCache()
+
+// set a base theme on which we will add our custom NR-defined theme (initially set to the default theme if exists in cache)
 const theme = {
     dark: false,
     colors: {
-        background: '#fff',
-        'navigation-background': '#ffffff',
-        'group-background': '#ffffff',
-        primary: '#0000ff',
+        background: defaultTheme ? defaultTheme.colors.bgPage : '#fff',
+        'navigation-background': defaultTheme ? defaultTheme.colors.surface : '#ffffff',
+        'group-background': defaultTheme ? defaultTheme.colors.groupBg : '#ffffff',
+        'group-outline': defaultTheme ? defaultTheme.colors.groupOutline : '#d1d1d1',
+        primary: defaultTheme ? defaultTheme.colors.primary : '#0094CE',
         accent: '#ff6b99',
         secondary: '#26ff8c',
         success: '#a5d64c',
-        surface: '#ffffff',
+        surface: defaultTheme ? defaultTheme.colors.surface : '#ffffff',
         info: '#ff53d0',
         warning: '#ff8e00',
         error: '#ff5252'
@@ -97,7 +109,7 @@ fetch('_setup')
             return
         case !response.ok:
             console.error('Failed to fetch setup data:', response)
-            return
+            throw new Error('Failed to fetch setup data:', response)
         case host.origin !== new URL(response.url).origin: {
             console.log('Following redirect:', response.url)
             const url = new URL(response.url)
@@ -257,10 +269,37 @@ fetch('_setup')
         app.mount('#app')
     })
     .catch((err) => {
-        if (err instanceof TypeError && err.message === 'Failed to fetch') {
-            forcePageReload(err)
+        function handleOnline () {
+            // remove the online event listener and reload the page
+            window.removeEventListener('online', handleOnline)
+            location.reload()
+        }
+
+        let error = {}
+        if (navigator.onLine) {
+            error = { error: err, type: 'server unreachable', message: 'There was an error loading the Dashboard.' }
+            // Add timer to reload the page every 20 seconds
+            setInterval(() => {
+                location.reload()
+            }, 20000)
         } else {
-            // handle general errors here
-            console.error('An error occurred:', err)
+            error = { error: err, type: 'no internet', message: 'Your device appears to be offline.' }
+            // Add event listener
+            window.addEventListener('online', handleOnline)
         }
+
+        store.commit('setup/setError', error) // pass the error to the Vuex store
+
+        // load minimal VueJS app to display error message and options to user
+        const app = Vue.createApp(App)
+            .use(store)
+            .use(vuetify)
+            .use(router)
+
+        const head = createHead()
+        app.use(head)
+        app.mixin(VueHeadMixin)
+
+        // mount the VueJS app into <div id="app"></div> in /ui/public/index.html
+        app.mount('#app')
     })

ui/src/store/setup.mjs

@@ -1,12 +1,16 @@
 // initial state
 const state = () => ({
-    setup: null
+    setup: null,
+    error: null
 })
 
 const mutations = {
     set (state, setup) {
         console.log('setup', setup)
         state.setup = setup
+    },
+    setError (state, error) {
+        state.error = error
     }
 }
 

ui/src/stylesheets/common.css

@@ -83,7 +83,7 @@ main {
     display: flex;
     align-items: center;
     justify-content: center;
-    background-color: #eee;
+    background-color: rgb(var(--v-theme-background, 238, 238, 238)); /* Fallback to light gray (#eee) */
 }
 
 .nrdb-placeholder {
@@ -92,12 +92,13 @@ main {
     flex-direction: column;
     align-items: center;
     justify-content: center;
-    color: #222;
     text-align: center;
     padding: 1.5rem 2rem;
-    border-radius: 6px;
-    border: 1px solid #d1d1d1;
-    background-color: #fff;
+    margin: 1rem;
+    border-radius: var(--group-border-radius, 6px);
+    border: 1px solid rgb(var(--v-theme-group-outline, 209, 209, 209)); /* Fallback to light gray (#d1d1d1) */
+    color: rgb(var(--v-theme-on-group-background, 34, 34, 34)); /* Fallback to dark gray (#222) */ 
+    background-color: rgb(var(--v-theme-group-background, 255, 255, 255)); /* Fallback to white (#fff) */
 }
 
 .nrdb-placeholder img {
@@ -119,7 +120,7 @@ main {
 
 .nrdb-placeholder .status-duplicates {
     font-weight: 400;
-    color: #222;
+    color: rgb(var(--v-theme-on-surface, 34, 34, 34)); /* Fallback to dark gray (#222) */
     margin-top: 0.5rem;
 }