Keep embedded app URL stable as initial runtime state arrives

neode-ui/src/views/appSession/__tests__/stableAppUrl.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from 'vitest'
+import { computed, ref, watch, nextTick } from 'vue'
+import { canonicalAppUrl } from '../appSessionConfig'
+
+describe('stable app iframe URL', () => {
+  it('does not replace the iframe source when runtime discovery adds only a root slash', async () => {
+    const reported = ref('http://node.test:7778')
+    const frameUrl = computed(() => canonicalAppUrl(reported.value))
+    let changes = 0
+    const stop = watch(frameUrl, () => { changes++ })
+    expect(frameUrl.value).toBe('http://node.test:7778/')
+    reported.value = 'http://node.test:7778/'
+    await nextTick()
+    expect(changes).toBe(0)
+    reported.value = 'http://node.test:7778/project/demo'
+    await nextTick()
+    expect(changes).toBe(1)
+    stop()
+  })
+  it('preserves deep paths, query strings and fragments', () => {
+    expect(canonicalAppUrl('https://node.test:7778/project/demo?view=preview#player'))
+      .toBe('https://node.test:7778/project/demo?view=preview#player')
+  })
+  it('keeps an absent app URL absent instead of opening the dashboard inside itself', () => {
+    expect(canonicalAppUrl('')).toBe('')
+  })
+})

neode-ui/src/views/appSession/appSessionConfig.ts

@@ -119,6 +119,12 @@ export const HOST_FRAME_APPS = new Set([
 /** Sites known to block iframes -- skip the timeout and go straight to fallback */
 export const IFRAME_BLOCKED_APPS = new Set<string>([])
 
+/** Stable iframe src while the initial runtime state replaces the fallback URL. */
+export function canonicalAppUrl(url: string): string {
+  if (!url) return ''
+  try { return new URL(url, window.location.origin).href } catch { return url }
+}
+
 /** Resolve app URL using direct port mapping (source of truth) */
 export function resolveAppUrl(id: string, routeQueryPath?: string, runtimeUrl?: string): string {
   // Demo: route to the app's mock UI or real external site (mempool.space,