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DejaOS Host Demo

DejaOS Host Demo is a lightweight, visual host application for DejaOS devices. It presents an app-launcher experience similar to a simplified mobile operating system: the device can configure its network and backend service, discover micro apps, install or remove them at runtime, and launch them from the home screen without restarting the Host application.

Built with Codex and the DejaOS Skill

The entire demo—including the device application, micro-app runtime, Node.js backend, browser management UI, sample micro apps, and supporting documentation—was implemented with Codex together with the DejaOS dejaos-app-dev-sdk2-0 Skill.

The Skill supplied DejaOS SDK 2.0 development guidance for worker boundaries, dxUi, dxEventBus, dxHttpClient, runtime resources, and embedded-device constraints, while Codex applied that guidance to build and validate the complete workflow.

Demo Screenshots​

Device Host and App Management​

Home ScreenApps Available from the Server
DejaOS Host home screenAvailable micro apps
Installed Apps on the Home ScreenInstalled App Management
Installed apps on the Host home screenInstalled micro-app list

Network Configuration​

EthernetWi-Fi
Ethernet configurationWi-Fi configuration

Both Ethernet and Wi-Fi support DHCP and static IP settings. Static configuration includes IP address, subnet mask, gateway, and DNS.

Runtime Micro Apps​

HTTP WeatherQuick NotesCalendar
HTTP Weather micro appNotes micro appCalendar micro app

Browser Management and Online Development​

DejaOS Host micro-app management page

The management page creates and publishes micro apps, tracks draft and published versions, and provides package downloads.

Online micro-app code editor

The prototype editor supports app.js, manifest.json, app metadata, visibility, version management, and custom 40×40 PNG icons.

Browse every device and management screenshot in the screenshot directory.

End-to-End Workflow​

  1. Create a micro app in the browser management UI.
  2. Edit its JavaScript, manifest, metadata, and icon, then publish a version.
  3. Configure the App Service address on the DejaOS Host device.
  4. The device obtains the published catalog through dxHttpClient.
  5. Select Install to download the package into /app/data/dejaos_host/apps/.
  6. The Host loads the entry script dynamically with dxStd.loadScript; no static import or Host restart is required.
  7. Open the new icon from the home screen. Remove it from App Manager or by pressing and holding its home-screen icon.

This validates the complete prototype path from online development and publication to device download, dynamic loading, execution, and removal.

Main Features​

  • Host-style launcher: A 480×854 device home screen with system tools and dynamically installed micro-app icons.
  • Network setup: Ethernet and Wi-Fi, with DHCP or static IP configuration and a connection timeout flow.
  • App Service configuration: Configure the backend by IP address, domain name, port, or complete URL.
  • Runtime installation and removal: Install, load, unload, and remove micro apps without restarting the device or Host application.
  • Custom app icons: Upload any PNG in the management UI and crop/resize it to the required 40×40 format.
  • Online development: Edit application code and metadata, save drafts, publish versions, and download packages.
  • Sample micro apps: Live weather through the backend's Open-Meteo proxy, local notes, and calendar views.
  • Time synchronization: Update the device status-bar time through the backend time API after networking succeeds.
  • Screenshot upload: Double-tap the blank center of a page's status bar to capture the screen and upload the PNG to the backend.

Architecture​

The demo contains three cooperating parts:

  • Device application (app/): A DejaOS SDK 2.0 project. The main worker starts a dedicated UI worker and network worker. Pages are managed by UIManager; cross-worker messages use dxEventBus.
  • Management UI (web/): A framework-free HTML, CSS, and JavaScript application for creating, editing, publishing, and downloading micro apps.
  • Backend (webapi/): A Node.js 20+ service using built-in modules only. It serves the management UI, app catalog and packages, time and weather APIs, and screenshot uploads.

Important Device Files​

  • app/src/main.js: Starts the Host workers.
  • app/src/uiWorker.js: Initializes dxUi, page routing, overlays, and the UI event loop.
  • app/src/networkWorker.js: Owns device networking, HTTP catalog/package operations, time sync, micro-app service requests, and screenshot uploads.
  • app/src/UIManager.js: Manages the single-screen page stack and shared fonts.
  • app/src/services/MicroAppLoader.js: Loads and unloads installed micro-app scripts dynamically.
  • app/src/services/AppRegistry.js: Maintains remote and installed app metadata.
  • app/src/pages/: Home, settings, network, App Service, App Manager, and micro-app host pages.

Source Code​

The complete source code is available here: DejaOS repository · apps/features/dejaos_host

The DejaOS development Skill used to build the entire demo is available here: DejaOS repository · skills/dejaos-app-dev-sdk2-0

Running the Prototype​

  1. Start the backend from webapi/ with npm start (Node.js 20 or later).
  2. Open http://localhost:8080/ to access the management UI.
  3. Deploy the app/ project to a compatible DejaOS SDK 2.0 device.
  4. Configure network access and set the device's App Service address to the backend URL.
  5. Publish a micro app in the browser, refresh the device catalog, and install it.

Prototype note: This demo focuses on validating the complete development-to-device workflow. Production authentication, device ownership, package signing, application isolation, debugging, and a formal micro-app SDK are intentionally outside its current scope.