Building HTML5 User Interfaces
with Franca for IoT devices

Tamas Szabo and Klaus Birken
itemis AG

Eclipse DemoCamp Luna, Stuttgart


  1. Franca Overview
  2. Internet of Things
  3. Franca/IoT showcase
  4. Demo
  5. Summary and next steps

Franca Overview


  • is a tool environment for definition and transformation of software interfaces
  • has been designed to facilitate software and system integration
  • is running on the Eclipse platform
  • is an open-source project hosted on Eclipse Labs since early 2012
  • has been proposed as an official Eclipse Project

A brief history of Franca

Franca feature overview

An example interface definition

Architecture of product with HTML5 UI

HTML5 UI connected to (embedded) application component(s).

HTML5 UI supported by Franca

  • Idea: Generate JS and C++ bindings from Franca interface
  • UI and application do not have to care about communication details.
  • Client: HTML5, CSS and JS
  • Server 1: Node.js and JS
  • Server 2: CommonAPI and C++
  • Server 3: ...

Using WebSockets for IPC

  • WebSockets is a standard (IETF RFC 6455)
  • bidirectional, low-latency, message-based
  • quite low-level, only provides raw messaging

Using WAMP as a standard protocol

  • WebSocket Application Messaging Protocol
  • officially registered WebSocket subprotocol
  • higher level messaging patterns: RPC and publish/subscribe
  • uses WebSockets, JSON and URIs

HTML5 UI with Franca: Comm. Stack

Architecture. The yellow layer is generated from Franca interfaces.

Benefits of using Franca for HTML5 UI

  • Clear, reusable interface definitions
  • Easy-to-use generated APIs
  • Multi-modal UI support (e.g., Speech, Gestures)
  • Flexible server implementation (incl. remote)
  • Additional tools can be used (e.g. contracts)

Internet of Things

Internet of Things

  • Let's connect all different kinds of things together within the Internet
  • Not just laptops and mobile phones, but all kinds of sensors and devices
  • Advanced connectivity of devices, more than simple M2M communication


  • Message Queue Telemetry Transport
  • Publish-subscribe based messaging protocol
  • Light-weight (small message overhead)
  • Based on the TCP/IP protocol
  • Various QoS for message delivery (at least once, at most once, exactly once)
  • Designed to be usable in constrained environments
  • Mosquitto: Message broker implementation
  • Open-source Eclipse project
  • MQTT Client implementation
  • Various languages (JS, Java, C/C++, Lua)

Franca/IoT showcase

The Franca/IoT showcase

  • Robot arm as IoT device
    • access via MQTT topics
  • HTML5 user interface for controlling the robot arm
    • direct control, and
    • example high-level application
  • Franca
    • define interfaces between UI and application
    • generate code for WebSocket communication

Showcase architecture


Summary and next steps

Final points

  • Benefits of using Franca
    • application logic could be designed independently from implementation
    • part of the implementation could be generated automatically
    • eases the integration of components from different domains, e.g., UI and IoT (1h in our case)
  • Future work
    • automatic generation of Franca/MQTT connector
    • add more IoT devices to the example (sensors, ...)


Thanks for your attention!