.. _webusb-sample:

WebUSB sample application
#########################

For a deeper dive into the WebUSB, refer to
https://github.com/WICG/webusb/blob/gh-pages/explainer.md

WebUSB API Specification:
https://wicg.github.io/webusb/

Sample Overview
***************

This simple echo application demonstrates the WebUSB enabled custom
class driver.

This application receives the data and echoed back to the WebUSB
based web application (web page) running in the browser at host.

This application is intended for testing purposes only. For running
real usecase, implement applications based on the WebUSB API.

Building and flashing
*********************

Refer to :ref:`arduino_101`
for details on building and flashing the image into an Arduino 101.

Testing with latest Google Chrome on host
*****************************************

This sample application requires latest Google Chrome, a web page
based on WebUSB API to connect to the USB device and http server
running on localhost to serve the web page.

WebUSB is a powerful new feature added to the Web and it is available
only to secure origins. This means the web page/site that used to
connect to the device must be served over a secure connection (HTTPS).

For testing and development purposes, there is a flag in Chrome
(--disable-webusb-security) that disables this CORS-like checks for
origins and allow any origin to ask the user for permission to connect
to a device. So, we use this flag to interact with the device through
http://localhost by starting up http server on host and serving the
web page.

Follow these steps to run the demo on your host system:

#. Run the latest Google Chrome on host.

#. If needed Enable "Experimental Web Platform Features" flag in
   chrome://flags/#enable-experimental-web-platform-features.

#. If needed Run chrome with the --disable-webusb-security switch to disable
   WebUSB's CORS-like checks for origin device communication.

#. Implement a web app (web page) using WebUSB API and run
   it on localhost.

   See the sample at https://github.com/finikorg/webusb-serial

   This sample web page demonstrate how to create and use a WebUSB
   interface, as well as demonstrate the communication between browser
   and WebUSB enabled device.

   To host the demo page locally: Clone the repo and start a web server
   in the appropriate directory.

   .. code-block:: console

      $ python -m http.server

#. Connect the board to your host.

#. Once the device is booted, you should see a notification from
   Chrome: "Go to localhost to connect.". Click on the notification
   to open demo page.

#. Click on Connect button to connect to the device.

#. Send some text to the device by clicking on the Send button. The demo app
   will receive the same text from the device and display it in the textarea.