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/
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.
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.
$ 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.