This project demonstrates a workaround for Firefox's lack of WebUSB support by leveraging its native messaging capabilities. A small native application acts as a bridge, receiving commands from a web page via native messaging and interacting directly with USB devices. The web page communicates with this intermediary application using a custom, WebUSB-like JavaScript API, effectively emulating WebUSB functionality within Firefox. This allows web developers to write code that interacts with USB devices in a consistent manner across browsers, handling the Firefox difference behind the scenes.
This GitHub project, "I-can't-believe-it's-not-WebUSB," addresses the frustration of Firefox users who want to interact with USB devices directly from web pages but are hampered by the browser's lack of WebUSB support. The project implements a workaround, not a true implementation of WebUSB, by leveraging Firefox's existing support for the serial API. Essentially, it acts as a bridge between a web page and a connected USB device.
The core functionality revolves around a native messaging host application. This small program, written in Python, runs outside the browser and has direct access to the system's USB devices. On the web page side, a JavaScript library communicates with this native host using the browser's native messaging capabilities. When a web page needs to interact with a USB device, the JavaScript library formats the request and sends it as a message to the native host.
The native host receives this message, parses the requested action, and then uses the pyusb library in Python to carry out the interaction with the specified USB device. The result of this interaction, whether it's data read from the device or a confirmation of a write operation, is then packaged into a response message and sent back to the JavaScript library in the browser. The library then makes this data available to the web page.
This setup effectively circumvents the absence of WebUSB in Firefox. While it doesn't offer the same level of integration or security as a native WebUSB implementation, it provides a functional alternative for developers who need to access USB devices from Firefox. The project focuses specifically on USB CDC-ACM devices (Communication Device Class - Abstract Control Model), which are commonly used for serial communication, essentially treating the USB device as a virtual serial port. Therefore, its applicability is primarily for devices that use this communication standard. The reliance on a separate native host application adds a layer of complexity compared to the seamless experience offered by WebUSB in supporting browsers, but provides a practical, albeit somewhat cumbersome, solution for interacting with USB devices from Firefox.
Summary of Comments ( 98 )
https://news.ycombinator.com/item?id=43360642
Hacker News commenters generally expressed frustration with Firefox's lack of WebUSB support, echoing the author's sentiments. Some pointed out that the Mozilla Developer Network (MDN) documentation misleadingly suggests WebUSB is supported, while others shared workarounds and alternative solutions, including using Chrome or a native messaging host. A few commenters questioned the security implications of granting websites access to USB devices, highlighting potential vulnerabilities. The complexity of adding WebUSB support in Firefox was also discussed, citing issues like sandboxing and driver interaction as potential roadblocks. One commenter offered a personal anecdote about the challenges of debugging WebUSB issues due to inconsistent browser implementations.
The Hacker News post "I-cant-believe-its-not-webusb: Hacking around lack of WebUSB support in Firefox" has generated a moderate discussion with several insightful comments focusing on the workaround presented, the complexities of WebUSB implementation, and potential security concerns.
One commenter points out the inherent irony and difficulty of making this kind of workaround secure. They highlight the potential for abuse if a malicious webpage could hijack the native messaging host, essentially defeating the purpose of the security sandbox. This comment raises a critical issue with the approach, suggesting that despite the cleverness, the security implications might outweigh the benefits.
Another user discusses the intricacies of WebUSB support and speculates on the reasons behind Firefox's decision not to fully implement it. They mention that WebUSB requires significant effort to implement securely and maintain, possibly posing challenges for browser vendors. They also touch upon the limitations of the workaround, particularly regarding access to isochronous endpoints which are crucial for certain USB devices like audio interfaces. This comment offers valuable context for understanding the technical hurdles involved in WebUSB implementation.
A different comment highlights the lack of detailed error messages in WebUSB, making debugging difficult for developers. This practical observation emphasizes the challenges faced by those working with WebUSB and hoping to integrate it into their applications.
One commenter also explores alternative approaches for cross-browser USB device access. They suggest WebHID and Web Serial as potentially viable options depending on the specific use case, offering practical alternatives to WebUSB.
Finally, a participant expresses their support for projects like this that attempt to bridge the gap in functionality between different browsers. They acknowledge the inherent challenges in maintaining such workarounds but appreciate the effort to provide a more unified experience for web developers.
In summary, the discussion revolves around the practicality, security implications, and technical challenges associated with the proposed WebUSB workaround. Commenters acknowledge the cleverness of the approach while also raising important concerns about its long-term viability and security. They offer alternative solutions and insights into the complexities of WebUSB implementation, providing a balanced perspective on the topic.