Developers Continue New Push With LibreOffice In The Web Browser Via WebAssembly

While there has been LibreOffice Online as a collaborative, web-based version of LibreOffice making use of the HTML5 Canvas for its UI, there hasn't been much activity there recently outside of the Collabora Online commercial variant. But developers are working on a current port of LibreOffice to the web browser using WebAssembly.

Developers Thorsten Behrens and Jan-Marek Glogowski presented at last weekend's FOSDEM Online 2021 on the work being done to port LibreOffice to work gracefully with WebAssembly for running the open-source office suite within the web browser.

Compared to the current LibreOffice Online / Collabora Online, the WebAssembly version would still be browser contained but allow more work to happen on the client rather than most of the work happening server-side. Running the current online office suite can also be costly, complexities in scaling, etc. Compiling LibreOffice with WebAssembly was looked at many years ago when WASM was in its infancy but now they are making progress with the modern code-base of LibreOffice and WASM.

Today's WebAssembly support across browsers is in much better shape and can handle much more, making LibreOffice WASM more feasible but still not trivial. Threading within WebAssembly has its own set of challenges and file / address space limits are among the issues being overcome. They have been able to build all of the code but not all of it runs yet within WASM environments and their initial focus has been just on LibreOffice Writer for documents.

Currently the LibreOffice WebAssembly port is working and performing the best within Google Chrome/Chromium. Developers are hoping by this summer to have LibreOffice Writer working more within the browser and to be rendered on an HTML5 Canvas interactively. The goal by autumn is to have a demo in place that also supports end-to-end encrypted editing -- another benefit not currently supported by LibreOffice Online.

Those curious about LibreOffice WebAssembly porting in 2021 can see this slide deck (PDF) going over the current status and challenges. Other LibreOffice talks from FOSDEM 2021 can be seen at FOSDEM.org.