modernize the html5 client

[totaam]

The code is old and ugly.
We should take advantage of modern browser technologies to cleanup the code.

[totaam]

Some useful pointers:

• How to Modernize Your Old ES5 Codebase Effortlessly?
• Migrating a 10,000-line legacy JavaScript codebase to TypeScript
• Choosing BetweenTypeScript vs JavaScript: Technology, Popularity

Other html5 tickets worth looking into:

• html5 client: webcam and microphone support #27 webcam and microphone support
• html5 video support enabled by default #25 html5 video support enabled by default
• html5 support for rencode #18 / handle bytes with rencode #84 rencode
• html5 sound delay #23 sound delay
• html5 native notifications api #19 native notifications api
• html toolbar improvements #90 toolbar

[totaam]

I'm not getting any help on this, and I still firmly believe that JavaScript is an awful language.
So don't expect miracles.

[totaam]

2019-08-20 12:45:15: Praecantatio commented

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All is not yet lost: there are two forks with potential:

https://github.com/andersevenrud/xpra-html5-client

https://github.com/sagemathinc/cocalc/blob/master/src/smc-webapp/frame-editors/x11-editor/xpra/README.md

For even greater performance and speed, might want to consider WASM and WebRTC

[totaam]

For even greater performance and speed, might want to consider WASM and WebRTC

FWIW:

• wasm already in use where it is useful: h264 decoding via broadway
• webrtc: hell no!

[totaam]

2020-02-19 18:28:07: Praecantatio commented

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Why not WebRTC?

[totaam]

Why not WebRTC?

Maybe one day: Xpra-org/xpra#1338
WebTransport is a much better fit: #143

[totaam]

Not sure this qualifies as modernizing, but switching to https://github.com/Benzinga/lz4js for lz4 greatly simplifies the codebase. From 7000 lines of unreadable JS to just 750.
I merged the 3 separate files by hand to avoid the requirejs mess: we don't want asynchronous loading and the whole define function incompatibility problems that spring up everywhere because of it.
And I added a utility decode function to simplify calling into lz4 since we only use it for decompressing packets with the size header.