Implement Metastream as a web app

[samuelmaddock]

Metastream is in the process of deprecating the Electron desktop app in favor of a web app with a required browser extension. See post on Patreon for details regarding reasons for this change.

In-development preview available at https://app.getmetastream.com/

Todo

• Compile Metastream for browsers
• Host using GitHub pages
  • Work-in-progress preview available for testing at https://app.getmetastream.com/
• Publish browser extension on Chrome Web Store
  • Published as Metastream Remote
• Publish browser extension on Firefox Add-on Store
  • Published as Metastream Remote
• Re-implement subset of Electron's <webview> features with web extension messaging
  • This is already mostly functioning, needs some more work around history state management
• Re-implement user identities with libsodium
• Implement WebRTC signaling server and client for multiplayer sessions
• Authenticate peers
• Host backend services
  • Dockerize signal server
  • LetsEncrypt certs for wss://
  • Setup WebRTC TURN server for relaying failed P2P connections (fixes P2P connectivity issues #74)
• Add support for site-specific scripts in extension
• Cache bust service worker offline content
• Network error handling
  • Implement exponential backoff for host reconnecting to signal server
• App update button
• Install to desktop main menu button
• Update git documentation, merge webapp branch
• Support pasting session URL into join page
• Change /lobby/:id routes to /join/:id
• BUG: Chat box extends past bounds in Firefox
• Public network testing
• Change website download buttons to launch web app
• Publish final update to Electron app with deprecation notice
• Update browser extension description on stores

Post-launch

• Show error when session already exists in another tab
• Bind global media playback hotkeys
• Request current tab URL in Metastream when clicking extension badge
• Redesign title bar? 🤔
• Add manual method of connecting to peer in case signal server is down 🤔

---

Features gained

• Metastream can be installed as a desktop app by implementing it as a Progressive Web App
• Better browser security (fixes Improve browser security #1)

Features lost

• Discord Rich Presence support
  • Includes custom avatars via Discord
• Distributed signalling solution (swarm-peer-server) for WebRTC connections
• Direct IP connections
  • Will likely be replaced by a dedicated server solution eventually
• Automatic fullscreening of videos that don't fill the app's viewport
  • I have some ideas for this, but it won't fully work for videos nested in an <iframe>

[cedws]

I can see this architecture being less flexible, but overall it seems like the right way to go. Massive thanks for your hard work that's going into this. I promise I'll send a few bucks your way at some point.