Replace Electron with PyWebview for Endless Key App

[starnight]

We have:

• Tested a simple pywebview application on Windows in EK Windows app: Test pywebview as the frontend. It works and reduces a lot of size (about 100 MB) by using the native webview from system.
• Directed the simple pywebview application browsing https://key.endlessos.org in Prototype moving the front-end of Endless Key app (Windows) from Electron to pywebview.
  • We notice Webview2 used by PyWebview on Windows can render PDF files with NVIDIA card correctly. However, current Endless Key app uses the webview provided by Electron, but hits PDF files are not well presented on Aspire A514-55G eqiupped with NVIDIA card.
  • The main Python is the main process. The Webview2 used by PyWebview will be the sub-process browsing a web page. So, that avoids Python's GIL issue between the Python application and the Webview2.

More benefits:

• Webview2 is the native webview from Windows. It has better compatibility with the hardware resource provided by the system.
• PyWebview is a Python library briding between Python application and native webview from system. The dependency can be set in the Pipfile directly, just like other Python package. Then, we can drop node.js and Electron which reduces maintenance and CI complexity.

The original Endless Key app is executed by running kolibri-electron, which is an Electron app.

1. Show the maximized webview window and browsing kolibri_explore_plugin's welcomeScreen.
2. Check KOLIBRI_HOME is created, or not.
   • If not, then this is a fresh run. Show WelcomeApp.showWelcome(). Then, choose the content from USB, or download from server. Here goes another code branch first. More ...
   • If yes, then check it should read content from Endless USB key, or not.
   • If not, ask user plug Endless USB key
   • If yes, next step.
3. Run kolibri server at backend. But, frontend has to wait kolibri server up.
4. If kolibri server is ready, then change frontend to Kolibri's explore. Finally, frontend works with kolibri server.

Here lists some key tech for transferring to PyWebview:

• IPC bewteen frontend and Python application: PyWebview's Javascript API
• Change webview's browsing URL: PyWebview's Change URL
• Ask webview execute js from Python: PyWebview's API evaluate_js
• HTTP client request: https://docs.python.org/3/library/http.client.html

[starnight]

Prototype the happy path without USB feature (2 weeks)

This could be tracked in Prototype moving the front-end of Endless Key app (Windows) from Electron to pywebview

• Set up kolibri with kolibri-explore-plugin and collection environment locally.
• PyWebview browsing kolibri_explore_plugin's welcomeScreen
• Gather environment variables for running Kolibri backend
• Assume this is a fresh run. Show WelcomeApp.showWelcome(). And, run kolibri server at backend with another thread.

Check KOLIBRI_HOME is created (2 days)

This follows previous prototype. With this feature, no more download action if KOLIBRI_HOME is created.

Add Endless USB key feature (1 week)

• Require Endless USB key?
• Detect USB state changes
• Integrate the USB features into prepare running Kolibri backend process

Integrate CI (3 days)

This is more related to build and packaging

[starnight]

Thanks to:

• 145

• endlessm/kolibri-explore-plugin/issues/748

The porting becomes simpler.

PR #161 is ready for review now.

[erikos]

Testing results are looking very promising for this one. I was able to use the app fine in Windows 11, using the build artifact.

[manuq]

This is ready to be deployed.

[vanessa-chang]

Verified Passed in Windows 7.8.3.0