Rewrite, with Welcome Page and session history

[mbektas]

• Sessions

  • There are two types of sessions: local and remote
  • Local session: Working Directory, files to open (optional)
  • Remote session: Server URL, persistSessionData flag
  • Sessions can be closed and new ones can be created without closing desktop app
  • 

• Welcome Page

  • 
  • Links to create new notebook, launch new JupyterLab session, open files / folders in new session, connect to existing local / remote JupyterLab servers
  • Recent session list with ability to relaunch
  • News on Welcome Page. Using Jupyter Blog feed. Clicking opens in external browser. News are cached, updated at every app launch.
  • Drag and Drop files / folder to open in a new session

• First Launch Screen

• 

• Configuration Changes

  • jupyterlab-desktop-data file removed
  • [USER-DATA-DIR]/app-data.json stores application data and cache (sessions, recent items, news)
  • [USER-DATA-DIR]/settings.json stores user defaults
  • [WORKING-DIRECTORY]/.jupyter/desktop-settings.json (workspace settings) overrides user defaults (e.g. Python path)
  • [WORKING-DIRECTORY]/.jupyter/desktop-workspaces stores workspaces for the working directory
  • Default Working Directory can be set
  • Default Python environment can be set
  • Prettified JSON config files
  • 
  • 

• CLI Changes

  • Specify working directory or Python path to use
  • Open multiple files
  • jlab --help with examples

• Connect to existing JupyterLab Server

  • 
  • Recent connections and locally running JupyterLab servers listed. user can enter new URLs

• Registry

  • Local Python environments are discovered at launch
  • Local JupyterLab servers running are discovered

• Server Status on title bar

  • Remote server status is not clickable anymore. User is expected to close session and connect to new server
  • Local server status clicks shows list of Python environments and allows browsing / specifying a Python path. Selecting new Python env relaunches JupyterLab at the same working directory without relaunching desktop app
  • 

• Startup Mode

  • 
  • Three modes: Show Welcome Page, Start New Session (old behavior), Restore Last Session

• Progress View

  • 
  • Shown during time consuming tasks such as new server launch and also when errors occur
  • Has subtle animation around JupyterLab icon
  • Progress messages shown on view with a title and message lines. They can be in HTML format. Provides sendMessageToMain method to enable action links

• Architectural Changes

  • Major refactoring and rewrite of the code-base
  • Simplification and clean-up
  • Changes towards support for multiple windows/sessions

Tasks

• Architectural redesign
• Separate app state and settings. Introduce workspace (working directory) settings
• Welcome Page
• Open notebook / folder from UI
• Recent session list and ability to reopen
• News feed from Jupyter Blog
• Close session and open new without relaunch
• Default Python env and working directory in Preferences dialog. Default working directory now configurable in UI
• Remote server URL history and autocomplete in UI
• User configurable startup modes: Welcome Page, New Local Session, Restore Last Session
• Cleaner, prettified JSON config files
• Drag - drop support on Welcome Page
• CLI with pythonPath and working directory options
• List and connect to existing local servers
• More user friendly Python env selection on UI using popup. New env applied without app restart. Existing environments are discovered and listed as options
• Progress view and better server launch error handling
• Check for bundled environment updates and update in Preferences dialog
• Refactor session create methods
• Refactoring, cleanup
• Testing

[krassowski]

I was running a version a few commits behind (b6a2795) for few days now and had overall good impressions. Some noticeable annoyances that I saw are:

1. When I start a new session from command line I see:
   
   not sure if this is a me problem or a real bug
2. (major UX) When changing environment using file picker the path is set in the input but then nothing happens. To actually change it I need to focus the input and press enter. It is very un-intuitve as the only button is the folder which opens the file picker dialog again. I think it is sensible to accept the choice upon getting the path from file picker..
3. (annoyance) when I change environment the zoom level is not saved. When I use my very large monitor I have to hit ctrl + shift + plus several times each time which is annoying (also because of Zoom with CTRL+= (equals) no longer works #550).
4. when I change virtual environment the notebooks that I had open do not get re-opened
5. (very minor) it would be a lovely addition if the scrollbar in the env picker was styled in dark mode, this is how it looks for me now:
   

Note: please feel free to move styling suggestions to follow up issues if you don't feel like tacking this, I am just trying to document these at source while we have a fresh memory of the relevant codebase.

[krassowski]

I guess that point (4) was already fixed by 119da42 but have not tested yet.

[krassowski]

Idea: one useful addition to the welcome screen could be a set of links to this repository ("Report a bug"/"Open a feature request"/"Contribute").

[mbektas]

@krassowski thanks for testing. (1) happens when you start another instance of the app. I am working on a fix for that. Regarding (2), there is tooltip with the requirement to hit 'Enter' but I will apply the selected path from file dialog as you suggest. I will look into (3). (4) is fixed in the latest as you guessed. I would like to leave (5) for later. There are other scroll bars (recents list, connect to server list) which might have the same issue.

[mbektas]

Idea: one useful addition to the welcome screen could be a set of links to this repository ("Report a bug"/"Open a feature request"/"Contribute").

I am not too sure about this, it would be better to keep welcome page simple and clean. We could add these links to about dialog.

[mbektas]

@krassowski I couldn't reproduce (3). it worked fine on macOS, Windows and Ubuntu for me. Zoom level persisted event on different sessions and after restart. by the way, I pushed fixes for (1) and (2).

[krassowski]

Some more comments:

• What do you think about adding "open welcome screen" item in the hamburger menu? currently one needs to close current session to get it I think.
• the environment picker/list does not close when clicking on title bar. It is a very minor but I do notice it sometimes.

[krassowski]

It seems that I no longer can open two sessions at once, I get this dialog

this prevents me from working on two projects simultaneously (or even say working on galata tests and jupyterlab/packages in two separate windows which used to be my workflow). This is a serious downgrade for me.

[mbektas]

Some more comments:

• What do you think about adding "open welcome screen" item in the hamburger menu? currently one needs to close current session to get it I think.
• the environment picker/list does not close when clicking on title bar. It is a very minor but I do notice it sometimes.

As you also mentioned in your next comment, currently only single session window is supported. I am planning to add multiple window support in the next release. but I will see if I can include in this PR. I am thinking of adding New Window menu item that opens welcome page in new window. Second instance launches from CLI or file double click would also cause a new window create if all open windows are in a jlab view mode.

You can click on the jlab view or hit Escape to close to Python env list. but I will also make sure title bar clicks hide it as well.

[krassowski]

I am planning to add multiple window support in the next release.

Just FYI, I will be staying with build prior to 1b2b2a8 and possibly apply patches locally as having multiple sessions is a critical feature for me.

I am thinking of adding New Window menu item that opens welcome page in new window.

Sounds like a good idea. FYI, on Ubuntu for example when I click on the icon in the OS launcher it already has a "New Window" option and it already worked like that prior to 1b2b2a8:

[mbektas]

@krassowski hiding the env select popup when titlebar is clicked turned out to be quite complex. It works on macOS but not on Linux / Windows. Since it is a window drag region, mouse events are not being received by the listeners.

I will try multiple window support in another PR but before releasing these changes. it will most likely be relatively easy thanks to this PR, but I have to try and see. This PR makes event handling specific to the SessionWindow, designed for the multiple windows.

By the way, I wouldn't stay before 1b2b2a8 . Because multiple instances would modify the shared app-data.json and settings.json files which may cause issues.