Use memoryStorageDriver

[agriyakhetarpal]

I think it is time now that we do this. This PR sets the storage to memoryStorageDriver (in-memory, non-persistent). Files uploaded to the Files widget and notebooks will not retain data if saved beforehand when reloaded because enableMemoryStorage is also true.

Reference: https://jupyterlite.readthedocs.io/en/latest/howto/configure/storage.html

[agriyakhetarpal]

On second thought: we should exercise caution before merging this, as the mere act of reloading the page will cause users to lose all their code – we want to avoid this in any scenario. One way to mitigate this issue is by resolving #104, which involves sharing the notebook and generating a shareable URL on initial load (which should be better handled after merging #192). We also need to ensure that the shareable link is always included in the URL. The shareable link is also present in view-only notebooks, so we should be checking for a token that allows editing the notebook. To achieve this, we will require #105, and we should securely store the sharing service token in the browser.

Current scenario

• User X authors a notebook
• They accidentally reload the page
• Their code and the sharing service token are lost

Expected scenario

• User X authors a notebook (they authenticate with the sharing service, and we automatically save the notebook right from the start, creating a shareable URL linked to the token)
• We securely store User X's sharing service authentication token in the browser
• We append the shareable ID to the URL
• If User X reloads the page, the notebook won't be present in the browser's storage (due to non-persistent storage), so we look for a saved sharing service token in the browser and load the page with the shareable URL (as the shareable ID will be present unless the user were to remove it themselves)
• This prompts us to retrieve the notebook from the storage of the sharing service. At this point, it will be a view-only notebook, but we will use the token to authenticate and remove the view-only header.
• The token's expiry will determine when the user has access to author the notebook. We can decide on an appropriate expiry time later (e.g., 1 day, 7 days, etc.). I'm not sure what the value is in CKHub right now.
  • We can check for the existing token before loading the notebook so as to bypass the momentary period in which the view-only header is visible to the user.

We have two options: we can either merge this PR now and I will create additional PRs for #104 and #105, or I can prepare those PRs first and then return to this one.

[krassowski]

Let's try this on staging, this will help to make a decision!

[agriyakhetarpal]

Yes, going forward with this as discussed. Merging!