Support for Persistent Storage in Web Browsers

[lidel]

Context

Right now every js-ipfs repo created in web browser context is created in the default, "temporary" storage space provided by the browser.

This means:

• there is no user prompt asking user to allow js-ipfs to store data (good UX)
• data is stored in a space that is
  • shared with entire Origin (other JS code can eat up the quota)
  • silently GC'd if Origin or global storage hits browser-vendor-specfic limits

Motivation

This is usually ok, as data cached in js-ipfs is expected to "disappear" (as in: go offline) when user closes the tab and app developers add some middleware responsible for pinning/persisting user data anyway.

That being said, there should be a programmatic opt-in to use persistent storage in the browser, just in case someone really wants data to be around, or expect a lot of data to be downloaded by their web app and don't want it to get GC'd. Imagine a game / VR app which is using IPFS for asset storage etc.

Note on this being vendor-specific

Below are only initial notes.
Make sure to re-check before starting work, as vendors may have changed it.

• We probably need to add optional configuration key that gets passed to js-datastore used in browser runtime.
  • Unsure about the value behind this new configuration key. Needs evaluation, could be a function that is called with the result of user decision, providing a way of idiomatic fallback, but needs evaluation of current vendor behavior.
• Persistent storage requires user to approve. Specific moment when "ask" occurs is browser-specific, at least that was the case ~2017:
  • chrome seems to be global per Origin Specify temporary or persistent mode for indexeddb storage database dexie/Dexie.js#467 (comment)
  • firefox supports requesting persistence at the moment IndexedDB is created: Specify temporary or persistent mode for indexeddb storage database dexie/Dexie.js#467 (comment)
• Upon request a pop-up/prompt will be displayed, and user accepts or rejects.

What needs to happen?

• document current behavior in Firefox, Chromium and Safari
• design configuration option that would work everywhere
• wire up configuration option to work in every supported browser and throw error otherwise

References

• https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API/Browser_storage_limits_and_eviction_criteria
• some notes on browser-specific behaviours:
  • chrome: Specify temporary or persistent mode for indexeddb storage database dexie/Dexie.js#467 (comment)
  • firefox: Specify temporary or persistent mode for indexeddb storage database dexie/Dexie.js#467 (comment)
• https://developers.google.com/web/updates/2016/06/persistent-storage
• Reliable persistence in browser context will be more and more important as more features in ipfs/libp2p stack start to rely on historical data: PeerStore improvements libp2p/js-libp2p#582
• Safari purging local storage after 7 days:
  • https://twitter.com/cvanw/status/1242700155180027904

[magniff]

Sup. Any progress on that one?

[SgtPooki]

js-ipfs is being deprecated in favor of Helia. You can #4336 and read the migration guide.

Please feel to reopen with any comments by 2023-06-02. We will do a final pass on reopened issues afterward (see #4336).

I think this functionality would make the most sense as a UI plugin / extension of a datastore/blockstore implementation in Helia. Closing this issue, but pinging @achingbrain for awareness.