[blink-dev] Intent to Experiment: Extending Storage Access API (SAA) to non-cookie storage

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Ari Chivukula

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Oct 26, 2023, 11:21:45 AM10/26/23
to blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com

Contact emails

ari...@chromium.org, wande...@chromium.org, joha...@chromium.org, hel...@google.com


Specification

https://arichiv.github.io/saa-non-cookie-storage/


Feedback

https://github.com/arichiv/saa-non-cookie-storage/issues


Intent to Prototype

https://groups.google.com/a/chromium.org/g/blink-dev/c/inRN8tI49O0


Summary

An origin trial, StorageAccessAPIBeyondCookies, will be made available which enables the proposed extension of the Storage Access API (backwards compatible) to allow access to unpartitioned (cookie and non-cookie) storage in a third-party context. The current API only provides access to cookies, which have different use-cases than non-cookie storage (discussed more in the Motivation section). The API can be used as follows (JS running in an embedded iframe):


// Request a new storage handle via rSA (this should prompt the user)

let handle = await document.requestStorageAccess({all: true});

// Write some 1P context sessionstorage

handle.sessionStorage.setItem("userid", "1234");

// Write some 1P context localstorage

handle.localStorage.setItem("preference", "A");

// Open or create an indexedDB that is shared with the 1P context

let messageDB = handle.indexedDB.open("messages");

// Use locks shared with the 1P context

await handle.locks.request(“example”, …);


The same flow would be used by iframes to get a storage handle when their top-level ancestor successfully called rSAFor, just that in this case the storage-access permission was already granted and thus the rSA call would not require a user gesture or show a prompt, allowing for “hidden” iframes accessing storage. 


Beyond calling this additional extension, access to non-cookie storage would match the current requirements for cookie access through the Storage Access API. For example, in Chrome, no prompt is shown when the origins are in the same RWS (Related Website Sets, the new name for First Party Sets). Origins that are not part of the same RWS would be subject to the prompting requirements of the Storage Access API in Chrome.  


The origin trial will be available from M120 until M124 (or after Tue, June 11, 2024 in any milestone).


Only Session Storage, Local Storage, Indexed DB, and Web Locks will be available initially, but other storage and communication mechanisms will be added to the Origin Trial in future milestones. These additions will be announced in this thread after each branch cut. Feedback from developers would aid us in prioritizing specific mechanisms for inclusion.


Blink component

Blink>StorageAccessAPI


Motivation

There has been increasing developer and implementer interest in first-party DOM Storage and Quota Managed Storage being available in third-party contexts the same way that Cookies already can be. In the absence of such a solution, we would in effect be pushing developers to migrate to Cookies from other storage mechanisms. There are tradeoffs between Cookie and non-Cookie storage (size, flexibility, server exposure, network request size, etc.) that could impact user experience from a privacy, security and performance perspective (e.g., cookies are included in HTTP requests and not just available via JavaScript). To prevent sub-optimal use of cookies and to preserve context, we propose a solution for developers to regain 3p access to unpartitioned storage to avoid user-facing breakage in browsers shipping storage partitioning.


TAG review

https://github.com/w3ctag/design-reviews/issues/906


Compatibility

The Storage Access API is already implemented in Safari, Firefox, and Chrome, but the proposed API shape would not change existing behavior without new arguments added.


Interoperability

Gecko: No Position Yet https://github.com/mozilla/standards-positions/issues/898

WebKit: No Position Yet https://github.com/WebKit/standards-positions/issues/262

Web developers: Positive


Debuggability

Storage written can be examined in devtools.


Is this feature fully tested by web-platform-tests?

Yes


Tracking bug

https://crbug.com/1484966


Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5175585823522816


Chris Harrelson

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Oct 27, 2023, 5:25:54 PM10/27/23
to Ari Chivukula, blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
Can you please also fill out the Goals for experimentation section?

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Ari Chivukula

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Oct 27, 2023, 9:00:22 PM10/27/23
to Chris Harrelson, blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
Done.

~ Ari Chivukula (Their/There/They're)

Rick Byers

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Nov 1, 2023, 11:35:06 AM11/1/23
to Ari Chivukula, Chris Harrelson, blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
This makes a lot of sense to me. I hate the idea of pushing folks to use cookies just due to SAA. 

I see the debate about wanting to deprecate the sync storage APIs, but I agree with you that this is not a useful lever in that debate. Instead we should come up with a holistic deprecation strategy. 

LGTM

Ari Chivukula

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Dec 4, 2023, 9:54:47 AM12/4/23
to blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
A blog post on how to participate in the OT is here: https://developer.chrome.com/blog/saa-non-cookie-storage/

Chrome 120 includes local storage, session storage, indexed db, and web locks.

Chrome 121 adds cache storage, origin private filesystem, quota, blob storage, and broadcast channel.

Shared Workers will be re-examined in a future extension, I hope to publish more on this within a month.

~ Ari Chivukula (Their/There/They're)

Ari Chivukula

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Jan 9, 2024, 3:04:18 PMJan 9
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Based on a report from an external developer a bug was found that caused the session/local storage on the SAA handle to sometimes be partitioned (instead of unpartitioned). The fix will be included in M122.

Please report any further issues to https://github.com/arichiv/saa-non-cookie-storage/issues, thanks!

~ Ari Chivukula (Their/There/They're)

Ari Chivukula

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Jan 17, 2024, 3:07:12 PMJan 17
to blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
Two additional explainers (each of which is an extension to Storage Access API (SAA) to non-cookie storage) have been published! Both of these are slated for inclusion in the existing origin trial (hopefully as part of M123).

The current Storage Access API requires that unpartitioned cookie access is granted if any unpartitioned storage access is needed. This forces unpartitioned cookies to be included in network requests which may not need them, having impacts on network performance and security. Before the extension ships, we have a chance to fix this behavior without a compatibility break.

There has been increasing developer and implementer interest in first-party workers being available in third-party contexts the same way that third-party cookies already can be. In the absence of such a solution, we leave developers without a robust way to manage cross-tab state for frames loading the same origin. This explainer proposes a solution for developers to regain third-party access to Shared Workers in select instances to avoid user-facing breakage in browsers shipping storage partitioning.

~ Ari Chivukula (Their/There/They're)

Ari Chivukula

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Jan 29, 2024, 1:41:43 PMJan 29
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Ari Chivukula

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Feb 20, 2024, 11:53:35 AMFeb 20
to blink-dev, Ben Kelly, Johann Hofmann, hel...@google.com
Chrome 123 is adding Shared Worker support to the SAA extension.

A blog post on how to participate in the OT is here: https://developer.chrome.com/blog/saa-non-cookie-storage/

~ Ari Chivukula (Their/There/They're)

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