On Monday, June 5, 2023 at 1:13:11 PM UTC+2 Nidhi Jaju wrote:
Thank you, Mike and Yoav! I filed a standards position request with WebKit, and they are supportive as well: https://github.com/WebKit/standards-positions/issues/194. That's great!! On Wed, May 31, 2023 at 9:33 PM Yoav Weiss <yoavwe...@chromium.org> wrote: Thanks for aligning with Firefox here! On Fri, May 26, 2023 at 5:32 AM Nidhi Jaju <nidhij...@chromium.org> wrote: Contact emailsnidhij...@chromium.org ExplainerNone Specificationhttps://fetch.spec.whatwg.org/#http-network-fetch Summary Makes Response.body be a readable byte stream instead of a "default" readable stream. This enables it to be used with bring-your-own-buffer (BYOB) readers, reducing garbage collection overhead and copies. As mentioned in the Activation section below, we plan to ship the ReadableStreamTeeCloneForBranch2 feature first, and then the FetchBYOB feature later. Blink componentBlink>Network>FetchAPI <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3ENetwork%3EFetchAPI> TAG reviewNone TAG review statusNot applicable Risks Interoperability and Compatibility Low risk because streams and fetch have already been standardized for a long time. Other browsers have implemented other parts of the standard, and Firefox has already shipped this behavior for many months and others will most likely also adapt this feature as well soon. *Gecko*: Shipped/Shipping (https://github.com/whatwg/ fetch/issues/267#issuecomment-1350303670) Already shipped in Firefox in 2022. *WebKit*: Positive (https://github.com/whatwg/fetch/pull/1593) @annevk from Apple approved the PR to update the spec with relevant changes and expressed interest as an implementer on behalf of Apple. *Web developers*: No signals *Other signals*: Deno is also interested in, and somewhat shipped, this behavior (https://github.com/denoland/deno/issues/17386). Activation Currently, to clone a body, we tee the body's stream, but teeing always returns two "default" streams, where the chunks are not cloned for both streams. Making Response.body into a byte stream, will mean that cloning it will result in cloning the chunks for the second stream, which is different behavior. In order to mitigate activation risks, we are splitting this change into two releases. One where the default teeing behavior will also start to clone for the second stream behind the " ReadableStreamTeeCloneForBranch2" feature flag, and then make Response.body a readable byte stream behind the "FetchBYOB" feature flag. Can you help me understand what potential breakage (if any) may look like? How would these 2 behavior changes break developer expectations? What would code that breaks as a result of this look like? The 2 changes are incremental, and will only break developer expectations if there are websites that rely on the output of cloning a request/response to have the same chunks as before or rely on modifying one of the chunks changing the other one. A code sample of where the behavior difference would be observable is: const request = new Request("image.jpg"); fetch(request).then((response) => { const cloned_response = response.clone(); const { value: value1 } = await response.getReader().read(); const { value: value2 } = await cloned_response.getReader().read(); if (value1 === value2) { console.log('old behavior'); } else { console.log('new behavior'); } }); In both the old and the new behaviour, the contents of the Uint8Array are the same, so it only makes a practical difference if a script modifies the output. Do we have a sense of an upper bound on potential breakage? e.g. a use counter for fetch response cloning? (An explainer that outlined that would've been helpful, but inline explanations are fine as well) WebView application risks Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications? Debuggability No special support needed. Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?Yes This feature will be purely implemented in Blink and so cross-platform support is automatic. Is this feature fully tested by web-platform-tests <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> ?Yes Flag nameReadableStreamTeeCloneForBranch2 and FetchBYOB I'm failing to find the FetchBYOB flag. Has it landed? Requires code in //chrome?False Tracking bughttps://bugs.chromium.org/p/chromium/issues/detail?id=1243329 Estimated milestonesShipping on desktop116Shipping on Android116Shipping on WebView116 Anticipated spec changes Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way). None. The spec change for BYOB support for Fetch was already landed at https://github.com/whatwg/fetch/pull/1593. Link to entry on the Chrome Platform Statushttps://chromestatus.com/ feature/5192003450568704 Links to previous Intent discussionsIntent to prototype: https://groups. google.com/a/chromium.org/g/blink-dev/c/Iyt6Ca9PiJQ/m/s_D7A0YwCgAJ -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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