fetch() upload streaming

[yoichio]

Hello TAG!

I'm requesting a TAG review of:

• Name: fetch() upload streaming
• Specification URL: https://fetch.spec.whatwg.org/#concept-body-stream
  • Commits: whatwg/fetch@0c470b5, whatwg/fetch@55141d7
• User needs: Uploading a Request made from a ReadableStream body whatwg/fetch#425, https://groups.google.com/a/chromium.org/forum/#!topic/blink-network-dev/bsVgOxNCzFc
• Tests: http://web-platform-tests.live/fetch/api/basic/request-upload.any.js
• Primary contacts (and their relationship to the specification): @yoichio

Further details:

• Relevant time constraints or deadlines: None
• I have read and filled out the Self-Review Questionnare on Security and Privacy. The assessment is here.
• I have reviewed the TAG's API Design Principles
• The group where the work on this specification is: WHATWG

We'd prefer the TAG provide feedback as (please select one):

• open issues in our GitHub repo for each point of feedback
• open a single issue in our GitHub repo for the entire review
• leave review feedback as a comment in this issue and @yoichio, @yutakahirano

[torgo]

Hi @yoichio thanks for this - is there an explainer that we can look at?

[yoichio]

No explainer for this.

Here is brief description why we want to implement this:

• Web author will be able to upload streaming data - possibly generated by devices, media, and so on.
  Some web clients want to talk to a streaming end-point directly without any intermediary translation.
  Traditionally, uploading streaming data was implemented on WebSocket but it has made client/server code messy. Fetch upload streaming makes that simpler.

Code sample:

const stream = new ReadableStream({start: controller => {
    controller.enqueue("f");
    controller.enqueue("bar");
    controller.close();
}});

let response = await fetch("http://example.com/", {method:"POST", body: stream});
let text = await response.text();
console.log(`Server responded "${text}"`);

[annevk]

I wonder if it might be a bit early to ask for review. There's a number of open issues that need to be addressed, right? https://github.com/whatwg/fetch/labels/topic%3A%20streams

whatwg/fetch#538 in particular seems concerning and without a good conclusion, though I haven't reviewed all in detail.

[yoichio]

Ping @yutakahirano and @domenic ?

[yutakahirano]

Thank you. I think not all of them are blocking, so I created a new label "upload-streaming-blocking", labeled whatwg/fetch#538.

https://github.com/whatwg/fetch/labels/upload-streaming-blocking

[torgo]

Ok we are happy to do a review but please confirm back to us that things are ready? Until then I'm going to close.

[annevk]

@torgo FWIW, I think we're in a better state now with those issues and whatwg/fetch#966 might be of interest to the TAG at some level.