Improve the Flutter SDK archive page

[chalin]

Page URL: https://flutter.io/docs/development/tools/sdk/archive.html
Page source: https://github.com/flutter/website/tree/master/src/docs/development/tools/sdk/archive.md

• Add a description of each of the channels. As requested by @Hixie (and reported by @sfshaza2): the page should contain a description of the channels.

  The channels are well documented in the Flutter's channels wiki page, which is referenced at the start of the Archive page:

  The Stable channel contains the most stable Flutter builds. See [Flutter’s channels][] for details.

  Is this good enough? If not, then I'd rather not have duplicate information. I'd then suggest moving at least the initial part of the wiki page text into the Archive page. WDYT @Hixie?

  Also, you mentioned that you might prefer an interface similar to the Dart SDK Archive page: with Version and OS drop downs? Or were you only giving that page as an example w.r.t. the channel descriptions?

• list sha256sums for download files (originally requested by @cbracken in Website download page should list sha256sums for download files #1955)

• Question is the Ref value really useful for users? @cbracken @Hixie

Overall, maybe we should just carry over the Dart SDK Archive design and implementation? Thoughts?

cc @kwalrath

[cbracken]

Question is the Ref value really useful for users? @cbracken @Hixie

Assuming the ref value in this case is the commit SHA from the repo, I'm not sure it adds much value. Since we use x.y.z version as the public-facing identification for a flutter version, and our versions are all clearly applied as git tags, users can pretty easily look up the commit SHA associated with the tag if they really need it -- e.g. via git show-ref --tags. Personally, I wouldn't bother including it on our download page.

[gspencergoog]

I've added a SHA256 to the metadata for archives with this PR: flutter/flutter#28472

The motivation isn't to identify the version, it is to allow people to be able to verify the download integrity.

They are in a key called "sha256" for each entry in the archives JSON.

[cbracken]

The motivation isn't to identify the version, it is to allow people to be able to verify the download integrity.

I suspect I somehow misread this issue. I was the one who originally filed the issue requesting shasums precisely for verification: #1955.

[StephenWithPH]

I landed here after following the thread from #1955. Although https://docs.flutter.dev/development/tools/sdk/releases still doesn't display checksums, the data is there in the json response from the server:

It would be nice if these were included on the displayed table of releases.