Implement HTTP/2

[DartBot]

This issue was originally filed by @sethladd

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Looks like HTTP/2 has a lot of implementations.

https://github.com/http2/http2-spec/wiki/Implementations

[iposva-google]

Added Library-IO, Area-Library, Triaged labels.

[lrhn]

Removed Type-Defect label.
Added Type-Enhancement label.

[kevmoo]

Issue #22607 has been merged into this issue.

[sgjesse]

The spec is now a Proposed Standard, https://lists.w3.org/Archives/Public/ietf-http-wg/2015JanMar/0478.html.

The implementation will start out as a package for inclusion into dart:io later.

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Set owner to @mkustermann.
Added Started label.

[sgjesse]

Issue #22661 has been merged into this issue.

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cc @mkustermann.

[sgjesse]

Marked this as blocking #22655.

[DartBot]

This comment was originally written by r.w.lincol...@gmail.com

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Would it be possible for this to be implemented in such a way as to optionally support use with the Chrome sockets API?

https://developer.chrome.com/apps/socket

Similar to the way the CDE folks have done with PicoServer in chrome_net:

https://pub.dartlang.org/packages/chrome_net

[ghost]

Hello there, any updates?

[kevmoo]

@mkustermann is cranking on it, although in a private repo. @sgjesse or he will be able to give more details.

[ghost]

Good to know, that no one forget about HTTP/2 impl. Thanks! 😃

[mkustermann]

We published now a first version of package:http2 and the repository is available under github.com/dart-lang/http2. Please note that this is an alpha version and there are things still missing.

[stevenroose]

It's been a year, how are things going?

[kevmoo]

CC @kasperl

[Reprevise]

Given http2 has been out for awhile... why is this issue still open? Although Dart's HttpClient should really be atleast using HTTP/2 by now, or given the option to specify the HTTP version.

[kevmoo]

CC @brianquinlan – I agree! I wish we had this out of the box. HTTP3 as well!

[Reprevise]

The implementation will start out as a package for inclusion into dart:io later.

Still waiting on the inclusion of http2 into dart:io. 😅 Really missing the network logs provided by Flutter's DevTools because I have to use Dio's http2 adapter. It's about time Dart's internal HttpClient got HTTP/2 support.

[brianquinlan]

Developers who need to support server push can use package:http2.

If you don't need server push then you can use package:cronet_http (on Android) and package:cupertino_http (on macOS/iOS), which both support HTTP, HTTP/2, and HTTP/3 over QUIC.

Is there a reason that this is not sufficient?

[Reprevise]

Is there a reason that this is not sufficient?

Well, Flutter loads it's images over Dart's HttpClient which is, as you know, is HTTP/1 with no option to change it. In addition, using cronet_http alienates users who don't have Google Play Services installed on their device, and having that embedded inflates the APK size by quite a bit. Clearly, http2 is meant to be included in Dart as per the comment above as well.

[brianquinlan]

Is there a reason that this is not sufficient?

Well, Flutter loads it's images over Dart's HttpClient...

package:http_image_provider adapts a package:http Client into an ImageProvider. The documentation for package:http has an example usage.

The same example also shows how to conditionally configure the Client based on the platform.

which is, as you know, is HTTP/1 with no option to change it. In addition, using cronet_http alienates users who don't have Google Play Services installed on their device, and having that embedded inflates the APK size by quite a bit.

Agreed that APK size is an issue for users who can't depend on GPS.

It should be straightforward to create an ImageProvider or package:http Client adapter for package:http2. The later would allow developers to pick the HTTP implementation that they want for their platform (including package:http2).

Our current advice for developers is to use package:http and then choose an appropriate implementation for their platform. Core Dart is unlikely to ever support more recent HTTP versions (such as HTTP/3 over QUIC) because the implementation would result in a significant increase in disk footprint.

[Reprevise]

Core Dart is unlikely to ever support more recent HTTP versions (such as HTTP/3 over QUIC) because the implementation would result in a significant increase in disk footprint.

I'd be fine with an official package that's just a wrapper over a native HTTP/3 library (via native assets perhaps), that'd work for me. I still think it's a shame that Dart's client will only ever support HTTP/1.1, perhaps greater HTTP/2 adoption will force Dart's hand.

There are some quirky aspects of using http2, like it's not as high-level as the http package is. Also, learned the hard way that http2 doesn't automatically decode gzip responses (nor does it ask for them like Dart's client does). There's an open issue in that package somewhere, though it's unlikely to be addressed.

Overall, I'd love the ability to use HTTP/3 but that doesn't seem like its coming to Dart anytime soon, and this issue is about HTTP/2 implementation in core Dart which also appears very unlikely, though this issue should probably remain open when the adoption inevitably rate climbs. Perhaps, http could support http2, maybe there's already an open issue, not sure.

[brianquinlan]

Overall, I'd love the ability to use HTTP/3 but that doesn't seem like its coming to Dart anytime soon, and this issue is about HTTP/2 implementation in core Dart which also appears very unlikely, though this issue should probably remain open when the adoption inevitably rate climbs. Perhaps, http could support http2, maybe there's already an open issue, not sure.

package:http provides an abstract Client interface that can support multiple implementations (like the excellent package:fetch_client). Ideally, an implementation of HTTP/2 should be done in terms of that Client and not be in the Dart SDK.