net/http: support status code 102 (Processing) in ResponseWriter #36734

majewsky · 2020-01-24T14:19:46Z

HTTP status code 102 (Processing) is defined by RFC 2518, section 10.1:

This status code SHOULD only be sent when the server has a reasonable expectation that the request will take significant time to complete. [...] The server MUST send a final response after the request has been completed.

As of now (Go 1.13.6), there is no way to actually send a 102 response because ResponseWriter.WriteHeader() can only be called once. Any successive calls are rejected (here).

Since the ResponseWriter interface cannot be extended without breaking backwards compatibility, a new interface should be added (and implemented by the existing ResponseWriter implementations) that exposes a function for sending an interim response with status 102.

toothrot · 2020-01-24T21:36:57Z

WebDAV specific features might be better suited for x/net/webdav. I'm not positive we could make this change in net/http while maintaining API compatibility.

/cc @bradfitz @nigeltao

bradfitz · 2020-01-24T22:05:53Z

I don't think we'd need API changes. We could just permit WriteHeader(102) followed by a non-1xx status later

florian-forestier · 2020-09-01T11:58:12Z

Hey,

Any update about this ? It would be a nice feature.

For my use case, it doesn't have any link with WebDAV. I have some very long requests, who can make hundreds of other requests to various requests, and adding this kind of functionality would enable my users to stay listening at the server. Currently, they are in timeout...

Also, for the net/http and not a WebDav-specific protocol, this improvement would permit developers to use HTTP 103 - Early Hints (https://tools.ietf.org/html/rfc8297, still experimental, but exists).

The change is pretty simple : if status is 1xx, we allow update, if not we reject as it is currently done. (show concerned line)

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. In conformance with RFC 8297, if the status code is 103 the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang#26089. Fixes golang#36734. Updates golang#26088.

gopherbot · 2020-11-13T19:01:21Z

Change https://golang.org/cl/269997 mentions this issue: net/http: allow sending 1xx responses

gopherbot · 2020-11-14T16:35:31Z

Change https://golang.org/cl/270157 mentions this issue: http2: allow sending 1xx responses

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. In conformance with RFC 8297, if the status code is 103 the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang#26089. Fixes golang#36734. Updates golang#26088.

gopherbot · 2021-02-10T20:28:28Z

Change https://golang.org/cl/291029 mentions this issue: http2: allow sending 1xx responses

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. In conformance with RFC 8297, if the status code is 103 the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang#26089. Fixes golang#36734. Updates golang#26088.

madCode · 2022-03-11T19:50:30Z

Hey @dunglas! What's the status of the linked PR? I see it's been in progress since Feb of 2021.

dunglas · 2022-03-12T22:03:43Z

@madCode it is ready, waiting for a final review by the core team.

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. In conformance with RFC 8297, if the status code is 103 the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang#26089. Fixes golang#36734. Updates golang#26088.

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. If the status code is in the 1xx range, the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang#26089. Fixes golang#36734. Updates golang#26088.

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. If the status code is in the 1xx range, the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes #26089 Fixes #36734 Updates #26088 Change-Id: Ib7023c1892c35e8915d4305dd7f6373dbd00a19d GitHub-Last-Rev: 06d749d GitHub-Pull-Request: #42597 Reviewed-on: https://go-review.googlesource.com/c/go/+/269997 Reviewed-by: Damien Neil <dneil@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>

Support for 1xx responses has recently been merged in net/http (golang#42597). As discussed in this CL (https://go-review.googlesource.com/c/go/+/269997/comments/1ff70bef_c25a829a), support for forwarding 1xx responses in ReverseProxy has been extracted in this separate patch. According to RFC 7231, "a proxy MUST forward 1xx responses unless the proxy itself requested the generation of the 1xx response". Consequently, all received 1xx responses are automatically forwarded as long as the underlying transport supports ClientTrace.Got1xxResponse. Fixes golang#26088 Fixes golang#36734

gopherbot · 2022-05-31T17:25:03Z

Change https://go.dev/cl/409536 mentions this issue: net/http: reverseproxy: forward 1xx responses

Currently, it's not possible to send informational responses such as 103 Early Hints or 102 Processing. This patch allows calling WriteHeader() multiple times in order to send informational responses before the final one. If the status code is in the 1xx range, the current content of the header map is also sent. Its content is not removed after the call to WriteHeader() because the headers must also be included in the final response. The Chrome and Fastly teams are starting a large-scale experiment to measure the real-life impact of the 103 status code. Using Early Hints is proposed as a (partial) alternative to Server Push, which are going to be removed from Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/21anpFhxAQAJ Being able to send this status code from servers implemented using Go would help to see if implementing it in browsers is worth it. Fixes golang/go#26089. Fixes golang/go#36734. Updates golang/go#26088. Change-Id: Iadb7be92844a3588ef4ce044f887ef5c1792f431 GitHub-Last-Rev: eee95b58b3b259781fc1052ed6143a0aa9284e04 GitHub-Pull-Request: golang/net#96 Reviewed-on: https://go-review.googlesource.com/c/net/+/291029 Run-TryBot: Damien Neil <dneil@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Damien Neil <dneil@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>

toothrot added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Jan 24, 2020

toothrot added this to the Backlog milestone Jan 24, 2020

dunglas mentioned this issue Nov 13, 2020

net/http: allow sending 1xx responses #42597

Closed

dunglas mentioned this issue Nov 14, 2020

x/net/http2: allow sending 1xx responses golang/net#87

Closed

dunglas mentioned this issue Feb 10, 2021

x/net/http2: allow sending 1xx responses golang/net#96

Closed

gopherbot closed this as completed in golang/net@9564170 May 13, 2022

dmitshur removed the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label May 17, 2022

dmitshur added the NeedsFix The path to resolution is known, but the work has not been done. label May 17, 2022

dmitshur modified the milestones: Backlog, Go1.19 May 17, 2022

dunglas mentioned this issue May 31, 2022

net/http/httputil: forward 1xx responses in ReverseProxy #53164

Closed

timofurrer mentioned this issue Apr 12, 2023

net/http: flush after writing 101 header shouldn't send headers again #59564

Closed

golang locked and limited conversation to collaborators May 31, 2023

gopherbot added the FrozenDueToAge label May 31, 2023

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

net/http: support status code 102 (Processing) in ResponseWriter #36734

net/http: support status code 102 (Processing) in ResponseWriter #36734

majewsky commented Jan 24, 2020

toothrot commented Jan 24, 2020

bradfitz commented Jan 24, 2020

florian-forestier commented Sep 1, 2020 •

edited

gopherbot commented Nov 13, 2020

gopherbot commented Nov 14, 2020

gopherbot commented Feb 10, 2021

madCode commented Mar 11, 2022

dunglas commented Mar 12, 2022

gopherbot commented May 31, 2022

net/http: support status code 102 (Processing) in ResponseWriter #36734

net/http: support status code 102 (Processing) in ResponseWriter #36734

Comments

majewsky commented Jan 24, 2020

toothrot commented Jan 24, 2020

bradfitz commented Jan 24, 2020

florian-forestier commented Sep 1, 2020 • edited

gopherbot commented Nov 13, 2020

gopherbot commented Nov 14, 2020

gopherbot commented Feb 10, 2021

madCode commented Mar 11, 2022

dunglas commented Mar 12, 2022

gopherbot commented May 31, 2022

florian-forestier commented Sep 1, 2020 •

edited