1830230 - Server sent events not displayed in the Network panel

Status: RESOLVED FIXED

(DevTools :: Netmonitor, defect, P2)

Description

[Jan Honza Odvarko [:Honza] (always need-info? me)]

STR:

1. Copy the attached PHP and HTML files into your webserver
2. Load the index.html file in Firefox.
3. The page should show "Server Time". The time should be updated every second.
4. Open DevTools and select the Network panel. Realod the page.
5. Select the server.php request
6. Select the Response panel, events are not displayed => BUG

Expected Result:
Server side events should be displayed in the Response tab.

Tested also in Chrome DevTools and it works, I can see the events.

Honza

Comment 1

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Attachment: index.html

Comment 2

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Attachment: server.php

Comment 3

[Hubert Boma Manilla (:bomsy)]

Thanks for reporting Honza.

This is likely related to Bug 1773181. The BUG here is that showing of the messages in response panel and the header information in headers panel are all blocked until the SSE channel for that request is closed.

In the STR above it never closes so we won't get those messages. I think that was the behaviour from when it was implemented, we should fix and show the messages as they come in.

Since its completely blocking the panels, i think we should prioritize fix.

i'll take a look

Comment 5

[florent.daligand]

With the growing adoption of Server-Sent Events in RAG applications and real-time AI workflows, this bug has become increasingly impactful for web developers. The lack of proper SSE debugging tools in Firefox dev tools is currently forcing developers (myself included) to switch to Chromium-based browsers for debugging these applications.
Given the rising prominence of SSE in modern web development, fixing this would help Firefox maintain its position as a viable development browser for current tech stacks.

Comment 6

[Alexandre Poirot [:ochameau]]

Bug 1557795 should help or even fix this issue. We have some more general issue around pending requests that goes beyond SSE.

Comment 7

[Hubert Boma Manilla (:bomsy)]

Attachment: Bug 1830230 - [devtools] Start sending multiple events as the response data is arrives r=#devtools

With this patch we begin sending multiple RESPONSE_CONTET events and a RESPONSE_END

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/e2cabf42277c
https://hg.mozilla.org/integration/autoland/rev/c5a4969c14ac
[devtools] Start sending multiple events as the response data is arrives r=webdriver-reviewers,devtools-reviewers,jdescottes

Comment 10

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/c5a4969c14ac

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/aa64bf055ae8
https://hg.mozilla.org/integration/autoland/rev/1414e67dcc5f
Revert "Bug 1830230 - [devtools] Start sending multiple events as the response data is arrives r=webdriver-reviewers,devtools-reviewers,jdescottes" for causing multiple failures

Comment 12

[Cristina Horotan [:chorotan]]

Backed out for causing Bug 1984562 and Bug 1984622

Backout link

Comment 13

[Iulian Moraru]

Backout merged to central: https://hg-edge.mozilla.org/mozilla-central/rev/1414e67dcc5f

Comment 14

[Florin Bilt]

(In reply to Iulian Moraru from comment #13)

Backout merged to central: https://hg-edge.mozilla.org/mozilla-central/rev/1414e67dcc5f

Perfherder has detected a devtools performance change from push 1414e67dcc5f3c7ee451e774ba5941a1af67e8e9. As author of one of the patches included in that push, we need your help to address this regression.

Please acknowledge, and begin investigating this alert within 3 business days, or the patch(es) may be backed out in accordance with our regression policy. Our guide to handling regression bugs has information about how you can proceed with this investigation.

If you have any questions or need any help with the investigation, please reach out to a performance sheriff. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
23%	damp custom.netmonitor.close.DAMP	linux1804-64-shippable-qr	e10s fission stylo webrender	12.30 -> 15.14

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a performance sheriff to do that for you.

You can run all of these tests on try with ./mach try perf --alert 46452

The following documentation link provides more information about this command.

Comment 15

[Julian Descottes [:jdescottes]]

(In reply to Florin Bilt from comment #14)

(In reply to Iulian Moraru from comment #13)

Backout merged to central: https://hg-edge.mozilla.org/mozilla-central/rev/1414e67dcc5f

Perfherder has detected a devtools performance change from push 1414e67dcc5f3c7ee451e774ba5941a1af67e8e9. As author of one of the patches included in that push, we need your help to address this regression.

Please acknowledge, and begin investigating this alert within 3 business days, or the patch(es) may be backed out in accordance with our regression policy. Our guide to handling regression bugs has information about how you can proceed with this investigation.

If you have any questions or need any help with the investigation, please reach out to a performance sheriff. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
23%	damp custom.netmonitor.close.DAMP	linux1804-64-shippable-qr	e10s fission stylo webrender	12.30 -> 15.14

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a performance sheriff to do that for you.

You can run all of these tests on try with ./mach try perf --alert 46452

The following documentation link provides more information about this command.

FWIW, the perf change on custom.netmonitor.close can be ignored, those tests are not very meaningful

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/1eb9f5f47bb0
https://hg.mozilla.org/integration/autoland/rev/0d112c50725d
[devtools] Start sending multiple events as the response data is arrives r=webdriver-reviewers,perftest-reviewers,devtools-reviewers,afinder,jdescottes

Comment 17

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/0d112c50725d