1555927 - Cacheable Http 204 (No Content) responses to GET request not cached

Status: RESOLVED FIXED

(Core :: Networking: Cache, defect, P2)

Description

[frederic.delaporte]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

Have an api which, on a GET request, responds a 204 No Content with a Cache-Control: Public,max-age=1200 directive, no expires, no pragma, no vary.
Query it through a GET ajax call in a Html page.
Query it again identically before expiration (typically by browsing again the page).

Actual results:

Firefox queried the api twice.

Expected results:

Firefox should have not queried the api a second time.

Chrome does just that : query only once, reusing the previous result from cache the second time.
The problem can be reproduced in a new profile.

Comment 1

[Kershaw Chang [:kershaw]]

Since nsHttpResponseHead::MustValidate returns true when the status is 204, we can't serve the response from the cache entry.

Not sure if we can simply add 204 in nsHttpResponseHead::MustValidate.
Honza, what do you think?

Comment 2

[Honza Bambas (:mayhemer)]

https://tools.ietf.org/html/rfc7231#section-6.3.5

A 204 response is cacheable by default; i.e., unless otherwise
indicated by the method definition or explicit cache controls (see
Section 4.2.2 of [RFC7234]).

we also write it on MDN: 204 No Content - HTTP | MDN

so, yes, we should add 204 to nsHttpResponseHead::MustValidate

Comment 3

[Kershaw Chang [:kershaw]]

Attachment: Bug 1555927 - Cache 204 response

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a73d370a3a6f
Cache 204 response r=mayhemer

Comment 5

[Narcis Beleuzu [:NarcisB]]

Backed out for wpt failures on heuristic.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/935c358f8c635132e0bb0d0be624294d9b720035
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=256743065&repo=autoland&lineNumber=30768

Comment 6

[Kershaw Chang [:kershaw]]

Oh, I was not aware of that we already have wpt test for 204 response.
I'll fix this.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a8eb1b6edb40
Cache 204 response r=mayhemer

Comment 8

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/a8eb1b6edb40