1507691 - Firefox does not include image/webp to HTTP Request's 'Accept' Header for html file

Status: RESOLVED FIXED

(Core :: Graphics: ImageLib, enhancement, P3)

Description

[Tetsuharu OHZEKI [:tetsuharu] (UTC+9)]

Firefox does not include image/webp to HTTP Request's 'Accept' Header for html file

## Actual Result

These are values of HTTP Request's Accept Header  sent from all useragents supporting WebP


### Firefox, 65a1, 0051c8d339a969d80b66e6ce243091a9dbb6a319

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8


### Google Chrome, Version 72.0.3611.0 (Official Build) canary (64-bit)

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8


### Edge 44.17763.1.0 (EdgeHTML 18.17763)

Accept: text/html, application/xthml+xml, application/xml; q=0.9, */*; q=0.8


## Expected Result


Should we contain 'image/webp' for HTTP Request Header's 'Accept' field?

Comment 1

[Andrew Osmond [:aosmond] (he/him)]

This should have done that just yesterday:

https://hg.mozilla.org/mozilla-central/rev/f8fefc9626c1

Comment 2

[Andrew Osmond [:aosmond] (he/him)]

I see now; I updated the Accept header for image requests, but you are suggesting it be provided for on all pages.

Comment 3

[Andrew Osmond [:aosmond] (he/him)]

Attachment: Bug 1507691 - Add image/webp to default HTTP Accept header.

Comment 4

[709922234]

When all browsers support webp, Do we no longer need to include "image/webp" in "Accept"?

Comment 5

[Tetsuharu OHZEKI [:tetsuharu] (UTC+9)]

(In reply to Andrew Osmond [:aosmond] from comment #2)
> I see now; I updated the Accept header for image requests, but you are
> suggesting it be provided for on all pages.

Yes!
It would be nice for some applications which switches image format on server side by "Accept" header.
I think some applications assumes that an UA includes "image/webp" to "Accept" header to rely on Chromium's implementation. 

But I also think a webdev also workarounds this problem with <picture/> and it might be more straight way.

So this is just compatibility issue "with Chrome"... :(

Comment 6

[Darkspirit]

(In reply to Tetsuharu OHZEKI [:tetsuharu] [UTC+9] from comment #5)
> But I also think a webdev also workarounds this problem with <picture/> and it might be more straight way.
Yeah, that and comment 1.

> So this is just compatibility issue "with Chrome"... :(
Such rare applications had to be adjusted for [Firefox and] Edge anyway, so there should be no need for this.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/243ce783ccfb
Add image/webp to default HTTP Accept header. r=dragana

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/3fee9c5dc2c2
Followup to fix broken test expecting accept header without image/webp. r=aosmond CLOSED TREE

Comment 9

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/243ce783ccfb
https://hg.mozilla.org/mozilla-central/rev/3fee9c5dc2c2

Comment 10

[Chris Mills [:cmills]]

Note to MDN writer's team:

I have a note to the Fx65 rel notes to cover this:
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/65#Other

I also updated the example Accept header shown on the Accept page to include image/webp, to draw more attention to this:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept

I'm not sure if we also want to record this in our browser compat data?

Comment 11

[Mark Straver]

I'm assuming this was prompted by people wanting to "save as" images and getting different results than <img> in-page.

Shouldn't this have been solved by applying what's talked about in bug 1347958 instead of just blanket-adding this conneg header to html file requests?

Comment 12

[tgross.ms.de]

Why did Firefox 66 went back to NOT sending image/webp to default HTTP Accept header?

Comment 13

[Darkspirit]

See bug 1417463.

Comment 14

[tgross.ms.de]

(In reply to Jan Andre Ikenmeyer [:darkspirit] from comment #13)

See bug 1417463.

I understand this, but it does NOT solve the problem reported here.

The important part is for applications to create html (img src etc.) according to what the client is able to display.

The / does not solve this - every browser, even IE, has this in its default Accept header. Without image/webp, applications are no longer able to serve .webp to Firefox!

Comment 15

[tgross.ms.de]

I am sorry, the last sentence in my previous comment was supposed to begin with
The */* does not solve this

Comment 16

[Tetsuharu OHZEKI [:tetsuharu] (UTC+9)]

(In reply to tgross.ms.de from comment #15)

I am sorry, the last sentence in my previous comment was supposed to begin with
The */* does not solve this

How about you use <picture/>?