Fix(HTTP): Update Prefer header syntax to allow lists #42575
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Updated the syntax block to show that multiple preferences are allowed as per the RFC. Added an example demonstrating multiple preferences in a single header. Fixes mdn#42535
Harish3005-cloud
requested review from
hamishwillee
and removed request for
a team
github-actions
bot
added
Content:HTTP
Contributor
|
Preview URLs Flaws (4)URL:
|
hamishwillee
approved these changes
Jan 4, 2026
Collaborator
hamishwillee
left a comment
hamishwillee
left a comment
There was a problem hiding this comment.
Thanks very much. There are a number of ways to show optional lists in HTTP section, but this is the most common one.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Updated the syntax block to show that multiple preferences are allowed as per the RFC. Added an example demonstrating multiple preferences in a single header. Fixes #42535
Description
I updated the "Syntax" section to reflect that the
Preferheader accepts a comma-separated list of preferences. I also added a new "Providing multiple preferences" example to demonstrate this behavior.Motivation
The RFC 7240 specification defines the
Preferheader grammar as1#preference, meaning multiple preferences are allowed in a comma-separated list. The previous documentation implied only a single preference was valid, which was misleading for developers trying to set multiple directives (e.g.,respond-asyncandwait).Additional details
Reference: RFC 7240 Section 2 - The Prefer Header Field
Related issues and pull requests