Skip to content

Update SF field format for params #3374

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
nidhijaju merged 4 commits into from
Feb 17, 2026
Merged

Update SF field format for params #3374

Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
b0be4b6
Update SF field format for params
nidhijaju Dec 24, 2025
7a6eb85
update comment
nidhijaju Dec 24, 2025
56194f0
handle error from parse a key
nidhijaju Jan 5, 2026
34e33b8
Merge branch 'main' into sf-field-format
nidhijaju Feb 17, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 23 additions & 30 deletions draft-ietf-httpbis-no-vary-search.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,7 @@ No-Vary-Search: params=("utm_source" "utm_medium" "utm_campaign")
And if the resource instead wants to take an allowlist-based approach, where only certain known query parameters semantically affect the served response, they can use

~~~~http-message
No-Vary-Search: params, except=("productId")
No-Vary-Search: except=("productId")
~~~~

Note that "cache busting" by sending unique query parameters to avoid retrieving a cached response can be made ineffective by the `No-Vary-Search` header field.
Expand Down Expand Up @@ -163,9 +163,9 @@ The `No-Vary-Search` HTTP header field is a structured field {{STRUCTURED-FIELDS
It has the following authoring conformance requirements:

* If present, the `key-order` entry's value MUST be a boolean ({{Section 3.3.6 of STRUCTURED-FIELDS}}).
* If present, the `params` entry's value MUST be either a boolean ({{Section 3.3.6 of STRUCTURED-FIELDS}}) or an inner list ({{Section 3.1.1 of STRUCTURED-FIELDS}}).
* If present, the `except` entry's value MUST be an inner list ({{Section 3.1.1 of STRUCTURED-FIELDS}}).
* The `except` entry MUST only be present if the `params` entry is also present, and the `params` entry's value is the boolean value true.
* If present, the `params` entry's value MUST be an inner list of strings ({{Section 3.1.1 of STRUCTURED-FIELDS}}).
* If present, the `except` entry's value MUST be an inner list of strings ({{Section 3.1.1 of STRUCTURED-FIELDS}}).
* The `except` entry MUST NOT be present if the `params` entry is also present.

The dictionary MAY contain entries whose keys are not one of `key-order`, `params`, and `except`, but their meaning is not defined by this specification. Implementations of this specification will ignore such entries (but future documents might assign meaning to such entries).

Expand Down Expand Up @@ -211,24 +211,19 @@ To _parse a URL variation config_ given _value_:
1. If _value_\["`key-order`"] exists:
1. If _value_\["`key-order`"] is not a boolean, then return the default URL variation config.
1. Set _result_'s vary on key order to the boolean negation of _value_\["`key-order`"].
1. If both _value_\["`params`"] and _value_\["`except`"] exist or neither exists, then return the default URL variation config.
1. If _value_\["`params`"] exists:
1. If _value_\["`params`"] is a boolean:
1. If _value_\["`params`"] is true, then:
1. Set _result_'s no-vary params to __wildcard__.
1. Set _result_'s vary params to the empty list.
1. Otherwise:
1. Set _result_'s no-vary params to the empty list.
1. Set _result_'s vary params to __wildcard__.
1. Otherwise, if _value_\["`params`"] is an array:
1. If any item in _value_\["`params`"] is not a string, then return the default URL variation config.
1. Set _result_'s no-vary params to the result of applying parse a key ({{parse-a-key}}) to each item in _value_\["`params`"].
1. Set _result_'s vary params to __wildcard__.
1. Otherwise, return the default URL variation config.
1. If _value_\["`except`"] exists:
1. If _value_\["`params`"] is not true, then return the default URL variation config.
1. If _value_\["`params`"] is not an array, then return the default URL variation config.
1. If any item in _value_\["`params`"] is not a string, then return the default URL variation config.
1. Set _result_'s no-vary params to the result of applying parse a key ({{parse-a-key}}) to each item in _value_\["`params`"].
1. If any item in _result_'s no-vary params is an error, then return the default URL variation config.
1. Set _result_'s vary params to __wildcard__.
1. Otherwise, if _value_\["`except`"] exists:
1. If _value_\["`except`"] is not an array, then return the default URL variation config.
1. If any item in _value_\["`except`"] is not a string, then return the default URL variation config.
1. Set _result_'s vary params to the result of applying parse a key ({{parse-a-key}}) to each item in _value_\["`except`"].
1. If any item in _result_'s vary params is an error, then return the default URL variation config.
1. Set _result_'s no-vary params to __wildcard__.
1. Return _result_.

{:aside}
Expand All @@ -255,33 +250,31 @@ The following illustrates how various inputs are parsed, in terms of their impac

| Input | Result |
|----------------------------------------+-----------------------------------------------------------|
| `No-Vary-Search: params` | no-vary params: __wildcard__<br>vary params: (empty list) |
| `No-Vary-Search: params=("a")` | no-vary params: « "`a`" »<br>vary params: __wildcard__ |
| `No-Vary-Search: params, except=("x")` | no-vary params: __wildcard__<br>vary params: « "`x`" » |
| `No-Vary-Search: except=("x")` | no-vary params: __wildcard__<br>vary params: « "`x`" » |
| `No-Vary-Search: params=()` | no-vary params: (empty list)<br>vary params: __wildcard__ |
| `No-Vary-Search: except=()` | no-vary params: __wildcard__<br>vary params: (empty list) |

The following inputs are all invalid and will cause the default URL variation config to be returned:

{:compact}
* `No-Vary-Search: key-order="not a boolean"`
* `No-Vary-Search: params="not a boolean or inner list"`
* `No-Vary-Search: params="not an inner list"`
* `No-Vary-Search: params=(not-a-string)`
* `No-Vary-Search: params=?1`
* `No-Vary-Search: params=?1, except=("x")`
* `No-Vary-Search: params=("a"), except=("x")`
* `No-Vary-Search: params=(), except=()`
* `No-Vary-Search: params=?0, except=("x")`
* `No-Vary-Search: params, except=(not-a-string)`
* `No-Vary-Search: params, except="not an inner list"`
* `No-Vary-Search: params, except=?1`
* `No-Vary-Search: except=("x")`
* `No-Vary-Search: except=()`
* `No-Vary-Search: except="not an inner list"`
* `No-Vary-Search: except=(not-a-string)`
* `No-Vary-Search: except=?1`

The following inputs are valid, but somewhat unconventional. They are shown alongside their more conventional form.

| Input | Conventional form |
|---------------------------------------------------+---------------------------------------------------|
| `No-Vary-Search: params=?1` | `No-Vary-Search: params` |
| `No-Vary-Search: key-order=?1` | `No-Vary-Search: key-order` |
| `No-Vary-Search: params, key-order, except=("x")` | `No-Vary-Search: key-order, params, except=("x")` |
| `No-Vary-Search: params=?0` | (omit the header field) |
| `No-Vary-Search: except=("x")`, key-order | `No-Vary-Search: key-order, except=("x")` |
| `No-Vary-Search: params=()` | (omit the header field) |
| `No-Vary-Search: key-order=?0` | (omit the header field) |

Expand Down