Vary
The Vary
HTTP response header describes the parts of the request message aside from the method and URL that influenced the content of the response it occurs in. Most often, this is used to create a cache key when content negotiation is in use.
The same Vary
header value should be used on all responses for a given URL, including 304
Not Modified
responses and the "default" response.
Header type | Response header |
---|---|
Forbidden header name | no |
Syntax
http
Vary: *
Vary: <header-name>, <header-name>, ...
Directives
- *
-
Indicates that factors other than request headers influenced the generation of this response. Implies that the response is uncacheable.
- <header-name>
-
A comma-separated list of request header names that could have influenced the generation of this response.
Specifications
Specification |
---|
HTTP Semantics # field.vary |
Browser compatibility
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