Expand description
If-None-Match
header, defined
in RFC 7232 §3.2
The If-None-Match
header field makes the request method conditional
on a recipient cache or origin server either not having any current
representation of the target resource, when the field-value is “*”,
or having a selected representation with an entity-tag that does not
match any of those listed in the field-value.
A recipient MUST use the weak comparison function when comparing entity-tags for If-None-Match (Section 2.3.2), since weak entity-tags can be used for cache validation even if there have been changes to the representation data.
ABNF
If-None-Match = "*" / 1#entity-tag
Example Values
"xyzzy"
W/"xyzzy"
"xyzzy", "r2d2xxxx", "c3piozzzz"
W/"xyzzy", W/"r2d2xxxx", W/"c3piozzzz"
*
Examples
use actix_web::HttpResponse;
use actix_web::http::header::IfNoneMatch;
let mut builder = HttpResponse::Ok();
builder.insert_header(IfNoneMatch::Any);
use actix_web::HttpResponse;
use actix_web::http::header::{IfNoneMatch, EntityTag};
let mut builder = HttpResponse::Ok();
builder.insert_header(
IfNoneMatch::Items(vec![
EntityTag::new(false, "xyzzy".to_owned()),
EntityTag::new(false, "foobar".to_owned()),
EntityTag::new(false, "bazquux".to_owned()),
])
);
Variants
Any
Any value is a match
Items(Vec<EntityTag>)
Only the listed items are a match
Trait Implementations
Returns the name of the header field.
Parse the header from a HTTP message.
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
This method tests for !=
.
type Error = InvalidHeaderValue
type Error = InvalidHeaderValue
The type returned in the event of a conversion error.
Try to convert value to a HeaderValue.
Auto Trait Implementations
impl RefUnwindSafe for IfNoneMatch
impl Send for IfNoneMatch
impl Sync for IfNoneMatch
impl Unpin for IfNoneMatch
impl UnwindSafe for IfNoneMatch
Blanket Implementations
Mutably borrows from an owned value. Read more
type Error = <T as TryIntoHeaderValue>::Error
pub fn try_into_pair(
self
) -> Result<(HeaderName, HeaderValue), <T as TryIntoHeaderPair>::Error>
pub fn vzip(self) -> V
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more