Struct hyper::header::EntityTag [−] [src]

pub struct EntityTag {
    pub weak: bool,
    // some fields omitted
}

An entity tag, defined in RFC7232

An entity tag consists of a string enclosed by two literal double quotes. Preceding the first double quote is an optional weakness indicator, which always looks like W/. Examples for valid tags are "xyzzy" and W/"xyzzy".

ABNF

entity-tag = [ weak ] opaque-tag
weak       = %x57.2F ; "W/", case-sensitive
opaque-tag = DQUOTE *etagc DQUOTE
etagc      = %x21 / %x23-7E / obs-text
           ; VCHAR except double quotes, plus obs-text

Comparison

To check if two entity tags are equivalent in an application always use the strong_eq or weak_eq methods based on the context of the Tag. Only use == to check if two tags are identical.

The example below shows the results for a set of entity-tag pairs and both the weak and strong comparison function results:

ETag 1 ETag 2 Strong Comparison Weak Comparison
W/"1" W/"1" no match match
W/"1" W/"2" no match no match
W/"1" "1" no match match
"1" "1" match match

Fields

Weakness indicator for the tag