Function reqwest::header::parsing::parse_extended_value

pub fn parse_extended_value(val: &str) -> Result<ExtendedValue, Error>

Parses extended header parameter values (ext-value), as defined in RFC 5987.

Extended values are denoted by parameter names that end with *.

ABNF

ext-value     = charset  "'" [ language ] "'" value-chars
              ; like RFC 2231's <extended-initial-value>
              ; (see [RFC2231], Section 7)

charset       = "UTF-8" / "ISO-8859-1" / mime-charset

mime-charset  = 1*mime-charsetc
mime-charsetc = ALPHA / DIGIT
              / "!" / "#" / "$" / "%" / "&"
              / "+" / "-" / "^" / "_" / "`"
              / "{" / "}" / "~"
              ; as <mime-charset> in Section 2.3 of [RFC2978]
              ; except that the single quote is not included
              ; SHOULD be registered in the IANA charset registry

language      = <Language-Tag, defined in [RFC5646], Section 2.1>

value-chars   = *( pct-encoded / attr-char )

pct-encoded   = "%" HEXDIG HEXDIG
              ; see [RFC3986], Section 2.1

attr-char     = ALPHA / DIGIT
              / "!" / "#" / "$" / "&" / "+" / "-" / "."
              / "^" / "_" / "`" / "|" / "~"
              ; token except ( "*" / "'" / "%" )