pub fn parse_retry_after(s: &str) -> Option<RetryAfter>Expand description
Parse a Retry-After field value per RFC 9110 §10.2.3.
ABNF: Retry-After = HTTP-date / delay-seconds where
delay-seconds = 1*DIGIT. The grammar is delay-seconds
disjoint from HTTP-date, so we try delay-seconds first
(cheaper, ambiguity-free — pure digits cannot match any of the
three HTTP-date forms which all start with an alphabetic weekday
name or token) then fall back to parse_http_date.
Returns None on syntactically invalid input (leading sign,
non-numeric characters in the delay-seconds form that also fail
every HTTP-date form, empty input, etc.). §10.2.3 makes
delay-seconds “a non-negative decimal integer” — we reject a
leading + or - even though Rust’s u64::parse would refuse
- natively, because + would otherwise parse successfully.