parseMaxAge function
Returns the max-age seconds from a Cache-Control cacheControl string,
or null if the directive is absent or its value is not a non-negative int.
Audited: 2026-06-12 11:26 EDT
Implementation
int? parseMaxAge(String cacheControl) {
final String? value = parseCacheControl(cacheControl)['max-age'];
if (value == null) {
return null;
}
final int? seconds = int.tryParse(value);
// A negative max-age is not meaningful; reject it like a parse failure.
if (seconds == null || seconds < 0) {
return null;
}
return seconds;
}