在下面收集的ABNF中,列表规则根据[RFC7230]的第1.2节进行了扩展。
Age = delta-seconds
Cache-Control = *( "," OWS ) cache-directive *( OWS "," [ OWS cache-directive ] )
Expires = HTTP-date
HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1>
OWS = <OWS, see [RFC7230], Section 3.2.3>
Pragma = *( "," OWS ) pragma-directive *( OWS "," [ OWS pragma-directive ] )
Warning = *( "," OWS ) warning-value *( OWS "," [ OWS warning-value ] )
cache-directive = token [ "=" ( token / quoted-string ) ]
delta-seconds = 1*DIGIT
extension-pragma = token [ "=" ( token / quoted-string ) ]
field-name = <field-name, see [RFC7230], Section 3.2>
port = <port, see [RFC7230], Section 2.7>
pragma-directive = "no-cache" / extension-pragma
pseudonym = <pseudonym, see [RFC7230], Section 5.7.1>
quoted-string = <quoted-string, see [RFC7230], Section 3.2.6>
token = <token, see [RFC7230], Section 3.2.6>
uri-host = <uri-host, see [RFC7230], Section 2.7>
warn-agent = ( uri-host [ ":" port ] ) / pseudonym
warn-code = 3DIGIT
warn-date = DQUOTE HTTP-date DQUOTE
warn-text = quoted-string
warning-value = warn-code SP warn-agent SP warn-text [ SP warn-date ]