php - PHP 中的 RFC1123 和 RFC2822 日期时间格式有什么区别？

Question

这是出于好奇，而不是因为此时我需要了解它，但在 PHP 手册中，它们是相同的；我看不出为什么同一件事有两种不同的数据格式。

http://php.net/manual/en/class.datetime.php

const string RFC1123 = "D, d M Y H:i:s O" ;
const string RFC2822 = "D, d M Y H:i:s O" ;

有什么线索吗？

Answer 1

RFC1123 是“Internet 主机的要求 - 应用和支持”，1989 年 10 月

RFC2822 是“Internet 消息格式”，2001 年 4 月

将 RFC1123 视为 RFC2822 的父级。它引用 RFC2822 作为日期/时间的适当规范，如下所示:

3.3. Date and Time Specification

Date and time occur in several header fields. This section specifies the syntax for a full date and time specification. Though folding white space is permitted throughout the date-time specification, it is RECOMMENDED that a single space be used in each place that FWS appears (whether it is required or optional); some older implementations may not interpret other occurrences of folding white space correctly.

date-time = [ day-of-week "," ] date FWS time [CFWS]

day-of-week = ([FWS] day-name) / obs-day-of-week

day-name = "Mon" / "Tue" / "Wed" / "Thu" / "Fri" / "Sat" / "Sun"

date = day month year

year = 4*DIGIT / obs-year

month = (FWS month-name FWS) / obs-month

month-name = "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" / "Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec"

day = ([FWS] 1*2DIGIT) / obs-day

time = time-of-day FWS zone

time-of-day = hour ":" minute [ ":" second ]

hour = 2DIGIT / obs-hour

minute = 2DIGIT / obs-minute

second = 2DIGIT / obs-second

zone = (( "+" / "-" ) 4DIGIT) / obs-zone