The DateTimeInterface interface

    (PHP 5 >= 5.5.0, PHP 7, PHP 8)

    Introduction

    DateTimeInterface was created so that parameter, return, or property type declarations may accept either DateTimeImmutable or DateTime as a value. It is not possible to implement this interface with userland classes.

    Common constants that allow for formatting DateTimeImmutable or DateTime objects through DateTimeImmutable::format() and DateTime::format() are also defined on this interface.

    Interface synopsis

    interfaceDateTimeInterface {
    publicconststringATOM = "Y-m-d\\TH:i:sP";
    publicconststringCOOKIE = "l, d-M-Y H:i:s T";
    publicconststringISO8601 = "Y-m-d\\TH:i:sO";
    publicconststringISO8601_EXPANDED = "X-m-d\\TH:i:sP";
    publicconststringRFC822 = "D, d M y H:i:s O";
    publicconststringRFC850 = "l, d-M-y H:i:s T";
    publicconststringRFC1036 = "D, d M y H:i:s O";
    publicconststringRFC1123 = "D, d M Y H:i:s O";
    publicconststringRFC7231 = "D, d M Y H:i:s \\G\\M\\T";
    publicconststringRFC2822 = "D, d M Y H:i:s O";
    publicconststringRFC3339 = "Y-m-d\\TH:i:sP";
    publicconststringRFC3339_EXTENDED = "Y-m-d\\TH:i:s.vP";
    publicconststringRSS = "D, d M Y H:i:s O";
    publicconststringW3C = "Y-m-d\\TH:i:sP";
    publicdiff(DateTimeInterface$targetObject, bool$absolute = false): DateInterval
    publicformat(string$format): string
    publicgetOffset(): int
    publicgetTimestamp(): int
    publicgetTimezone(): DateTimeZone|false
    public__wakeup(): void
    }

    Predefined Constants

    DateTimeInterface::ATOM
    DATE_ATOM
    Atom (example: 2005-08-15T15:52:01+00:00)
    DateTimeInterface::COOKIE
    DATE_COOKIE
    HTTP Cookies (example: Monday, 15-Aug-2005 15:52:01 UTC)
    DateTimeInterface::ISO8601
    DATE_ISO8601
    ISO-8601 (example: 2005-08-15T15:52:01+0000)

    Note: This format is not compatible with ISO-8601, but is left this way for backward compatibility reasons. Use DateTimeInterface::ISO8601_EXPANDED, DateTimeInterface::ATOM for compatibility with ISO-8601 instead. (ref ISO8601:2004 section 4.3.3 clause d)

    DateTimeInterface::ISO8601_EXPANDED
    DATE_ISO8601_EXPANDED
    ISO-8601 Expanded (example: +10191-07-26T08:59:52+01:00)

    Note: This format allows for year ranges outside of ISO-8601's normal range of 0000-9999 by always including a sign character. It also addresses that that timezone part (+01:00) is compatible with ISO-8601.

    DateTimeInterface::RFC822
    DATE_RFC822
    RFC 822 (example: Mon, 15 Aug 05 15:52:01 +0000)
    DateTimeInterface::RFC850
    DATE_RFC850
    RFC 850 (example: Monday, 15-Aug-05 15:52:01 UTC)
    DateTimeInterface::RFC1036
    DATE_RFC1036
    RFC 1036 (example: Mon, 15 Aug 05 15:52:01 +0000)
    DateTimeInterface::RFC1123
    DATE_RFC1123
    RFC 1123 (example: Mon, 15 Aug 2005 15:52:01 +0000)
    DateTimeInterface::RFC7231
    DATE_RFC7231
    RFC 7231 (since PHP 7.0.19 and 7.1.5) (example: Sat, 30 Apr 2016 17:52:13 GMT)
    DateTimeInterface::RFC2822
    DATE_RFC2822
    RFC 2822 (example: Mon, 15 Aug 2005 15:52:01 +0000)
    DateTimeInterface::RFC3339
    DATE_RFC3339
    Same as DATE_ATOM
    DateTimeInterface::RFC3339_EXTENDED
    DATE_RFC3339_EXTENDED
    RFC 3339 EXTENDED format (example: 2005-08-15T15:52:01.000+00:00)
    DateTimeInterface::RSS
    DATE_RSS
    RSS (example: Mon, 15 Aug 2005 15:52:01 +0000)
    DateTimeInterface::W3C
    DATE_W3C
    World Wide Web Consortium (example: 2005-08-15T15:52:01+00:00)

    Changelog

    VersionDescription
    8.2.0 The constant DateTimeInterface::ISO8601_EXPANDED was added.
    7.2.0 The class constants of DateTime are now defined on DateTimeInterface.

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