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    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

    interface DateTimeInterface {
    /* Constants */
    public const string ATOM = "Y-m-d\\TH:i:sP";
    public const string COOKIE = "l, d-M-Y H:i:s T";
    public const string ISO8601 = "Y-m-d\\TH:i:sO";
    public const string ISO8601_EXPANDED = "X-m-d\\TH:i:sP";
    public const string RFC822 = "D, d M y H:i:s O";
    public const string RFC850 = "l, d-M-y H:i:s T";
    public const string RFC1036 = "D, d M y H:i:s O";
    public const string RFC1123 = "D, d M Y H:i:s O";
    public const string RFC7231 = "D, d M Y H:i:s \\G\\M\\T";
    public const string RFC2822 = "D, d M Y H:i:s O";
    public const string RFC3339 = "Y-m-d\\TH:i:sP";
    public const string RFC3339_EXTENDED = "Y-m-d\\TH:i:s.vP";
    public const string RSS = "D, d M Y H:i:s O";
    public const string W3C = "Y-m-d\\TH:i:sP";
    /* Methods */
    public diff(DateTimeInterface $targetObject, bool $absolute = false): DateInterval
    public format(string $format): string
    public getOffset(): int
    public getTimestamp(): int
    public getTimezone(): DateTimeZone|false
    public __wakeup(): void
    }

    Predefined Constants

    DateTimeInterface::ATOM string
    DATE_ATOM
    Atom (example: 2005-08-15T15:52:01+00:00)
    DateTimeInterface::COOKIE string
    DATE_COOKIE
    HTTP Cookies (example: Monday, 15-Aug-2005 15:52:01 UTC)
    DateTimeInterface::ISO8601 string
    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 string
    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 ensures that the timezone part (+01:00) is compatible with ISO-8601.

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

    Changelog

    Version Description
    8.4.0 The class constants are now typed.
    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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    User Contributed Notes 1 note

    up
    5
    bohwaz
    2 years ago
    Please note that if you are using DATE_RFC7231 format (used in HTTP/1.1), you'll need to change the DateTime object timezone to GMT *before*, or you'll encounter weird results, as this format DOES NOT convert the date to GMT.

    So if you have a DateTime object using UTC+01:00 as its timezone, you will get a difference of 1 hour between your resulting date string and what should be the "correct" date.

    Recommended use:

    <?php
    $date_gmt     = clone $date;
    $date_gmt->setTimezone(new \DateTimeZone('GMT'));
    echo     $date_gmt->format(DATE_RFC7231);
    ?>
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