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函数文档

wp_generate_uuid4()

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概述

wp_generate_uuid4() 是 WordPress 中用于生成随机 UUID（版本 4）的函数，返回一个符合标准格式的字符串。该函数基于 mt_rand() 实现，但开发者需注意其潜在的重复生成风险。

关键要点

  • 函数生成一个随机 UUID（版本 4），返回 36 字符的字符串，格式为 8-4-4-4-12 的十六进制数字，用连字符分隔。
  • UUID 是 128 位值（16 字节），应视为大小写不敏感，函数始终返回小写字符串。
  • 由于使用 mt_rand()，在相同种子下可能产生重复 UUID，导致碰撞问题，建议在需要高唯一性时考虑替代方案。
  • 函数自 WordPress 4.7.0 版本引入，常用于 WP_Application_Passwords 和 WP_Customize_Manager 等类中。

注意事项

  • mt_rand() 的随机性依赖于种子，重复种子会生成相同 UUID，可能引发碰撞，需谨慎使用。
  • 用户贡献笔记中提到，可通过 mt_srand() 结合其他参数（如微秒时间、用户 IP）来改善随机性，但这不是官方推荐做法。
📄 原文内容

Generates a random UUID (version 4).

Return

string UUID.

Source

function wp_generate_uuid4() {
	return sprintf(
		'%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
		mt_rand( 0, 0xffff ),
		mt_rand( 0, 0xffff ),
		mt_rand( 0, 0xffff ),
		mt_rand( 0, 0x0fff ) | 0x4000,
		mt_rand( 0, 0x3fff ) | 0x8000,
		mt_rand( 0, 0xffff ),
		mt_rand( 0, 0xffff ),
		mt_rand( 0, 0xffff )
	);
}

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Used by Description
WP_Application_Passwords::create_new_application_password()wp-includes/class-wp-application-passwords.php

Creates a new application password.
WP_Application_Passwords::get_user_application_passwords()wp-includes/class-wp-application-passwords.php

Gets a user’s application passwords.
WP_Customize_Manager::establish_loaded_changeset()wp-includes/class-wp-customize-manager.php

Establishes the loaded changeset.
WP_Customize_Manager::_publish_changeset_values()wp-includes/class-wp-customize-manager.php

Publishes the values of a changeset.
WP_Customize_Manager::save_changeset_post()wp-includes/class-wp-customize-manager.php

Saves the post for the loaded changeset.
WP_Customize_Manager::save()wp-includes/class-wp-customize-manager.php

Handles customize_save WP Ajax request to save/update a changeset.
WP_Customize_Manager::__construct()wp-includes/class-wp-customize-manager.php

Constructor.

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Changelog

Version Description
4.7.0 Introduced.

User Contributed Notes

  1. Skip to note 3 content


    thanasisxan


    You must log in to vote on the helpfulness of this noteVote results for this note: 4You must log in to vote on the helpfulness of this note

    It should be noted that using this function to generate uuid’s WILL lead to collisions by creating duplicates, I found out not the fun way.

    The function mt_rand() used will always produce the same sequence of random numbers given the same seed. So every time a seed is repeated, the same exact UUID is generated.

    To get around this, you would need to seed it using something else for example: 

    mt_srand( crc32( serialize( array( microtime( true ), 'USER_IP', 'ETC' ) ) ) );

  2. Skip to note 4 content


    Philipp Stracker


    You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note

    Sample result: 11223344-5566-7788-99AA-BBCCDDEEFF00

    A UUID represents a 128-bit value (16 bytes): It contains four 4-byte digits that are represented in hex notation, and are segmented by 4 “-” symbols. The total length is 36 characters.

    The “-” symbols appear after byte 4, byte 6, byte 8 and after byte 10.

    Because it’s a hex-value, a UUID should be treated in a case-insensitive manner:
    11223344-5566-7788-99AA-BBCCDDEEFF00 is identical to 11223344-5566-7788-99aa-bbccddeeff00

    This function always returns a lower-case string.

    To get a 32-character string (same as MD5) you could use: