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email_exists()

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概述

email_exists() 函数用于检查指定邮箱地址是否已在 WordPress 中注册。它返回关联的用户 ID 或 false，常用于用户注册流程中验证邮箱唯一性。

关键要点

  • 参数：$email（字符串，必需），要检查的邮箱地址
  • 返回值：成功时返回用户 ID，失败时返回 false
  • 用途：验证邮箱是否已被注册，防止重复注册
  • 相关函数：可与 username_exists() 结合使用进行用户验证
  • Hook：提供 email_exists 过滤器，允许自定义返回值

代码示例

$email = 'myemail@example.com';
$exists = email_exists( $email );
if ( $exists ) {
    echo "That E-mail is registered to user number " . $exists;
} else {
    echo "That E-mail doesn't belong to any registered users on this site";
}

注意事项

  • 此函数在 SHORTINIT 模式下未定义，使用时需确保环境支持
  • 内部基于 get_user_by() 实现，依赖用户数据表
  • 适用于主题和插件开发，特别是注册和用户管理功能
📄 原文内容

Determines whether the given email exists.

Description

For more information on this and similar theme functions, check out the Conditional Tags article in the Theme Developer Handbook.

Parameters

$emailstringrequired
The email to check for existence.

Return

int|false The user ID on success, false on failure.

More Information

This function will check whether or not a given email address ($email) has already been registered to a username, and returns that users ID (or false if none exists). See also username_exists.

This function is normally used when a user is registering, to ensure that the E-mail address the user is attempting to register with has not already been registered.

Source

function email_exists( $email ) {
	$user = get_user_by( 'email', $email );
	if ( $user ) {
		$user_id = $user->ID;
	} else {
		$user_id = false;
	}

	/**
	 * Filters whether the given email exists.
	 *
	 * @since 5.6.0
	 *
	 * @param int|false $user_id The user ID associated with the email,
	 *                           or false if the email does not exist.
	 * @param string    $email   The email to check for existence.
	 */
	return apply_filters( 'email_exists', $user_id, $email );
}

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Hooks

apply_filters( ’email_exists’, int|false $user_id, string $email )

Filters whether the given email exists.

Uses Description
get_user_by()wp-includes/pluggable.php

Retrieves user info by a given field.
apply_filters()wp-includes/plugin.php

Calls the callback functions that have been added to a filter hook.
Used by Description
WP_REST_Users_Controller::update_item()wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php

Updates a single user.
send_confirmation_on_profile_email()wp-includes/user.php

Sends a confirmation request email when a change of user email address is attempted.
edit_user()wp-admin/includes/user.php

Edit user settings based on contents of $_POST
register_new_user()wp-includes/user.php

Handles registering a new user.
wp_insert_user()wp-includes/user.php

Inserts a user into the database.
wpmu_validate_user_signup()wp-includes/ms-functions.php

Sanitizes and validates data required for a user sign-up.

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Changelog

Version Description
2.1.0 Introduced.

User Contributed Notes

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    Codex


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    Example
    If the E-mail exists, echo the ID number to which the E-mail is registered. Otherwise, tell the viewer that it does not exist.

    $email = 'myemail@example.com';
$exists = email_exists( $email );
if ( $exists ) {
	echo "That E-mail is registered to user number " . $exists;
} else {
	echo "That E-mail doesn't belong to any registered users on this site";
}