Using WordPress ‘pre_user_nickname’ PHP filter

‘pre_user_nickname’ allows you to modify a user’s nickname before it is saved during the user creation or update process in WordPress.

Table of contents

Usage

To use this filter, you need to add your custom function to it using add_filter():

add_filter('pre_user_nickname', 'your_custom_function', 10, 1);
function your_custom_function( $nickname ) { 
// Your custom code here 
}

Parameters

• $nickname (string): The user’s nickname.

Examples

Capitalize First Letter of Nickname

function capitalize_first_letter($nickname) {
    return ucfirst($nickname);
}
add_filter('pre_user_nickname', 'capitalize_first_letter', 10, 1);

This example ensures that the first letter of the user’s nickname is always capitalized.

Replace Spaces with Hyphens

function replace_spaces_with_hyphens($nickname) {
    return str_replace(' ', '-', $nickname);
}
add_filter('pre_user_nickname', 'replace_spaces_with_hyphens', 10, 1);

This example replaces any spaces in the user’s nickname with hyphens.

Append User Role to Nickname

function append_user_role_to_nickname($nickname) {
    $user = wp_get_current_user();
    $role = array_shift($user->roles);
    return $nickname . '_' . $role;
}
add_filter('pre_user_nickname', 'append_user_role_to_nickname', 10, 1);

This example appends the user’s role to their nickname.

Add Prefix to Nickname

function add_prefix_to_nickname($nickname) {
    return 'WP_' . $nickname;
}
add_filter('pre_user_nickname', 'add_prefix_to_nickname', 10, 1);

This example adds a “WP_” prefix to the user’s nickname.

Set Nickname to Email Local Part

function set_nickname_to_email_local_part($nickname) {
    $user = wp_get_current_user();
    $email = $user->user_email;
    $local_part = substr($email, 0, strpos($email, '@'));
    return $local_part;
}
add_filter('pre_user_nickname', 'set_nickname_to_email_local_part', 10, 1);

This example sets the user’s nickname to the local part of their email address (the part before the @ symbol).