Using WordPress ‘pre_user_nickname’ PHP filter

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

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).