Create Unique ID for user

Question

I have to create a membership site, but I need to give every user that registers a automatic ID number.

For example,

• User 2 - has a code - pay-102

• User 3 - has a code - pay-103

I did a forum search and found this, its pretty much what I am asking - What is the fastest way to generate a unique id number when registering a user

I've got a piece of code that will add it to the user panel in the admin area:

function fb_add_custom_user_profile_fields( $user ) {
?>
<h3><?php _e('Extra Profile Informations', 'themename'); ?></h3>
<table class="form-table">
    <tr>
        <th>
            <label for="memnumber"><?php _e('memnumber', 'themename'); ?>
        </label></th>
        <td>
            <input type="text" name="memnumber" id="memnumber" value="<?php echo esc_attr( get_the_author_meta( 'memnumber', $user->ID ) ); ?>" class="regular-text" /><br />
            <span class="description"><?php _e('Please enter your Membership number.', 'themename'); ?></span>
        </td>
    </tr>
</table>
<?php }
function fb_save_custom_user_profile_fields( $user_id ) {
if ( !current_user_can( 'edit_user', $user_id ) )
    return FALSE;
update_usermeta( $user_id, 'memnumber', $_POST['memnumber'] );
}
add_action( 'show_user_profile', 'fb_add_custom_user_profile_fields' );
add_action( 'edit_user_profile', 'fb_add_custom_user_profile_fields' );
add_action( 'personal_options_update', 'fb_save_custom_user_profile_fields' );
add_action( 'edit_user_profile_update', 'fb_save_custom_user_profile_fields' );

How do I populate that field, with an incremental number that is assigned?

Answer 1

Here is some code that reads the highest number from the user meta table and then adds +1 to that number. This saves that number for each newly registered user. The code is triggered via the action hook "user_register".

add_action( 'user_register', 'assignuserid');

function assignuserid($user_id) {
   global $wpdb;
   $latestid=$wpdb->get_var("SELECT meta_value from $wpdb->usermeta where meta_key='memnumber' order by meta_value DESC limit 1;");
   update_user_meta( $user_id, 'memnumber', $latestid+1 );
}

Note: If the "pay-" is fixed, it does not need to be part of the code that stores the value, only part of the output. i.e:

echo "Your userid: PAY-"+$userid.

Answer 2

Here is a better solution:

add_filter("user_register", "get_unique");
function get_unique($user_id){
    $prefix = "PAY-";
    do {
        $unique = mt_rand();
        $unique = substr($unique, 0, 3);
        $unique = $prefix . $unique;
    } while (!check_unique($unique));
    return update_usermeta( $user_id, 'memnumber', $unique );//$unique;
}
function check_unique($unique) {
    global $wpdb;
    $result = $wpdb->get_var("SELECT meta_value from $wpdb->usermeta where meta_key='memnumber' AND meta_value = '$unique'");
    if(empty($result))
        return true;
    return false;
}