How to create Unique User ID in WordPress - wordpress

Question

I need to add a users from WordPress backend. So, I want to generate unique User IDs for them. But I can achieve it. Can somebody help me out on this.
Here is what I cam so far. It is better if I could append the WordPress default generated unique user id to end of my field.
// Customize the user fields
function custom_user_profile_fields($user) {
$rand = randomGen(1000,5000,1);
$auth_Token = '2021-ABCD-'.$rand[0];
?>
<h3>Profile Information</h3>
<table class="form-table">
<tr>
<th><label for="srn">Student Registration Number</label></th>
<td>
<input type="text" class="regular-text" name="srn" value="<?php echo (get_option('srn') ? esc_attr( get_the_author_meta( 'srn', $user->ID ) ) : $auth_Token); ?>" id="srn" readonly /><br />
</td>
</tr>
</table>
<?php
}
add_action( 'show_user_profile', 'custom_user_profile_fields' );
add_action( 'edit_user_profile', 'custom_user_profile_fields' );
add_action( "user_new_form", "custom_user_profile_fields" );
function save_custom_user_profile_fields($user_id) {
# again do this only if you can
if(!current_user_can('manage_options'))
return false;
# save my custom field
update_usermeta($user_id, 'srn', $_POST['srn']);
}
add_action('user_register', 'save_custom_user_profile_fields');
add_action('profile_update', 'save_custom_user_profile_fields');
When a user added I can't get the previously saved Index Number to the field. It's generating another and showing again. As I am not an expert for this, could anybody help me out with this?
Thanks in advance

Answer 1

You were on the right path to solve the problem, but you made some mistakes.
You can use the working code below:
Creation of fields
add_action( 'user_new_form', 'bks_add_student_reg_number_field' );
add_action( 'edit_user_profile', 'bks_add_student_reg_number_field' );
add_action( 'show_user_profile', 'bks_add_student_reg_number_field' );
function bks_add_student_reg_number_field( $user ) {
?>
<h3><?php _e("Extra profile information", "blank"); ?></h3>
<table class="form-table">
<tr>
<th><label for="student_reg_number"><?php _e("Student Registration Number"); ?></label></th>
<td>
<?php if (is_object($user)) { ?>
<input type="text" name="student_reg_number" id="student_reg_number" value="<?php echo esc_attr( get_the_author_meta( 'student_reg_number', $user->ID )); ?>" class="regular-text" readonly disabled="disabled"/><br />
<?php } else { ?>
<input type="text" name="student_reg_number" id="student_reg_number" class="regular-text" /><br />
<span class="description"><?php _e("Please enter Student registration number."); ?></span>
<?php } ?>
</td>
</tr>
</table>
<?php }
This creates a field option at new user generation and edit form.
The field is only enabled when a new user is created. If the registered user has already have a value the value would be shown with no access to change it.
Save field value
add_action( 'user_register', 'bks_student_reg_number_field' );
function bks_student_reg_number_field($user_id) {
// You can maybe add checks here whch would determine if the users role is customer
// or not or maybe validate the number.
if(!current_user_can('manage_options'))
return false;
$reg_value = get_user_meta($user_id, 'student_reg_number', true);
if (isset( $_POST['student_reg_number']) && $_POST['student_reg_number'] !== $reg_value) {
update_user_meta($user_id, 'student_reg_number', $_POST['student_reg_number'].'-'.$user_id);
}
}
Only user_register hook is used to prevent updation on profile edit.
You can see the user_id appended with a - infront of it in the field and the field is readonly and disabled.
If you want user to be able to edit the id after registering as well then. do the following.
Add profile_update hook. add_action( 'profile_update', 'bks_student_reg_number_field' ); as well so that the code runs when you update the user as well.
Remove readonly and disabled attribute from the form.
The code is TESTED and WORKS.