How to register a user to a group by an invitation code?

Question

I'm working on a site where I'd like anyone to be able to sign up, but people who sign up with an invitation code would automatically be registered to an existing group associated with that code. How can I do this?

I have not yet chosen how groups will be created, but I know that this can be done with one of these plugins: Groups, User Groups or Simple Groups. The same with invitation codes, there are very good plugins for this: CM Invitation Codes, Register Plus Redux or Pie Register. What is missing is an intermediate tool (code/function) that will associate some groups with some invitation codes.

Answer 1

Not sure how you want to handle groups, but it could just be user_meta.

Regardless, you could use Gravity Forms + user registration add-on to process a user registration and determine what group the user should be added to. This should work even if you are using third-party hooks.

If it's simple user_meta, you can just check for that wherever you want to limit membership, and avoid stacking up tons of third party plugins.

Here is an example.

// assign group based on code input
add_action('gform_after_submission', 'the_grouper', 10, 2);
function the_grouper($entry, $form){
    $current_user = wp_get_current_user();
    $current_user_id = $current_user->ID;

    switch $entry['group_code'] {
        case 'CODE_123' :
            $group = 'group_123';
            break;

        case 'CODE_ABC' :
            $group = 'group_abc';
            break;
        // etc

        default:
            $group = false;
            break;
    }

    if($group){
        update_metadata('user', $current_user_id, 'the_group', $group);
    }
}

Answer 2

This is what you need! A simple solution...

http://codecanyon.net/item/gravity-forms-invitation-codes/11441758