restrict-content-pro-mailchimp.php

<?php
/*
Plugin Name: Restrict Content Pro - MailChimp User Sync
Description: Sync RCP members with MailChimp (opt-in)
Version: 1.0
Author: Danny van Kooten
Author URI: http://dvk.co/
*/

add_action( 'rcp_after_password_registration_field', 'rcp_mailchimp_add_profile_fields' );
add_action( 'rcp_profile_editor_after', 'rcp_mailchimp_add_profile_fields' );
add_action( 'rcp_form_processing', 'rcp_mailchimp_save_profile_fields', 10, 2 );
add_action( 'rcp_user_profile_updated', 'rcp_mailchimp_save_profile_fields', 10 );

add_filter( 'mailchimp_sync_should_sync_user', 'rcp_mailchimp_should_subscribe', 10, 2 );
add_filter( 'mailchimp_sync_subscriber_data', 'rcp_mailchimp_user_data', 10, 2 );

function rcp_mailchimp_add_profile_fields( $user_id = 0 ) {
    $selected = $user_id && get_user_meta( $user_id, 'rcp_mailchimp', true );

    ?>
    <br />
    <p>
        <label style="width: 100%; float: none;"><input type="checkbox" name="rcp_mailchimp" value="1" <?php checked( $selected ); ?>> Subscribe to our newsletter?</label>
    </p>
    <?php
}

function rcp_mailchimp_save_profile_fields( $posted, $user_id ) {

    if( is_numeric( $posted ) ) {
        $user_id = $posted;
        $posted = $_POST;
    }

    if( $posted['rcp_mailchimp'] ) {
        update_user_meta( $user_id, 'rcp_mailchimp', 1 );
    } else {
        delete_user_meta( $user_id, 'rcp_mailchimp' );
    }
}

function rcp_mailchimp_should_subscribe( $should, $user ) {

    if( ! $should ) {
        return false;
    }

    $should = (bool) get_user_meta( $user->ID, 'rcp_mailchimp', true );

    return $should;
}

function rcp_mailchimp_subscriber_data( MC4WP_MailChimp_Subscriber $subscriber, WP_User $user ) {

    // map of RCP subscription ID => MailChimp interest ID
    $map = array(
        '1' => "interest-id-1",     // Trade Membership
        '2' => "interest-id-2",     // Artist Membership
        '3' => "interest-id-3",     // Associate Membership
        '4' => "d8v1k2ilx",         // Corporate Membership
        '5' => "a0192m3az",         // Supporter Membership
    );

    // get RCP subscription ID
    $subscription_id = rcp_get_subscription_id( $user->ID );

    // see if this maps to a known interest
    if( isset( $map[ $subscription_id ] ) ) {
        $interest_id = $map[ $subscription_id ];
        $subscriber->interests[ $interest_id ] = true;
    }

    // return modified subscriber object
   return $subscriber;
}