Membership Users Exporter

<?php
/*
Plugin Name: Membership Users Exporter
Author: Hoang Ngo
Version: 1.0
*/
add_action('admin_menu', 'me_main_menu');
add_action('wp_loaded', 'me_export_users');
function me_main_menu()
{
    add_menu_page(__("Membership Users Exporter", "me"), __("Membership Users Exporter", "me"), 'manage_options', 'me_main_menu', 'membership_users_exporter');
}

function me_export_users()
{
    if (!current_user_can('manage_options')) {
        return '';
    }
    if (isset($_POST['me_export'])) {
        $users = get_users();
        $data = array();
        global $wpdb;
        foreach ($users as $user) {
            $street_address = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "Street Address"
            ));
            $apt = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "Apt / Unit No."
            ));;
            $city = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "City"
            ));;
            $provide = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "Province"
            ));;
            $postal = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "Postal Code"
            ));
            $country = $wpdb->get_var($wpdb->prepare(
                "SELECT `value` FROM wp_bp_xprofile_data WHERE user_id = %d AND field_id = (SELECT id FROM wp_bp_xprofile_fields WHERE `name` = %s);", $user->ID, "Country"
            ));
            $subscription = array(
                'name' => '',
                'start' => '',
                'end' => '',
                'id' => ''
            );
            $member = new Membership_Model_Member($user->ID);
            $rels = $member->get_relationships();
            if (is_array($rels)) {
                foreach ($rels as $id) {
                    $sub = new Membership_Model_Subscription($id->sub_id);
                    $subscription['name'] = $sub->sub_name();
                    $subscription['start'] = $id->startdate;
                    $subscription['end'] = $id->expirydate;
                    $subscription['id'] = $id->sub_id;
                    break;
                }
            }
            $tmp = array(
                'user_login' => $user->user_login,
                'user_nicename' => $user->user_nicename,
                'user_email' => $user->user_email,
                'First Name' => $user->first_name,
                'Last Name' => $user->last_name,
                'Street Address' => $street_address,
                'Apt / Unit No.' => $apt,
                'City' => $city,
                'Provide' => $provide,
                'Postal Code' => $postal,
                'Country' => $country,
                'Subscription ID' => $subscription['id'],
                'Subscription' => $subscription['name'],
                'Start Date' => $subscription['start'],
                'Expiry Date' => $subscription['end']
            );
            $data[] = $tmp;
        }
        //build header
        if (!empty($data)) {
            $headers = array_keys($data[0]);
            $data = array_merge(array($headers), $data);
            me_download_send_headers("data_export_" . date("Y-m-d") . ".csv");
            echo me_array2csv($data);
            die;
        }
    }
}

function membership_users_exporter()
{
    ?>
    <div class="wrap">
        <form method="post">
            <h2><?php _e("Export Users", "me") ?></h2>
            <button name="me_export" type="submit"><?php _e("Download CSV", "me") ?></button>
        </form>
    </div>
<?php
}

function me_array2csv(array &$array)
{
    if (count($array) == 0) {
        return null;
    }
    ob_start();
    $df = fopen("php://output", 'w');
    fputcsv($df, array_keys(reset($array)));
    foreach ($array as $row) {
        fputcsv($df, $row);
    }
    fclose($df);
    return ob_get_clean();
}

function me_download_send_headers($filename)
{
    // disable caching
    $now = gmdate("D, d M Y H:i:s");
    header("Expires: Tue, 03 Jul 2001 06:00:00 GMT");
    header("Cache-Control: max-age=0, no-cache, must-revalidate, proxy-revalidate");
    header("Last-Modified: {$now} GMT");

    // force download
    header("Content-Type: application/force-download");
    header("Content-Type: application/octet-stream");
    header("Content-Type: application/download");

    // disposition / encoding on response body
    header("Content-Disposition: attachment;filename={$filename}");
    header("Content-Transfer-Encoding: binary");
}