Adding Custom Columns To CSV Export

There are two steps to adding custom columns to a members or payments export:

1. Add your column header
2. Add the column data for each member or payment

Adding Your Column Header

A custom column is added with the following filter: rcp_export_csv_cols_{$export_type}, where $export_type is either "members" (for a memberships export) or "payments" (for a payment export).

Here's an example for adding a new "Referrer" column to the memberships export:

/**
 * Add new export column for "Referrer".
 * 
 * @param array $columns Default column headers.
 * 
 * @return array
 */
function ag_rcp_members_export_referrer_header( $columns ) {
    $columns['referrer'] = __( 'Referrer' );

    return $columns;
}
add_filter( 'rcp_export_csv_cols_members', 'ag_rcp_members_export_referrer_header' );

Adding The Column Value For Each Row

The next step is to add the corresponding value for each member or payment.

Memberships

For memberships, this is done with the   rcp_export_memberships_get_data_row filter. Two parameters are passed in:

1. $row (array) - An array of key/value pairs for the current membership. 
2. $membership (RCP_Membership) - RCP_Membership object for the current membership being exported.

Here's an example for adding the referrer metadata for each membership:

/**
 * Add the referrer meta value for each membership.
 * 
 * @param array          $row        Array of data to be exported for the current membership.
 * @param RCP_Membership $membership Membership object.
 * 
 * @return array
 */
function ag_rcp_memberships_export_referrer( $row, $membership ) {
	$row['referrer'] = rcp_get_membership_meta( $membership->get_id(), 'referrer', true );

	// Or you can add a piece of user meta like this:
	// $row['my_field'] = get_user_meta( $membership->get_customer()->get_user_id(), 'my_custom_field', true );

	return $row;
}
add_filter( 'rcp_export_memberships_get_data_row', 'ag_rcp_memberships_export_referrer', 10, 2 );

Payments

For payments, this is done with the  rcp_export_payments_get_data_row filter. Two parameters are passed in:

1. $row (array) - An array of key/value pairs for the current payment.
2. $payment (object) - Payment object from the database. The payment ID can be retrieved with: $payment->id

Here's an example for adding the transaction ID for each payment (note: you also need to add the column header, as explained previously):

/**
 * Add the transaction ID value for each payment.
 * 
 * @param array  $row     Array of data to be exported for the current payment.
 * @param object $payment Payment object from the database.
 * 
 * @return array
 */
function ag_rcp_payments_export_transaction_id( $row, $payment ) {
    $row['transaction_id'] = $payment->transaction_id;

    return $row;
}
add_filter( 'rcp_export_payments_get_data_row', 'ag_rcp_payments_export_transaction_id', 10, 2 );