A Slash command to retrieve earnings in Restrict Content Pro for the specified time period. Based on http://wpninjas.com/using-slack-slash-commands-to-get-edd-sales-info/

edd-slack-slash-command.php

<?php

function pw_rcp_earnings_slash_command() {

    # Check to make sure this is a Slash Command Request
    if ( ! isset( $_REQUEST['slack_slash'] ) && 'your_custom_string' != $_REQUEST['slack_slash'] )
        return false;

    # Check to see if a token has been passed as well
    if ( ! isset( $_REQUEST['token'] ) )
        return false;

    # Set additional text strings if sent
    $text = isset ( $_REQUEST['text'] ) ? $_REQUEST['text'] : '';

    # Check that the token is the one that was set in Slack
    if ( 'your_slack_token' == $_REQUEST['token'] ) {

        # Gather EDD sales data
        $stats = new RCP_Payments;
        $args  = array();

        # check additional text to display appriate data
        switch ( $_REQUEST['text'] ) {
            case 'day':
                $args['date']['day'] = date( 'd' );
                $args['date']['month'] = date( 'n' );
                $args['date']['year'] = date( 'y' );
                break;
            case 'month':
                $args['date']['month'] = date( 'n' );
                $args['date']['year'] = date( 'y' );
                break;
            case 'year':
                $args['date']['year'] = date( 'y' );
                break;
            case 'lifetime':
                // Default for get_earnings()
                break;
        }

        echo '$' . $stats->get_earnings( $args );
        # We need to die or you will send a bunch of html that Slack won't be able to handle
        die();
    }

}
add_action( 'init', 'pw_rcp_earnings_slash_command' );