fg-events-manager-hack.php

<?php
/*
Plugin Name: FG Events Manager Hack
Plugin URI:
Description: Modifies the behaviour of Events Manager plugin
  Add the start event date in the permalink using the format /YYYY/mm/dd
Author: Frédéric GILLES
Version: 1.0
*/

/**
 * Add the start event date in the permalink
 *
 * @param string $event_link Event link
 * @param object $object Event object
 * @return string Event link
 */
function fg_events_manager_get_permalink($event_link, $object) {
    $start_date = $object->event_start_date;
    $start_date = str_replace('-', '/', $start_date);
    $event_slug = get_site_option('dbem_cp_events_slug');
    $event_link = str_replace($event_slug, $event_slug.'/'.$start_date, $event_link);
    return $event_link;
}

add_filter('em_event_get_permalink', 'fg_events_manager_get_permalink', 10, 2);

/**
 * Add a rewrite rule to accept the date in the permalink
 *
 */
function fg_events_manager_add_rules() {
    $event_slug = get_site_option('dbem_cp_events_slug');
    add_rewrite_rule($event_slug.'/\d+/\d+/\d+/(.+)$', 'index.php?post_type=event&name=$matches[1]', 'top'); // single event

    //flush_rewrite_rules(); // To remove
}

add_action('init', 'fg_events_manager_add_rules', 9); // Must be run before events manager

/**
 * Plugin activation
 *
 */
function fg_events_manager_activate() {
    fg_events_manager_add_rules();
    flush_rewrite_rules();
}

register_activation_hook( __FILE__, 'fg_events_manager_activate' );

/**
 * Plugin deactivation
 *
 */
function fg_events_manager_deactivate() {
    flush_rewrite_rules();
}

register_deactivation_hook( __FILE__, 'fg_events_manager_deactivate' );