Properly flush rewrite rules on plugin activation

Question

I am working on a plugin which register a custom post type, using a custom rewrite structure, defined as follows:

  /**
   * create_ldp_type - LDP Resource post type creation and registration
   *
   * @return {type}  description
   */
  public function create_ldp_type() {
      register_post_type('ldp_resource',
          array(
              'labels'  => array(
                  'name'              => __('Resources', 'wpldp'),
                  'singular_name'     => __('Resource', 'wpldp'),
                  'all_items'         => __('All resources', 'wpldp'),
                  'add_new_item'      => __('Add a resource', 'wpldp'),
                  'edit_item'         => __('Edit a resource', 'wpldp'),
                  'new_item'          => __('New resource', 'wpldp'),
                  'view_item'         => __('See the resource', 'wpldp'),
                  'search_items'      => __('Search for a resource', 'wpldp'),
                  'not_found'         => __('No corresponding resource', 'wpldp'),
                  'not_found_in_trash'=> __('No corresponding resource in the trash', 'wpldp'),
                  'add_new'           => __('Add a resource', 'wpldp'),
              ),
              'description'           => __('LDP Resource', 'wpldp'),
              'public'                => true,
              'show_in_nav_menu'      => true,
              'show_in_menu'          => true,
              'show_in_admin_bar'     => true,
              'supports'              => array('title'),
              'has_archive'           => true,
              'rewrite'               => array('slug' => 'ldp/%ldp_container%'),
              'menu_icon'             => 'dashicons-image-filter',
      ));
  }

I was previously flushing the rewrite rules on an init hook, and as it seems not to be a proper solution I decided to switch on using the register_activation_hook method. As I am using the object-oriented approach, all my hooks are wrapped and called from the object constructor:

  /**
   * Default Constructor
   **/
  public function __construct() {
    register_activation_hook( __FILE__, array($this, 'wpldp_rewrite_flush' ) );
    register_deactivation_hook( __FILE__, array($this, 'wpldp_flush_rewrite_rules_on_deactivation' ) );

    register_activation_hook( __FILE__, array($this, 'generate_menu_item') );
    register_deactivation_hook( __FILE__, array($this, 'remove_menu_item' ) );

    // Entry point of the plugin
    add_action('init', array($this, 'wpldp_plugin_update'));
    add_action( 'init', array($this, 'load_translations_file'));
    add_action( 'init', array($this, 'create_ldp_type'));
    add_action( 'init', array($this, 'add_poc_rewrite_rule'));

  }

The code for my wpldp_rewrite_flush method is the following:

 public function wpldp_rewrite_flush() {
    // Register post type to activate associated rewrite rules
    $this->create_ldp_type();
    $this->add_poc_rewrite_rule();

    // Flush rules to be certain of the possibility to access the new CPT
    flush_rewrite_rules( true );
 }

I made sure that this code is executed by doing some debugging. I have been reading a lot of posts which all gives this solution as the best one, but my issue is that my custom post types cannot be accessed (404 error).

The URLs I am trying to access are of type http://localhost/wordpress/ldp/actor/benoit-alessandroni/, actor being a custom taxonomy term (a ldp_container. Using a call to flush_rewrite_rules() right after my call to register_post_type in the create_ldp_type method is working just fine, but I know that's not ok.

So, do you see anything obvious which could explain the issue ?

Thanks in advance,

Answer 1

Simple way: In my plugins, register_activation_hook always have a line like delete_option('rewrite_rules'); when I'm creating custom post types. WordPress will properly rebuild them.

I've provided a detailed answer

Also another inspiring answer here