Save custom post meta, not saving the data

4 comments

1. You rely on register_meta_box_cb to display your meta box and to hook save logic into save_post. The problem is that WordPress runs register_meta_box_cb (which hooks into add_meta_boxes) only when metaboxes need to be displayed – i.e. when the edit or add post pages are visited. But when WordPress is saving posts, it does not need to display the metaboxes, so register_meta_box_cb, add_events_metaboxes, and your save_post hook never get called.

   The simplest solution is to remove your register_meta_box_cb argument, and hook your add_events_metaboxes function to the admin_init event.

   add_action('admin_init', 'add_events_metaboxes');
   

   You can do this just under your add_action('init', 'event_list_init') hook.

   Find a gist here.

2. According to the WordPress documentation, register_meta_box_cb :

   will be called when setting up the meta boxes for the edit form.

   Which is too late to hook into the save_post.

   So I suggest you separately hook into the save_post somewhere in your functions.php file:

   Registering post type

   $args   = array(
       ....
       'register_meta_box_cb'  => 'add_events_metaboxes',
       ....
   );
   register_post_type( 'events', $args );
   

   Render the metabox

   function add_events_metaboxes(){
      new eventsListMetaBox();
   }
   
   class eventsListMetaBox{
       public  function  __construct(){
           add_meta_box('wpt_events_date', 'Events Date', array($this, 'fisa_events_date'), 'events', 'side', 'high');
       }
   
       function fisa_events_date() {
           ...
       }
   }
   

   Saving the metabox

   add_action( 'save_post', 'fisa_events_date_save' );
   
   function fisa_events_date_save(){
       global $post;
       $post_id = $post->ID;
   
       // Use wp_verify_nonce and other checks to verify everything is right
   
       $events_date =  array(
                           sanitize_text_field( $_POST['_fisa_date_from']),
                           sanitize_text_field($_POST['_fisa_date_to'])
                       );
       update_post_meta($post_id, '_fisa_events_date', $events_date);
   }
   

   Please keep in mind that WordPress is not intended to operate fully Object-Oriented, thus there may be problems using its hooking system with OOP concepts.

3. As exposed in other answers, the issue is that register_meta_box_cb callback will only deal with the following:

   save_post is not covered in the callback and has to be independent. This action hook happens:

   whenever a post or page is created or updated, which could be from an import, post/page edit form, xmlrpc, or post by email

   As you’re using a Class to wrap the meta box creation, I’d suggest wrapping everything inside it.
   _{PS: check comments and add necessary checks inside save_post callback.}

   <?php
   class MyEvents {
       public  function  __construct(){
           add_action( 'init', array( $this, 'init' ) );    
           add_action( 'save_post', array( $this, 'save_post' ), 10, 2 ); // no need to change priority to 1
       }
   
       public function init(){
           $labels = array(
               'name'                  => _x( 'Events', 'post type general name' ),
               'singular_name'         => _x( 'Event', 'post type singular name' ),
               'menu_name'             => _x( 'Events List', 'admin menu' ),
               'name_admin_bar'        => _x( 'Events List', 'add new on admin bar' ),
               'add_new_item'          => __( 'Add New Event' ),
               'new_item'              => __( 'New Event' ),
               'edit_item'             => __( 'Edit Event' ),
               'view_item'             => __( 'View Event' ),
               'all_items'             => __( 'All Events' ),
               'search_items'          => __( 'Search Events' ),
               'not_found'             => __( 'No Events found.' ),
               'not_found_in_trash'    => __( 'No Events found in Trash.' )
           );
           $args   = array(
               'labels'                => $labels,
               'description'           => __( 'Create Events' ),
               'public'                => true,
               'publicly_queryable'    => true,
               'show_ui'               => true,
               'show_in_menu'          => true,
               'query_var'             => true,
               'rewrite'               => array( 'slug' => 'event' ),
               'capability_type'       => 'post',
               'has_archive'           => true,
               'hierarchical'          => true,
               'menu_position'         => 6,
               'register_meta_box_cb'  => array( $this, 'add_metaboxes' ),
               'menu_icon'             => 'dashicons-calendar-alt',
               'supports'              => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'comments' )
           );
           register_post_type('events',$args);
       }
   
       public function add_metaboxes() {
           add_meta_box( 'wpt_events_date', 'Events Date', array( $this, 'the_metabox' ), 'events', 'side', 'high' );
       }
   
       public function the_metabox( $post ) { // No need for "global $post", it's passed as parameter
           wp_nonce_field( 'events_date_fromto', 'events_datefromto_nonce' );
           $dates = get_post_meta( $post->ID, '_fisa_events_date', true);
           $from = $dates ? $dates[0] : false;
           $to = $dates ? $dates[1] : false;
           echo '<label for="_fisa_date_from">Date From</label>';
           printf(
               '<input id="fisa-event-datefrom" type="text" name="_fisa_date_from"  class="widefat" value="%s" />',
               $from ? $from : ''
           );
           echo '';
           echo '<br/><br/>';
           echo '<label for="_fisa_date_to">Date To</label>';
           printf(
               '<input id="fisa-event-dateto" type="text" name="_fisa_date_to"  class="widefat" value="%s" />',
               $to ? $to : ''
           );
       }
   
       public function save_post( $post_id, $post_object ) { // second parameter has useful info about current post
           /* BRUTE FORCE debug */
           // wp_die( sprintf( '<pre>%s</pre>', print_r( $_POST, true ) ) );
   
           /**
            * ADD SECURITY AND CONTENT CHECKS, omitted for brevity
            */
           if( !empty( $_POST['_fisa_date_from'] ) ) {
               $events_date =  array(
                                   sanitize_text_field( $_POST['_fisa_date_from']),
                                   sanitize_text_field($_POST['_fisa_date_to'])
                               );
               update_post_meta($post_id, '_fisa_events_date', $events_date);
           }
       }
   }
   new MyEvents();
   

4. Simplest & most flexible solution is to use Advanced Custom Fields.

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