How to limit Query Loop on Media Gallery to current post's medias (custom field)?

How To
10

I’m going to share this for the community and hoping this gets better along the way. I was trying to query the medias uploaded to a post through a custom field (Metabox/Advanced Images) and display them in a Gallery using the Bricks query loop for Medias (Query Loop – Bricks Academy). But since the images are not automatically attached to the current post they are being uploaded to (it is acknowledged by Metabox support), the query using “child of : {post_id}” does not work.

I have found out there are two steps necessary :

#1 Amend Query Post_in For Gallery (given by Bricks support), replace “mg_projet_galerie_images” by your own custom field and “yeamho” by the ID of your element with the query loop. Using this technique, you do NOT set “child of: {post_id}”, you leave it blank :

<?php 

add_filter( 'bricks/posts/query_vars', function( $query_vars, $settings, $element_id ) {

    if ( $element_id !== 'yeamho') return $query_vars;
        
    $gallery_images = (array) rwmb_meta( 'mg_projet_galerie_images', ['size' => 'full'] );
    $gallery_images_ids = array_keys($gallery_images);
    
    // if no gallery images, set empty string array
    $gallery_images_ids = count($gallery_images_ids) > 0 ? $gallery_images_ids : [''];
    
    $query_vars['post__in'] = $gallery_images_ids;

    return $query_vars;
}, 10, 3 );

#2 Make sure the uploaded media attachments are automatically attached to the current post they uploaded to (replace “mg_projet_galerie_images” by your own custom field). It appears for me I do not necessarily need to set the query loop (media type) to “child of: {post_id}” as explained in the Bricks academy tutorial. To automatically attach/detach images to the post use this code (edit : replace with newer one below) :

<?php

add_action('save_post', 'update_image_data');

function update_image_data($post_id){
    $images = get_post_meta($post_id, 'mg_projet_galerie_images', true);
    if(!empty($images)){
        foreach($images as $image){
            wp_update_post(array('ID' => $image, 'post_parent' => $post_id));
        }
    }
}

Now to make this better, I have to find a way to remove (un-attach) the medias if removed from the current post. I hope this will help some of you.

EDIT 2023/01/13 : I found the way to automatically attach & detach images from post when removed from the custom field (MetaBox Advanced Image) :

<?php
add_action('save_post', 'update_detach_image_data');

function update_detach_image_data($post_id) {
    $current_images = get_post_meta($post_id, 'mg_projet_galerie_images', false);
    if(!empty($current_images)){
        foreach($current_images as $current_image){
            wp_update_post(array('ID' => $current_image, 'post_parent' => $post_id));
        }
    }

    $query_args = array(
        'post_type' => 'attachment',
        'post_parent' => $post_id,
        'post_status' => 'any',
        'posts_per_page' => -1,
        'fields' => 'ids',
        'no_found_rows' => true
    );
    $attachments_query = new WP_Query($query_args);
    $attachments = $attachments_query->posts;

    $detach_images = array_diff($attachments, $current_images);
    if (!empty($detach_images)) {
        foreach ($detach_images as $detach_image) {
            wp_update_post(array('ID' => $detach_image, 'post_parent' => 0));
        }
    }
}
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