I a problem with getting the query for custom taxonomy to work in this function. The $filter is filled with data but the get_posts() does not use it? The query works without the tax_query and there are: custom posts with the correct taxonomy(list)... want am I missing?

add_action( 'restrict_manage_posts', 'add_export_button' );
function add_export_button() {
    $screen = get_current_screen();

if (isset($screen->parent_file) && ('edit.php?post_type=certificate'==$screen->parent_file)) {
        ?>
        <input type="submit" name="export_all_posts" id="export_all_posts" class="button button-primary" value="Export All Posts">
        <script type="text/javascript">
            jQuery(function($) {
                $('#export_all_posts').insertAfter('#post-query-submit');
            });
        </script>
        <?php
    }
}

add_action( 'init', 'func_export_all_posts' );
function func_export_all_posts() {
    if(isset($_GET['export_all_posts'])) {
        if(isset($_GET['list'])) {
            $filter =  strval($_GET['list']);
        };
        $arg = array(
                'post_type' => 'certificate',
                'post_status' => 'publish',
                'posts_per_page' => -1,
                'tax_query' => array(
                    array(
                        'taxonomy' => 'list',
                        'field'    => 'slug',
                        'terms'    => $filter ,
                    )
                    ),
            );

        global $post;
        $arr_post = get_posts($arg);

        if ($arr_post) {

        header('Content-type: text/csv');
        header('Content-Disposition: attachment; filename="wp.csv"');
        header('Pragma: no-cache');
        header('Expires: 0');

        $file = fopen('php://output', 'w');

        fputcsv($file, array('Post Title', 'URL'));

            foreach ($arr_post as $post) {
                setup_postdata($post);
                fputcsv($file, array(get_the_title(), get_the_permalink()));
            }

            exit();
        }
    }
}

I a problem with getting the query for custom taxonomy to work in this function. The $filter is filled with data but the get_posts() does not use it? The query works without the tax_query and there are: custom posts with the correct taxonomy(list)... want am I missing?

add_action( 'restrict_manage_posts', 'add_export_button' );
function add_export_button() {
    $screen = get_current_screen();

if (isset($screen->parent_file) && ('edit.php?post_type=certificate'==$screen->parent_file)) {
        ?>
        <input type="submit" name="export_all_posts" id="export_all_posts" class="button button-primary" value="Export All Posts">
        <script type="text/javascript">
            jQuery(function($) {
                $('#export_all_posts').insertAfter('#post-query-submit');
            });
        </script>
        <?php
    }
}

add_action( 'init', 'func_export_all_posts' );
function func_export_all_posts() {
    if(isset($_GET['export_all_posts'])) {
        if(isset($_GET['list'])) {
            $filter =  strval($_GET['list']);
        };
        $arg = array(
                'post_type' => 'certificate',
                'post_status' => 'publish',
                'posts_per_page' => -1,
                'tax_query' => array(
                    array(
                        'taxonomy' => 'list',
                        'field'    => 'slug',
                        'terms'    => $filter ,
                    )
                    ),
            );

        global $post;
        $arr_post = get_posts($arg);

        if ($arr_post) {

        header('Content-type: text/csv');
        header('Content-Disposition: attachment; filename="wp.csv"');
        header('Pragma: no-cache');
        header('Expires: 0');

        $file = fopen('php://output', 'w');

        fputcsv($file, array('Post Title', 'URL'));

            foreach ($arr_post as $post) {
                setup_postdata($post);
                fputcsv($file, array(get_the_title(), get_the_permalink()));
            }

            exit();
        }
    }
}

• custom-post-types
• wp-query
• custom-taxonomy
• get-posts
• csv

• Not sure it would affect anything, but don't think you need that global $post in there as you're querying the posts to the $arr_post array – Tim Hallman Commented Dec 9, 2018 at 19:26
• Other than that, perhaps try adding 'operator' => 'IN' to your tax_query array. – Tim Hallman Commented Dec 9, 2018 at 19:27
• Actually, wrap your 'terms' in an array, like this 'terms' => array($filters). I believe that is your problem. – Tim Hallman Commented Dec 9, 2018 at 19:30
• Thank you very much for your reply, Tim. I have now tried: 'operator' => 'IN' and to place the terms in an array and the drop the "global $post". But nothing seems to work when making the query for custom taxonomy. – Jesper Commented Dec 10, 2018 at 9:50

2 Answers 2

I'm fairly sure you just need to pass an array for terms like this:

$arg = array(
     'post_type' => 'certificate',
     'post_status' => 'publish',
     'posts_per_page' => -1,
     'tax_query' => array(
          array(
               'taxonomy' => 'list',
               'field'    => 'slug',
               'terms'    => array($filter)
           )
      ),
);

The problem was that I used the toolset plugin to generate the taxonomy which caused some priority confusion. Adding this to my functions.php solved the problem:

remove_action('init', 'func_export_all_posts');
add_action('init', 'func_export_all_posts', 99);

Ref: https://toolset/forums/topic/wp_query-does-not-work-with-taxonomy-at-the-backend