Current taxonomy name (not term!) given a post ID

Question

I can find everywhere infos on how to get the terms for a specific a post, but I only need the taxonomies names. I mean:

tax: Taxonomy1 terms: term1, term2, etc

tax: Taxonomy2 terms: term1, term2, term3, etc

My post is setted as Taxonomy1.term1, Taxonomy2.term3 OK.

What I want is to know that my post is on Taxonomy1 and Taxonomy2, NOT that is on term1 and term3.

How can I do it? (and by the way, I'm speaking of custom taxonomies and custom post types)

Answer 1

$t = get_post_type($post);
$taxonomies = get_object_taxonomies($t);

$taxonomies will contain the names of the different taxonomies of your post.

Answer 2

I've just found an undocumented function (in wp-includes/taxonomy.php). It's a shortcut that uses get_object_taxonomies(): get_post_taxonomies($post_id). It returns the taxonomy names.

Anyway, I've just coded another symple function:

function get_taxonomies_info($id){
    global $wpdb;
    return $wpdb->get_results($wpdb->prepare("
        select tax.taxonomy as taxonomy, group_concat(tr.name) as term_names, group_concat(tr.term_id) as term_ids
        from " . $wpdb->prefix . "term_taxonomy tax
        INNER JOIN " . $wpdb->prefix . "term_relationships rel ON tax.term_taxonomy_id =rel.term_taxonomy_id
        INNER JOIN " . $wpdb->prefix . "terms tr ON tr.term_id = tax.term_id
        WHERE rel.object_id = %d
        GROUP BY taxonomy
    ",$id));
}

It will return an array of objects like this:

array(2) {
  [0]=>
  object(stdClass)#115 (3) {
    ["taxonomy"]=>
    string(21) "taxonomy name"
    ["term_names"]=>
    string(16) "term name"
    ["term_ids"]=>
    string(1) "4"
  }
  [1]=>
  object(stdClass)#114 (3) {
    ["taxonomy"]=>
    string(17) "soluzioni_manuali"
    ["term_names"]=>
    string(51) "term name 1,term name 2"
    ["term_ids"]=>
    string(3) "2,3"
  }
}

So for every row you'll have 1 taxonomy, a comma separated list of terms of THAT taxonomy, a comma separated list od the terms ids.

Obviously, one can easily change the function, maybe adding some other options (for example a filter-out taxonomy array)

Hope it helps

Answer 3

Get all the taxonomy terms of the post, then look at the taxonomy property of them.

See code comments for more details:

global $post;

// get all the taxonomies registered for the post type    
$allcustomtaxes = get_taxonomies(
  array('public'=> true,'_builtin' => false, 'object_type'=> array($post->post_type) )
);

// get the terms assigned to post, in all custom taxonomies
$terms = wp_get_object_terms($post->ID, $allcustomtaxes);

// get the 'taxonomy' property of terms objects, removing duplicates
$belongs = empty($terms) ? array('none'), array_unique(wp_list_pluck($terms, 'taxonomy'));

// example usage:
echo 'Post ' . $post->title . ' belongs to ' . implode(', ') . $belongs;