add_action and do_action

Question

I am trying to hook a function to wp_head that adds some meta tags, but I does not work correctly. Here is my code:

add_action( 'wp_head', 'add_meta_tags' , 2, 1 );
do_action('add_meta_tags',$pick_data);
function add_meta_tags($pick_data) {
    $h=$pick_data[0]->h_team;
    $a=$pick_data[0]->a_team;
    echo '<meta property="og:title" content="'.$h.' vs '.$a.'" />' . "\n";


}

The function is executed, but the parameter ($pick_data) is not passed. So I am getting in my head:

<meta property="og:title" content=" vs " />

What am i doing wrong?

Answer 1

Please check also wp-includes/general-templates.php but wp_head() hooks 'wp_head' like this:

function wp_head() {
    do_action( 'wp_head' );
}

So I would change your code like this for example:

add_action( 'wp_head', 'my_prepare_pick_data' );
add_action( 'my_add_meta_tags', 'my_add_meta_tags' );

function my_prepare_pick_data() {
    $pick_data = new YourPickDataClass(); // change this as you like
    do_action( 'my_add_meta_tags', $pick_data );
}

function my_add_meta_tags( $pick_data ) {
    $h = $pick_data[0]->h_team;
    $a = $pick_data[0]->a_team;
    echo '<meta property="og:title" content="', $h, ' vs ', $a, '" />', "\n";
}