How to update WordPress post_meta dynamically

Question

I am trying to insert/update post meta when the user registers. Before writing that action, I am testing this code on the page so whenever the page refresh it will insert/update the post meta.

Question: However, the below code is not inserting/updating anything in post meta. Can anyone tell me what is wrong in this code or how to fix it?

$groupItem = get_post(123);

if ($groupItem && $groupItem->post_type == 'cpt_group') {

    $meta     = 'group_users';
    $user_ids = get_post_meta($groupItem->ID, $meta, TRUE);

    if ( ! $user_ids) {
        $user_ids = [];
        add_post_meta($groupItem->ID, $meta, array_push($user_ids, 26));
    } else {
        update_post_meta($groupItem->ID, $meta, array_push($user_ids, 26), $user_ids);
    }
}

For testing, I am triggering on the page load. I just write above the loop. However, I have tried using the `user_register` action hook as well as passing `$user_id` but that didn't work either. — Code Lover, Mar 09 '20 at 05:00

score 0 · Answer 1 · answered Mar 08 '20 at 22:20

0

You could use, serialized data instead of php array to meta_value.

Look into the serialize() and unserialize() functions.

They are transforming an object or an array to a text-representation to save it to a text field in the database.

When you receive the data, you need to unserialize it and you will get back your saved object or an array

answered Mar 08 '20 at 22:20

Fatih Toprak

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But WordPress returns an array then why should I use serialize? – Code Lover Mar 09 '20 at 04:58
it could be true but, have you tried inserting just json or string instead of update/inserting an array ? This is point for serialized/unserialized data etc – Fatih Toprak Mar 13 '20 at 14:15
Also; Notice that update_post_meta can save data as array but it is automatically serialized. If you want to get the value back as array you should use the flag $single of the get_post_meta. – Fatih Toprak Mar 13 '20 at 14:16

score 0 · Answer 2 · answered Mar 09 '20 at 10:18

This is not tested, but I think this should work.

The get_post_meta will automatically serialize your array in the database, but it will also unserialize. Remove the false.

I'm a little confused by your if statement in your question. I can update this if this isn't what you want. But this will update the post_meta

    $groupItem = get_post(123);

    if ($groupItem && $groupItem->post_type == 'cpt_group') {

        $meta     = 'group_users';
        $user_ids = get_post_meta($groupItem->ID, $meta); // without false, it returns an array

        // user_ids is an array
        $user_ids[] = '26'; // Array Push
        // update_post_meta - if not already set, it will set it.
        update_post_meta($groupItem->ID, $meta, $user_ids); 
    }

Wordpress `get_post_meta` will return an array. There is no need to serialize or unserialize data. — Code Lover, Mar 09 '20 at 15:37

How to update WordPress post_meta dynamically

2 Answers2