I have a function in php as shown below:

function hello_world( $post ) {
    echo '<pre>'; print_r($post); echo '</pre>'; // Line A
    echo '<pre>'; print_r($post->post_meta); echo '</pre>'; // Line B
    return $post->post_meta;
}

I have added Line A and Line B in the function above for debugging purposes. In the function hello_world above, Line A returns list of all posts whereeas Line B doesn't return anything.

I am wondering what changes I need to make in the wordpress or php code above so that Line B returns list of posts.

Edit 1:

Added code for $loc_query

function area_search( $abc ) {
        if ( $abc ) {
            $loc_query = new \WP_Query( [
                's'           => $abc,
                'post_type'   => 'abc-xyz',
                'post_status' => 'publish',
            ] );
        } else {
            $loc_query = new \WP_Query( [
                'post_type'   => 'abc-xyz',
                'post_status' => 'publish',
                'ep_integrate' => true,
                'orderby' => 'title',
                'order'   => 'ASC',
            ] );
        }
        $result = array_map( __NAMESPACE__ . '\hello_world', $query->posts );
        echo '<pre>'; print_r($result); echo '</pre>'; // Line A
        return group( $result );
    }

I have a function in php as shown below:

function hello_world( $post ) {
    echo '<pre>'; print_r($post); echo '</pre>'; // Line A
    echo '<pre>'; print_r($post->post_meta); echo '</pre>'; // Line B
    return $post->post_meta;
}

I have added Line A and Line B in the function above for debugging purposes. In the function hello_world above, Line A returns list of all posts whereeas Line B doesn't return anything.

I am wondering what changes I need to make in the wordpress or php code above so that Line B returns list of posts.

Edit 1:

Added code for $loc_query

function area_search( $abc ) {
        if ( $abc ) {
            $loc_query = new \WP_Query( [
                's'           => $abc,
                'post_type'   => 'abc-xyz',
                'post_status' => 'publish',
            ] );
        } else {
            $loc_query = new \WP_Query( [
                'post_type'   => 'abc-xyz',
                'post_status' => 'publish',
                'ep_integrate' => true,
                'orderby' => 'title',
                'order'   => 'ASC',
            ] );
        }
        $result = array_map( __NAMESPACE__ . '\hello_world', $query->posts );
        echo '<pre>'; print_r($result); echo '</pre>'; // Line A
        return group( $result );
    }

• custom-post-types
• wp-query
• post-meta

Share Improve this question edited Jul 6, 2020 at 18:59 user1950349 asked Jul 6, 2020 at 18:26 user1950349user1950349 10122 bronze badges 16

• How you are calling the function? – Sabbir Hasan Commented Jul 6, 2020 at 18:36
• like this $result = array_map( __NAMESPACE__ . '\hello_world', $loc_query->posts ); – user1950349 Commented Jul 6, 2020 at 18:38
• 1 can you share the code of $loc_query and the arguments ? – Sabbir Hasan Commented Jul 6, 2020 at 18:55
• 1 It's very unusual to see $post->post_meta, that's not how you should be retrieving post meta. Use get_post_meta – Tom J Nowell ♦ Commented Jul 6, 2020 at 19:21
• 1 No, get_post_meta is a function, it isn't a method on the post object. I've just looked at your edit and you don't use a normal post loop, call none of the standard loop functions, and appear to be directly using the internals of WP_Query, all very unusual. What exactly are you trying to do that required this code? This looks like an X Y question, where you asked how to implement your solution, when you should have asked how to solve your problem – Tom J Nowell ♦ Commented Jul 6, 2020 at 19:24

 |  Show 11 more comments

1 Answer 1

Sorted by: Reset to default 1

Your code is interfering with the internal structure of WP_Query and WP_Post, and making assumptions about how it works. This is extremely unusual, and not best practice when developing with WordPress.

Case in point, officially there is no post_meta member variable on that class ( https://developer.wordpress/reference/classes/wp_post/ ). That's not how you fetch a posts meta key/values.

Instead, use a standard post loop, and standard API calls.

Here's what a standard WP_Query post loop should look like:

$args = [
    // parameters go here
];
$query = new WP_Query( $args );
if ( $query->have_posts() ) { 
    while ( $query->have_posts() ) {
        $query->the_post();
        // display the post
        the_title();
        the_content();
    }
    wp_reset_postdata();
} else {
    echo "no posts were found";
}

Note that a standard post loop lifecycle happens, as well as all the expected hooks. You can do work inside the while loop for each post. For example, fetching all the post meta. To do that, use the get_post_meta function:

$all_meta = get_post_meta( get_the_ID() );

It might be tempting to think that a WP_Post object follows the naive OO dream of an all encompassing API for posts, a one-stop representation of a single post and all the things that there is to know and can be done about it. But in reality it's a data container. You won't find class methods or methods of sub-classing it.

Additionally, by poking around and directly accessing the internal data structures, you bypass a lot of functionality and risk your code being broken in the future. For example post meta gets fetched in advance and stored in WP_Cache to avoid query duplication. There are also filters that allow plugins and other code opportuniities to make changes or fix things.