WordPress: how to return meta with query_posts?

Question

I'm doing an AJAX request using admin-ajax.php whereby I filter posts based on which check-box is checked. It's working great, although I'm struggling to find a way to return the meta details of each post.

I'm just using query_posts to get my data as below:

    function ajax_get_latest_posts($tax){

    $args= array(
        'post_type'=>'course',

    'tax_query' => array(
         array(
        'taxonomy' => 'subject',
        'field' => 'slug',
        'terms' => $tax
    )
    )

);

$posts=query_posts( $args);


return $posts;
}

How would I modify this to also return meta data? I know I can filter the posts by meta data using meta_query, but I just want to display the data in my posts.

Answer 1

EDIT:

Besides the solution outlined bellow, if you're using WordPress >= 3.5(as you should be :) ), you can simply make use of the magic methods of the WP_Post object.

Basically the WP_Post object(which is what the posts array from pretty much every query result that comes from WP_Query consists of) is using PHP's __get() and __isset() magic methods. These methods allow you to use properties of an object that are not defined in the object itself.

Here's an example.

foreach ( $posts as $key => $post ) {
    // This:
    echo $post->key1;
    // is the same as this:
    echo get_post_meta( $post->ID, 'key1', true );
}

If you make a print_r( $post ) or var_dump( $post ), you will not see the "key1" property of the $post object. But the function __get() allows you to access that property.

===========================================================

You have two general options in my opinion - loop through the posts and get the data that you need, like so(this code will go right after $posts = query_posts( $args );):

foreach ( $posts as $key => $post ) {
    $posts[ $key ]->key1 = get_post_meta( $post->ID, 'key1', true );
    $posts[ $key ]->key2 = get_post_meta( $post->ID, 'key2', true );
}

Or hook to the the_posts filter hook and do the same thing there(more work, but if you have multiple functions that need to add that data to each post - it might be easier). This code would go to your functions.php or your plugin's files(if you're making a plugin):

function my_the_posts_filter( $posts ) {
    foreach ( $posts as $key => $post ) {
        $posts[ $key ]->key1 = get_post_meta( $post->ID, 'key1', true );
        $posts[ $key ]->key2 = get_post_meta( $post->ID, 'key2', true );
    }

    return $posts;
}

And then you would change your

$posts=query_posts( $args);

line to this:

add_filter( 'the_posts', 'my_the_posts_filter', 10 );

$posts = query_posts( $args );

remove_filter( 'the_posts', 'my_the_posts_filter', 10 );

Considering the fact that this would happen inside of an AJAX request, you can technically get rid of the remove_filter() call, but it's good to have it just in case you're going to make any other post queries in your code.