Apply the_content filter to a custom field with multiple values

The question:

I have a custom meta box set up that allows users to paste the Youtube URL of a video so that it can be embedded into a post/page.

The meta box can be repeated so that a user can add as few or as many URL’s as they wish so I’m using this code snippet to display each as a list item;

    $video = get_post_meta($post->ID, 'youtube-url');
    foreach ($video as $vid) {
        echo '<li>'.$vid.'</li>';

Is there a way that I can run the_content filter on each individual list item so that I can make use of oEmbed that is shipped with WordPress?

Or perhaps there’s a more efficient way…

The Solutions:

Below are the methods you can try. The first solution is probably the best. Try others if the first one doesn’t work. Senior developers aren’t just copying/pasting – they read the methods carefully & apply them wisely to each case.

Method 1

All you need to do use apply_filters.

foreach ($video as $vid) {
    echo '<li>'.apply_filters('the_content',$vid).'</li>';

It may be more efficient to concatenate a string and then run the filter on the whole thing.

$lis = '';
foreach ($video as $vid) {
    $lis .= '<li>'.$vid.'</li>';
echo apply_filters('the_content',$lis);

I haven’t benchmarked the one versus the other but given that the latter calls the filter once and the former many times, I’d bet on the latter.

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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