WordPress hook for visiting a post

Question

I am very new to WordPress plugin development.

I have been searching this for a quite a while now but I am currently creating a plugin and I need my plugin to start logging the amount of views a post has had. I already know what I want this part of to do however I am having trouble find out how to a PHP function for when a post is viewed by a visitor to my WordPress site.

Could someone please show me what the WordPress hook/event is to run a function on post view/load? I want to do this without the use of template as well.

Answer 1

I assume you are looking for a conditional to check if you are on a post page.

You can do so by using is_single():

if (is_single()) {
    // Update your post views here
}

If you insist on using filters or hooks, you can use the_content filter:

add_filter( 'the_content', 'update_post_views' );
function update_post_views($content){
    if (is_single()) {
        $id = get_the_ID();
        // Now update your post's views
    }
    return $content;
}

Answer 2

First, let's try to add post views to the dashboard -> posts. First, we add a new column there:

add_filter('manage_posts_columns', function($columns) {
    return array_merge($columns, ['post_views' => 'Views']);
});

Then, we are going to show the number of views. We assume that (Like many other guides on the web), there is a meta key post_views holding the number of post views.

add_action('manage_posts_custom_column', function($column) {
    if ($column === 'post_views') {
        $count = get_post_meta(get_the_ID(), 'post_views_count', true);
        echo empty($count) ? 'no views :(' : "$count view :)";
    }
});

You should be able to see this new column on the posts admin table.

Finally, we have the real code to update the post_views meta every time a post is visited.

function jj_count_post_views($content)
{
    if (is_single() && !is_preview()) {
        $postId = get_the_ID();

        update_post_meta(
            $postId,
            'post_views_count',
            (int) get_post_meta($postId, 'post_views_count', true) + 1
        );

        remove_filter('the_content', 'jj_count_post_views');
    }

    return $content;
}

add_filter('the_content', 'jj_count_post_views');

Please notice that the remove_filter is necessary, because some plugins use the_content filter to do more stuff to the content (like SEO plugins), so the_content will be called multiple times. Thanks to this answer.

Also, remove && !is_preview() if you want to count all the views, even the preview ones.

P.S. Add all those codes inside theme functions.php and it works.