How to use posts_search filter in WordPress

Working with WordPress hooks can be a bit tricky, but it’s also super powerful! Today, we’re diving into the posts_search filter. This filter lets you modify the search SQL used in the WHERE clause of WP_Query. To start using it, you’ll need to register it using add_filter. This can be done in your theme’s functions.php file or a custom WordPress plugin. Pro tip: creating a custom plugin for your hooks can prevent any issues when you update your theme.

Here’s how you can use this filter effectively:

Example 1: Search by Title Only

Here’s an example where we customize the search to focus on titles only. This can be useful if you’re trying to refine search results to be more specific to post titles.

    function weplugins_search_by_title_only( $search, $wp_query ) {
        global $wpdb;
        if(empty($search)) {
            return $search; // skip processing - no search term in query
        }
        $q = $wp_query->query_vars;
        $n = !empty($q['exact']) ? '' : '%';
        // Custom SQL logic here
        $search = ""; // replace with your SQL logic
        return $search;
    }
    add_filter( "posts_search", "weplugins_search_by_title_only", 10, 2 );
    

Example 2: Modify Search Defaults

This example demonstrates how you can use the hook to modify the default search behavior according to your website’s requirements. You can conditionally update the $search variable as needed.

    function weplugins_modify_posts_search_defaults($search, $query) {
        // Update the $search variable as per your needs
        return $search;
    }
    add_filter( "posts_search", "weplugins_modify_posts_search_defaults", 10, 2 );
    

Example 3: Removing a Hook Callback

Sometimes, you might need to remove a previously registered hook. Here’s how you can remove the posts_search filter using remove_filter. Make sure to use the same callback name, priority, and number of arguments.

    remove_filter( "posts_search", "weplugins_modify_posts_search_defaults", 10, 2 );