Wordpress search query modify query vars - wordpress

Question

A client has requested that I make the characters "S" and "$" interchangeable in the search function, i.e. "Search Query" and "$earch Query" should return identical results.
Is there a way to accomplish this?

Answer 1

Change it before WP queries the database:
$the_replacements = array(
'$' => 'S',
);
function modify_search_vars($search_vars) {
global $the_replacements;
if (!empty($search_vars['s']) && !empty($the_replacements[$search_vars['s']])) {
$search_vars['s'] = $the_replacements[$search_vars['s']];
}
return $search_vars;
}
add_filter('request', 'modify_search_vars', 99);

Answer 2

This seems to work well enough I guess..
add_action('pre_get_posts', 'modified_search');
function modified_search($query){
global $wp_query;
if($query->is_search){
global $wpdb;
$original_query = get_search_query();
$modified_query = preg_replace("/(s|S)/", "$", $original_query);
$new_query = "
SELECT $wpdb->posts.ID
FROM $wpdb->posts
WHERE $wpdb->posts.post_status = 'publish'
AND (($wpdb->posts.post_title LIKE '%$original_query%') OR ($wpdb->posts.post_content LIKE '%$original_query%') OR ($wpdb->posts.post_title LIKE '%$modified_query%') OR ($wpdb->posts.post_content LIKE '%$modified_query%'))
ORDER BY $wpdb->posts.post_date DESC
LIMIT 0, 10
";
$results = $wpdb->get_results($new_query);
$post_ids = array();
foreach ($results as $post_id){
$post_ids[] = $post_id->ID;
}
$query->set('post__in', $post_ids);
}
}
I'm sure there are ways to improve that, and I'm more than happy to implement suggestions, but this appears to return results using both search terms, so it's good enough.