This wordpress hack is right to allow your user’s searches contents only into a specific post type. You just need to apply this code to your wordpress function.php file Continue reading →

function __search_by_title_only( $search, &$wp_query )
{
    if ( empty($search) )
        return $search; // skip processing - no search term in query
    $q =& $wp_query->query_vars;
    // wp-includes/query.php line 2128 (version 3.1)
    $n = !empty($q['exact']) ? '' : '%';
    $searchand = '';
    foreach( (array) $q['search_terms'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}($wpdb->posts.post_title LIKE '{$n}{$term}{$n}')";
        $searchand = ' AND ';
    }
    $term = esc_sql( like_escape( $q['s'] ) );
    if ( empty($q['sentence']) && count($q['search_terms']) > 1 && $q['search_terms'][0] != $q['s'] )
        $search .= " OR ($wpdb->posts.post_title LIKE '{$n}{$term}{$n}')";
    if ( !empty($search) ) {
        $search = " AND ({$search}) ";
        if ( !is_user_logged_in() )
            $search .= " AND ($wpdb->posts.post_password = '') ";
    }
    return $search;
}
add_filter( 'posts_search', '__search_by_title_only', 10, 2 );