Pagination broken when merging search results with additional WP_Query

3 comments

1. I think the only solution is to skip the sql pagination and handle it only via php.
   My idea involves 2 functions, one hooked on pre_get_posts, the second to filter the_posts.

   The first function does 2 things:

   1. unset the paged value for search, in this way all the posts are returned from the SQL query.
   2. save the queried paged value in global variable, in this way can be used in the second function that run later

   Here the function:

   function filter_my_search_query( $query ) {
     if ( is_search() && $query->is_main_query() && ! is_admin() ) {
       global $the_original_paged;
       $the_original_paged = $query->get('paged') ? $query->get('paged') : 1;
       $query->set('paged', NULL );
       $query->set('nopaging', TRUE );
     }
   }
   add_action('pre_get_posts', 'filter_my_search_query', 1);
   

   Now the search query return all the posts, with no pagination, and the paged required is saved in the global variable $the_original_paged.

   So we can filter the_posts merging the wanted additional posts, then get only the correct posts based on required page and posts per page setting, and finally reset the paged and other $wp_query properties to let pagination link works:

   function add_posts_to_search_query( $posts ) {
     global $wp_query, $the_original_paged;
     if ( ! is_main_query() || is_admin() || ! is_search() || is_null($the_original_paged) )
         return $posts;
     // the wanted posts per page here setted on general settings
     $perpage = get_option('posts_per_page'); 
     remove_filter( 'the_posts', 'add_posts_to_search_query' );
     $new = new WP_Query( 'year=2012&monthnum=12&day=12&nopaging=1' );
     $merged = array_merge( $posts, $new->posts );
     $wp_query->found_posts += $new->found_posts;
     // getting the right posts based on current page and posts per page
     $wp_query->posts = array_slice($merged, ( $perpage * ($the_original_paged-1) ), $perpage );
     // set the paged and other wp_query properties to the right value, to make pagination work
     $wp_query->set('paged', $the_original_paged);
     $wp_query->post_count = count($wp_query->posts);
     $wp_query->max_num_pages = ceil( $wp_query->found_posts / $perpage ); 
     unset($the_original_paged); // clean up global variable
     return $wp_query->posts; 
   }
   add_filter('the_posts', 'add_posts_to_search_query');
   

2. Filter the main query to include the additional posts. You can add query params with pre_get_posts or modify the SQL with posts_request or posts_where.

   Filter posts_results or the_posts to arrange the returned posts.

   function filter_posts_where($where)
   {
       $where .= 'OR …' /* post_date is 2012-12-12 */;
   
       return $where;
   }
   
   function filter_the_posts($posts)
   {
       usort($posts, 'compare_posts');
   
       return $posts;
   }
   
   function compare_posts($a, $b)
   {
       // compare "author" and dates?
       if     /* … */ return  1;
       elseif /* … */ return -1;
       else           return  0;
   }
   

3. I could not completly solve all the issues involved in this question but for reference I post the current state here:

   function SQ_the_posts($posts, $q = false) {
       if( is_search() && is_main_query() ){
   
               global $wp_query;
   
               $authorposts = $wp_query->posts;
               $paged = get_query_var('paged');
   
               remove_filter( 'the_posts', 'SQ_the_posts' );
               $query = new WP_Query( 'year=2012&monthnum=12&day=12' );
               add_filter( 'the_posts', 'SQ_the_posts' );
   
               $otherposts = $query->posts;
               $mergedPosts = array_merge( $authorposts, $otherposts  );
   
               $wp_query->found_posts += $query->found_posts;
               $initialMaxNumPages = $wp_query->max_num_pages;
               if ($paged > $initialMaxNumPages) {
                       $wp_query->posts = $otherposts;
                       $wp_query->post_count = $query->post_count;
                       $posts = $otherposts;
               }
   
               $wp_query->max_num_pages = ($wp_query->found_posts > 0) ? $wp_query->found_posts / 10 : 0;
               $wp_query->max_num_pages += ($wp_query->found_posts % 10) ? 1 : 0;          
       }
       return $posts;
   }
   add_filter( 'the_posts', 'SQ_the_posts' );
   

   What it does:

   • Queries the author and other posts
   • Calculates the correct amount of pages for both queries
   • Renders the first ten items of the second query when the max_num_pages of the first query is exceeded

   What doesn’t work:

   • If for example the first query (author search query) results in 9 pages and the second query returns 5 pages the pagination shows correctly 14 pages. But when I click on page 10 pagination shows “page 10 of 5” because the 9 pages of the first query are not available anymore on that page. Is there any way to fix this?
   • The second query needs to be enhanced that the current page gets translated to its correct paging equavalent e.g. page 10 for the total queries means a paged parameter of “1” for the second query.

   Still I’m amazed that there is no easy approach. In case anybody is able to solve these issues based on my answer (copy+paste) I’d be happy to mark it as accepted!

Comments are closed.