Individual rss feed entry length for categories?

Question

I know how to retrieve the rss2 feed from a category in wp, namely adding /feed behind the category name. However when I do this, not all entries from that feed are included in the rss, this is because I set the feed restriction to be 50 at the admin backend.

I would like to know if a feed length could be set indiviually for each category/feed programatically.

I could not find any api settings for the size of the feeds ... any help is welcome here.

Thanks for your help.

Answer 1

You should be able to use pre_get_posts and set the posts_per_page to 50 conditionally (on being feed for categories). Unfortunately there is this unresolved trac ticket.

The only work-around is to do hook into post_limits and replace the LIMIT part of the SQL query directly.

add_action('post_limits','wpse71759_category_rss_limit',10,2);
function wpse71759_category_rss_limit($limit, $query){

     if( $query->is_feed() && $query->is_category() ){
          $paged =  $query->get('paged') ? (int) $query->get('paged') : 1;
          $per_page = 50;
          $page_start = ($paged-1)*$per_page;

          return "LIMIT $page_start, $per_page";
     }
     return $limit;
}

Answer 2

add_filter('query', 'sql_query_feed_filter');
function sql_query_feed_filter($sql){
    global $wp_query;

    if ($wp_query->is_feed == true &&  isset($wp_query->query_vars['custom_taxonomy']) &&  in_array($wp_query->query_vars['custom_taxonomy'], array('slug1','slug2')) ){
        if (strpos($sql, 'SELECT SQL_CALC_FOUND_ROWS') !== false){
            list($sql,) = explode('LIMIT', $sql);
        }
    }
    return $sql;
}

all you need to do is just edit this function and repalce taxonomy by your category taxonomy and edit slug to much your category...