Replace query_posts with pre_get_posts

Question

I have a static front page that checks if the user is logged in, and if he/she is a number of x posts from a specific category is displayed. For that I was using this code:

query_posts('cat=2&showposts=5'.'&orderby=date&order=desc');
while (have_posts()) : the_post();
the_content();
endwhile;

Now I found out that's not right to use query_post and that I should use pre_get_posts instead. I've tried to do this but somehow my page breaks down saying that my server is configured incorrectly.

Answer 1

Without seeing the broken code it is hard to say, but your filter should look something like this:

function pregp_wpse_97354($qry) {
  if (is_front_page() && is_main_query() && is_user_logged_in()) {
    $qry->set('cat',2);
    $qry->set('posts_per_page',5);
    $qry->set('orderby','date');
    $qry->set('order','DESC');
  }
}
add_action('pre_get_posts','pregp_wpse_97354');

You mentioned something about the user being logged in, which your code does not check for, but I threw that in. This will run before the theme templates load so if this is conditional on the user being logged in you need to include that check in the filter callback.